Earwig WHAT’S EATING MY PLANT?! have been around about 400 million and know a thing or two about feasting on your vegetable plants. Bonnie Bunn consumed. Other times, a plant (Coleoptera), caterpil- hewing damage is perhaps the may look ragged and, upon inspec- lars (Lepidoptera), grasshoppers Cmost widely recognized type of tion, have chewed edges or centers. (), and termites (Isoptera). injury to plants. Sometimes plants are cut at the base Some of the more common in- Insects with mouthparts consist- and fall over, and sometimes only the sects in Wyoming that cause prob- ing of two opposing mandibles, or upper or lower surfaces of a plant lems in vegetable gardens include jaws, cause chewing damage. Spring are eaten, leaving a brown, scorched beetles (Colorado , cu- and early summer are prime times for appearance or openings between the cumber beetle, flea beetles, Mexican major damage to vegetables, espe- veins, called skeletonization. beetle), caterpillars (armyworm cially seedlings. Chewing damage inside a plant is and cutworm, corn earworm, cab- Chewing damage can take many usually referred to as mining or boring. bage looper, imported cabbage forms. Foliage or flowers may sim- Many of the insect orders have worm, tomato hornworm), earwigs, ply disappear as they are completely chewing mouthparts, including grasshoppers, leafminers, and slugs.

Beetles consume leaf tissue between leaf Caterpillar damage on a broccoli leaf. Earwig feeding damage on cabbage. veins, causing a lacy or skeletonized type of injury, such as on this bean leaf.

18 BARNYARDS & BACKYARDS Beetles Earwigs Leafminers Beetle damage varies with , The diverse diet of earwigs These insects tunnel between size, and growth stage. Mexican bean includes primitive plants (mosses, the upper and lower leaf surfaces, beetle (Epilachna varivestis) larvae feed lichens, and algae), vascular plants, feeding on the soft inner tissue and on the underside of bean leaves pro- fungal spores, small invertebrate ani- avoiding the tough epidermis. They ducing a lacy appearance, also known mals, and decaying organic matter. As are often classified by the pattern of as skeletonizing, while the adults chew opportunistic predators, they provide the mine they create. When larvae holes in leaves. Adult flea beetles also a benefit by preying upon plant pests are mature, they cut the leaf surface, chew holes in leaves, causing charac- such as , scales, caterpillars, drop to the soil, and pupate. The two teristic “shothole” injury (many small maggots, and mites. In contrast, most commonly found leafmining holes or pits in leaves). See photo their herbivorous (plant eating) be- insects that cause problems in gar- lower right.The adults of the Colorado havior makes them a common pest dens include the spinach leafminer potato beetle (Leptinotarsa decemlin- in agricultural crops, home gardens, (Pegomya hyoscyami) and the veg- eata), however, leave notching wounds and landscapes. Earwigs feed on the etable leafminer (Liriomyza sativae). along leaf margins. buds, flowers, fruits, and leaves caus- ing direct plant damage, reduced crop Slugs These pests are not insects but Caterpillars yields, and aesthetic injury to a broad Caterpillars, such as the cab- mollusks that are more closely related range of agricultural plants including bage looper (Trichoplusia ni) and to shellfish, such as mussels and vegetable fruits, leafy vegetables, and the imported cabbageworm (Pieris clams. Slugs are active at night or on herbs. Earwigs often require interven- rapae) cause holes in leaves and may dark, cloudy days. They seek relief tion to reduce plant damage. occasionally cause serious defolia- from the sun and heat in shade un- tion when feeding. Initial feeding is Grasshoppers der plants, rocks, wood, or compost concentrated on outer leaves, but as Grasshoppers use their chewing piles. They need moisture to thrive the caterpillars mature, their feed- mouthparts to tear away plant tissue. but survive in reasonably dry condi- ing tends to intensify and moves into In addition to leaves, they also feed on tions by hiding in protected areas. the heads of plants such as cabbage many aboveground plant parts such as Slugs feed on a wide variety of and broccoli, creating tunnels. Other flowers, fruits, seed heads, and stems. living plants, on fungi, and decaying caterpillars such as cutworms, in The most damaging grasshopper spe- plant materials. They are particularly addition to feeding on foliage, chew cies have broad habitat preferences damaging to new seedlings and ma- buds, shoots, and may cut seedlings and host plant ranges. These species turing vegetables or fruits that touch close to the ground. Caterpillars of are capable of building up over several the soil. They chew irregular holes corn earworm (Helicoverpa zea) tun- years to high numbers in local areas that have smooth edges in leaves. nel into various fruiting vegetables in and migrating considerable distances They eat flowers and clip off small addition to chewing on leaves. as vegetation is consumed. plants and plant parts. They damage

Symptoms of grasshopper feeding Leafminer larvae hatch from small, oval “Shothole” damage on this eggplant leaf include irregularly shaped holes on the and begin feeding inside leaf tis- caused by flea beetles. edges or within the foliage. sue leaving mines.

SPRING 2016 19 , tomatoes, basil, , when plants are young or more vul- , cabbage, and many other nerable to feeding damage. Rotating vegetables. crops from to year will decrease soil-dwelling insect populations and Management diseases from accumulating. Promote Plan ahead: Having a knowledge healthy plants (provide the needed of pest biology and behavior as well nutrients, fertilizer, water, etc.). They as the host plant will aid in planning will be less susceptible to insect what, when, and how to manage injury. pests in a garden. This knowledge Other preventative strategies will allow use of preventative strate- include selecting plant varieties best gies where possible. Examples of adapted to an area, using resistant va- preventative strategies include adjust- Row covers can protect young plants rieties when available, using certified ing your planting schedule. Planting from many kinds of insects. They are seed, using row covers, and planting typically used to exclude insects from early and/or late crops can help avoid a diversity of crops. Fall tillage will feeding or laying eggs on leaves. the major activity period of insects help decrease overwintering sites for many insects that dwell in the soil or control measures will vary with plant Pesky insect pest under plant debris. species and maturity, the insect spe- Monitor for pests: Search for cies and developmental stage, as control insect pests and diseases regularly. well as the location and climate. Monitoring helps identify and target These resources arm home- Row covers: Row covers exclude susceptible life stages and assists insects from feeding and/or laying owners and agriculturalists in timing control measures. When, eggs and are often used when plants with photographs, websites, where, and how you monitor for are young and vulnerable. and control methods. pests varies with the different plant Traps/baits: Traps for earwigs Book – Garden Insects of and insect species in which you are (tuna fish can with bacon grease, North America: The Ultimate interested. In general, you’ll want to rolled cardboard as a refuge trap) scout for pests and diseases about and baits for grasshoppers (wheat Guide to Backyard Bugs. W.S. once per week in the spring and ev- bran plus carbaryl, Corry’s Bug Bait, Cranshaw ery two weeks in the fall. Check areas and Sevin 5 Bait) or Nosema locus- For websites, books, apps along borders and interiors. Examine tae (a microscopic fungi, NOLO the overall plant health, check leaves Bait Biological or Planet Natural • Utah State University and fruits for spots, and evidence Semaspore Bait) can help decrease Extension newsletter – of chewing, discoloration, rot, etc. their populations. bit.ly/utahnews Also take note of the pattern of plant Enhance biodiversity: Plant a Information about insect decline or injury; insect injury tends variety of plants so there is spatial pests in garden, on farm, in to be aggregated or patchy. Consider and temporal diversity. Beneficial home that the injury could be associated insects often need a source of nectar with another problem such as irriga- or pollen to complete their lifecycle • University of Wyoming tion, herbicide spraying, or weather throughout the season. A diversity College of Agriculture and damage. Monitoring helps identify of plants will make the garden more Natural Resources – when the threshold for treatment has attractive to these beneficial insects, bit.ly/uwentomology been reached and action needs to which will provide biological control be taken. The threshold for starting for many pest insects.

Insect pests may only gaze longingly from afar at plants in Bonnie Bunn’s garden; putting mandible to plant may bring swift retribution. She is the vegetable integrated pest management associate at Utah State University and can be reached at [email protected].

Trade or brand names used in this publication are used only for the purpose of educational information. The information given herein is supplied with the understanding that no discrimination is in- tended, and no endorsement information of products by the University of Wyoming Extension is implied. Nor does it imply approval of products to the exclusion of others, which may also be suitable.

20 BARNYARDS & BACKYARDS