Natural Enemies of Corn Pests

Photo by Jewel Kinilitan-Bissdorf

Corn Scientific name: Zea mays Family: Poaceae

Growth stages Pests For weeds and diseases please see further down on this page. For rodents, snails and slugs please click here

Seed Sown seeds

Ants Seedcorn maggot White grub Wireworm

Seedling Stage Roots

Root knot nematode Seedcorn maggot White grub Wireworm

Stem

Cutworm

Leaves

Corn flea beetle Corn leafhopper Corn stalk borer Cutworm Rice/Corn seedling maggot

Vegetative Stage Stems

Corn borer Corn stalk borer

Leaves

Aphids Armyworm Corn borer Corn stalk borer Locusts

Reproductive Stage Silk

Corn borer Corn earworm Japanese beetle Spider mites

Tassel

Corn borer Corn earworm Spider mites

Corn ear

Corn borer Corn earworm Corn stalk borer

Grain

Corn borer Corn earworm Corn stalk borer Smut

Maturation stage Corn ear

Corn borer Corn earworm

Grain

Corn borer Corn earworm

Rice/Corn seedling maggot

Photo courtesy of IRRI & University of Queensland

Natural enemies Parasitoids 1. Trichogramma

Predators 1. Ground beetle 2. Spider

Management and cultural practices 1. Plant at the beginning of the rainy season to avoid seedling flies during seedling emergence. This is applicable to areas where there are 2 distinct seasons: wet and dry. 2. Avoid planting during the peak of seedling maggot population. Inspect the neighboring fields planted 1 week ahead of manifestation of damaged leaves and deadheart. 3. Inspect seedlings thoroughly after emergence. Damage begins during crop emergence. During heavy infestation replanting the area is deemed necessary.

Photo courtesy of Sylvie Chenus, Cornell University

Trichogramma Common Name: Trichogramma, Tricon Scientific name: Trichogramma spp. Hymenoptera:Trichogrammatidae Type Egg parasites Hosts Trichogramma species parasitize eggs of over 200 species of moth and caterpillars. Among these are; the rice and corn stem borer, cabbageworm, tomato hornworm, Heliotis and Helicoverpa species, codling moth, cutworm, armyworm, webworm, cabbage looper, fruit worms, and sugarcane borer. Description Trichogramma adults are extremely small. The female adult lays her eggs on other moths' eggs. First, she examines the eggs by antennal drumming, then drills into the eggs with her ovipositor, and lays one or more eggs inside the moth's eggs. She usually stays on or near the host eggs until all or most of them are parasitized. When the parasitized moth's eggs turn black, the larvae parasites develop within the host eggs. The larva eats the contents of the moth's eggs. Adults emerge about 5-10 days later depending on the temperature. Adults can live up to 14 days after emergence. Female adults can lay up to 300 eggs. Conservation and management

Trichogramma species differ in their searching behavior, host preferences, response to environmental conditions, and suitability in biological control uses. The timing of Trichogramma releases in the field is important. Non-parasitism could be due to the use of less suitable Trichogramma strains to the host pests, environmental conditions, and untimely release of parasitoids. It is best to release of parasitoids at the beginning of a pest infestation (when moths are first seen in the field), followed by regular releases until a natural breeding population of Trichogramma is established. An example of this approach is the corn borer control. The first release should be during the first appearance of moths and corn borers' eggs in the cornfields. Weekly releases thereafter are to ensure the Trichogramma population build-up and parasitism occurrence. The build-up of the parasitoids depends on the presence of the pest or alternative hosts and food for adults. It is important to regulary monitor pest population, egg parasitism (parasitized eggs are black in color), and the larval infestation. Trichogramma are released as pupae in parasitized host eggs. The pupae can be pasted on cards or put in various containers. To be successful in the field, food, host eggs and shelter must be available. Modify cropping practices by practicing crop rotation and by planting cultivars which are favorable to Trichogramma population build-up such as wild carrots, dill, golden rod, leguminous plants, and flowering vegetables. Adults feed only on nectar, pollen, and honeydew. Many of these species are found naturally occurring in agricultural and garden habitats. Many adult parasitoids and predators benefit from sources of nectar and the protection provided by refuges such as hedgerows, cover crops, and weedy borders. Avoid indiscriminate use of hazardous pesticides to ensure their presence in agricultural fields.

Photo courtesy of IRRI & University of Queensland

Ground beetle

Common name: Carabid Scientific name: Calosoma spp., Cicindela spp., Megacephala spp., Ophionea nigrofasciata, Pterostichus spp. Coleoptera:Carabidae Type Generalist predator Hosts Cabbage root maggots, cutworms, snails, slugs, (Ellis; Bradley, 1996: pp. 294-295), leaffolder and planthoppers larvae (Rice IPM, 2001). Description Eggs are normally laid singly in the soil. Larva is elongated and tapered toward the end, worm-like in appearance and have a large head directed forward. Pupa is brownish black, small and found in the soil. Adult ground beetles or Carabids are about 2-6cm long, dark shiny brown to metallic black, blue, green, purple, or multi-colored. They vary in shapes,- from elongated to heavy-bodied, - tapered head end with threadlike antennae, and have a ringed wing cover. Some species do not use their wings however, like many other insects they are also attracted to light. They use their wings to fly at night to be near to the source of light. Their heads are usually smaller than their thorax. Both adults and larvae have strong pincher-like mandibles. They have prominent long legs, which make them fast moving insects. Most species are nocturnal and they hide during the day in soil crevices, under rocks and stones, decaying logs, leaf litter, or composting materials. When disturbed or when other vertebrates prey upon them, they emit an odor or gas, as a type of defense mechanism, preventing them from being eaten by other predators. Ground beetles live on or below the ground, hence the name. Development from the egg to the adult stage takes about a year, although adults may live 2 to 3 years or longer. Conservation 1. Practice mulching in some sections of your field to provide a habitat for the ground beetles. 2. Provide permanent beds and perennial plantings to protect population. 3. Plant white clover and/or amaranth as ground covers (Ellis; Bradley, 1996: p. 295).

Photo courtesy of IRRI & University of Queensland

Spider Arachnida:Araneae

Type Generalist predator

Hosts Brown planthoppers, stem borers, leafhoppers, moths, flies, and other agricultural pests they can catch.

Description 1. Crab Spiders (Thomisidae) are colorful crab-like spiders generally found on the blossoms of plants. They have the tendency to camouflage in their habitat so as to catch prey, unaware as they pass by. They are called crab spiders because their first four legs are larger than their hind legs and because of their capability to walk forward, backward, or sideways like a crab (CABI, 2000). 2. Dwarf spiders (Atypena formosana) are very small and are always mistaken for spiderlings (newly hatched spiders) of other spider species. They measure about 1 to 5 mm in length. Adults have three pairs of spots or gray markings on the dorsal part of their spherical abdomen. They are normally found in groups at the base of a plant. They build webs and catch their prey by trapping them in their webs. However, they can hunt directly and feed on 4-5 leafhopper/planthopper nymphs a day, and also other small insects (IRRI, 2001). 3. Grass spiders are moderately sized, brownish-gray weavers of funnel-shaped webs. Their webs are not sticky and can often be found on low-growing shrubs (CABI, 2000). 4. Jumping spiders (Phidippus sp. ) are brown jumping spiders with brown hairs covering their body. They have two bulging eyes and these are arranged in three distinct rows. They have broadly or partly ovoid abdomens with light transverse basal bands. They feed on leafhoppers and other small insects (IRRI, 2001). 5. Long-jawed spiders (Tetragnatha maxillosa) have long legs and bodies, measuring 6 to 10 mm in length. Their eyes are arranged in two distinct rows. Their abdomens are brownishyellow, with or without markings and are usually four or more times longer than their width. They prey on moths and flies and can consume 2 to 3 preys a day. Once their prey are caught, these are wrapped with silk in their webs (IRRI, 2001).

6. Orb weavers, Argiope spiders (Aranaeus spp.) are large yellow-black garden spiders which produce zigzag stitches in the bottom center of large webs hanging between stems of plants. They have poor vision and can locate their preys by the vibrations and tension on their web threads (IRRI, 2001). 7. Wolf spiders (Lycosa pseudoannulata) have forked or Y-shaped median light bands on their outer coverings. Wolf spiders prey on moths and butterflies. They feed on 5 to 15 preys daily and they eat each other when their population is high (IRRI, 2001).

Some spiders' eggs are laid in a cluster in silken sacs, while some species lay their egg masses covered with silks within folded leaves. Some of these sacs are attached to the mother spiders or mothers stay nearby to guard their egg sacs. Eggs usually hatch into spiderlings within three weeks. The spiderlings may remain attached to the mother for several days on some species, but for some species they are left on their own. Spiders are not insects. They have 8 legs while insects have 6. They do not have wings whereas insects do. They have two body sections; a united head and thorax and abdomen, while insects have three; head, thorax, and abdomen. A female can produce 200-400 eggs but only 60-80 spiderlings can hatch from these. Females can survive 2-3 months. In some species, females die after laying eggs. All spiders are poisonous to insects but only a few species are poisonous to humans, the Black widow and the Brown recluse (CABI, 2000; IRRI, 2001).

Conservation Mulching along some sections in dikes of rice paddies, in field corners, or a portion of the fields can increase the number of spiders. They can hide in the layer of mulch that serves as their alternate habitat. They can also prey on other small insects inside the mulch. Remember, that the more food the spiders can eat, the faster their population build-up will become. Cover crops are also important to provide over-wintering sites of spiders sacs. A spider population depends on the availability of food, the habitat, and the environmental conditions. Avoid use of pesticides as much as possible, for broad-spectrum insecticides can easily kill them (Reissig; et al., 1986: pp. 119-127).

White grubs

Photo courtesy of Texas A&M University Department of Entomology

General Information Common name: White grub Scientific name: Holotrichia spp., Leucopholis irrorata Coleoptera:Scarabaeidae

Host plants White grubs feed on the roots of corn, sorghum, sugarcane, cotton, soybean, strawberry, potato, rice, bean, and other cultivated crops.

Distribution India, Indonesia, Madagascar, Malaysia, Philippines, Canada, USA

Damage White grubs feed on the main roots of the plants. They cut the main stems and roots of plants below the surface of the soil. They tunnel into tubers of root vegetables and root crops. These feeding habits affect the underground portion of the stems and roots causing the plant to wilt and eventually die (Hammond, 1944).

Description The white grubs are the larvae of Japanese and May/June beetles. They are white or yellowish in color, with tan or brown heads, and with 6 spiny legs. They have fleshy, wrinkled C-shaped bodies. Upon hatching they are quite small but can measure up to 2-4 cm when they mature (Chamberlin; Callenbach, 1943).

Natural enemies Parasitoids

1. Tiphia wasp

Predators 1. Ants 2. Birds 3. Chicken

Bacteria Bacillus popilliae and B. lentimorbus are microbial insecticide products that kill grubs and adult Japanese beetles. Infected grubs are filled with a milky white liquid full of bacterial spores. They inoculate the soil as they move (Ellis; Bradley, 1996: pp. 460-461). The advantages of using commercial preparations of B. popilliae are; they are host specific meaning, only effective against Japanese beetles and their persistence is longer lasting (Cornell University, 2003).

Monitoring Monitor white grub population prior to planting. To sample, in 50 x 50 cm soil area, dig soil about 15 cm deep using shovel or hole-digger. Sieve the soil. Repeat this method randomly at least 10 times. Economic threshold levels are: 1 white grub found in sandy soil and an average of 2 white grubs in silty-loam soil (University of Illinois Extension, 1999).

Management and cultural practices 1. Remove old plants and weeds. Plow and harrow the field twice during sunny days to expose grubs to predators and weather. Hot sunny days destroy many of the exposed eggs and kill newly hatched grubs. 2. Grow healthy plants by planting good seeds, providing enough water and fertilizer. Healthy plants can tolerate grub feeding without serious damage. Other healthy ones compensate for damage to one root. 3. Ensure proper drainage. Grubs love moist soil, especially with decaying organic matter. Female beetles prefer to lay eggs on moist-decaying organic matter. 4. If heavy infestation occurs, avoid planting the same crops the whole year. Practice crop rotation always. Soybean is found to be resistant to white grubs. 5. Good trap crops are African marigold, sunflower, mirabilis, and castor. Repellents plants are chives, garlic, tansy, and catnip. The crops trap and repel adult beetles from attacking the main crop grown (Golden Harvest Organics, 2003).

Photo courtesy of The Ohio State University

Tiphia wasp Scientific name: Tiphia vernalis, T. koreana, T. popilliavora, T. pygidialis Hymenoptera:Tiphiidae

Type Grub parasite

Hosts Larvae of Japanese beetles and scarab beetles (IRRI, 2001)

Description The female wasp burrows into the ground in search of a grub. She lays her eggs on a white grub. She stings the grub to temporarily paralyze it and lays a single egg on a specific location (depending on her species). The paralyzed grub recovers from the sting to be the source of food when the egg hatches. The tiny wasp's larva starts to feed by biting the grub's skin. It feeds slowly on the body fluids of the grub. The larva molts 5 times taking about 2-3 weeks to complete. Before pupating, the larva eats the remainder of its host and then spins a small, fuzzy, brown ovate-shaped cocoon. Adult Tiphia wasps are shiny dark-colored and about 1cm-2cm long wasps. They are similar to winged black ants. The female wasps' bodies are heavily set built for digging soil in search of beetle grubs. The male wasps are slender and smaller, have tiny hooks at the end of their abdomens which are used for mating. Tiphia wasps feed primarily on the honeydew emitted by aphids, scale insects, and leafhoppers but they also feed on the nectar of blossoms. Tiphia wasps are native to Japan, Korea, and North China. They are now found in cooler climates where they have been introduced to control Japanese beetles and other scarab beetles (CABI, 2000).

Conservation Tiphia wasps' presence is greatly influenced by the availability of adult food sources. The female adults feed in the morning in vegetations for food, such as nectar or honeydews (emitted by aphids or whiteflies), before looking for grubs to deposit their eggs. Under favorable conditions they can parasitize up to 60% of beetle larvae in a given area. Like other insects, they are killed by pesticide, so it is not advised to use pesticides indiscriminately (Ohio State University, 2003).

Cutworm

Photo courtesy of Clemson UniversityDepartment of Entomology

General Information Common name: Cutworm Scientific name: Spodoptera litura, S. littoralis, S. frugiperda, S. eridania Lepidoptera:Noctuidae Synonyms: Cotton leaf armyworm, Climbing worm, Common cutworm, Tobacco caterpillar

Host plants Cotton, crucifers, cucurbits, solanaceous, groundnut, maize, sweet potatoes, rice, wheat, legumes, onions

Distribution Africa, Australia, Pacific Islands, southern Europe, Asia

Damage Seedlings are often cut off at ground level. Cutworm larvae can be found in the soil (up to a depth of about 5 cm) near the plant host. They always curl-up when disturbed. Cutworms feed only at night. Generally, they are not found on plants or on the soil surface during the day. n Young caterpillars eat the soft leaves of the plant. The full grown caterpillars are capable of eating the entire plant. The newly hatched larvae feed from the base towards the tip of the leaf. At this stage, they first feed on the epidermis and may discolor the entire leaf surface. The yellowing of the leaves is a typical symptom of Spodoptera when they cause damage to thickleaf plants such as castor. But the larvae can devour the entire leaves of rice and other cereals (Mochida, 1973: pp. 16-24). In beans, larvae will feed on leaves, buds, flowers, and pods. Larger larvae will tunnel into and destroy the bean pod and seeds. In corn, larvae will feed on leaves, silk, and ears.

Description

Eggs are tiny pearl white, round, and have a ridged surface. The newly hatched Spodoptera larvae are greenish and about 1 mm long. The full-grown larva has a cylindrical body, brown or brownish-black with a tinge of orange. The thoracic segments have one to two dark spots near the base of the legs. The abdominal segments generally have two light brownish lateral lines on each side, one above and one below the spiracles. Above the top lines are broken lines composed of velvet semi-crescent patches that vary in color among cutworms. The pupa is black or brown in color and measures about 22.5 mm long and 9.2 mm wide. The adult has dark brown forewings with distinctive black spots and white and yellow wavy stripes. The hind wings are whitish with grayish margins. The total developmental period from egg to adult is about 35-40 days.

Other cutworm species Black cutworm (Agrotis ipsilon) Eggs are white, ball-shaped, and sculptured with numerous vertical ridges. They are laid in groups of 10-20 eggs. Newly hatched larvae are about 5 mm and nearly 5 cm long when fully grown. Their color ranges from gray to nearly black. The center along the back has a pale rather indistinct narrow stripe. The skin texture distinguishes them from other cutworms. It consists of convex, rounded, coarse granules with smaller granules interspaced in between. The moths are brownish in color with black slashes near the outer edges of the front wings. Adults are similar in size and shape with other cutworm species. There is no distinguishing characteristic to differentiate them from other cutworms.

Photo courtesy of University of Nebraska

Variegated cutworm (Peridroma saucia) Variegated cutworms are dull-colored ranging from 1.5-5 cm in length. Mature larvae are 3.8-5 cm long with a smooth skin. Body color varies from pale gray to dark mottled-brown intermixed with red and yellow dots. There is usually a narrow orange-brown stripe on the sides. This climbing cutworm usually feeds on buds and leaves of plants. Granulate cutworm (Feltia subterranean)

Granulate cutworm larva is gray to reddish-brown with dull yellowish sub-dorsal markings on the abdominal segments. The head is yellowish to brownish. The under-surface of the body is flecked with white. It causes its most serious damage by cutting-off small plants near the ground. If the plant is too large to be severed at ground level, the larva climbs the plant and feeds on the foliage.

Natural enemies Parasitoids 1. Braconid Snellenius manilae is a small Braconid wasp species. It looks like Cotesia except that it has a triangular closed cell on its front wing and has hairy eyes. This parasitoid wasp is host specific. It only parasitizes cutworm larvae. A female wasp lays 3-5 eggs in a cutworm larva. The parasite eats the body fluids and the larva for its development. Cocoons are formed next to the host's body. Lifecycle takes about 4-8 days. A wasp lives for about 1 week (Reissig; et. al., 1986: pp. 99-109; IRRI, 2001). 2. Cotesia 3. Tachinid fly

Predators 1. 2. 3. 4.

Ground beetle Lacewing Praying mantis Weaver ant

Monitoring To monitor for cutworm, count damage and freshly cut leaves, freshly cut young plants, and holes in leaves and in stems.Economic threshold level is 2-4% plants cut below the ground or 6-8% plants cut above the soil surface (University of Nebraska, 2001). Widely accepted threshold are 2, 3, 5, and 7 cut plants per 100 plants during seedling stage (Tooker, 2009)

Management and cultural practices 1. Removal of weeds in and around fields will reduce egg-laying sites and will help in the prevention of cutworm infestation. Do this at least 2-3 weeks before planting to reduce the incidence of cutworm larvae transferring to newly planted crops. 2. Plow and harrow fields properly before planting. This will destroy eggs and expose larvae to chicken, ants, birds, and other predators. 3. In rice fields, keep area flooded. This will prevent cutworm population. 4. Plant corn, alfalfa, or beans after rice. This will provide rich fauna for beneficial insect species which will control cutworm build-up. 5. Interplant main crops with onion, garlic, peppermint, coriander, or garlic every 10-20 rows to repel cutworms. Sunflowers and cosmos can also be planted as a trap crop in or around fields (Garden Guides, 2001).

Photo courtesy of Cornell University

Cotesia Common name: Cotesia wasp, Cotesia Scientific name: Cotesia spp. Hymenoptera:Braconidae

Type Larva parasitiods

Hosts Armyworm, bollworm, cabbage looper, cabbageworm, celery looper, corn earworm, cutworm, diamondback moth, gypsy moth, hornworm, stem borer, tobacco budworm, webworm

Description Eggs are ovate, clear, and shiny and increase in size after they are laid. They hatch 2 days later. The first instar parasitoid larvae begin feeding internally after 3-4 days. The immature parasitoids develop through three larval instars in the host body, and then emerge from the host by chewing through the skin. After emergence from the host, the last instar larvae immediately spin cocoons and pupate. Pupae vary according to species; some are either in an irregular mass of yellow silken cocoons attached to the host larva or to plant leaves, and some in white cocoon, about a size of rice grain. The cocoons are usually found inside host feeding tunnels in leguminous plants. Pupation takes 4-6 days after which adults emerge. Adults are small wasps, about 3-7mm in length. They are dark-colored and look like flying ants or tiny flies. They have two pairs of wings and chewing-lapping mouthparts. They have curved antennae, the males having much shorter antennae than the females. A female abdomen has a downward curve extension, called the ovipositor- with which she lays her eggs. The adult female looks for hosts in leaves and in tunnels of crops. Some species lay about 15-65 eggs in the body cavity of the host while some lay a single egg. A single wasp can parasitize 200-300 host caterpillars during its 10 to 14-day life. The life cycle, from egg to adult, is approximately 15-30 days, depending on the species and the temperature.

Conservation Cotesia wasps can be conserved by planting flowering herbs as a source of food for the adults such as; wild carrot, wild mustard, and sweet alyssum.

Photo courtesy of IRRI & University of Queensland

Tachinid fly Common Name: Diptera Scientific name: Bombyliopsis abrupta, Lixophaga sp. Diptera:Tachinidae

Type Larvae and adult parasitoid

Hosts Aphids, armyworm, beetles, bollworm, bugs, cabbage looper, cotton stainer, cutworm, grasshoppers, hornworm, leafhoppers, mole crickets, moths, sawflies, scale insects, stem borers, stick insects (CABI, 2000).

Description Eggs are ovate-shaped and white in color. They are found in the skin of the host insect or in leaves near the host and are hatched when the host ingests them. The larvae or maggots are worm-like and lack appendages like all other fly larvae. They are greenish-white in color. They have three larval instars and then leave the hosts to pupate in the soil. Before pupation, some mature maggots produce hard cocoons. The larval stage takes about 4 days to 2 weeks depending on the climatic conditions. The newly hatched larvae enter into its host and feed on the content before pupating into the soil. Some tachinid species are hosts' specific, for example for a certain species; it is parasitic only on leaf rolling caterpillars, or only on sugarcane stem borer. Pupae are oblong, yellowish and turn dark-reddish as they mature. Adults measure between 3 and 10 mm and have very stout bristles at the tips of their abdomens. They look very similar to the common housefly but are larger with stocky and soft bodies. They vary in appearance from gray black to brightly colored, or sometimes looking like bees. Adult Tachinid flies have only 1 pair of wings. They feed on honeydews and flower pollen. Different species have varied modified sucking type mouthparts: the cutting sponging, the piercing-sucking, and lapping-

sponging. Adult flies are found in almost all crop habitats, either resting on foliage or feeding on nectars and pollen. Additionally for females, they search for hosts to lay their eggs. The female adult lays her eggs near or into the larvae, or on another insect. She can lay as many as 1000-2000 eggs in her lifetime. Adults can live from 3 days to 2 months depending on the species (IRRI, 2001). However, the Uzi fly (Exorista sorbillans or E. bombycis) is an important pest of the mulberry silkworm and other silkworm species in Asia (CABI, 2000).

Conservation Reducing the use of insecticides and providing sources of food like dills, parsley, clover and other herbs are the most efficient ways to conserve Trachinid flies in agricultural ecosystems (Ellis; Bradley, 1996: pp. 328-329).

Photo courtesy of Clemsom UniversityDepartment of Entomology

Lacewing Common Name: Brown lacewing, Green lacewing, Aphid lion Scientific name: Chrysoperla carnea, Chrysopa rufilabris Neuroptera:Chrysopidae

Type Generalist predator

Hosts Aphids, leafminer, mealybugs, thrips, whitefly (Ellis; Bradley, 1996: p. 449), armyworms, bollworms, cabbage worm, codling moths, corn borer, cutworm, DBM, fruitworm, leafhopper nymphs and eggs, potato beetle, scale insects, spider mites, and caterpillars of most pest moths. If given the chance, they can also prey on adult pests.

Description

Eggs are found on slender stalks or on the underside of leaves. Each egg is attached to the top of a hair-like filament. Eggs are pale green in color. Larvae are known as aphid lions. Newly hatched, they are grayish-brown in color. Upon emerging, larvae immediately look for food. They grow to about 1 cm in length. They attack their prey by taking them with their large sucking jaws and injecting paralyzing poison, and then sucking out the body fluids of the pest. A larva can eat 200 or more pests or pest eggs a week. An older larva can consume 30-50 aphids per day. It can consume more than 400 aphids during its development. The larvae resemble alligators with pincers like jaw. However, they become cannibalistic if no other prey is available. They feed for 3 to 4 weeks and molt three times before pupation. They cover their bodies with prey debris. Pupae are cocoons with silken threads. These are found in cracks and crevices. The pupal stage lasts for approximately 5 days. Adults are green to yellowish-green with four, delicate transparent wings that have many veins and cross veins. Adults are about 18 mm long, with long hair-like antennae and red-gold eyes. Each adult female may deposit more than 100 eggs. Many species of adult lacewings do not prey on pests. They feed on nectar, pollen, and honeydew. An adult will live for about four to six weeks depending on the climatic conditions.

Conservation Flowering plants such as dill, cosmos, sunflower, carrots, dandelions are good source of pollen and nectar for adults. Provide source of water during dry season.

Photo courtesy of R. Bessin, University of Kentucky

Praying mantis Common name: Praying mantids (plural) Mantodea:Mantidae Some important mantids species 1. 2. 3. 4.

African mantis (Sphodromantis spp.) found in Africa Chinese mantis (Tenodera aridifolia sinensis) found in China Devils flower mantis (Blepharoppsis mendica) found in Asia Giant Malaysian shield mantis (Rhombodera basalis) found in Malaysia

5. 6. 7. 8. 9.

Giant mantis (Hierodula spp.) found in Asia Ghost mantis ( Phyllocrania Paradoxa) found in Africa and Madagascar Indian flower mantis (Creoboter meleagris) found in India Leaf mantis (Deroplatys spp.) found in Asia Madagascan marbled mantis (Polyspillota aeruginosa) found in West Africa and Madagascar, Nigeria and Kenya 10. Malaysian orchid mantis (Hymenopus coronatus) found in Indonesia, Malaysia, and Sumatra 11. Spiny flower mantis (Pseudocreobotra spp.) found in Africa 12. Twig mantis (Popa spurce) found in Africa 13. Wondering violin mantis (Gongylus gongylodes) found in India and Sri Lanka

Type Predator

Hosts Aphids, fruit flies, grasshoppers, caterpillars, and they eat each other when no food is available.

Description The eggs are laid in groups. Each group of eggs is encased in a foamy substance that hardens into a tough protective casing called ootheca. Eggs hatch after 3 - 8 weeks, although not all eggs will hatch as young mantids. The young mantids are hatched as pro-nymphs. They are surrounded by a protective membrane and move like grubs to the surface of the ootheca. In some species, there is a single exit hole at the bottom of the ootheca, where the young emerge individually. In others, the young emerge through the oothecal wall nearest the egg cell and will hang on silken cord from the ootheca until the skin hardens. The adult praying mantis varies in color depending on the habitat it is living in. It camouflages the leaves, flowers, twigs, barks, trees where it is found. Its size varies depending on the species, from about 3 cm-18cm. It has strong spine-forelegs and usually sits and waits motionless among vegetation for prey, with its forelegs held together in a prayerful manner, hence the name 'Praying mantis'. It has strong mouthparts for chewing, large eyes, well-set on its mobile triangular head, with antennae that are slender and segmented. It has a neck that can rotate its head while waiting for prey. Some species have powerful forewings for protection and flying. While flying, it can be mistaken as for a small bird. Other species are wingless, odd-looking, flower/leaf-shaped, and others are so thin to be recognizedthat they are hardly recognizable. They will rise up in a threatening manners ready to attack, when disturbed. A female adult should be well fed prior to mating or else she will kill the male once she is hungry after mating. A female mantis lays up to a few hundred frothy liquid eggs in habitats where mantids live.

Conservation Avoid indiscriminate use of pesticides, for pesticides kill and reduce the numbers of praying mantids and other beneficial insects. Maintain vegetation to provide natural habitats for the mantids.

Photo courtesy of Takumasa Kondo

Weaver ant Scientific name: Oecophylla smaragdina Hymenoptera:Formicidae Other name: Green tree ant

Type Generalist predator

Hosts Citrus stinkbug, leaf-feeding caterpillars, aphids, citrus leafminer, leafhoppers, plant hoppers, bugs, moths, adult black bugs, and small animals.

Description The life cycle of the ant has four stages: egg, larva, pupa, and adult. The queen ant starts the ants' nests/colonies. She flies and searches for mate/s. She can mate with one or a few males ( one at a time) in the air, or on low vegetation, or on the ground. Once mated, she looks for a nest site, either on trees or open fields. Once situated, she gets rid of her wings, seals herself into a small chamber and lays a small batch of eggs. The eggs then hatch into larvae. The queen is located in one nest and her eggs are distributed to all the other nests where workers and soldier ants are found. She spends her life laying eggs. The workers are females and do the work in the nest. The larger ones are the soldiers who defend their colony. Fertilized eggs develop into females (workers and the queen) and unfertilized eggs into males. Female ants have 2 copies of each chromosome while males have one. The larvae feed on the unfertilized eggs as food which the queen lays especially for them. The first brood of workers are normally smaller since she can only provide a limited amount of food. Once the ants mature, they leave the nest and begin to look for preys. They bring food to the queen and their siblings so that later offspring are bigger. As the colony reaches maturity, it begins to produce the queens and males for the next generation. Males can remain in the nests for some months and most of them will die within a few days after leaving their nests. The larvae have special glands to produce lots of strong silks (adults do not produce silk). One colony is found over several nests that may be placed in various locations in a tree, or several trees,

or in fields. The worker ants form a chain along the edge of the leaf and pull the edges together by shortening the chain by one ant at a time. Once the leaf edges are in place, each ant holds one larva in its mandibles and gently squeezes the larva to produce silk. The silk is used to glue the leaf edges together. Adult weaver ants are reddish to brown in color and have 10-segmented antennae with 2-segmented clubs. Their eyes are relatively larger than those of other species of ants. They do not have stingers, but can give painful bites caused by the chemicals secreted from their abdomen. They make nests in trees or on leaves of legumes, or in bunds or levees of the fields. They have the most complex nests among ants' nests. They use fresh leaves to build nests . Weaver ants get their name from their habit of binding fresh leaves with silk to form their nests. Their lifecycle spans a period of 8 to 10 weeks.

Conservation and management Weaver ants thrive well in undisturbed places and plenty of green leaves. Plant fruit trees or shrubs in or around your new citrus orchard however, banana, sapodilla, and papaya are less suitable. Introduce only native weaver ants to the orchard when no black ants' species are present to ensure the establishment of a weaver ant colony. Provide them with food during the dry season such as dried fish and shrimp, cut into pieces that are small enough for the individual ant to carry. Put bamboo or wooden strips between trees to guide the ants to transfer from one tree to another for them to build new colonies in other trees. To expand weaver ants' colonies to other field crops, tie a rope to a tree where they live, to guide them to the areas you want them to colonize. Monitor regularly the ant colonies. Like other insects, ants are easily being killed by pesticide. Ask for assistance from your local agriculturist office.

Armyworm

Photo courtesy of University of Arkansas

General Information Common name: Armyworm Lepidoptera:Noctuidae

Host plants Armyworm larva feeds on almost all agricultural crops.

Distribution India, Asia, Australia, New Zealand, Canada, and USA

Damage The larvae can eat the entire leaves of field crops and grasses. When feeding, they chew from the leaf edges until only the midrib is left. They feed on various crops and grasses during their migration, and often bare crops of tender leaves after passing through. They travel from field to field in great numbers, hence the name "armyworm".

Description

Source: University of Nebraska-Lincoln r

The larvae are described to differentiate the several armyworm species from each other.

1. American or Southern armyworm, Fall armyworm, Grass worm, Overflow worm (Spodoptera frugiperda) Mature larvae measure 3.6-4 cm long. They are gray to black in color with alternately bright and pale yellow stripes running longitudinally along their bodies. Black crescent spots are found next to the stripes (IRRI, 2001). 2. African armyworm, Black armyworm (S. exempta) Mature larvae measure up to 4 cm long and are generally black, heads faintly mottled with

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dark brown spots, and with light yellow stripes at their backs. They are characterized by the presence of C-shaped dark spots along their backs (IRRI, 2001). Grass armyworm, Rice swarming caterpillar (S. mauritia) Mature larvae are 3.8-4 cm long and have shades of green, gray, or brown with dark dull dorsal and subdorsal longitudinal stripes. Two rows of C-shaped black spots are distinct along the backs (Reissig; et. al., 1986: pp. 99-109). Paddy armyworm, Rice armyworm, True armyworm, Rice ear-cutting caterpillar (Mythimna separata) Mature larvae are 3-4 cm long and are green to pink in color, with longitudinal light grey to black stripes running along the entire length of their bodies. They have brown to orange heads with an A-marking (Reissig; et. al., 1986: p. 102). Yellow striped armyworm (Spodoptera praefica) Mature larvae are about 4 cm long and black in color with yellow or orange stripes along their sides. These are bordered below by a white-stripe on each side. They have an inverted-white-Y on the front of the heads (IRRI, 2001). Armyworm (Pseudaletia unipuncta) The full grown larva is 3-4 cm long with two orange stripes on each side. Above and below the spiracles, there is a pale- orange and white-bordered stripe. Less distinctive brown stripes are found on the body (CABI, 2000). Beet army worm (S. exigua). The larvae are 3-4 cm long, green in color with many light stripes along the backs and a broader stripe down the sides. The undersides are usually yellow color (Ellis; Bradley, 1996: pp. 270-271.10).

Morphology Eggs of armyworms are white and are found in clusters. One egg mass contains 200-300 eggs. These turn yellowish when mature. Hatching occurs in about 2-5 days. The larva varies its colors according to the species. Sizes vary from 2-4.5 cm long. The larva has 6 small legs just behind the head and 10 fleshy legs at the rear. The larva eats voraciously as it grows. It digs 3-6 cm below the soil surface to pupate. The pupa is brownish red in color and about 2-3 cm long. Pupation takes about 7-16 days depending on the climatic conditions. The moth has 3- 4 cm wingspan and 1.5 cm long. Colors vary from light green, light pink, tan, to dark brown in color. The tiny white dot in the center of each forewing is an important feature to identify the armyworm moth. The moth is seldom seen because it is active only at night time, either mating or searching for suitable egg-laying sites. The female moths lay eggs on the lower leaves of growing grasses or small grains.

Natural enemies Parasitoids 1. Braconid

2. Cotesia 3. Tachinid fly

Predators 1. 2. 3. 4. 5.

Damsel bug Ground beetle Lacewing Praying mantis Weaver ant

Monitoring To monitor the presence of armyworm, conduct visual inspection by going around the field. Look in field margins, low areas where plants have lodged, beneath plant debris around the base of plants, and underneath the plant leaves. Examine 100 plants at random by examining 20 plants from 5 locations. The general recommendation of the economic threshold level on grain crops is 60 larvae per linear meter (Scott, 2003).

Management and cultural practices 1. Practice proper field sanitation. Cut weeds from bordering fields. Remove weeds regularly to reduce breeding sites and shelter for armyworm. Remove all plant debris after harvesting. 2. Employ proper seed selection when seeds for sowing are taken from the previous harvest. Adults might have laid eggs on the seeds during armyworm infestation. 3. Plow and harrow field thoroughly. Sometimes, the small grains or grasses are plowed-under after the eggs are laid on them. As the field is planted and the plants begin to grow, the larvae will continue to develop and will start attacking the plants.

Photo courtesy of IRRI & University of Queensland

Braconid

Common Name: Bracon Scientific name: Bracon spp. Hymenoptera:Braconidae

Type Eggs, larvae, pupae, and adult parasitoid

Hosts Ants, aphids, armyworms, beetle's larvae, bollworms, cabbageworms, caterpillars, codling moths, corn borers, cutworms, imported tent caterpillars, leafhoppers, leafminers, maggots, midges, plant bugs, scales, tomato hornworms, weevils

Description Eggs and larvae of Bracons are found inside the hosts' bodies. The larvae are tiny, cream-colored grubs that feed in or on other insects. Larvae molt five times and undergo 5 instars. Pupae of some species live and pupate within the host until they mature; others pupate in silken cocoons on the outside of the body of the host, while others spin silken cocoons away from the host. Adult wasps are tiny, about 2.5 mm in size, slender black or brown with threadlike waists. Female wasps lay eggs into the eggs of hosts' pests but prefer caterpillars' bodies. In cases where aphids are the host pests, aphids are not killed instantly. Aphids continue to feed on plants tissues until the Braconid larvae inside their bodies completely consume them. The fullygrown Braconid larvae cement the dead aphids to the leaf surface making aphids' shells black and mummified. About a week later, the adult Bracon wasps cut round holes in the mummiesand emerge. The empty mummies remain on the leaf. The presence of mummies in a colony of aphids is a sign that Bracons are present.

Conservation Adult Bracons feed on nectar, honeydew, or pollen before laying eggs. Dill, parsley, yarrow, zinnia, clover, alfalfa, parsley, cosmos, sunflower, and marigold are flowering crops that attract the native braconid populations and provide good habitats for them.

Source: University of Georgia

Damsel bug Common name: Nabids Scientific name: Nabis ferus, N. aternatus, N. capsiformis Hemiptera:Nabidae

Type Generalist predator

Hosts Aphids, armyworms, asparagus beetle, Colorado potato beetle eggs and nymphs, corn earworm, corn borer, imported cabbageworm, leafhoppers, mites, moth eggs, sawfly larvae, and tarnished plant bug nymphs. Although they can survive for about two weeks without food, they will eat each other if no other prey is available.

Description Eggs are deposited in soft plant tissues where they are so difficult to find. Nymphs resemble adults and develop through 5 nymphal stages in about 50 days. Adults are tiny, about 2-4 mm long, with slender bodies and are yellowish or gray or reddish-brown in color. They have piercing-sucking mouthparts, a 4-segmented beak, elongated heads, and 4 long segmented antennae. They are fast runners with long slender back legs and enlarged forelegs for grasping prey. They are commonly found in most agricultural crops, especially legumes, throughout the year. Adults begin laying eggs soon after emergence.

Conservation They prefer to live in soybeans, grassy fields, and alfalfa. You can collect damsel bugs in alfalfa fields and release them around your garden.

Corn borer

Photo courtesy of Kansas State University Department of Entomology

General Information Common name: Corn borer Scientific names: Ostrinia furnicalis, O. nubilalis Lepidoptera: Crambidae Synonyms: Asian corn borer, Oriental corn borer, European corn borer

Host plants Corn is the preferred crop but it will infest other plants, including bean, cotton, tobacco, beet, celery, potato, pepper, tomato, soybean, sorghum, and weeds.

Distribution Asia and in all areas where corn is grown

Damage Corn borer larvae begin feeding on leaf surface or in the whorl. There are pinholes on leaves at the whorl stage. As the plant grows, they bore holes into leaf midribs down into the stalks. Excreta or frass are found near entrance holes. Tassels are clumped where they later feed. Stalks and tassels are broken. They feed last on corncob and cause ear to drop, in severe cases (PCARRD, 1981).

Description The egg is white and laid in masses like fish scales. An egg mass has 5-50 eggs. The egg mass or 2-3 more can be found on the plant leaf. Eggs become cream-colored and dull as they mature. Before hatching, the black heads of the larvae can be seen through the transparent egg membrane. Eggs hatch 4-9 days later. The larva is flesh colored, ranging from light gray to light pink with small round dark brown spots on each segment. The larva has a brown head and indistinct reddish stripes running the length of its body. A mature larva is about 2-3 cm in size. The reddish brown pupa is found inside the larval

home (inside the stems or ear where it has been feeding). The pupa is reddish-brown and approximately 2-2.5 cm long with segments evident on half of the body. The pupal stage lasts about 2 weeks. The adult female is a creamy, brownish yellow moth, and about 3 cm long. The forewings of the female are usually lighter in color than that of the male. The hind wings of both males and females have light markings. The reddish-brown male has a long slender body and is smaller than the female (Bureau of Plant Industry, 1987: pp. 13-14).

Natural enemies Parasitoids 1. Braconid 2. Tachinid fly 3. Trichogramma

Predators 1. 2. 3. 4. 5. 6. 7.

Hoverfly Lacewing Ladybird beetle Minute pirate bug Praying mantis Spider Weaver ant

Monitoring Monitor plant growth throughout the growing season to observe crop conditions and to recognize the potential corn borer attack. To monitor, start looking for corn borer egg masses when the plant is a month old. The egg masses are found on the surface and underneath the leaves near the midrib. Randomly select 50 plants and count the total number of egg masses and multiply by 2 to obtain the number per 100 plants. The critical levels of corn borer are: 40% of plants are infested during whorl stage; 3-4 egg masses/100 plants are found; and 40% of the remaining tassels are infested after detasseling (Bureau of Plant Industry, 1987: pp. 10-17).

Management and cultural practices 1. Practice proper plant spacing within the rows. Sow 1-2 seeds per hill. Crowded plants are difficult to weed, to fertilize, and to monitor crop condition. 2. Practice crop rotation. Grow leguminous crops as rotation crops. This will improve the soil structure; destroy the weeds and corn borer lifecycle. 3. Plant together with other farmers. Late or early planting will provide stem borer an environment for their continuous breeding activities.

4. Practice proper field sanitation. Corn borer laid their eggs on grasses and weeds surrounding your field. Ideally, all crop residues should be cut for animal feeds immediately after harvest. The remaining stubbles should be burned and be plowed under.

Hoverfly Common name: Flower fly, Syrphid fly, Syrphidae Scientific name: Eristalis spp., Volucella spp. Diptera:Syrphidae

Type Generalist predator

Hosts Aphids, thrips, psyllids, scale insects, small caterpillars, and larvae of Heliotes

Description Eggs are tiny, about 1mm in size, ovate-shaped, and glistening-white. These are found laid singly and close to the developing aphid colony in the leaves, shoots, or stems of the plants. They hatch within 2-3 days. The larvae, known as Syrphids, are legless slug like maggots, about 1-13 mm in length depending on their larval stages. They usually have a mottled-gray, beige, or light-green color. They lift their pointed heads to look for preys. Once preys are located, their mouthparts suck out the contents of the preys. Larvae are frequently found feeding on aphids in the sheltered and curled portion of leaves. They blend well with their habitat and therefore they must be looked for closely to locate them. Pupae are teardrops shaped and are found in the soil surface or in the plant's foliage. Adult hoverflies are true flies with only two wings instead of four which most insects have. Adults are large and beautiful insects about 13 mm long. They have a dark head, a dark thorax, and a banded yellow and black abdomen. They closely resemble bees or wasps rather than flies. Their habit of hovering like humming birds gave them the names hoverflies or flower flies. They are expert hoverers, able to remain absolutely stationary in midair. In some species, males will hover in certain spots to attract the attention of females while other species patrol a wider area of up to 100 yards to feed and mate. They dart from flower to flower making them easy to distinguish from the bees and wasps. They feed on pollen, nectar, and honeydew. They are good pollinators.

Conservation Hoverflies are attracted to all flowering plants but even more so to small-flowered herbs like wild mustard, coriander, dill, lupins, sunflower, and fennel. It is advisable to have multiple crops as adults basically feed on pollen and nectar and it is advisable to allow flowering weeds such as wild carrot and yarrow to grow between crop plants. Hoverflies' larvae are most noticeable in the latter half of the growing season when aphids are established.

Photo courtesy of L. T. Kok

Ladybird beetles Common names: Ladybird beetles, Ladybugs, Lady beetles, Coccinellid, Coccinellid beetles Scientific names: Harmonia conformis, H. axyridis, Hippodamia convegens Coleoptera:Coccinellidae

Type Generalist predators

Hosts Aphids, leaffolders, leafhoppers, mealybugs, planthoppers, scales, spider mites, whiteflies, and other leaf feeding insects.

Description Eggs are yellow to orange in color, football-shaped, and are laid in circular clusters of 10 -50 eggs on the underside of leaves or near the aphid colony. Newly hatched larvae are gray or black and less than 4 mm long. They emerge as dark alligator-like flightless creatures with orange spots. Adult larvae can be gray, black, or blue with bright yellow or orange markings on the body. They are usually patterned with colors similar to their parents, and many are adorned with spines. They have long sharp mandibles and feed on small insects like their adults. The larvae are elongate and slightly oblong in shape. They undergo four instars before pupating. The pupae are usually brightly patterned and can be found attached to the leaves and stems of plants where larvae have fed and developed. Adults are oval to hemispherical and strongly convex with short legs and antennae. Most species are brightly colored. Body length ranges from 0.8-16 mm. Their colors tell other predators that they are tasteless and toxic. When disturbed, some of them emit a strong smelling yellow liquid as a protection against other predators. Their colors vary from red, orange, steel blue, yellow brown, or yellow elytra, frequently spotted or striped with black. They feed on pollen, nectar, water, and honeydew but aphids or other prey are necessary for egg production. They are the best-known predators of aphids and are capable of eating up to 50-60 per day and about 5000 aphids in their lifetime.

Many species are well-known for their use in biological control, and have been distributed to various parts of the world to combat insect pests of agricultural crops. However, members of the subfamily Epilachninae are foliage feeders and are sometimes pests of several crops.

Conservation Lady bird beetles are found in most agricultural and garden habitats. Their presence indicates that natural biological control is occurring. It is important to maintain habitats planted with several flowering crops. These give the ladybird beetles varied food sources. When food is not available, they tend to eat each other. Their beneficial predatory behavior and activities are continuous when there is no indiscriminate use of synthetic pesticides.

Photo courtesy of Department of Entomology, Texas A&M University.

Minute pirate bug Common Name: Minute pirate bugs, Insidious flower bugs Scientific name: Orius tristicolor, O. insidiosus Hemiptera:Anthocoridae

Type Generalist predator

Hosts Aphids, bollworm, potato leafhopper nymphs, spider mites, scale insects, insect eggs, small corn borers' larvae, thrips, other small caterpillars, whiteflies

Description

Eggs are elongated, very small, about 0.25 mm, and are clear or milky white in color. The red eyes of the embryo are seen through the shell before hatching. Eggs are laid inside the plant tissues. Incubation takes about 4-7 days. Nymphs are small, wingless, teardrop-shaped and yellow-orange to brown in color. Nymphs pass through five instars before becoming adult. With each molt, the young closely resemble the adults they will eventually become. The nymphal stage takes about 2 weeks. Adults are also very tiny, about 2 mm long, ovate, and black with white wing patches. Their head and thorax are shiny and black, and their beak extends to between the bases of the first pair of legs. They have flattened bodies that are colored black or brown with lighter markings like pirate flags, hence the name. They possess efficient searching behavior and are voracious general feeders. They are able to aggregate in areas of high prey density and increase their numbers rapidly where food is abundant. They can consume 30 or more spider mites per day. Both nymphs and adults feed on a variety of pests as their primary source of food. Their lifecycle takes about 20 days under optimum conditions to complete. Adults live for about 3 - 4 weeks.

Conservation Minute pirate bugs are commonly found where there are flowering shrubs and weeds. These insects are also found in corn, peanut, peas, cotton, soybeans, alfalfa, strawberries, and grapes. When they are in corn silks, they eat the corn earworm eggs and other small insects found on the silks. Insecticide applications to crops can greatly reduce their numbers.

Corn earworm

Photo source: Minnesota Vegetable IPM Newsletter University of Minnesota

General Information Common name: Corn earworm Scientific names: Helicoverpa/Heliothis zea, H. armigera Lepidoptera:Noctuidae Synonyms: Tomato fruitworm, Sorghum headworm, Cotton bollworm

Host plants Corn, sorghum, soybean, peanut, tobacco, cotton, cowpea, tomato, okra, pechay, radish, lettuce, and beans

Distribution Helicoverpa/Heliothis zea is found in Canada, South America, and USA while H. armigera is found in Asia

Damage Larvae feed on leaves, tassels, whorl, silks, and within ears. When larvae feed on corn silks, they clipped these off prior to feeding on the corn ears. The ears are the preferred sites for corn earworm attack. Ear damage is characterized by extensive excrement at the ear tip. They remain feeding in the tip areas until they leave to pupate in the soil.

Description Eggs are pinhead-sized and yellow-green in color. These are found singly laid on the silk and occasionally on the husks of the corn ear. Hatching occurs within about 2-5 days.

Larvae vary in color from bright green, pink, brown, to black, with lighter undersides. Alternating light and dark bands run lengthwise along their bodies, the heads are yellow and the legs are almost black. Mature larvae vary in length about 3-5 cm. They drop to the ground to burrow into the soil to pupate. The larval stage lasts from 12-24 days. Pupae are yellowish green and turn brown as they mature. Pupation takes place under the soil. Pupal period is 12-24 days. An adult male is yellow-brown while a female is orange-brown in color. It has a wingspread size of about 3.8cm. Each female may deposit 200-2,000 eggs in her entire lifetime. Total development period from egg to adult is 34-45 days.

Natural enemies Parasitoids 1. Braconid 2. Tachinid fly 3. Trichogramma

Predators 1. 2. 3. 4. 5. 6. 7.

Damselfly Hoverfly Lacewing Ladybird beetle Minute pirate bug Praying mantis Spider

Monitoring Start corn earworm monitoring 1-2 weeks prior to the silking stage. To monitor, look for eggs and small larvae in the silk and husk. Moth population can be monitored with light traps and pheromone traps. Generally, the presence of 5-10 moths caught every night by light traps in the field is sufficient to stimulate pest control practices (Hoffman; Wilson; Zalom, 1991).

Management and cultural practices 1. Practice crop rotation. Avoid planting crops successively that are hosts to corn earworm like corn, cotton, sorghum, tobacco, soybean, and tomato. 2. Choose corn varieties with tight husks to prevent larva from entering. These varieties show some characteristics and tolerance to the feeding habits of the corn earworm. Ask assistance from the local agriculturist office for these varieties are available in the markets. 3. Two weeks before planting, remove weeds and grasses to destroy earworm larvae and adults harboring in those weeds and grasses.

4. Plow and harrow fields at least 2 times before sowing seeds. This will expose pupae of corn earworm to chicken, birds, ants and other predators. Corn earworm pupates in the soil. After harvest, remove corn stubbles by feeding to carabaos and cows.

Photo courtesy of IRRI & University of Queensland

Damselfly Common Names: Bog dancer, Damselfly, Damsel, Narrow wing Scientific name: Agriocnemis femina femina, A. pygmaea Odonata:Calyopterygidae

Type Generalist predators

Hosts Leafhoppers, moths and butterflies, plant hoppers (Shepard; Barrion; Litsinger, 1987: p. 127)

Description Eggs are laid in emerging plants, in floating vegetation, or directly in the water. The hatched eggs do not go through the larval and pupal stages. A naiad (nymph of damselfly) lives in water, has an elongated body, long legs, and three leaf-like appendages or gills on its tail. These appendages are used for oxygen transport. A naiad molts several times before emerging. At this stage, naiads are very good predators. They prey aquatic insects and other arthropods within their reach. They grab their prey with their modified lower jaw. At the last stage, a naiad swims out of the water and clings to a plant to dry its skin. After a few minutes of drying in the sun, its outer skin splits open at the head and the adult damselfly strains to pull itself out of its old skin. The new legs harden to hold onto the plant. Its wings slowly expand and are pumped open by fluid from its abdomen. An adult damselfly has a long thin body which is green, blue, red, yellow, black, or brown and is

often brightly colored. It has an oblong head with bulging eyes and very short antennae. When resting, it holds its four large membranous wings of nearly equal size vertically rather than horizontally. It is a delicate and weak-flying insect. Its wings are usually clear except for a spot at the end of the wing called a stigma. The male sex organ is located at the front part of the abdomen. Damselflies commonly fly in pairs during mating. Damselfly adults use their hind legs, which are covered with hairs to capture prey as they fly. They hold the prey in their legs and devour it by chewing. Adults are usually found flying near plants, usually in irrigated rice fields during the daytime throughout the year. The damselfly's mating pattern is unusual. The male deposits sperm by bending the abdomen forward and then clasping the female behind the head with its claspers on the tip of his abdomen. The female then loops her abdomen forward and picks up the sperm from the male. The mating pairs are seen flying and clinging in tandem. Most species have one generation per year depending on the species, although they complete their life cycle from 1-2 years.

Conservation Damselflies live in rice paddies, streams, and ponds with good water quality at low and middle elevations. They are often used as an indicator of whether the water is clean or not (IRRI, 2001). To conserve them, avoid using indiscriminate use of pesticides.

Aphids

Photo courtesy of INRA Versailles

General Information Common name: Aphids Hemiptera:Aphididae Synonym: Blackflies, Greenbugs, Greenflies, Plant lice Important aphid species Black bean aphid (Aphis fabae) Corn leaf aphid (Rhopalosiphum maidis)

Cotton aphid (Aphis gossypii) Cowpea aphid (A. craccivora ) Greenbug (Schizaphis graminum Groundnut aphid (Aphis craccivora) Soybean aphid (A. glycines) Cabbage aphid (Brevicoryne brassicae)

Host plants Aphids are pests of vegetables, legumes, plantation crops, shrubs, flowers, fruit trees, and ornamental plants.

Distribution Worldwide

Damage The mouths of the aphids are like tiny straws. The aphids, both the nymphs and the adults, pierce the plant tissues to feed on plant sap. The leaf becomes severely distorted when the saliva of aphids are injected into it. The heavily infested leaves can turn yellow and will eventually wilt because of excessive sap removal. Aphids feeding on flower buds and fruits cause malformed flowers and fruits. Aphids produce large amounts of a sugary liquid waste called honeydew. A fungus, called sooty mold, grows on honeydew deposits that accumulate on leaves and branches, turning leaves and branches black. The appearance of a sooty mold on plants is an indication of an aphid infestation. In cotton, heavy infestation causes crinkling and cupping of leaves, defoliation, square and boll shedding, staining of the lints, and stunted growth. In beans, the growing points are withered, brown, or dead. The leaves are crinkled and mottled. They become sticky because of black sooty mold growing on them. The plants are stunted and deformed. In crucifers, the infested seedlings are distorted and stunted. Their continued feeding on mature plants causes wilting, yellowing and a general stunting of the plants. In corn, the leaves will wilt, curl, and have yellow patches. The tassels and silks are covered with honeydew. Damage, during the late-whorl and pollination stages, causes shortening of the internodes, shriveled and shrunken ears, and empty cobs.

Description Eggs are very tiny, shiny-black, and are found in the crevices of bud, stems, and barks of the plant. Nymphs look like the young adults, they mature within 7-10 days, and are then ready to reproduce. Adults are small, 3-4 mm long, soft-bodied insects with two projections on the rear end and two long antennae. Their body color varies from yellow, green, brown, to purple. Females can give birth to live nymphs as well as can lay eggs. However, the primary means of reproduction for most aphid

species is asexual, with eggs hatching inside their bodies, and then giving birth to living young. Winged adults, black in color, are produced only when it is necessary for the colony to migrate, or there is either overcrowding in colonies, or unfavorable climatic conditions.

Natural enemies Parasitoids 1. Braconid

Predators 1. 2. 3. 4. 5. 6. 7. 8.

Aphid midge Damsel bug Ground beetle Hoverfly Lacewing Ladybird beetle Rove beetle Spider

Monitoring To monitor aphid populations, examine the undersides of the leaves and the bud areas for groups or colonies of aphids. Prompt control is necessary as aphids can multiply rapidly.

Management and cultural practices 1. Grow different crops or grow crops in rotation every cropping season. This practice provides food, shelter, and it increases the number of natural enemies that prey on aphids. At the same time, it disrupts the aphids' lifecycle and maintains its population below the economic threshold level 2. When transplanting, use aphid-free seedlings only, because often they are the source of infestation. Typically aphid populations introduced through transplanting are not evenly distributed in the field but rather form clusters of infestation. 3. Plant trap crops such as lupine, dill, nasturtiums, and timothy grass near the crop to be protected (The Bug Lady, 2004). Anise, chives, garlic, onions, and radish are also good companion crops (Ghorganics, 2004). 4. Control and kill ants. Plow and flood the field. This will destroy ant colonies and expose eggs and larvae to predators and sunlight. Ants use the aphids to gain access to nutrients from the plants. 5. Avoid using heavy doses of highly soluble nitrogen fertilizers. Aphids love tender, juicy leaves. Instead apply fertilizer into 3 phases: during seeding, vegetative, and reproductive stages of plant growth.

Photo courtesy of Jim Kalisch & Barry Pawson, UNL Entomology.

Rove beetles Common Name: Staphylinid Scientific name: Aleochara bilineata Coleoptera:Staphylinidae

Type Rove beetle larvae are maggots and pupae parasites when they are about to pupate, but both adult and larva are generalist predators

Hosts Both adults and larvae are predators of root maggots' eggs and larvae, mites, worms, nematodes, and other small insects. Adults tend to be cannibalistic, eating their own eggs and attacking other adults when food supply is low.

Description Eggs are tiny, about 0.5 mm long and 0.4 mm wide, pear-shaped, pale green in color, and are covered with a gelatin-like material. These are laid by female adults in the soil among the roots of the root-maggot infested plants. The eggs hatch 5-10 days later. The first instar larvae are pale brown, about 1.5 mm long, slender, segmented, and tapered toward the anterior. They have large heads. The parasitic second and third instar larvae are white, have rudimentary legs, and are found within the host puparium. Before pupating, a larva will actively search for a host (pupa of maggot) in the surrounding soil. It will pupate in the pupa of the maggot by entering into its cocoon and feeding its contents, and then pupate itself inside for about 3-4 weeks before emerging as an adult. It is possible that two or more larvae enter into one maggot pupa but only one will survive and mature. Adult rove beetles are brown, reddish-brown, or black or have gray markings on the wings and abdomen, with slender elongate bodies. Their wing covers are shorter than the abdomen where most part of the abdomen is exposed. Both adults and larvae have well-developed 'jaws' cross in front of the head. They live mostly in decaying organic matter but are also found in moist agricultural soils or in habitats where large numbers of fly larvae live. When disturbed, they run very fast, with their abdomen lifted upward, like that of scorpions. Adults are good fliers as well.

Conservation Provide ground covers or mulches within and around fields for rove beetles love to stay in moist decaying organic matter; provide hiding sites and alternative habitats and plant flowering borders, hedges, and other perennial habitats as a source of food and shelter; and provide protection by not spraying broad spectrum pesticides.

http://www.oisat.org/crops/staple_food/corn.html

Aphidoletes aphidimyza (Diptera: Cecidomyiidae) The aphid midge, Aphidoletes aphidimyza, is a cecidomyiid fly whose larvae are effective predators of aphids. Initially a new species was described for every different prey attacked, and at least 24 previously described species have been determined to be A. aphidimyza. This midge is an important component of biological control programs for greenhouse crops and is widely sold in the U.S.

Appearance Adult aphid midges are small (2-3 mm), delicate, mosquito-like flies with long, dangling legs and long antennae. Eggs are oval, minute (about 0.1 mm by 0.3 mm), and orange. The larvae, which look like orange maggots, are tiny, growing through three instars from minute to 2-3 mm. Depending on their food source, they are bright orange to red, and their bodies narrow toward the head. The larvae have strong "jaws" with which they grasp their prey.

Habitat (Crops) Cole crops, potatoes, greenhouses, backyard gardens, ornamentals, orchards, berries. In the greenhouse A. aphidimyza has become very important for aphid control on long term vegetable crops. Although very few field introductions have been reported, studies indicate there is the potential for aphid control in many outdoor crops. A. aphidimyza has been found on cabbage, apples, blueberries, and ornamental bushes, and is recognized as being an important naturally occurring control agent of aphids on Russian and Egyptian cotton.

Pests Attacked A. aphidimyza attacks over 60 species of aphids.

Life Cycle Each female may live for one to two weeks and deposit, singly or in clusters, about 70 upright, orange eggs on leaves among aphids. The eggs hatch in two to four days. The midge larva paralyses each aphid by attacking its leg joints and then sucks it dry, leaving a blackened, collapsed aphid attached to the leaf.

In greenhousese the larvae drop to the soil less than a week after hatching and burrow to pupate; adults emerge about one to two weeks later. In the field, larvae develop in one to two weeks, and pupation may take up to three weeks. The life cycle in the field may range from three to six weeks, and there may be three to six generations per year, depending heavily on daylength. Adult midges fly at night and are rarely seen; they feed on honeydew. Aphid midges overwinter as larvae in cocoons in the soil, pupating in spring. Adults emerge in late spring, mate the night of emergence, and the mated females begin the search for aphids. Most eggs are laid during the first few days after emergence.

Relative Effectiveness Adult midges are very efficient at locating aphid colonies. In one study, A. aphidimyza located the one infested plant out of 75. One larva needs a minimum of 7 aphids in order to complete the life cycle, but it may eat as many as 80. In addition, larvae kill more aphids than they consume. Greenhouse vegetable integrated pest management programs in Canada recommend the use of these midges, often in conjunction with releases of the parasitoid wasp, Aphidius matricariae, for aphid control. The larvae are most common from mid- to late summer in the field. Mass released aphid midges have adequately controlled aphids in small backyard garden trials.

The onset of shorter daylength toward the end of summer can induce diapause. This can be averted in the greenhouse by nocturnal use of 100 W incandescent light bulbs spaced 22 m apart when the canopy is open, with closer spacing when the canopy is dense.

Pesticide Susceptibility Most sprays are toxic to midges. Adults may be more susceptible than larvae.

Conservation Aphid midges are native to much of North America and will overwinter, although winter mortality may be high. High humidity and shelter from high temperatures and strong winds will encourage midge activity. In greenhouse environments, adult midges are most effective at 20-26 degrees C with high humidity. Adults also need a source of honeydew for feeding and to improve egg laying. Larvae need slightly moist soil for successful pupation. For general information about conservation of natural enemies, see Conservation in the Tutorial section on this site, Feature Article on conservation in Volume II, No. 1 of Midwest Biological Control News.

http://www.biocontrol.entomology.cornell.edu/predators/Aphidoletes.html http://www.biocontrol.entomology.cornell.edu/predatorsTOC.html

http://aseanipm.da.gov.ph/publications/