Insect Pests of Grain Sorghum, Soybean and Sunflower

1. Insect Pestsof Grain Sorghum, Soybean and Sunflower Tom A. Royer Oklahoma State University NCIS MPCI & Crop-Hail Sunflower, Soybeans, Cotton & Grain Sorghum School August 23, 2006

2. Insect Pests of Grain Sorghum • There are many potential pests that feed on the foliage and panicle. The results of their activities can cause seedling death, lodging and unfilled seed Oklahoma State University

3. Insect Pests of Soybean • In the past, there were few pests that caused significant damage to soybean. In resent years, several pests have mad their presence felt throughout the soybean growing region. Oklahoma State University

4. Insect Pests of Sunflower • Sunflowers are native to North America, therefore we have a wide variety of insect pests and their associated natural enemies. • Damage occurs to the seedling, foliage, stalk, developing head,and seed. Oklahoma State University

5. Insect Pests of Grain Sorghum, Soybean and Sunflower • There are numerous pests of these crops, but I will focus on the pests that can cause damage symptoms that resemble hail damage Oklahoma State University

6. Insect Pests of Grain Sorghum, Soybean and Sunflower • Seed/seedling feeders • Stem/stalk feeders • Foliage feeders • Seed feeders Oklahoma State University

7. Seed/seedling Feeders in Sorghum, Soybean and Sunflower • Wireworms would be a problem for stand establishment in cool soils that delay rapid early growth (early-planted crop). Feed on germinating seed and newly emerged seedlings. Oklahoma State University

8. Seed/seedling Feeders in Sorghum, Soybean and Sunflower • Seed corn maggots are a problem in cool soils with higher organic matter. (early-planted crop). Feed on germinating seed. Oklahoma State University

9. Seedling feeders in Sorghum, Soybean and Sunflower • Cutworms: several species attack these crops • Black cutworm • Dingy cutworm • Darksided cutworm • Sandhill cutworm • Many others Oklahoma State University

10. Seedling feeders in Sorghum, Soybean and Sunflower • Look for stand loss • Look for weak, slow • growing plants • Slow growing conditions (cool weather) favors cutworm damage • Follow-up with presence of insect Oklahoma State University

11. Seedling feeders in sorghum • Chinch bugs: • Adults: 1/6 inches, black body and white wing covers • Nymphs: reddish-brown with band of white across back • 40-day lifecycle Oklahoma State University

12. Seedling feeders in sorghum Feed in groups at base of plant, may often feed below soil line, 7-10 bugs can stunt small seedlings Migrate from wheat, often see most severe injury at edge of field Oklahoma State University

13. Sorghum stalk feeders • Southwestern Corn Borer: • More of a pest of corn, it occasionally attacks sorghum • Hollows out stem, causing lodging. Not a major pest of sorghum Oklahoma State University

14. Soybean stem feeders • Three-cornered alfalfa hopper • Piercing-sucking mouthparts. It feeds and circles around the stem effectively girdling it. Oklahoma State University

15. Soybean stem feeders • Soybean Stem Borer • Longhorned beetle. • Larva is damaging stage, tunneling in stem. They overwinter below girdle, in stem. Oklahoma State University

16. Soybean stem feeders • Soybean Stem Borer • Longhorned beetle. • Larva is damaging stage, tunneling in petioles and stems. They overwinter below girdle, in stem. • They also feed on giant ragweed, cocklebur • Larvae tunnel downward, causes lodging on mature plants • Damage often remains unnoticed because it occurs so late. Oklahoma State University

17. Sunflower stem feeders • Stem weevils: • Sunflower stem weevil (Cylindrocopturus adspersus) • Black stem weevil (Apion occidentale) • Dectes stem larva Oklahoma State University

18. Sunflower stem feeders • Larvae feed on stem cortex, moving down stem as they mature • Cause weakened stalks, particularly a problem when harvest is delayed. • Can help transmit Phoma stem rot Oklahoma State University

19. Soybean defoliators Fall Armyworm Corn earworm Grasshopper Oklahoma State University

20. Sorghum defoliators • Fall armyworm/corn earworm: • Damages both whorl and panicle, but most often seen in whorl • Control in whorl is generally not profitable Oklahoma State University

21. Sunflower defoliators Grasshoppers Thistle Caterpillar Sunflower Beetle Oklahoma State University

22. Defoliators In SunflowerNature of Damage • Pests that feed on foliage. Chewing mouthparts. • Damage leaves, causing indirect damage to sunflower yield • Reduce photosynthesis, slow growth, shift plant’s emphasis to compensating for foliage loss • Probably information that would help with assessing yield loss from hail. Oklahoma State University

23. Sorghum seed feeders • Corn earworm/Fall armyworm: • Damages both whorl and panicle • When feeding on head, they will eat seed until it passes “soft dough”. Oklahoma State University

24. Corn earworm/Fall armyworm: Damages both whorl and panicle When feeding on head, they will eat seed until it passes “soft dough”. Sorghum seed feeders Oklahoma State University

25. Sorghum seed feeders • Sorghum midge: • Larvae feed for 7 - 9 days, total lifecycle is about 2 weeks • Larvae completely destroy the seed • Adults emerge, leaving white pupal case dangling from floret and can re-infest late blooming suckers or fields. Heads are “blasted”. • Johnson grass is alternate host: do not overwinter well in Oklahoma Oklahoma State University

26. Soybean seed feeders • Corn earworm • Also known as podworm, feeds on foliage and maturing pods • Occurs in mid to late season • Can severely injure pods Oklahoma State University

27. Soybean seed feeders • Bean leaf beetle • Overwinters as adult: 1-3 generations • Feeds on foliage and been pods. • Most damaging to pods. Oklahoma State University

28. Soybean seed feeders • Stinkbugs • Typical “stinkbug” shape, green about 7/8 to 1 inch long • Piercing-sucking mouthparts • Lay barrel-shaped eggs, often coppery colored Oklahoma State University

29. Soybean seed feeders • Piercing-sucking mouthparts inserted into developing pods • Cause shriveled, misshapen, and discolored seeds that are lower in weight Oklahoma State University

30. Sunflower seed feeders • Head clipper weevils chew holes around the stem, effectively girdling it. It breaks over, and could be mistaken for hail injury. Oklahoma State University

31. Sunflower seed feeders • Sunflower midge is a pest, usually in the northern plains, that causes the head grow in a distorted way (folding, convoluted). It could mimic hail damage under the right circumstances. Oklahoma State University

32. Grasshoppers in Soybeans • Grasshoppers will feed on pods, causing chewing injury. This also allows entry for seed disease-causing organisms. Oklahoma State University

33. Grasshoppers in Sorghum • Grasshoppers will feed on developing seed. • Grasshoppers may be more of a problem in conservation tillage because they may be laying eggs in fields which won’t be disturbed by tillage. Eggs may survive better, hatch slightly later, and grasshoppers may be more uniformly distributed in the field. Oklahoma State University

34. Grasshoppers in Sunflowers • Grasshoppers are a sporadic problem in Oklahoma, because they can build up in large numbers and caused physical damage to the leaves and seed. Oklahoma State University

35. Insect Pestsof Grain Sorghum, Soybean and Sunflower Tom A. Royer Oklahoma State University NCIS MPCI & Crop-Hail Sunflower, Soybeans, Cotton & Grain Sorghum School August 23, 2006