Issue link: http://winesandvines.uberflip.com/i/90739
WineEast Grapegrowing A single grape berry moth larva infests two berries (left), while a whole cluster (right) is under attack from several immature GBM. activity was recorded, which indicated that cluster phenology could also be use- ful as an indicator of when to apply the first insecticide. Grapegrowers in some of the hottest counties in the Gulf Coast region of Texas have since adapted to using a combina- tion of phenological cues and pheromone trap catch data to time the first insecti- cide application for the season and have gone from three to four GBM insecticide treatments per year to just one or two. Growers are encouraged to rotate insecticide products with those having a different mode of action group as noted by the Insecticide Resistance Action Committee (IRAC.)6 Insecticide use for control of GBM would perhaps be much less than is required in cooler climates. In Texas, growers are encouraged to continue using pheromone traps in conjunction with phenological cues such as berry size to determine the best time to apply treatments. Degree-day accumulation may serve as an additional 110 WINES & VINES NOVEMBER 2012 Future strategies for GBM control Several new products are available for the control of grape berry moth in vine- yards. As history has shown, repeated use of one chemical can lead to possible resistance development by the pest. Researchers in New York and Pennsyl- vania discovered this phenomenon with repeated application of carbaryl insecti- cide.1