Last year I planted brussel sprouts that were incredibly healthy until...
Last year I planted brussel sprouts that were incredibly healthy until cabbage loopers invaded. I tried hand removing them daily but they were relentless. Around August I gave in and sprayed the plants with neem oil, and the loopers still demolished my plants. My garden has mostly sandy soil and last year did drain less than ideally (an area of planned improvement for the coming year), in case the moisture could have been part of my problem. Is there anything preventative I can do in this years garden to quell the cabbage loopers from overtaking my brussel sprouts? Thank you for your help!
Both Imported cabbage worm and cabbage looper will eat up your Brussels sprouts before you can (Actually Imported cabbage worm is more common and its little white moth flitting about gardens is a common sight.) You might want to look at the info on both of these in the HGIC website's Grow It Eat It section under Vegetable > Common Problems > Insects. Here's the link: http://extension.umd.edu/growit/insect-pests-vegetables
Both of these pests are profiled.
Since you already know that these larvae are a problem, we strongly recommend using the floating row cover on your plants this growing season. Drape it loosely over the transplants to give them plenty of room to grow, and seal the fabric edges by covering with soil so that insects cannot crawl in.
Row cover usually traps too much heat to be used all summer. There are micromesh products available that do not trap heat, but they are more costly and probably too small for Brussels sprout plants.
When your sprouts outgrow the row cover, feel confident using Bt or spinosad to kill the larvae. Mixing in a spreader-sticker product will make it adhere better to the waxy leaves.
These products work on small, not full-sized, caterpillars. So keep a sharp lookout and spray before they get a chance to get large. This may require spraying about every 10 days. Familiarize yourself with the moths of these two pests so you can be more aware of their egg-laying presence. The white Imported cabbage worm moths are easy to spot, but the cabbage looper not as much.
Thank you! I will definitely try the floating row cover!