sweet broom caterpillar infestation - Knowledgebase Question

irvine, Ca
Question by lmnazareno
April 12, 2010
My sweet broom is being ravaged by caterpillars (yellow with black alternating the length of the body). Besides picking them off, is there a systemic product or topical product I can use to control them?

Answer from NGA
April 12, 2010


Without seeing them, it's hard to say what they are. It sounds as though either they hatched from the undersides of your plant's leaves, or somehow they spread the word quickly about your Sweet Broom. You can try to remove them by hand, or a common control for caterpillars is Bt (Bacillus thuringiensis). It is available at most garden centers under the names Dipel or Thuricide. Bt is in an insecticidal bacterium that you apply when caterpillars are small. When used as recommended, it is not harmful to pets, people or the environment. Bt contains spores of a lethal bacteria that germinate in the gut of a caterpillar after ingestion and causes them to stop feeding-and eventually kills them. If you leave the caterpillars alone, they will turn into butterflies or moths. If you decide to leave them alone, let's hope you have some lovely butterflies or moths in the coming weeks to make up for the loss of the leaves on your plant.

A comment from retiredrdhsbcglobal
September 15, 2017
I was devastated to see the number of caterpillars on my sweet broom and was tempted to destroy them by placing the branches in warm soapy water as advised but then I read that they will turn into moths or butterflies so now I am hesitant to destroy them nor the plant. What would you do, there are over 100 on each of my two plants? Am I making a mistake??

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