Specific Crops

Perimeter trap cropping in winter squash, pumpkin, and summer squash

Over the past years, you have probably have heard a lot from us about perimeter trap cropping to manage striped cucumber beetle in cucurbit crops. The system has proven itself as an effective, cost-saving method for managing this pest. Systemic or foliar insecticides in the trap crop border are effective in halting the beetles in the border and protecting the main crop.

PTC systems can reduce insecticide use by over 90% if implemented correctly, but this is not the only benefit. By spraying only the border of your crop you're leaving the main part of the field as a refuge for pollinators and natural enemies of insect pests. Leaving the main crop unsprayed may also help to delay the development of insecticide resistance in the striped cucumber beetles – a few beetles will always bypass the border, and thereby escape selection for resistance.

The first trap crop that we looked at was Blue Hubbard, but many growers told us that Blue Hubbard is difficult to market and other border trap crops were needed. In 2006 we evaluated buttercup and kabocha squash as border crops, and they worked just as well as Blue Hubbard. Markets for these crops are strong. Any Cucurbita maxima variety is likely to be very attractive. This species includes many giant and specialty pumpkin varieties; the only one we do not recommend as a border crop is Turk’s Turban because unlike most C. maxima varieties it is highly susceptible to bacterial wilt which is vectored by the beetles. You can even plant a border of mixed C. maxima around your butternut squash, acorn squash, and other winter squashes that are C. pepo, or C. moschata types. This will provide you a wide variety of interesting squash to market. We've tested this system extensively and found that as long as the trap crop border is planted on good land and remains intact the system works remarkably well. In most cases, growers who use this system never need to apply insecticides to their main butternut crop at all. In Connecticut, they've found the system to work equally well with cucumbers and summer squash. Zucchini tends to be more attractive than summer squash, and some varieties such are so attractive that they could be used as a trap crop. We've also seen PTC work well in pumpkin crops, as long as the pumpkins in the main crop are C. pepo and not C. maxima. Remember, many giant and specialty pumpkins are actually C. maxima species, and would make good trap crops.

On organic farms, growers often treat the main crop with kaolin clay (Surround WP) which serves as a repellent. For transplants, using this before planting is very efficient and lasts for a week or so if there are not heavy rains. Spinosad used in the border will kill striped cucumber beetles in the border; pyrethrin is less effective.

Every year we talk to more growers who adopt this system. The reduction in pesticide costs can be dramatic, and more than offset the small amount of time and care it takes to plant and treat a solid perimeter trap crop. If you would like to try this system and have any questions, or just want to find out more about how it works, please call Andy Cavanagh at 413-577-3976.

--authors: Andrew Cavanagh and Ruth Hazzard, Umass Extension Vegetable program.

Additional information:

Using perimeter trap crops to manage striped cucumber beetle and bacterial wilt -- 2007 Overview.

2007 PPT on Perimeter Trap Cropping in Butternut Squash

Perimeter Trap Cropping Works in Butternut Squash

Two-row perimeter of buttercup squash around a main crop of butternut.