Ayanava Majumdar, Alabama Cooperative Extension System
Squash producers are bugged by three major insect pests. Cucumber beetles are early season pests that can severely damage transplants and delay plant maturity. Squash bugs are often the next wave of mid-season insects that lay a number of eggs on the leaves, stems, flowers, and fruits. Squash bug nymphs and adults can form large aggregates on fruits and cause direct plant damage. Both cucumber beetles and squash bugs transmit diseases. The last major insect pest of squash is the vine borer that can infest gardens as well as commercial plantings. Heat or water stress can hasten the devastation caused by vine borer larvae that live inside the stem. In all cases, most common organic insecticides appear to provide low to poor control of the pests. So, we have to think out of the box for managing insects like the squash bugs and here is an alternate IPM strategy.
One of the most recent studies completed in Alabama for squash bug control focused on the use of Hubbard squash as a trap crop. Hubbard squash establishes quickly after planting and grows vines like crazy, just like kudzu! In all our studies, we planted two rows of Hubbard squash trap crop around 3-4 rows of yellow squash (main crop). Once you have figured out where the squash bugs are migrating from, you can actually plant more rows of yellow squash and less of Hubbard to maximize your profits. Remember to plant the trap crop at least two weeks ahead of the main crop and on good ground for maximum effectiveness. Don’t ignore the trap crop and don’t forget to scout!
In the recently completed large scale study at Cullman, we observed over 4,500 squash bug eggs on the Hubbard squash trap crop (especially New England variety) and only 285 eggs on the main crop (see image below – click for a larger view). This is about a 15 times reduction in pest numbers!! We did see squash bug adults land on the yellow squash but they quickly move on to the Hubbard where they will hide and lay the majority of eggs. This study also provided evidence regarding an area-wide effect of trap crop on insects with limited amount of trap crop. For example, yellow squash planted about 400 feet away from the Hubbard had nearly 10 times lower number of squash bug eggs. It is evident that trap crop placement is very important along with the attention provided to the planting time.