For dryland soybean, weekly rainfalls are needed throughout flowering and podfill in order to obtain above average yields. Stress during reproductive development leads to pod shed and reduced seed size which in turn has a direct impact on seed yield. There are several ways that the effects of drought can be reduced. If farmers are using Roundup Ready varieties, the addition of First Rate to Roundup Ultra will assist with morningglory control. Refer to the 2000 Pest Management Handbook for control recommendations, crop and weed growth stages for application, and efficacy ratings for soybean herbicides.
Insects can be more difficult to control under drought conditions.
This is due to the reduced occurrence of beneficial insects and diseases of destructive insects. Begin scouting each soybean field at first bloom and repeat every five to seven days. Economic thresholds for every destructive insect are listed in the Clemson Pest Management Handbook. Remember, after first bloom the crop can tolerate a 15 to 20 percent foliage loss without losing yield potential. For pod feeders, the thresholds are two large corn earworms or one stinkbug per row foot in wide rows.