Submitted to: Phytopathology News
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2006
Publication Date: 6/1/2006
Citation: Hill, C.B., Pabon, A., Hobbs, H.A., Hartman, G.L. Effect of stink bug feeding and fungicide application on green stem disorder of soybean. Phytopathology News. 96:S48
Technical Abstract: Green stem disorder of soybean (Glycine max (L.) Merrill) causes stems to remain green after pods and seeds are fully ripe, making plants more difficult to harvest. The cause of the disorder is unknown, however, differences in relative sensitivity to the disorder among soybean cultivars have been observed. In this study, field cage experiments were conducted in 2004 and 2005 to determine the effects of insect feeding, in particular, stink bugs (Euschistus servus (Say), Acrosternum hilare (Say)), and application of a fungicide (pyraclostrobin + boscalid) on incidence of green stem in a sensitive and an insensitive cultivar. Four main-plot treatments with three placed inside field cages (control, stink bugs, fungicide) and an uncaged control, and two sub-plot treatments, soybean cultivars 441RR (low sensitivity) and S2463-4 (high sensitivity) were arranged in a split-plot design in three randomized complete blocks. There was a highly significant cultivar x treatment x year interaction in a combined analysis across years (P<0.01). Green stem incidence ranged from 0.6% for 441RR in the caged control in 2004 to 83% for S2463-4 in the uncaged control in 2005. 441RR consistently had lower incidence than S2463-4. The fungicide significantly increased incidence in S2463-4 both years (14 and 33% in 2004 and 2005, respectively) and in 441RR in 2004 (6%) compared to the caged control. Stink bug feeding did not have an effect on green stem incidence.