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Eastern New York Field Crops Pest Report, 2003

For 6/30/03:

Eastern New York Weed Day

Date:  Tuesday, JULY 8Where: CORNELL/VALATIE RESEARCH FARM, Valatie, NY (State Farm Road off Route 9 just north of Valatie)
Time: 9:30 a.m. Registration, 10:00 - 12:00 p.m. Field Crop Weed Control
Note: CCA and DEC Credits have been requested
Why Come: You can learn and see the newest strategies for controlling weeds in field corn!

Alfalfa

General Crop Condition
Alfalfa at the Cornell/Valatie Research Farm was about 38 to 40 inches tall and lodged over (June 24). Alfalfa at the SUNY Cobleskill Farm was 8 to 10 inches tall (June 27).


Alfalfa Weevil in decline or not!

There have been many fields over threshold for alfalfa weevil on re-growth in Chenango, Fulton, Montgomery, Herkimer, Otsego, Oneida and Madison Counties, while in the Franklin and Clinton Counties there are not!

This last week at the Cornell/Valatie Research Farm I found no alfalfa weevil larvae (June 24). Where did they go? They all pupated! What does this mean? It means the potential for alfalfa weevil damage to occur this year is over. Well, at least in these few fields.

Check out the New York State alfalfa weevil development predication map!

... and see our on-line publication, IPM for Alfalfa Weevil. 1.2 Mb pdf file

Potato Leafhopper
Potato leafhopper infestations are at low to moderate levels across Eastern New York. We have not had any fields over threshold yet this season. The current hot weather might change this trend and infestation levels could increase dramatically in a short period of time. Make sure to encourage your growers to look at fields weekly if possible and ALWAYS watch new seedings closely. As you know, new seedings are at high risk to potato leafhopper damage. Yes, even varieties that are resistant to potato leafhopper need to be watched closely when they are newly seeded.

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

Picture of potato leafhopper

Verticillium wilt
Verticillium wilt can be a serious disease limiting yield and the number of productive years of an alfalfa stand. An early symptom includes V-shaped discoloration at the tip of a leaflet. As the disease progresses, leaflets wilt, turn yellow or pink, and often curl or twist. The curl and twisting of leaflets is the most characteristic symptoms of Verticillium wilt. Taproots appear healthy and sound, but have a dark ring (the water-conducting tissues) which is evident when the taproot is cut in cross section. Verticillium wilt symptoms may be more obvious in the second cutting.

For more information, check out our NEW on-line publication, Diseases of Alfalfa (Wilts and Rots) Management Guide 216k pdf file

Green Lacewing
I've seen a few green lacewing adults at the SUNY Cobleskill Farm (June 27). Adults feed in the evening or night on nectar, pollen, and aphid honeydew. Larvae are very active predators of aphids and other small insects in many agricultural crops. Adults are light green and long, slender antennae, golden eyes and have large lace-like wings that are 1/2 to 1/3 inches long. Larva are called antlions, and
look like a little green-gray alligator. Antlions have sickle-shaped jaws, that penetrate the prey and injects a paralyzing venom, then sucks out the body fluids. The larvae will reach about a1/2" long before they pupate.

Learn more about Green Lacewings.

Field Corn

General Crop Condition
Field corn this week was between the 2 and 7 leaf stage across many regions of Eastern New York (June 30).

Anthracnose leaf blight
While we were conducting an early season field corn pest twilight meeting in Orange County we discovered that many of the corn plants had anthracnose leaf blight on the lower leaves. Conditions were very good for this disease with the early wet weather and in a no-tilled field. Anthracnose inoculum survives on the corn residue left on the surface from the previous season. Anthracnose leaf blight appears as round to elongate, tan to brown water-soaked lesions, up to inch long and first appear on the lower leaves. Older lesions turn gray with small black specks in the center. To control anthracnose leaf blight use resistant hybrids, rotate corn with non-grass crops or cleanly plow under infected residue.

Picture of Anthracnose leaf blight

Last weeks IPM Question!
What do corn rootworm and fireflies have in common?
About the time you start to see fireflies is generally when corn rootworm larvae start to feed on corn roots.

IPM Question of the Week!
What are the weeds in New York that are resistant to triazine herbicides?

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!
Beth Spaugh (Clinton County)
Jeff Miller (Oneida County)David Norton (TAg Scout: Chenango, Fulton, Montgomery, Herkimer, Otsego, Madison, Oneida Counties)
Kathryn Evans (Madison County)
Kevin Ganoe (Chenango, Fulton, Montgomery, Herkimer, Otsego Counties)
Richard Gast (TAg Scout: Franklin County)
Ken Wise (Eastern New York)
Larry Hulle (Orange County)
Jonathan Wisbeski (Orange County)

Happy Scouting!
Ken Wise