Presentation on theme: "Soybean Insect Pest Management - 2009 Phillip Roberts and Bob McPherson University of Georgia."— Presentation transcript:
Soybean Insect Pest Management - 2009 Phillip Roberts and Bob McPherson University of Georgia
Soybean IPM Scouts / Consultants Offers great value to growers. Must know insect pest populations and species makeup to make Good Decisions. Economic Thresholds Insecticide Selection Timing of Applications Evaluation of Sprays Early Detection of Potential Problems Insects/Weeds/Fertility/Diseases/etc.
Lesser Cornstalk Borer Understand Risk Hot and Dry Late planting Burnt residue Preventive treatment Rescue (POST) treatment Difficult to control established infestations
Common Pests of Soybeans Foliage Feeders
Larvae have 3 pair of abdominal prolegs Same looping movement as Soybean loopers Very active when disturbed Often attacked by a number of parasites, predators, and diseases Generally not treated for alone Common Pests of Soybeans (Green Clover Worm)
Larvae have 4 pair of abdominal prolegs Usually very pronounced white line but color may vary Very active when disturbed Voracious feeders usually starting in the top of the canopy and moving downward May feed on petioles cutting pods to the ground Migratory Common Pests of Soybeans (Velvetbean Caterpillar)
Larvae have 2 pair of abdominal prolegs Larvae are tapered toward the head Eggs deposited singularly, usually on the bottom side of the leaf surface Eggs similar to corn earworm but somewhat flattened Often attacked by pathogens Migratory Common Pests of Soybeans (Soybean Looper)
Foliage Feeder Thresholds for Soybeans Green Cloverworm Velvetbean Caterpillar Soybean Looper Avg. / 25 Sweeps 6040 20 sm. or 15 lg. Avg. / Row Foot 1088 sm. or 6 lg. 30% Prior to Full BloomFull Bloom-Mid Pod FillAfter Full Pod Fill 25%15%
Will not provide consistent control of VBC Soybean Insecticide Trial Midville 2007 Pyrethroid Susceptibility?
Dimilin / Boron Apply at R2-R3 Stage Dimilin 2 ozs/acre Controls GCW and VBC, suppresses SBL Long Residual Boron 0.25 lbs B/acre R2-Full bloom – an open flower at one of the two uppermost nodes on the main stem with a fully developed leaf. R3-Beginning pod growth – pod 3/16 inch long at one of the four uppermost nodes on the main stem with a fully developed leaf.
Soybean Insecticide Trial Midville 2007
IGR is slower acting.
Soybean Insecticide Trial Stripling Irrigation Research Park 2007
Common Pest of Soybeans (Stink bug Identification) Green Southern Green / Green Stink bugBrown Stink bug Southern Green Photos by Herb Pilcher, www.ipmimages.org
Piezodorus guildinii Red Banded Stink Bug Major problem in Louisiana soybeans, present in Georgia (can be difficult to control).
Egg to Adult 35-40 days (adults may live several weeks) Stink Bug Life Cycle Southern Green Stink Bug
Feeds primarily on fruiting structures and meristematic tissues. Injects enzymes to dissolve plant tissues. Physical destruction of seed/tissues. Introduces or allows entry (wounds) of some pathogens and decay organisms. Stink Bug Feeding
Multiple Cultivated and Wild Hosts Landscape/Farmscape (Strong Movers) Move from one host to another throughout the growing season (host suitability).
A 24-acre commercial cotton field was sampled weekly at a density of 20 bolls/acre Developing bolls were dissected weekly and examined for internal damage Spatial maps were created to visualize damage 9 Sept 07 31 Aug 07 In-Field Distribution Stink Bugs (Clumped, Edge Effects)
Common Pest of Soybeans (Stink bug Damage) Most damaging during pod fill Damage results in unfilled, malformed or shrunken pods Aborted pods
Bloom-Mid Pod FillMid Pod Fill-Maturity Avg. / Row Foot0.331 Avg. / 25 Sweeps36 *Seed bean threshold, 1 stink bug per 6 row feet. Stink Bug Thresholds for Soybeans Trap Cropping is an effective management strategy.
Insecticide Susceptibility Southern green, green, and brown stink bugs are the primary stink bugs in the southeast. Species makeup varies by location, crop, and in time. Pyrethroids provide good control of southern green and green but only fair control of brown stink bugs (high rates improve control). OPs provide good control of southern green, green, and brown.