Squash producers and gardeners 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 and only 285 eggs on the main crop (Fig. 1). 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. In all our studies, we first established an excellent stand of Hubbard squash and delayed the planting of yellow squash; the latter seems to catch up and do fine in terms of yield and the quality of produce. We eliminated all insecticide treatments in the large study and still got a wonderful crop (Fig. 2). Even the big round fruits of Hubbard squash are marketable and tasty to eat. Finally we have a trap crop that can pay for itself!
One of the major disadvantages of trap crop system is that it takes up space due to its prolific growth habit. Hubbard is also susceptible to a number of diseases – so planting should be done during optimum time. Dead seedlings can be replanted to maintain a good stand of the trap crop. If you are interested in more results, then please visit the Alabama Vegetable IPM project website and look at the ‘squash pest’ training module for videos and factsheets. Also join us on the vegetable IPM page on Facebook.
Alabama Beginning Farms Update: Are you a producer or market gardener with less than 10 years of experience? Then the Alabama Beginning Farms website is a useful starting point for you. Visit www.aces.edu/beginningfarms and explore resources about on-farm services, microloan programs, and educational events all at one place! Bookmark the website today and watch the monthly webinars on the last Monday of each month at 9 a.m. Recordings of past webinars are also available.
Annual Fruit and Vegetable Conference: The Alabama Fruit and Vegetable Growers Annual Conference will be in Clanton on November 17 and 18, 2016. Keep checking www.afvga.org for more information about registration details and agenda.