Eastern New York Field Crops Pest Report, 2002

For 7/8/02:

Alfalfa

General: Alfalfa was 15 to 30 inches tall and starting to bloom this week at SUNY Cobleskill (July 3).

Potato Leafhopper: I found moderate levels of potato leafhopper in 6 alfalfa fields at the SUNY Cobleskill farm this week. While there were no fields over threshold the number of potato leafhoppers is increasing (July 3). Keep those nets sweeping fields!

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

Grass & Pasture

True Armyworm: Lisa Fields, (Schoharie County) reports low captures of true armyworm moths (June 5).

Field Corn

General: Field corn is looking good and is between V3 and V6 stage of development this week at the SUNY Cobleskill (July 3).

Kate Chabarek (Dutchess and Columbia Counties) reports that a few fields of corn are starting to show drought stress (July 3).

The Corn Rootworm Saga Continues

Is the western corn rootworm the only corn rootworm in New York? We should be so lucky? NO! There are three species of corn rootworm in New York: western corn rootworm, northern corn rootworm and southern corn rootworm. Of the three, the southern corn rootworm is a minor pest in New York and not a concern for our field corn producers. Southern corn rootworm is also called the "spotted cucumber beetle" and feeds on cucurbits (cucumber, squash, melons, and pumpkins) and other host plants.

How to Identify Corn Rootworm Adults

Western Corn Rootworm, Diabrotica virgifera virgifera
Female Western Corn Rootworm is 5/16 inches long with three black strips alternating with yellow. Male Western Corn Rootworm is mostly black with a small area on the posterior end that is yellow-green.

Northern Corn Rootworm, Diabrotica barberi
Both male and female Northern Corn Rootworm are uniformly pale green and are a 1/4" long.

Coming next week: How to determine if your fields are at risk for corn rootworm.

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

Deer Damage: I have seen deer damage in corn along the edges of the fields this week at the SUNY Cobleskill Farm (JULY 3). Aside from "early harvest" Does anyone want to share their experiences with controlling deer in corn?

Weeds

Weed Quiz- Triazine-Resistant Weeds in New York
Are there certain species of weeds resistant to triazine herbicides in New York? YES

• Smooth Pigweed

• Common Lambsquarters

• Common Ragweed

• Common Groundsel

How do you know if you have triazine-resistant weeds?
If weeds continue to grow in a field where triazine herbicides were sprayed this might indicate you have triazine-resistant species of weeds.

Triazine herbicides are: atrazine (many trade names), simazine (Princep), metribuzin (Sencor DF), hexazinone (Velpar L), prometon (Pramitol 25 E). Please note that there are several triazine herbicides that are used in mixes of other families of herbicides.

How do you prevent herbicide resistant weeds?
Remember not to routinely use the same family of herbicide on the same field each year, because this promotes the selection of resistant weeds.

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

Happy Scouting!