Insect Management and Conservation Tillage in Oklahoma Kristopher Giles & Tom Royer Department of Entomology & Plant Pathology
Topics for Discussion Critical Insects/Mites Effect of Conservation Tillage Greenbugs and other aphids Army cutworm White grubs Wheat curl mite Hessian fly
Topics for Discussion Critical Insects/Mites Effect of Conservation Tillage Greenbugs and other aphids reduced threat Army cutworm reduced threat White grubs increased threat Wheat curl mite increased threat Hessian fly increased threat
Topics for Discussion General lifecycle Management Tools Effects of tillage on pest Cultural Controls Rotations Planting date Resistant varieties Insecticides
Greenbug Lifecycle Winged adults move into field in fall Females produce live young soon after becoming adults, produce 35 young in one week at optimal temperatures Feeding damage visible, and can cause substantial yield loss.
Greenbug Management Tools for Greenbug Management Tillage conservation tillage will likely help reduce colonization and survival of greenbug Crop rotation Rotation to non-host crops does not directly affect greenbugs Planting Date Has some influence on greenbug outbreaks, limits fall window of migration, however mild falls can open window. Resistant varieties Greenbug resistance is available
Greenbug Management Tools for Greenbug Management Insecticides Seed treatment: effective on fall generations Foliar applications effective tool for active infestations Need to determine applications based upon wasp activity
Aphid and Parasitoid Binomial Sequential Sampling Glance n Go Sampling with Parasitoids http://www.ento.okstate.edu/gbweb/
Aphid and Parasitoid Binomial Sequential Sampling Glance n Go Sampling with Parasitoids
Topics for Discussion Critical Insects/Mites Effect of Conservation Tillage Greenbugs and other aphids reduced threat Army cutworm reduced threat White grubs increased threat Wheat curl mite increased threat Hessian fly increased threat
Hessian Fly Lifecycle Adult fly is brown, looks like a small mosquito 1/8 inches. Adults live for about 3 days Mated females can begin to lay eggs about 1 hour after mating and lay about 200 eggs Larvae feed on stems under leaf sheath, cause stunting or lodging
Hessian Fly Lifecycle Volunteer wheat Wheat for grain Wheat at harvest Early planted wheat (for grazing) Over summering generation infests wheat in fall One to 3 generations from fall to harvest (major one in March) Emergence is often triggered by favorable temperatures (45 to 50 degrees, and after a rain event).
Hessian Fly Management Tools for Hessian fly Management Volunteer Wheat: Removal of volunteer wheat deprives adults from a food source to lay eggs Tillage conservation tillage will allow increased survival of Hessian fly Plowing old straw to 4 to 6 inches is very effective Crop rotation Rotation to non-host crops can reduce populations Delayed planting important tool for reducing H. fly infestations, in north Resistant varieties Important, need to know predominant races of H. fly
Hessian Fly Management Variety Resistance: There are at least 12 Hessian fly biotypes, based upon their susceptibility to identified genes. Primarily Biotypes A, B, C, D, Gp These biotypes can shift easily, if a single source of resistance is deployed over a wide area
Hessian Fly Management Variety Resistance: Resistant Duster* Partially Resistant Chisholm* Ike 2174 2145 Centerfield* OK102 OKfield Susceptible varieties: Custer Jagger Jagalene OK 101 Endurance Deliver 2137 Overley OK Bullet TAM
Hessian Fly Management Tools for Hessian fly Management Insecticides Seed treatment: effective on fall generations Foliar applications not tested, and variable in results SE U.S., spring applications of Warrior timed to catch adult emergence limited success not tested in OK
Hessian Fly Management (Chemical Control Seed treatments: Gaucho and Cruiser are effective on fall generations, but not on spring Kansas field data: Gaucho 480 @48 g/100 kg provided 100% control, no control of spring infestation Testing in OK Cruiser @34 g/100 kg (0.9 fl oz/cwt) provided 100% control in fall, no control of spring infestation
Hessian Fly Management Burning straw will partially reduce HF, but many pupae drop to soil surface at harvest and are hard to kill
Topics for Discussion Critical Insects/Mites Effect of Conservation Tillage Greenbugs and other aphids reduced threat Army cutworm reduced threat White grubs increased threat Wheat curl mite increased threat Hessian fly increased threat
Topics for Discussion Critical Insects/Mites Effect of Conservation Tillage White grubs increased threat Rotation and delayed planting reduce HF Wheat curl mite increased threat Destroy Volunteer Delay Planting Varieties resistant/tolerant to wheat streak mosaic
Insect Management and Conservation Tillage in Oklahoma Kristopher Giles & Tom Royer Department of Entomology & Plant Pathology
Army Cutworm
White Grub Lifecycle
Wheat Curl Mite Lifecycle