Several weeks ago I put in our fall crop of lettuces. Here in Northern California we get two lettuce growing seasons, in the spring and fall. They were doing beautifully until one day I found that something was ravaging them and leaving behind little mounds of poo.
Caterpillar ravaged plant
The culprit I discovered was a little green caterpillar, about an inch long. I pulled off and squished 20 of the suckers in our little lettuce patch. The next day I pulled off another 10. The following day I found a whole bunch of babies. Grrrrr. What to do?
Here are two solutions. The first is probably the most effective. Spray the plants with Bacillus thuringiensis, otherwise known as “BT”. BT is a naturally-occurring soil bacterium that produces poisons that will kill the caterpillars when ingested. It is completely non-toxic to humans and animals.
The second solution is to place a cardboard plant collar around the plant. This dissuades the caterpillars. Don’t ask me how, it just does. The plants with the collars weren’t bothered by the bugs. Those without were.