How to Kill Caterpillars on Petunias
Petunias (Petunia x hybrida) are colorful perennial flowering plants that grow on the ground and in pots, sometimes as annuals. The plants thrive in full sun and in soil that drains quickly. Petunias are also hosts to two moth caterpillars. Tobacco budworms and variegated cutworms feed on the plants' thick foliage and flower buds. Cultivation and different insecticide options help to control the pests. Does this Spark an idea?
Things You'll Need
- Container
- Liquid detergent
- Bacillus thuringiensis, wettable powder
- Sprayer
- Spinosad
- Synthetic pyrethrin
Instructions
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Fill a container with soapy water. Pick the caterpillars off the petunia plant and drop them in the water to kill them.
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Dilute Bacillus thuringiensis in wettable-powder form at the rate listed on the product label. Spray small caterpillars that have just hatched out of the eggs with the solution. They die within three days. The formula does not kill eggs, pupae or the moths. Do not save any of the prepared spray for later. Make a new batch if more eggs hatch. Bacillus thuringiensis is a low-toxicity biological insecticide.
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3
Shake a bottle of Spinosad and dilute 4 tbsp. in 1 gallon water. Spinosad is an insecticide labeled for organic gardening. Add the preparation to a sprayer. Spray the caterpillars with the product to kill them.
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Spray the tobacco budworm with an insecticide that contains permethrin, esfenvalerate, cyfluthrin or bifenthrin -- all synthetic pyrethrins -- as its active ingredient. Natural pyrethrin is not effective against this caterpillar. Apply the product according to the frequency listed on the label. Use the same chemicals to treat the soil surrounding petunias infested with variegated cutworms. The pests hide in soil and mulch, crawling up the plants at night to feed. Apply the pesticide to the soil according to the manufacturer's instructions.
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References
- University of California: Petunia--Petunia x hybrida
- University of California: Foliage-Feeding Caterpillars
- University of California: Active ingredient: Bacillus thuringiensis
- LivingWithBugs: Monterey Garden Insect Spray
- Colorado State University Extension; Tobacco (Geranium) Budworm; W.S. Cranshaw; November 2006
- North Dakota State University; Variegated Cutworm; Janet Knodel
- Photo Credit Comstock/Comstock/Getty Images
