|CULBREATH, A - University Of Georgia|
|BRANCH, W - University Of Georgia|
|Holbrook, Carl - Corley|
|TILLMAN, B - University Of Florida|
Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2009
Publication Date: 1/15/2010
Citation: Culbreath, A.K., Branch, W.D., Holbrook Jr, C.C., Tillman, B. 2009. Response of new peanut cultivars and breeding lines to phorate insecticide for management of tomato spotted wilt. Proceedings American Peanut Research and Education Society 41:79-80.
Interpretive Summary: not required
Technical Abstract: In the southeastern U.S., management of tomato spotted wilt (TSW) of peanut (Arachis hypogaea L.), caused by Tomato spotted wilt Virus (TSWV), is dependent upon integration of cultivars such as Georgia Green, with partial field resistance, with other factors that suppress TSW epidemics. In-furrow applications of phorate insecticide often provide suppression of TSW in addition to preventing direct injury of peanut foliage by thrips larvae. Several peanut cultivars and breeding lines have been developed with levels of field resistance to TSWV greater than that of the moderately resistant cultivar Georgia Green. The objective of this study was to determine the effects of in-furrow applications of phorate insecticide on severity of TSW and yield in several of these new lines. Field trials were conducted at the UGA-CPES Lang-Rigdon Farm, Tifton, GA in 2007 and 2008. Experimental design was a split-plot with three or four replications. Whole plot treatments consisted of in-furrow application of phorate (1.12 kg ai/ha) and no in-furrow insecticide. Sub-plot treatments consisted of 13 genotypes in 2007 and 14 genotypes in 2008. In 2007, treatment main effects and phorate-¬genotype interactions were significant for final incidence of TSW. In 2007, final incidence of TSW in Georgia Green was 55.8% and 30.1% (LSD = 11.0) in nontreated and phorate treated plots, respectively. In plots with no insecticide, all other entries had final TSW incidences lower than those of Georgia Green. In plots with insecticide, lowest ranking final TSW incidence was 11.2 % in C 724-¬19-25, and final incidence in Tifguard, York, and AP-3 were similar. There was no significant reduction in TSW with addition of phorate in those four entries. Addition of phorate resulted in significant reduction of spotted wilt in AT-3085A, Georgia-06G, AP-4, and Florida-07, and in plots treated with phorate, incidence of TSW in those four lines was similar to that in York, Tifguard, C 724-¬19-25, and AP-3. In 2007, only genotype main effects were significant for yield. Across insecticide treatments, yields ranged from 3275 kg/ha in AT 3081R to 4969 kg/ha (LSD = 519 kg/ha) in C 724-¬19-25. Yields of Georgia Green and Georgia 01R were similar to that of AT 3081R, and yields of Florida-07, Tifguard, AP-3, and Georgia-06G were similar to that of C 724-19-25. In 2008, main effects were significant for both TSW incidence and yield, but interaction effects were not. Across genotypes, incidence of spotted wilt was 16.6% and 7.8% (LSD = 2.9) in nontreated and phorate treated plots, respectively. Across insecticide treatments, final incidence of TSW was 26.8, 22.6 and 21.3% in AT-215, Florida Fancy, and Georgia Green, respectively. All other entries had TSW incidence lower (LSD = 6.1 %) than those genotypes. Final incidence of TSW was 6.3% in C 724-19-¬25, and was similar to that in AP-3, Georgia-03L, Florida-07, Georgia Greener, Georgia-06G, Tifguard, AT 3085, and Georgia-07W. Across genotypes, yield was 7316 kg/ha and 7884 kg/ha (LSD = 277) for nontreated and phorate treatments, respectively. Across insecticide treatments, yield ranged from 6232 kg/ha in AT-215 to 8363 kg/ha in Georgia-06G (LSD = 615 kg/ha). Yields of Georgia Green were similar to that of AT-215, and yields of AT 3085A, Florida-07, Tifguard, Georgia¬07W, McCloud, and C724-19-25 were similar to that of Georgia-06G. Yield increase with use of phorate was 1165 kg/ha for AT 3085 and was over 750 kg/ha for AT 215, Georgia Greener, Florida¬07, and Georgia-06G.