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Eastern New York Field Crops Pest Report, 2003

For 8/19/03:

Alfalfa

General Crop Condition
Alfalfa looked very good and was 18 to 20 inches tall at the SUNY Cobleskill farm. (Aug. 12).

Potato Leafhopper
Populations of potato leafhoppers were moderate to low this last week (August 12) at the SUNY Cobleskill farm. The continued thunderstorms and heavy rain might be keeping infestations low. Be sure to scout fields to make sure populations are below threshold.

For more information, see Potato Leafhopper on Alfalfa Management Guide, 302k pdf file

Picture of potato leafhopper

Field Corn

General Crop Condition
Field corn at the SUNY Cobleskill farm was in late pollination this last week (August 12).

Corn Rootworm
Field corn at the SUNY Cobleskill farm was in late pollination this last week (August 12).

Scouting Tip
While driving to a TAg meeting this week I saw a few fields that had uneven development. When you have a field of corn that is uneven in development it is scouted differently than a field that is uniform. In an uneven cornfield, scout 55 plants randomly through the field for corn rootworm keeping tract of western and northern. Remember northern count as a 1/2 and a western is equivalent to 1. The action threshold is one corn rootworm per plant thus; you need an average of 55 beetles or more on 55 plants.

How to Monitor for Corn Rootworm

Fall Weed Considerations
In the fall, weeds are fully-grown and easily identified. Correctly identifying and recording weeds helps you select the most economical method of control. Knowing whether the weed is a broadleaf, grass, sedge, summer or winter annual, biennial, or perennial is critical in selecting the right weed control measures. Remember, while herbicides are widely used for weed control other methods like crop rotation, cultivation, proper fertilization, planting dates, banding pre-emergence herbicides, crop spacing, plant populations, cover crops and combinations of these techniques should also be part of an integrated weed control program.

Conduct your fall weed surveys from late August through October. Sketch out a map, walk each 1/4 of the field, and record the weeds you observe. While no economic thresholds have been developed for weeds in New York, we recommend using a weed rating scale. The following scale can help you determine the severity of weed infestations in cornfields.

Evaluating Weed Presence- Weed Rating Scale:
Determine the intensity of each weed species as follows:

None: No weeds present

Few: Weeds present but very few plants within the field. Enough plants to produce seed but not enough to cause significant economic loss in the current year.

Common: Plants dispersed throughout the field, an average of no more than 1 plant per 3 feet (.91m)
of row, or scattered spots of moderate infestation.

Abundant: Fairly uniform concentrations across field. Average concentrations of no more than 1 plant per foot (.30m) of row or scattered spots of severe infestations.

Extreme: More than 1 plant per foot (.30m) of row for broadleaf weeds and 3 plants per foot of row for grasses, or large areas of severe infestations.

So take a few minutes and encourage growers to look at their fields---it will help save on weed control costs and increase crop production. Remember, if you don't look, you will never know.

Check out our on-line publication: Weed Management in Field Corn

Do weeds indicate what insect pests may infest a cornfield next year?
See the next exciting issue of Eastern New York Field Crops Pest Report!

Soybeans

Soybean Aphid
During a TAg meeting in Cherry Valley this last week we discovered low populations of soybean aphids in a very nice looking field of soybeans.

Here is a picture of soybean aphids on a leaf provided by Keith Waldron and the soybean aphid team. You will find them on the underside of the leaves.

For more information on Soybean Insect Pests check out our on-line publication: Soybean Insect Pests Management Guide

Do you know the number of growing degree-days in your region today?
Check this website: NEW YORK GROWING DEGREE-DAY TRACKER
(Base Temp. 50F)

Contributors to this week's pest report!
Jeff Miller (Oneida County)
Beth Spaugh (Clinton County)
David Norton (TAg Scout: Chenango, Fulton, Montgomery, Herkimer, Otsego, Madison, Oneida Counties)
Kevin Ganoe (Chenango, Fulton, Montgomery, Herkimer, Otsego Counties)
Richard Gast (TAg Scout: Franklin County)
Keith Waldron (NYS Field Crops and Livestock IPM Coordinator)
Ken Wise (Eastern New York)

Happy Scouting!
Ken Wise