From Boll Weevil to Plant Bugs: A Review of the Major Cotton Insects in the Midsouth

1. From Boll Weevil to Plant Bugs: A Review of the Major Cotton Insects in the Midsouth Why Plant Bugs are Now the # 1 Pest of Cotton in the Midsouth U.S. Gus Lorenz – Professor, Extension Entomologist

2. Mid-south Plant Bug Crew Gus Lorenz, Scott Akin, and Glenn Studebaker – University of Arkansas Scott Stewart – University of Tennessee Angus Catchot, Jeff Gore, Don Cook, Fred Musser – Mississippi State University Roger Leonard – Louisiana State University Kelly Tindall – University of Missouri Ryan Jackson, Clint Allen -- USDA-ARS Stoneville

3. With great appreciation Presents 2011 Friends of Southern IPM Pulling Together Award to The Mid-South Entomologist Working Group University of Arkansas Mississippi State University University of Tennessee Louisiana State University University of Missouri USDA-ARS, Stoneville, Mississippi “Progress occurs when courageous, skillful leaders seize the opportunity to change things for the better.” Harry Truman

4. Reasons for “The Bug Problem” • Broad-spectrum insecticide use has declined and “coincidental” control has been reduced • Boll Weevil Eradication • Selective insecticides • Bt cotton (“in-plant” selective insecticide) • “Soft” foliar insecticides • “Second-generation” Bt cotton • Decreasing commodity price (raising EIL) • Increasing costs of inputs (raising EIL) • Weather impacts • Warmer winters in recent yrs (higher success in overwintering) • Impact on winter weed vegetation • Early-maturing soybean, corn, CRP land: “nurseries” • Insecticide resistance development and control difficulties

5. Boll Weevil Formerly, the Primary Economic Pest of Cotton

6. Why Boll Weevil Eradication Program Was Needed The boll weevil was considered the key pest in cotton production because early season insecticide use to control weevils also eliminated many beneficial insects. As early-season boll weevil spraying was eliminated, we felt beneficial insects could increase in number and become effective in controlling other cotton pests, like worms and aphids. • We told growers that in eradicated areas we can: • Delay their initial spray operations, • Reduce pesticide rates, • Use alternative pesticides or genetically engineered cotton varieties, • Or lengthen the intervals between sprays to reduce their operating costs while controlling any remaining cotton pests. We weren’t thinking about plant bugs….

7. Dark Red Shows Most Intense U.S. Cotton Production Counties Implies Areas With Production Advantage

9. Arkansas Boll Weevil Eradication Program Light blue = SW Zone Red = SE Zone Yellow = Central Zone Dark Blue = NE Ridge Zone Green = NE Delta Zone It was/is our belief that: Arkansas production could not continue and compete globally without eradication of the Boll Weevil. This is also true of other cotton producing states.

10. Arkansas Boll Weevil Eradication Program • The Boll Weevil Eradication federal-state-grower cost share program is increasing AR cotton growers competitive position due to • Increased yields • by protecting the plant and allowing the plant to reach its full yield potential • by allowing the plant to achieve uniform maturity, which aids in growth, defoliation, harvesting and ginning • Improved quality • Reduced costs • from reduced primary and secondary pest insect applications and related costs

11. Arkansas Boll Weevil Eradication Program • The Boll Weevil Eradication federal-state-grower cost share program • Is a plus for the environment due • to reduced insecticide use and increased activity of beneficial insects • The long-term environmental benefits that come from eradicating the boll weevil are significant. • - After the boll weevil is eradicated from an area, the need for insecticides is significantly reduced, and in many areas nearly eliminated. • - Cotton growers experience a 40 to 90 percent reduction in their overall use of insecticides. • - A weevil-free environment allows growers to rely less on insecticides and to make full use of beneficial insects in developing their long-term pest management strategies.

12. Midsouth Cotton Production and The Boll Weevil Eradication Program…What We Wanted/ Expected vs What We Got

13. Bollworm/ Budworm Complex • Before development of transgenics were very difficult and costly to control • Transgenics very effective for budworm, not as good for bollworm • Only recently replaced by plant bug as the number • one pest of cotton

14. Economic Impact of Helicoverpa zea In soybeans, an average of one larvae per row foot can reduce yields by approximately 1.9 bushels per acre. Annual corn yield losses range from 5-7 % for field corn and 10-15 % for corn canned for human consumption. Corn Earworm Soybean Podworm Sorghum Headworm Cotton Bollworm An average of one larva per grain sorghum seed head can reduce yields by 5 percent and two larvae per seed head can cause 9-10 % yield loss. Inthe US, an average of 223, 293 bales of cotton is lost to the bollworm/budworm larvae each year.

16. Bt Cotton • Bollgard • Insertion of gene from Bacillus thuringiensisthat encodes for expression of Cry1Ac toxin by plant • Planted on 70-85% of acreage in Arkansas • Excellent control of tobacco budworm (99.9%) • Good control of bollworms prior to bloom • 65% bollworm control in blooming cotton (variable) • Some suppression of armyworms, • but little help with soybean looper

17. Bollworm Control with Bollgard: Is it as good as it used to be?? • In 1997 we estimated 1-2 applications/ year on Bt • In 2002, SE AR averaged about 3 applications • In 2003, some growers sprayed as many as 6X • 2004 low worm numbers • 2005 pyrethroid applications back up • What’s up?? 2005 Comments on Bollgard Efficacy Bollgard II Acreage begins to increase

18. Second Generation Bt Cottons • Better control of lepidopteran pests • Reduce the chance of developing tobacco budworm resistance to Bt cotton • Bollgard II (Monsanto) • Cry 1Ac and Cry 2Ab (endotoxins) • WideStrike (DowAgrosciences) • Cry1Ac and Cry1F (endotoxins) Further reduced applications that coincidentally controlled plant bugs

19. Thrips Widestrike Conventional Bollgard Bollgard II

20. Gus Lorenz (University of Arkansas, 2004) WideStrike vs. Bollworms PHY 410 R Border Not Treated for Bollworms PHY 470 WR PHY 410 R PHY 410 R PHY 470 WR PHY 470 WR Untreated Untreated Treated 3X Treated 2 X Treated 1X -

22. Factors That Influence Pest Populations • Landscape Diversity • Cultivated Crops • Wild Hosts • Proximity to each other • Planting Date and Tillage Practices • Pest Management Practices Across the Landscape • What you do in one crop can influence the other • Resistance • Traits • Pesticide Usage • Environment- Weather

23. Changes in Mid-South Cotton Acreage Year/State Total Planted Cotton Acres % Reduction From 2006 2009 MS/LA/AR/TN 1,344,344 63% 2008 MS/LA/AR/TN 1,595,611 56% 2007 MS/LA/AR/TN 2,341,000 35% 2006 MS/LS/AR/TN 3,596,000

25. Changes in Pest Status • While the shift to reduced tillage or no-till has been positive for growers by decreasing production costs and improving profits it has created some pest control challenges • As we’ve discovered timing of burndowns and efficacy of treat- ments can make a big difference on insect populations

26. Wild Hosts for TPB • Sampling conducted by the USDA researchers has shown tarnished plant bugs can be found on more than 350 species of wild host plants. In early spring, this can include buttercup, cutleaf evening primrose, butterweed, annual fleabane, sourdock, vetch, crimson clover, henbit

27. Landscape Effects with TPB

28. Reasons for “The Bug Problem” • Broad-spectrum insecticide use has declined and “coincidental” control has been reduced • Boll Weevil Eradication • Selective insecticides • Bt cotton (“in-plant” selective insecticide) • “Soft” foliar insecticides • “Second-generation” Bt cotton • Decreasing commodity price (raising EIL) • Increasing costs of inputs (raising EIL) • Weather impacts • Warmer winters in recent yrs (higher success in overwintering) • Precipitation variation • Early-maturing soybean, corn, CRP land: “nurseries” • Insecticide resistance development and control difficulties

29. What Does The Future Hold ??????

30. What We (Entomologists) Know • The bug problem is real and will likely persist or become pronounced…..stink bugs • We know the efficacies of current insecticides and how/when to use them effectively • We recognize research-based treatment thresholds are the best available guidelines for protecting yield and fiber quality • We must not rely on insecticides alone to control these pests • We need new MOA insecticides

31. Thank You

32. Entomology Crew- Lonoke 2010