Saving poisoned caterpillars

We’ve been raising caterpillars indoors and suddenly some begin spitting bright green fluid. They’re poisoned! We panic! What to do? Can we save them?

Before worrying about how it happened, get them to safety NOW. That’s the most important thing.


Wash hands well before and after touching caterpillars or their food

Second, rinse the caterpillars under gently running water and place them in a clean rearing container.

It’s better to be in a fresh clean container without food than to be in a container that may have the source of poison in it. Whether the problem was something on your hands, the rearing container, or the food, those three bases are now covered.

Third, if you wish to talk with people about what happened and what to do, you can do so now.

Your first concern should be to get your caterpillars as safe as possible. It is important to place food with your caterpillars but if you aren’t sure if the problem was the food, it may be more important to talk to people who may be able to help you determine the source of poison.

NOTE: Rinsing the caterpillar only cleans the outside of the caterpillar.

If it was placed with or exposed to poisons that touched the outside of its skin and it didn’t eat or breathe too much of it, it often can be saved. If it has breathed or eaten too much of a poison, it will be too late.

Fourth, supply your caterpillars with safe food.

Quickly locate safe, untreated host plant. If you are absolutely positive that your host plant is not treated, use it. Watch closely in case there was contamination from an unknown source.

Fifth, watch your caterpillars closely. Sometimes it is impossible to save them, no matter what you do. If they have been exposed to, ingested, or breathed too much pesticide, nothing can be done. Many times situations like this are simply an opportunity to learn. Share your experiences with others so that we all can learn.

Even experienced people make huge mistakes. Even after over a decade of experience, having raised well over a million butterflies, I made the mistake of using a bug bomb in my laundry room, sealed and 30′ away from a rearing habitat with caterpillars. Much to my shock, every caterpillar died. It never occurred to me that the pesticide could go through the seals and reach the habitat. I still believe it is impossible – yet I saw it with my own eyes and saw the results. You can see the stained habitat below. There is no denying that the pesticide made it through the sealed door.

Green vomit from pesticide