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Recycle A to Z

alternatives to pesticides - bugs/pests - Cabbage Worm (Imported)

 

                              cabbage worm

       Actual Size:     Butterfly 1” – 2”      Larva 1 1/4”

Adult imported cabbageworms are the white butterflies (with black tips and 2-3 spots on each wing) that flit about in the garden for almost the entire growing season. The larvae, which are medium green, eat large, ragged holes in leaves of cabbage-family plants and cabbage heads and soil the leaves with dark green excrement.

Prevention
Cover plants with a floating row cover all season or until fully mature.

Physical control
Hand-picking imported cabbageworm larvae in light infestations can be very effective. Eggs are conical and light in color and are laid on the undersides of leaves of cabbage family plants such as broccoli and cauliflower.  They can be scraped away easily with your fingernail. Use yellow sticky traps to catch female butterflies.

Biological control
Paper Wasps - The relatively docile paper wasps, which pose no threat to humans, are known to eat imported cabbageworm larvae (caterpillars) and other soft-bodied insects such as aphids.

Least-toxic chemical control
Bacillus thuringiensis (Bt) - Bt is a bacteria used to control certain pest larvae, primarily caterpillars. Bt is not toxic to humans or other mammals but will kill butterfly (“friendly”) caterpillars as well as the problem ones. The bacterium kills larvae by interfering with digestion. Bt lasts on leaf surfaces five to seven days and must be ingested to be effective. There are many strains of Bt commercially available now, including strains for controlling mosquito and beetle larvae.

 

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