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NY Weekly Field Crop Pest Report, 2005

September 16, 2005 Volume 4 Number 22

1. View from the Field

2. Fall Weed Management in Winter Wheat

3. Do weeds indicated what insect pest may infest a corn field next year?

4. Soybean Aphid: Fall Update

5. Growing Degree Days in NYS

6. Clipboard Checklist

7. Contact Information

View From the Field

Ken Wise

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This is the last NYS Weekly Field Crops Pest Report for this season. I hope it was useful for your extension programming. We will follow-up with an evaluation survey soon. We look forward to your feedback. It will be very helpful to us when we prepare the pest report for the next season to have your suggestions.

Fall Weed Management in Winter Wheat

Julie Stavisky, NYS IPM

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Weed maps and records from field observations should be reviewed now as wheat planting is getting underway. The most important weed threats in the fall are the winter annuals that establish in the fall as wheat seedlings emerge and begin to grow. Winter annuals include chickweed, purple deadnettle, shepherd’s purse, henbit, and corn chamomile. The weeds and wheat are actively growing on warm fall days, and they compete for nutrients and water. Severe weed infestations can interfere with the wheat’s ability to establish a healthy stand in the fall.

Corn chamomile is especially difficult to control in the spring, but can be controlled with a fall herbicide application when rosettes are still very small. For more information, please visit the Weed Control in Small Grains section of the 2005 Cornell Guide for Integrated Field Crop Management.

Do weeds indicate what insect pests may infest a corn field next year?

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Conducting a weed survey may identify conditions attractive to certain insect pests. Some weeds serve as over-wintering sites for common stalk borer, hop-vine borer, and potato stem borer. The black cutworm moth lays eggs on several species of weeds in the spring. Larvae of these insects migrate from weeds to emerging corn in the spring. Here are some weeds that attract these insect pests:

Insect Pest

Weeds

Common stalk borer

ragweed and other large stemmed broadleaf weeds

Potato stem borer

quackgrass, green foxtail, barnyard grass, and dock

Hopvine borer

quackgrass and other grasses

Black cutworm

grasses, annual broadleaves such as common chickweed

Common billbug

yellow nutsedge

Soybean Aphids: Fall Update

Julie Stavisky, NYS IPM

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As soybeans have been nearing maturity, I have observed very few winged forms of the soybean aphid (SBA). In other years, winged forms of the SBA have been common by mid September. I’ve been watching buckthorn for winger aphids, too, though I have yet to see an aphid on buckthorn.

What would the appearance of winged forms of SBA tell us? Winged forms, or migrants, start to appear in the late summer or early fall when SBA are getting ready to move out of soybeans to their winter hide-outs. Migrating winged aphids fly to find buckthorn plants, where they lay eggs in the protected areas around the buds of buckthorn.

The movement of SBA in and out of fields can be indicative of future aphid infestations. By collecting SBA in suction traps in Illinois, researchers successfully predicted whether it would be a bad SBA year or a not-so-bad SBA year in 2003 and 2004. In the fall of 2002, they collected many winged SBA moving to buckthorn. They predicted high SBA populations in 2003. Nearly every soybean field was infested in 2003. In the fall of 2003, they collected very few aphids in transit to winter homes. They speculated that SBA might be less numerous in 2004. Their speculation proved correct. Last fall, using results from suction trap collections, University of Illinois entomologists predicted high SBA populations for 2005. This prediction again was verified by widespread infestations of SBA in many parts of the Midwest. Another factor they consider when making these predictionsis the numbers of predators, especially the multicolored Asian lady beetle. Large numbers of the lady beetle in the fall led to fewer SBA the following spring.

For more information about the suction trap network in Illinois, visit the Soybean Aphids Suction Trap Network. Although information gathered in the Midwest may not prove to be a predictor for SBA outbreaks in New York, we may be able to learn from our neighbors to the west, and make observations of our own regarding movement of winged SBA from soybean to buckthorn.

Growing Degree Days in NYS

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March 1 - September 14, 2005

Location

Base 50 F

Batavia

2194*

Chazy

2079

Clifton Park

2785

Geneva

2284

Ithaca

2196

Prattsburg

2091

* missing data

Source: http://newa.nysaes.cornell.edu/

Clipboard Checklist

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General:

• Update crop production activity records by field, including harvest date, pesticides used, nutrient inputs including manure, etc.

• Check fall harvest equipment, sharpen chopper knives, check shear clearances, check protective shields on all harvest machinery

• Prepare bunkers, silos for incoming silage.

• Clean, disinfect and prepare grain bins and dryers.

• Mow weeds around barn, grain storage bins, farm buildings, pastures, control weeds, brambles.

Alfalfa & Hay:

• Monitor fields for weeds and diseases: record information on type and location for future cropping decisions.

• Record hay yields by field and quality by storage facility; take samples for forage analysis

Field Corn:

• Observe corn for weeds, stalk rots / lodging, and nutrient and moisture deficiencies

• Harvest corn silage at 65 to 70% moisture and high moisture shelled at 25 to 30% grain, and high moisture ground-ear at 30 to 35% moisture.

• Record corn silage yields by field and quality by storage facility, take samples for forage analysis

• Take Soil Samples for fertility analysis

• Take Fall Weed Survey following harvest.

Soybeans:

• Monitor for pod, stem and foliar diseases.

Small Grains:

• Plant Winter Wheat (after fly-free date)

• Conduct a fall weed survey

Livestock:

• House and stable> fly populations may increase in barns and confinement areas in the next few weeks. This occurs as these flies look for warmer habitats when cooler temperatures begin to occur.

Contact Information

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Julie Stavisky: IPM Area Educator, Livestock and Field Crops, Western NY
Phone: (315) 331-8415
Fax: (315) 331-8411
Email: js38@cornell.edu

Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360
Email: jkw5@cornell.edu

Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316
Email: klw24@cornell.edu