Chad Lee © 2006 University of Kentucky 1

Wheat: Weeds & Insects

Presentation by: Chad Lee, Grain Crops Extension Specialist

University of Kentucky

Chad Lee © 2006 University of Kentucky 2

Most of the information comes from:

ID-125: A Comprehensive Guide to Wheat Management in Kentucky

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Objectives

• Weed management options• Insect management options

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Weed Management

• Burndown Herbicides (no-till)– Gramoxone

• contact, acts quickly, spray coverage critical

– Glyphosate• systemic, acts slowly, coverage less critical

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Weed Management

• Fall and Spring Applications– Buctril

• mustards, field pennycress

– Harmony Extra XP• common chickweed, curly dock, henbit,

mustards, pennycress, shepherd’s-purse, wild garlic

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Weed Management

• Fall or Spring Application• Hoelon

– annual ryegrass

• Osprey– annual ryegrass

http://forages.oregonstate.edu/

Apply one application only, prior to joint (Feekes 6)

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Weed Management

• Fall and Spring Applications– Banvel

• shepherd’s-purse, garlic• Only on tillered, established stands

– 2,4-D• mustards, pennycress, shepherd’s-purse• Only on tillered, established stands

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Weed Management

• Fall and Spring Applications– Sencor

• common chickweed, henbit, mustards, pennycress, shepherd’s-purse

• Only on wheat varieties recommended on Sencor label

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Weed Management

• Preharvest Treatments– Glyphosate– 2,4-D

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Insect ManagementOct Nov Dec Jan Feb Mar Apr May Jun

Aphids a,b

Armyworm

Fall Armywormb

Cereal Leaf Beetle

Hessian Flyb

Figure 8-1. Small Grain Insect Scouting Calendar

The red portions indicate periods of possible economic populations.a Early planting and warm fall weather increase potential for aphids and BYDV.b Wheat planted before October 15 is subject to attack by this insect.

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Insect Management: Aphids

• Transmits Barley Yellow Dwarf Virus• Scout in Fall: until temps fall below

45 ºF.• Scout in Spring: once temps rise

above 45 ºF.

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Insect Management: Aphids

• Scouting heads prior to Feekes 10.1

• Scout entire plant, esp. near soil line prior to heading.

• Count aphids per plant in 1-ft row.

• Repeat two more times across the field.

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Insect Management: Aphids

Number of aphids per foot of wheat row required to support an insecticide application for management of BYD.

Crop age (post emergence)

Aphids/Foot of Row

30 days 3

30 to 60 days 6

More than 60 days 10

http://www.uky.edu/Agriculture/PAT/recs/crop/recgrn/smgaph2.htm

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Insect Management: Aphids

• Scouting heads after Feekes 10.1• Count aphids per head in 1-ft row.• Repeat two more times across the field.

Rating Number of Aphids

0 – none none

1 – slight < 50

2 – moderate 50 – 100

3 – severe > 100

Threshold Level

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Insect Management: Aphids

http://www.uky.edu/Agriculture/PAT/recs/crop/recgrn/smgaph2.htm

2.56 to 3.84 fl oz 30 (Grain and hay)Foliar Insecticide Rate per Acre Days to Harvest

Di-Syston 8E (Disulfoton)

4 to 12 fl oz 30 (Do not graze or cut for

forage)

Lannate 90 SP (methomyl)

1/4 to 1/2 lb7 (Grain)

10 (Grazing or feeding)

Malathion 57% EC (Malathion)

1 1/2 to 2 pts 7

Mustang Max(Wheat only)

3.2 to 4.0 fl. oz. 14 (grain, forage & hay)

Penncap-M(Methyl parathion)

2 to 3 pts 15 (Harvest or grazing)

Warrior (Lambda-cyhalothrin)

2.56 to 3.84 fl oz 30 (Grain and hay)

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Insect Management: Hessian Fly

• Larvae are found between leaf sheath and stalk at base of plant.

• Scout once after first frost in fall and from early spring until June.

• Thin, stunted, chlorotic patches in the field.

• No rescue treatment.

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