UTAH PESTS Staff
Utah Plant Pest Diagnostic Lab
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Vegetable Garden Insect Pests
Common and problematic insect pests vegetable growers encounter during the late spring and early summer include flea beetles, spinach leafminer, and cabbage worms.
Flea beetles (Fig. 1) are small, black and brown beetles that jump quickly when disturbed. Adults spend the winter in protected places in the garden under soil clods and plant debris, and begin feeding on seedlings in the spring causing stunting and seedling death (Fig. 2). They damage plants by chewing small holes or pits in the cotyledons and leaves. Common plants attacked include potato, tomato, eggplant, radish, cabbage, broccoli, Brussels sprouts, corn, beans, and other vegetables. Management tactics include good seedbed preparation to accelerate seedling growth, high seeding rates and removal of affected plants, floating row covers to exclude adults, and insecticides [carbaryl (Sevin), spinosad (Success, Entrust), azadirachtin (Aza-Direct, Neem Oil), bifenthrin (Aloft, Hi-Yield Bug Blaster II), permethrin (Hi-Yield 38 Plus, Green Light Conquest), pyrethrin (Fertilome Triple Action Plus, Maxide Insect Killer, Worry Free Home Pest Control), and diatomaceous earth].
Tan and brown blotches on the leaves of spinach, Swiss chard, beets and other leafy greens indicate infestation with spinach leafminer (Fig. 3). The adult is a true fly, or Dipteran, that emerges from soil in the spring and lays white egg masses on the undersides of leafy greens. The young maggot burrows within the leaves forming “leafmines”. There are several generations per year. Early spring and fall plantings may escape infestation. Cover young plants with floating row cover (Reemay), and pick and destroy infested leaves to reduce the leafminer population. Frequent cultivation around plants can destroy overwintering pupae in the soil. Insecticides can protect leaves, but be mindful of the required interval between application and harvest (read the label). Effective insecticides include spinosad, azadirachtin, permethrin, and pyrethrin.
-Diane Alston, Entomologist
Featured Picture of the Quarter
Spiders are excellent predators of insects. This jumping spider (Tutelina sp.: Salticidae) was caught on film attacking a field ant along the Temple Fork River. It kills prey by stalking, pouncing, and injecting venom. The ant is ready to eat after the spider liquefies the contents with digestive enzymes.
-photo by Ryan Davis