Chemical and organic control of caterpillars

If caterpillar numbers are too high for picking off by hand, insecticides can be used.

Insecticides should be used only as a last resort. Before application, ensure plants are receiving the appropriate cultural care and take steps to protect natural predators. 

Organic sprays containing natural pyrethrums can be used. These products have a short persistence so may need to be applied a number of times before the caterpillar population is under control. 

Contact (spray) insecticides, particularly synthetic pyrethroids such as lambda-cyhalothrin, deltamethrin, and cypermethrin, are used to control caterpillars. Acetamiprid, a systemic neonicotinoid insecticide, is also available. 

Follow instructions carefully when using insecticides. Plants in flower should not be sprayed due to the danger insecticides pose to bees and other pollinating insects. Insecticides can cause an outbreak of red spider mite since they often kill benefical insects that control caterpillars.