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

XIV. Pasture and Forage Insects

G. D. Buntin, R. D. Hudson, W. G. Hudson, and W. A. Gardner

Acreages of forage and pasture crops have declined in recent years to about 1.3 million acres of grass pastures and an additional 600,000 acres of grass hay pastures in 1997. Although losses per acre generally are low and treatment thresholds are large, this extensive acreage produces large combined losses for forage and pasture insects in Georgia. Losses are greater for hay than pastures because hay crops have greater yield potential and market value.

Rainfall was below normal which reduced forage yields later in the summer. The number one pest of perennial grass forages, primarily bermudagrass was mole crickets. Mole crickets damaged green pastures in southern Georgia especially in the Flatwoods region often requiring replanting. Mole cricket damage has declined in some fields in four counties where the parasitic nematode Steinernema scapterisci has been released. The white grub complex, mostly Phyllophaga spp., Cyclocephala sp. and Green June beetle larvae caused damage in some fields, with damage levels being somewhat greater than the previous year. Green June beetle larvae were particularly damaging to fescue pastures in northern Georgia. Fall armyworm, twolined spittlebug, and leafhoppers/planthoppers caused damage in some fields.

Alfalfa acreage in Georgia was about 30,000 acres on 1997. The alfalfa weevil was the number one pest of alfalfa with most fields being treated to control this insect. Dry weather induced damage by the potato leafhopper in some fields.

¹ Application cost not included.

NOTE: Hay crops consisted of 600,000 acres of grasses (hybrid bermudagrass 75%; tall fescue 20%; and other grasses 5%), with an average yield of 2.5 tons per acre. Alfalfa acreage was 30,000 acres with an average yield of 3.5 tons per acre. Grass and clover hay were valued at $60 per ton and alfalfa hay was worth $120 per ton. Permanent pasture consisted of 500,000 acres of bahiagrass and 800,000 acres of fescue, fescue/clover mixtures, and fescue/common bermudagrass. Average yield was estimated at 1.0 ton per acre with a value of $55 per ton. An additional 400,000 acres of temporary pasture (mostly small grains and sorghum) was grazed. There were 150,000 acres of sorghum, and millet silage was harvested. Silage and temporary pasture crops were included as pasture grasses (Troy Johnson, Extension Agronomist, Athens, GA, personal communications).