Eastern New York Field Crops Pest Report, 2002

For 7/12/02:

Alfalfa

General: Alfalfa was harvested early this week at SUNY Cobleskill (July 10).

Potato Leafhopper: I found low levels of potato leafhopper in 9 recently harvested alfalfa fields at the SUNY Cobleskill farm this week (July 10).

Terry Lavigne (Albany County) reports finding potato leafhopper resistant alfalfa showing potato leafhopper damage (July 5). He collected 90 potato leafhoppers in three samples.

Aaron Gabriel (Washington County) reports a new seeding of alfalfa over threshold for potato leafhopper (July 8).

Check out our on-line publication, Potato Leafhopper Management in Alfalfa

Grass & Pasture

Fall Armyworm: Lisa Fields, (Schoharie County) reports low captures of true armyworm moths (July 11).

Field Corn

General: Field corn is looking good and is between the V4 and V7 stage of development this week at the SUNY Cobleskill. No-till corn is slightly behind conventional corn in development (July 10).

Raymond Kennett (Dutchess and Columbia Counties) reports that many fields of corn are very drought stressed (July 10).

The Corn Rootworm Saga Still Continues
How to determine if your fields are at risk for corn rootworm

Corn rootworm populations build in a cornfield from year to year. Fields that are not rotated and remain in corn for several years are most at risk from corn rootworm damage. A three to four year rotation reduces the risk that a cornfield will reach an action threshold for corn rootworm. This spurs the question, „Do you scout a 1st year cornfield after sod for corn rootworm.‰ Yes, because any pollinating cornfield can attract corn rootworm. Even worse, late pollinating corn can attract many hungry corn rootworm beetles from fields where they did not get enough pollen. After the beetles eat their fill on late season pollen they will lay eggs in the soil. So YES, you have to scout ALL cornfields for corn rootworm that are going to be planted to corn next year. You do not need to scout fields that will be rotated out of corn next year.

Check out our on-line publication, Corn Rootworm Management in Field Corn.

European Corn Borer: European corn borer (ECB) injury is evident in corn at several locations in ENY (SUNY Cobleskill, Dutchess, Columbia Counties, and Washington County) What does ECB damage look like? Larvae feed on the leaves of corn and cause shot-hole damage. Borers may enter the midrib or tassel causing them to break. Extensive tunneling within the host plant can contribute to stalk breakage.

Is European corn borer generally a serous pest in New York State for field corn?

Weeds

Are there any other species of herbicide resistant weeds reported in the northeast?

Yes. There are several other weeds besides, Smooth Pigweed, Common Lambsquarters, Common Ragweed, Common Groundsel, that are resistant to herbicides in the Northeast. Why is this important to know? Because many of these species of weeds grow in New York, it‚s always possible that these or other species of weeds could also develop herbicide resistance. Remember, not to routinely use the same family of herbicide on the same field each year, because this promotes the selection of resistant weeds.

See Herbicide Resistant Weeds of USA

Soybeans

Soybean Aphids: Soybean aphids in Central New York are being found in fields and still remain at low infestation levels this week (July 9).

Japanese Beetles: Terry Lavigne (Albany County) reports some defoliation of soybeans by Japanese beetles (July 11). Remember that soybeans can withstand large amounts of defoliation before yield is affected.

See Soybean Insect Defoliation Assessment

Happy Scouting!