Development and implementation of a trap cropping system to suppress stink bugs in the southern Coastal Plain
The project goal is to demonstrate a trap cropping system to manage the three major stink bug pests, Euschistus servus (Say), Acrosternum hilare (Say), and Nezara viridula (L.), as well as other minor true bug species in vegetable production in the southern coastal plain. The biologically-based, integrated strategy will be customized for the spring and fall planting seasons. Briefly, we will use a series of tactics including preferred host plants that will attract and concentrate the stink bugs and their natural enemies in the trap crop instead of the cash crop, suppress some species (primarily Euschistus spp.) by trap out, suppress others by mechanical removal, bring all species into greater contact with their natural enemies and thereby reduce the damage in the cash crop.
Objective 1. To implement and demonstrate a trap cropping system for stink bug management that is widely adaptable in the southern coastal plain.
Objective 2. To establish an effective outreach program to deliver the information to clientele.
Stink bug response to trap crops: Each of the plant species tested offer different attributes at differing times during the course of their growth patterns from planting to senescence. Okra, field peas, sesbania and buckwheat attracted a wide array of beneficial insects including the tachinid parasites of stink bugs. These plants along with the sorghum and millet matured at different times offering the preferred food source – the seeds- to stink bugs at different times over the course of the 60-90 day maturation period. Buckwheat attracted all of the main pest species during the late flowering and seed formation stage 3-5 weeks after planting. Sorghum and millet were the most attractive plants to the bugs which concentrated on specific parts of the plant when they were available.
Following maturation and use of the seed heads by the bugs, the plants in the plots were ratooned (cut) to 0.5 m in height. The millet and sorghum responded well to this technique and reformed seed heads in about 3-4 weeks which extended the life of the plots. Millet and sorghum were also amenable to ratooning 20-60 days after planting and before maturation which also provided a staggered attractive food source for the bugs. Successful ratooning enables fewer planting dates and lower costs due to the extended life of the trap crop in the seed forming stage when it is in the most attractive to the bugs.
Limitations and future research: The planting dates, ratooning times and other details of the system must be further refined along with the addition of semiochemicals to enhance natural enemies. Effective management of the stink bugs within the plots and the effective spatial relationships among the trap and main crops must be determined.