FFA Agronomy Insect Identification Practicum Study Guide Wyoming 2015 6March2015 Prepared by Scott Schell Assistant Extension Entomologist [email protected] Important Information About this Guide: • The information in this guide will allow you to successfully answer all of the questions on the Wyoming FFA Agronomy- Entomology exam. • Some terms have been generalized. For example the mouth parts of spider mite are not actually a piercing-sucking beaks but they function like them. • The insect Order Homoptera has recently been incorporated into Hemiptera. This may not withstand scientific scrutiny. Most all except for the very newest entomology textbooks still call them Homoptera so we will maintain that nomenclature for now to avoid confusion. • References such as “Garden Insects of North America” and “Entomology and Pest management” would make an excellent additional study material. Alfalfa looper Order Lepidoptera Life cycle - complete Economic Impact -– vegetative part destruction by larvae Mouth parts – chewing on larva; proboscis on adult Alfalfa loopers are greenish caterpillars, tapered from back to front, that can exceed 25mm in length when ready to pupate. Because of the arrangement of legs (only 3 abdominal prolegs) they walk with a looping “inch worm” type motion. Usually only two generations per year of this pest occur in Wyoming. Alfalfa Weevil Larvae and feeding damage Order Coleoptera Economic Impact - – vegetative part destruction , primarily the by the larvae pupa Life cycle - complete Mouth parts – chewing on adult and larvae. The adult’s coloration varies from gray to brown; 4 to 6mm long Adult Larval stages Aphids – corn leaf species in the Family Aphididae, Order Homoptera Economic Impact – damage by removal of plant fluids Life cycle - incomplete Mouth parts - piercing-sucking beak Green colored with a dark pair of cornicles on posterior (they look like exhaust pipes). Many species of aphid adults can be seen with wings (alate) and without wings (apterous) at various times of the year. Body length 1 to 2 mm. Aphids – Russian wheat species in the Family Aphididae, Order Homoptera Economic Impact – damage by removal of plant fluids Life cycle - incomplete Mouth parts - piercing-sucking beak Many species of aphid adults can be seen with wings (alate) and without wings (apterous) at various times of the year. Many species have a pair of prominent cornicles on posterior (they look like exhaust pipes) . The Russian wheat aphid has very small ones them and is uniformly colored pale green. Body length 1 to 2 mm. Aphids – spotted alfalfa species in the Family Aphididae, Order Homoptera Economic Impact – damage by removal of plant fluids Life cycle - incomplete Mouth parts - piercing-sucking beak Many species of aphid adults can be seen with wings (alate) and without wings (apterous) at various times of the year. Aphids with red eyes and spots on the back, found feeding on alfalfa will be spotted alfalfa aphids. Body length 1 to 2 mm. Aphids – sugarbeet root species in the Family Aphididae, Order Homoptera Economic Impact – damage by removal of plant fluids Life cycle - incomplete Mouth parts - piercing-sucking beak Many species of aphid adults can be seen with wings (alate) and without wings (apterous) at various times of the year. In the early spring the sugarbeet root aphid forms petiole galls on cottonwood trees. The galls break off and the aphids fly into sugarbeet fields . The next generations are wingless and feed on the fibrous roots attached to the main storage taproot and secrete a white waxy substance around the roots. Body length 1 to 2 mm. Armyworm larva Order Lepidoptera Economic Impact -– vegetative part destruction Life cycle - complete Mouth parts – chewing on larva, proboscis on adult Larvae “march” in mass in search of food, giving them their common name. They will crawl up on vegetation to feed. Maturing larvae can exceed 25mm in length. Adult Assassin bugs Economic Impact - beneficial predator Life cycle - incomplete Mouth parts - piercing-sucking beak All members of the insect Family Reduviidae , Order Hemipterashare this common name. Most are black or brown but not all are. Adults of various species range from 10 -25 mm in length. Bean leaf beetle Order Coleoptera Economic Impact – vegetative part destruction on bean species Life cycle - complete Mouth parts – chewing on both adult and larvae Their coloration is extremely variable. All forms have a black triangle at the junction of the front wings, behind the head (see arrow) Body length 5 to 7mm. Larvae do a little damage to roots. The adults feed heavily on the leaves. Blister beetles Order Coleoptera Economic Impact – poisonous to livestock if ingested when they are Incorporated into alfalfa hay Life cycle - complete Mouth parts – chewing The family Meloidae’s common name is blister beetle but 4 members in the genus Epicauta are the main pests when they swarm on alfalfa, that is in bloom, when it is harvested. The crushed beetles contain cantharidin, a powerful blister agent, which contaminates the hay and can kill livestock. Boll weevil Order Coleoptera Economic Impact – fruit/flower destruction of cotton Life cycle -complete Mouth parts – chewing adult and larvae A small 6mm long beetle with an elongated face with chewing mandibles. They are a serious pest on cotton. The adult female chews a wound into the developing cotton boll and deposites eggs in the pit. The eggs hatch and the larva feed on the developing cotton boll. Adult on a cotton boll Chinch bug Order Hemiptera Economic Impact – damage by removal plant fluids from turf grasses Life cycle - incomplete Mouth parts - piercing-sucking beak Wings on the adult vary from short to full length but have the typical combination of a thick leathery portion and a thin membranous section. Egg to adult from shown. Adults up to 4mm long. Colorado potato beetle Order Coleoptera Economic Impact – vegetative part destruction Life cycle -complete Mouth parts – chewing larvae and adult Major pest of potato and tomatoes as adult and larvae. Adult beetles are 10mm long Adult larva Corn earworm larva Order Lepidoptera Economic Impact - on corn seed head destruction Life cycle - complete Mouth parts – chewing as larva, proboscis on adult In addition to corn, cotton, tomato, it also attacks Adult artichoke, asparagus, cabbage, cantaloupe, collard, cowpea, cucumber, eggplant, lettuce, lima bean, melon, okra, pea, pepper, potato, pumpkin, snap bean, spinach, squash, sweet potato, and watermelon. Green and brown color morphs of the larva Corn rootworm larva (Three species of beetles in the genus Diabrotica ) Order Coleoptera Economic Impact – vegetative part (root) destruction Life cycle - complete Mouth parts – chewing larvae and adult. 3 species of corn rootworm adult Beetles 5 to 6.4 mm long. The dark plate on the top of the tail end of the larva is a diagnostic character (see arrow) makes them look two headed. Larvae reach 8 to 10 mm. Cutworm larva A member of the Noctuidae family of moths. Order Lepidoptera Larva spend much of the time out of sight Economic Impact – vegetative part destruction under the soil litter. They cut off plants at Life cycle - complete ground level giving them their common name. Mouth parts – chewing as larvae, proboscis on adult Typical adult – called a miller moth Earwig (common name of all members of the order) Order Dermaptera Economic Impact – fruit/flower damage Life cycle - incomplete Mouth parts - chewing The European species is the most common pest in US. European corn borer larva Order Lepidoptera Adult Economic Impact – vegetative part destruction Life cycle - complete Mouth parts – chewing on larva, proboscis on adult Ostrinia nubilalis larva can attack other crops besides corn that have stems big enough for the larva to enter. Adults have 25 mm wing span on average. Larva inside the stem of a corn plant. Field Crickets Order Orthoptera Economic Impact – vegetative part destruction Life cycle - incomplete Mouth parts – chewing as adult and nymph At high population levels field crickets can damage crops. They can be black or brown and as adults can be 25 mm long. Very long antennae as compared to grasshoppers. Males chirp to call in mates Flea beetle – many species of small, jumping beetles in the Family Chrysomelidae Order Coleoptera Economic Impact – vegetative part destruction Life cycle - complete Mouth parts – chewing as adults and larvae Attack many crops and even trees and shrubs by some species. Most species less than 3 mm. Adult beetles with enlarged hind femurs for jumping: typically brown, black, or iridescent Granary weevils - Sitophilus species Order Coleoptera Economic Impact – attack stored grain, can render the grain unfit for human consumption, will feed on and deposit an egg into intact grain kernel Life cycle - complete Mouth parts – chewing on adult and lava A 2.5 mm long adult weevil, after emerging from a single kernel of stored grain. Slantfaced Grasshoppers - subfamily Gophocerinae, several are major rangeland pests Order Orthoptera Economic Impact – vegetative plant part destruction Life cycle – incomplete metamorphosis Mouth parts – chewing as adult and nymph Typical adult with enlarged hind legs for jumping; avg. size ranges from 20mm to 60mm as adults. Typical Annual Lifecycle Bandwing Grasshoppers - subfamily Oedipodinae, several important pests but most are not Order Orthoptera Economic Impact – vegetative part destruction Life cycle - incomplete Mouth parts – chewing as adult and nymph Some species spend the winter as a freeze tolerant nymphs. Typical grasshopper with enlarged hind legs for jumping; avg. size ranges from 25mm to 80mm as adults. Good fliers, the males often make “clicking” noises to attract females. Usually very well camouflaged nymphs, Adults usually have colorful banded hind wings Typical nymph Green lacewing Eggs on “stalks” Order Neuroptera Economic Impact - beneficial predator Life cycle - complete Mouth parts – chewing Many species of lacewings. Adults rarely exceed 19mm. Lacewing refers the fine venation of the wings. Adult usually reach 10 to 12 mm in body length.