Mario Bautista
Q: My kale is getting holes in it, but the only insect I see nearby are white butterflies with a small black dot on their wings. How can I protect my kale so I have something to harvest?
A: The white butterflies near your kale are a good indication that the imported cabbageworm (the larva of the butterfly) is what’s eating your kale. The larvae are bright green caterpillars with a velvety appearance, and when small they can be hard to see because they blend in with plants. As they feed, these larvae increase in size and usually leave behind dark green frass near the base of leaves.
If plants are small, hand-removing larvae from the leaves can be effective. However, if plants or the population of cabbageworms is large, you may want to dust plants with the biopesticide Bacillus thuringiensis kurstaki (Btk), which is a strain of bacteria that kills larvae that consume it. Insecticides labeled for use on vegetables such as those containing insecticidal soap or spinosad may also be applied, which tend to be most effective on smaller larvae. If using a pesticide, always read and follow the instructions on the product label prior to use.
Finally, row covers or netting can be placed over plants, but this is most effective if applied before you see the butterflies. Learn more about the imported cabbageworm and ways to prevent damage here: tinyurl.com/35s472xu.
