winter wheat grasshopper control 4 wks

Subject: winter wheat grasshopper control 4 wks From: "Blodgett, Sue" <blodgett@montana.edu> Date: 10/08/2004 To: <AgEnto@listserv.montana.edu>, "William T. Lanier" <wlanier@montana.edu>, "Tharp, Cecil" <ctharp@montana.edu>, <rscott@gustafson.com> ------_=_NextPart_001_01C4AD7D.7763C996 boundary="----_=_NextPart_002_01C4AD7D.7763C996" ------_=_NextPart_002_01C4AD7D.7763C996 charset="us-ascii" Early seeded winter wheat is more vulnerable to damage by grasshopper than later plantings because the plants emerge while adult grasshoppers are still actively feeding. Seedling plants are quite vulnerable to insect damage and plants may be killed if damage is severe. Increased grasshopper pressure also may occur after a light fall frost that kills broadleaf weeds, such as sunflowers, in areas adjacent to winter wheat. Grasshoppers losing this forage source may move quickly into winter wheat and cause damage. However, grasshopper mortality increases through the fall as nighttime temperatures decline. A heavy frost will reduce or eliminate grasshopper numbers.=20 =20 Thresholds found in the High Plains IPM Guide=20 http://highplainsipm.org/HpIPMSearch/Docs/GrasshopperGuide-Cropland.htm should be lowered for fall grasshopper control in winter wheat. Adult grasshoppers can consume a great deal of plant material in a short time and seedling plants are vulnerable as they emerge. Light (11-20 hoppers/sq yd) to moderate (20-40 hoppers / sq yd) grasshopper populations in the field and/or borders can cause stand loss along borders. Timing of border treatments is critical for optimum grasshopper control. The best time to spray the borders is just before the wheat emerges. If the application is made too early, there will be no residual insecticide activity in the borders when the wheat emerges and grasshopper populations may build back too quickly. If it is applied too late, some of the earliest emerging wheat may already be damaged. In most years, border treatments either of the crop border and/or of the area surrounding the crop are adequate to control the grasshopper problem. A border treatment of 150 feet should be adequate depending on the size of the grasshopper source area, but narrower border treatments also provide some benefit.=20 =20 =20 Seed treatments are also effective. We are looking at some of the seed treatment products including Cruiser, Pancho and Gaucho at both low and high rates on grasshopper control in winter wheat at the Central Ag Research Center. You'll be seeing results of this trial during winter meetings. =20 =20 =20 Sue Blodgett, Assoc Prof & IPM Coordinator Dept Entomology Montana State University Bozeman, MT 59717 Phone (406) 994-2402 Fax 994-6029=20 blodgett@montana.edu =20 ------_=_NextPart_002_01C4AD7D.7763C996 charset="us-ascii"

Early seeded winter wheat is more vulnerable to damage by grasshopp= er than later plantings because the plants emerge while adult grasshoppers are still actively feeding. Seedling plants are quite vulnerable to insect dama= ge and plants may be killed if damage is severe. Increased grasshopper p= ressure also may occur after a light fall frost that kills broadleaf weeds, such as sunflowers, in areas adjacent to winter wheat. Grasshoppers losing this for= age source may move quickly into winter wheat and cause damage. However, grasshopper mortality increases through the fall as nighttime temperatures decline. A heavy frost will reduce or eliminate grasshopper numbers. =

Thresholds found in the High Plains IPM Guide http://highplainsipm.org/HpIPMSearch/Docs/GrasshopperGuide-Cropland.h= tm should be lowered for fall grasshopper control in winter wheat. Adult grasshoppers can consume a great deal of plant material in a short time and seedling plants are vulnerable as they emerge. Light (11-20 hoppers/s= q yd) to moderate (20-40 hoppers / sq yd) grasshopper populations in the field and/or borders can cause stand loss along borders. Timing of border treatments is critical for optimum grasshopper control. The best time to spray the borders is just before the wheat emerges.= If the application is made too early, there will be no residual insecticide activity in the borders when the wheat emerges and grasshopper populations = may build back too quickly. If it is applied too late, some of the earliest emerging wheat may already be damaged. In most years, border treatmen= ts either of the crop border and/or of the area surrounding the crop are adequate to control the grasshopper problem. A border treatment of 150 feet should be adequate depending on the size of the grasshopper source area, but narrower border treatments also provide some benefit.

Seed treatments are also effective. We are looking at some of= the seed treatment products including Cruiser, Pancho and Gaucho at both low and high rates on grasshopper control in winter wheat at the Central Ag Research Center. You’ll be seeing results of this trial during win= ter meetings.

Sue Blodgett, Assoc= Prof & IPM Coordinator

Dept Entomology

= Montana State University

Bozeman, MT 59717

Phone (406) 994-240= 2 Fax 994-6029

blodgett@montana.ed= u

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