NEW UTAH PESTS FACT SHEETS

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Codling Moth Mating Disruption

UTAH PESTS Staff 

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

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].
 

Fig. 1.  The western flea beetle is shiny black, and jumps when disturbed.

SPINACH LEAFMINER

Fig. 3.  Spinach leafminer is a fly whose maggots tunnel within the leaves of spinach, beets, Swiss chard, and other greens.

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.

CABBAGE WORM

Fig. 4.  Cabbageworm larvae are sluggish in movement, and have velvety hairs.

Fig. 5.  Cabbage loopers move like an inchworm, and are hairless.

There are two common caterpillars that attack cabbage and its relatives (e.g., broccoli, cauliflower, kale, etc.) in Utah – the imported cabbageworm and the cabbage looper.  The imported cabbageworm adult is a pretty white butterfly that can be seen flitting through the garden as it searches for host plants to lay eggs.  The immature stage, or caterpillar, is lime green with short fuzzy hairs on its body.  The cabbage looper adult is a brown moth and the caterpillar is light green with white stripes down its body (Fig. 5).  Its “looping” crawl causes its back to arch as it pulls its hind end forward like an inchworm.  The caterpillars chew ragged holes in the leaves and contaminate the harvested product with their frass (excrement) and bodies.  To protect plants from egg-laying, cover them with floating row cover, or use a stiff spray of water from the hose to remove caterpillars.  Insecticides that have low toxicity to humans and are effective against young caterpillars include Bacillus thuringiensis (Dipel, Thuricide), spinosad (Success, Entrust), and insecticidal soap (Safer’s).

-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