Summary of Losses from Insect Damage and Costs of Control in Georgia - 1997

XX. Soybean Insects

R. M. McPherson, R. D. Hudson, and D. C. Jones

Soybeans were harvested from 410,000 acres in 1997, an increase of 20,000 from the previous year. Georgia's average yield in 1997 was 21 bushels per acre, down 5 bushels from the 1996 production. Soybean prices also were down, averaging $6.75 per bushel, making the value of the 1997 crop worth $58 million.*

Stink bugs were the number one pest in Georgia soybeans in 1997. Heaviest infestations were in the southeastern and southern parts of the state. Total losses due to this pest were over $3.1 million in 1997, up substantially from the 1996 levels. Control was good at most locations, but some treatments were applied late, or not at all, in fields that were heavily infested late in the season.

Velvetbean caterpillar losses also were much higher in 1997, costing growers over $2.0 million, making this the number two pest. Caterpillar populations were very high in some locations (especially the southern countries) and caused severe defoliation (60% and higher) if not controlled in a timely manner. Insecticide control was very good for this pest. A dimilin/boron treatment on soybeans during the early pod-forming stage of development was very effective and efficient in these fields with high velvetbean caterpillar populations.

Soybean loopers were the third most costly soybean insect pest in 1997. Economically damaging populations of loopers were primarily associated with late-maturing soybeans. Total losses due to loopers was relatively low, approaching $0.4 million, and was mostly control costs.

Corn earworms and lesser cornstalk borers ranked as the fourth and fifth most important pests on the crop. Corn earworm losses were low in 1997, totalling just over $0.3 million, up a little from 1996. Lesser cornstalk borers losses were also low in 1997, totalling just over $0.2 million, down considerably from the 1996 losses.

All other insect pests accounted for $174,000 in 1997. Most of these losses were due to threecornered alfalfa hoppers, beet armyworms, whitefringed beetles and other beetles. Most of these pests were in localized or isolated areas.

^*Georgia Farm Report. 1998. Volume 98, Number 5.

¹Includes application costs.
²Yield units measured in bushels.
³ Includes the southern green, green and brown stink bugs.
⁴"Others" include threecornered alfalfa hoppers, beet armyworms, whitefringed beetles, and other beetles (bean leaf beetles, spotted cucumber beetles, and banded cucumber beetles).