MARK ABNEY / TIFTON, GEORGIA
Insects and mites can cause severe economic loss, but not every field will be infested with damaging populations every year. Understanding the risk factors that contribute to pest outbreaks and weekly scouting are the foundations of successful insect management. Below are some of the most common and/ or economically important arthropod pests of peanut, conditions that favor their development, and scouting tips.
Thrips:
•Favorable conditions: Thrips occur in most peanut fields, but early planting, conventional tillage, single row pattern, and no at-plant insecticide increase the risk of injury.
·Scouting Tips: Look for adult and immature thrips in the first three to four weeks after emergence. Immature thrips are usually found in folded terminal leaflets.
Lesser cornstalk borer (LCB).1-
•Favorable conditions: Hot, dry, well drained sandy soils, and open crop canopy
·Scouting Tips: Look for wilted stems and silk tubes, remove plants and check tap root, pods, and stems for feeding injury and larvae. Moths are a good sign of LCB infestation. Plants in a “skip” or at the ends of rows with bare soil around them will usually be attacked first.
Threecornered alfalfa hopper (TCAH).L
•Favorable conditions: TCAH can be found in most fields, but densities tend to be highest when soil moisture is adequate for optimum peanut growth. Populations increase as the summer progresses. ·Scouting Tips: Adults fly when disturbed; they are also easily collected in sweep nets. Nymphs are responsible for much of the injury to peanut, but they are difficult to see. Drop cloth sampling or careful examination of vines is required to find nymphs.
Southern corn rootworm and banded cucumber beetle (Rm.1-
.Favorable conditions: Heavy-textured soils with good moisture increase risk. Larvae cannot survive in dry soil.
·Scouting Tips: RW larvae live entirely below ground. Dig adjacent to peanut rows or remove plants to examine pods for damage and check the soil for larvae.
Potato leatbopper (PLH)J.
•Favorable conditions: PLH is found sporadically in peanut fields every year. Infestations often begin along field margins.
·Scouting Tips: Adults fly when disturbed; nymphs are similar in appearance to adults but cannot fly. Look for hopperburn CV-shaped yellowing of leaflet tips), especially near field edges. Hopperburn will persist after the insects have left the field; determine if infestations are active before making a treatment decision.
V elvetbean caternillar (VBC)J.
•Favorable conditions: VBC does not overwinter in Georgia, and infestations do not typically reach threshold densities until later in the summer.
·Scouting Tips: Scouting for caterpillars is best accomplished by vigorously shaking vines to dislodge the insects onto a drop cloth. Sample three feet of row at ten locations in a typical 4 0 to So acre field. All caterpillars should be identified and counted and their size noted.
Two Spotted Sider Mite (TSSM)J.
•Favorable conditions: TSSM infestations are most likely to develop when conditions are hot and dry. In out-break years, non-irrigated corners of irrigated fields can be severely injured while the irrigated portion of the field has few or no mites. Areas near field margins are usually infested first.
·Scouting Tips: Check field edges. Small patches of yellowing peanuts are an early indication of infestations. At low densities, mites are difficult to see and are usually found on the lower surface of leaves. Early detection is important.
MARK ABNE / UNIVERSITY OF GEORGIA
