1. Oklahoma State University Critical Insects and Conservation Tillage in Oklahoma Tom A. Royer Department of Entomology & Plant Pathology Conservation Tillage 101, Enid, OK. February 8, 2006

2. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphids  Army cutworm  White grubs  Wheat curl mite  Hessian fly

3. Oklahoma State University Topics for Discussion General lifecycle Management Tools  Effects of tillage on pest  Cultural Controls Rotations Planting date Resistant varieties  Insecticides

4. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphidsreduced threat  Army cutworm  Hessian fly  White grubs  Wheat curl mite

5. Oklahoma State University 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.

6. Oklahoma State University 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

7. Oklahoma State University 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

8. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphidsreduce threat  Army cutwormreduce threat  Hessian fly  White grubs  Wheat curl mite

9. Oklahoma State University Army Cutworm Lifecycle Moths arrive in fall from mountain ranges, lay eggs in tilled, thin or newly established stands. Feed throughout winter, can tolerate very cold temperatures Become active in early spring, can cause severe damage

10. Oklahoma State University Army Cutworm Management Tools for Army Cutworm Management  Tillage conservation tillage will likely help reduce colonization and survival of army cutworm  Crop rotation Rotation to non-host crops does not directly affect army cutworm  Planting Date Won’t greatly influence army cutworm outbreaks  Resistant varieties Army cutworm resistance is not useful

11. Oklahoma State University Army Cutworm Management Tools for Army Cutworm Management  Insecticides Foliar applications effective tool for active infestations

12. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphidsreduce threat  Army cutwormreduce threat  White grubsincrease threat  Wheat curl mite  Hessian fly

13. Oklahoma State University White Grub Lifecycle May/June beetles arrive in spring, lay eggs in weedy, untilled fields. 1,2, 3-year lifecycles. Grubs feed for one to two years, typically are more of a problem the second year when 3 rd instar grubs

14. Oklahoma State University White Grub Management Tools for White Grub Management  Tillage Conservation tillage will slightly increase colonization and re- colonization of white grubs, especially if fields contain grassy, weedy fallow, and tree stand is nearby (creek bottom)  Crop rotation Rotation to non-host crops can reduce white grub infestations  Planting Date Delayed planting can help with white grub infestations  Resistant varieties No resistance is known

15. Oklahoma State University White Grub Management Tools for White Grub Management  Insecticides Foliar applications are NOT effective tool for active infestations

16. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphidsreduce threat  Army cutwormreduce threat  White grubsincrease threat  Wheat curl miteincrease threat  Hessian fly

17. Oklahoma State University Wheat Curl Mite Lifecycle Adult mites measure 1/100 inches, are white, cigar- shaped, with 4 legs. They can grow from egg to adult in 8 days at optimum temperatures (77 O F) Hosts: wheat, corn, oats, barley and foxtail millet (and jointed goatgrass) Transmit wheat streak mosaic virus

18. Oklahoma State University Wheat Curl Mite Management Tools for Wheat Curl Mite Management  Tillage Conservation tillage will likely increase risk of survival of wheat curl mite, unless volunteer is destroyed at least two weeks before crop is planted  Crop rotation Rotation not a concern, but planting next to other host crops (corn) can serve as a green bridge if corn is late planted.  Planting Date Can influence wheat curl outbreaks; avoid early planting  Resistant varieties Look for resistant/tolerant varieties to wheat streak mosaic

19. Oklahoma State University Wheat Curl Mite Management Tools for Wheat Curl Mite Management  Insecticides Foliar applications are not an effective tool for active infestations

20. Oklahoma State University Topics for Discussion Critical Insects/MitesEffect of Conservation Tillage  Greenbugs and other aphidsreduce threat  Army cutwormreduce threat  White grubsincrease threat  Wheat curl miteincrease threat  Hessian flyincrease threat

21. Oklahoma State University Hessian Fly Lifecycle Adult fly is brown, looks like a small mosquito 1/8 inches. Adults typically 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

22. Oklahoma State University Hessian Fly Lifecycle 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). Wheat at harvest Volunteer wheat Early planted wheat (for grazing) Wheat for grain

23. Oklahoma State University Hessian Fly Management Tools for Hessian fly Management  Tillage conservation tillage will likely allow increased survival of Hessian fly  Crop rotation Rotation to non-host crops can reduce populations  Delayed planting important tool for reducing H. fly infestations, especially in north  Resistant varieties Important, need to know predominant races of H. fly

24. Oklahoma State University Hessian Fly Management Removal of volunteer wheat deprives hatching adults from a food source to lay eggs Plowing old straw to a depth of 4 to 6 inches is a very effective way of reducing over summering Hessian fly Burning straw will reduce, but many pupae drop to soil surface at harvest, so burning is not nearly as effective

25. Oklahoma State University Hessian Fly Management Crop rotation  Wheat is the preferred host for Hessian fly  Use of other crops can reduce the over wintering source of fly pupae  Hessian fly can travel up to a mile from their hatching site

26. Oklahoma State University Hessian Fly Management Variety Resistance:  There are at least 12 Hessian fly biotypes, based upon their susceptibility to identified genes.  A collection of Hessian fly taken from North central OK was screened.  These biotypes can “shift” easily, if a single source of resistance is deployed over a wide area Biotype A: 41% Biotype B: 16% Biotype C: 22% Biotype D: 13% Biotype F: 4% Biotype I: 1% Biotype L: 2% H13 resistance gene, present in Molly, was 100% resistant to the sample.

27. Oklahoma State University Hessian Fly Management Variety Resistance:  There are some hard red winter wheat varieties that have resistance, but the resistance is not put in wheat varieties as a priority. Susceptible varieties:  Custer  Jagger  Jagalene  OK 101 Resistant (Moderate)  Chisholm  Ike  2137  2145

28. Oklahoma State University Hessian Fly Management Tools for Hessian fly Management  Insecticides Seed treatment: effective on fall generations Foliar applications not tested, and variable in results

29. Oklahoma State University Hessian Fly Management (Chemical Control Seed treatments:  They are effective on fall generations, but not on spring  Gaucho and Cruiser are effectifve In the SE U.S., spring applications of Warrior, timed to catch adult emergence has had some limited success, but has not been tested in OK. Kansas greenhouse data:  Gaucho 480 @ 48 g/100 kg seed (1.6 fl oz/cwt) provided 100% control  Cruiser @ 39 g/100 kg (1 fl oz/cwt) provided 92% control Kansas field data:  Gaucho 480 @48 g/100 kg provided 100% control, no control of spring infestation  Cruiser @34 g/100 kg (0.9 fl oz/cwt) provided 100% control in fall, no control of spring infestation

30. NT = No till, T = conv. till C= corn, W=Wheat Oklahoma State University Hessian Fly Management Data Collected from Wheat Fields in Kay County OK 2005 TillageCrop Rotation Plant Date Seed Treatment Plants Infested Tillers Infested NTW/WEarlyNo61%41% NTW/WEYes0% NTW/WENo89%40% TW/WENo22%5% NT Close Close to wheat stubble C/WENo94%51% NT Far ½ mile from stubble CWENo33%10% NTC/WLNo0%

31. Oklahoma State University Critical Insects and Conservation Tillage in Oklahoma Tom A. Royer Department of Entomology & Plant Pathology Conservation Tillage 101, Enid, OK. February 8, 2006