Two-Spotted Spider Mite (Tetranychus urticae) Description The adult mite is barely visible to the naked eye, roughly 0.5–1.0 mm in length, rounded, eight-legged and yellowish-brown with two dark spots on the sides of the abdomen. Nymphs look similar to the adults but are smaller. The larvae have six legs instead of eight. Overwintering females are orange/red.…Continue readingSpider Mite
Tarnished Plant Bug (Lygus lineolaris) Description Tarnished plant bug (TPB) adults are approximately 5 mm (0.2 in.) in length, mottled, yellowish-to-reddish-brown in colour and have a small triangle shape on their back. The nymph stage does not resemble the adults but can be misidentifed as aphids, although they lack the cornicles (“tailpipes”) that aphids possess.…Continue readingTarnished Plant Bug
Description Millipedes are not insects but arthropods. They are hard-shelled, cylindrical and approximately 2.5–5 cm (1–2 in.) long. They get their name (milli: thousands, pedes: legs) from having many legs — two short pairs of legs per body segment in the adult stage. Adult millipedes are dark reddishbrown to grey-black in colour and have hardened…Continue readingMillipedes
Japanese Beetle (Popillia japonica) Description Japanese beetle grubs are similar to European chafer and June beetle grubs, but are much smaller and have a different raster pattern (anal bristles) that can be identified using a hand lens (see grub section at beginning of the insect chapter of OMAFRA Agronomy Guide for Field Crops – Publication…Continue readingJapanese Beetle
BEAN LEAF BEETLE (Certoma trifurcata) Description The bean leaf beetle (BLB) adult is approximately 5 mm (0.2 in.) in length and may or may not have four black parallelogram shaped spots found on the wing covers. Adult beetles can vary in colour but are most often yellow-green, tan or red. All have a small black triangle…Continue readingBean Leaf Beetle
Description The potato leafhopper (PLH) is a pest of alfalfa and dry edible beans. The adult is a pale green, wedge-shaped, winged insect about 3 mm long with piercing and sucking mouthparts. It is most broad towards the head, tapering evenly to the wing tips. It has a row of six rounded, white spots behind…Continue readingPotato leafhopper
Photo credit: B. Hall Description The primary crops at risk are corn, soybeans, newly seeded forages, and canola. Juvenile and adult slugs are soft-bodied, legless, greyish or mottled in appearance and have a slimy or gelatinous covering that protects them from drying out. They are essentially snails without a shell. The head has two pairs…Continue readingSlugs
Seedcorn maggot (Delia platura) Description Crops at risk include corn, soybeans, and dry edible beans. The seedcorn maggot is a small (6–10 mm or 0.2–0.4 in.), yellowish-white, headless, legless larva. The body tapers to the front, with two small protracting mouth hooks. The adults resemble a small, elongated housefly that is slender, light grey and…Continue readingSeedcorn maggot
Grubs (European chafer, June beetle or Japanese beetle) Various types of grubs can attack field crops, primarily corn, soybeans, forages and winter cereals. European chafer and June beetle are the most common problem grubs in Ontario field crops, although Japanese beetle grubs can also cause damage. Proper identification of the species of grub present in…Continue readingGrubs
