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Insect Pests of Grain Sorghum, Soybean and Sunflower Tom A. Royer Oklahoma State University NCIS MPCI & Crop-Hail Sunflower, Soybeans, Cotton & Grain Sorghum.

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Presentation on theme: "Insect Pests of Grain Sorghum, Soybean and Sunflower Tom A. Royer Oklahoma State University NCIS MPCI & Crop-Hail Sunflower, Soybeans, Cotton & Grain Sorghum."— Presentation transcript:

1 Insect Pests of 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 Oklahoma State University 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

3 Oklahoma State University 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.

4 Oklahoma State University 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. Insect Pests of Sunflower

5 Oklahoma State University 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

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

7 Oklahoma State University 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.

8 Oklahoma State University 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.

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

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

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

12 Oklahoma State University 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 Seedling feeders in sorghum

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

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

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

16 Oklahoma State University 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.

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

18 Oklahoma State University 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 Sunflower stem feeders

19 Oklahoma State University Fall ArmywormCorn earworm Grasshopper Soybean defoliators

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

21 Oklahoma State University Grasshoppers Thistle Caterpillar Sunflower Beetle Sunflower defoliators

22 Oklahoma State University Defoliators In Sunflower Nature 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.

23 Oklahoma State University 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”.

24 Oklahoma State University 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”.

25 Oklahoma State University 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

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

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

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

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

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

31 Oklahoma State University 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. Sunflower seed feeders

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

33 Oklahoma State University 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.

34 Oklahoma State University 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.

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


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