NYS IPM Field Crops Weekly Pest Report-August 15, 2022

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Are you aware of Tar Spot?

Tar spot was first detected in New York State last year. When you are out scouting be on the lookout for this new disease of corn in NYS. If you think you have this disease in your fields, contact your Regional Cornell Area Field Crop Specialist. For Identification of this disease please view the following website:

https://blogs.cornell.edu/nwny-dairy-livestock-field-crops/2021/10/29/tar-spot-in-corn-confirmed-in-wny/

 

Western Bean Cutworm

Peak flight of the western bean cutworm moths was the first week in August. Make sure to scout pretassel corn that is going to be harvested for grain.  Western bean cutworm does not cause economic losses in silage.

For more information, view the following website: https://cals.cornell.edu/field-crops/corn/insects-corn/western-bean-cutworm

This is a photo of western Bean Cutworm larvae feeding a ear of corn

Western Bean Cutworm larvae

2022 Field Corn Pheromone Trapping Network

Fall Armyworm

Fall armyworm moth captures have been low this last week.   For more information, please view the following website: https://extension.entm.purdue.edu/fieldcropsipm/insects/fall-armyworm.php

This is a phot of fall armyworm damage to fields corn. There are a lot of long hole elongated up and down the leaf from larval feeding.

Fall Armyworm Damage

Downy Mildew on Soybeans

Downy mildew is starting to appear in soybean fields. This disease generally does not cause yield losses. Even if you wanted to control downy mildew the current fungicides are not all that effective.

For more information, please view the following website:

https://cals.cornell.edu/field-crops/soybeans/diseases-soybeans/downy-mildew

Downy Mildew on Soybeans

Downy Mildew on Soybeans

Potato Leafhopper in Alfalfa

Potato leafhopper (PLH) infestations have been low this week. There were a few reports of PLH over threshold in new seedings. It is very important to scout new seedings since they are more vulnerable to PLH when very small.

As we start getting closer to fall the potato leafhoppers will start to migrate back to their overwintering sites in the southern US. It is best to continue to scout for potato leafhopper.

For more information on thresholds and management, view the following video:

IPM for Potato Leafhopper on Alfalfa

A photo of potato leafhopper damage to alfalfa

Potato Leafhopper Damage to Alfalfa

Soybean Aphids on Soybeans

Soybean aphid populations have been low this last week. Make sure to continue to scout for the aphid until the R6 stage of growth. Natural enemies play a major factor in controlling soybean aphids. This may be one of the reasons we have not had large infestations this year.   For more information, view the following website:  https://cals.cornell.edu/field-crops/soybeans/insects-soybeans/soybean-aphid.

this is a photo of Soybean Aphids on a soybean stem

Soybean Aphid

Japanese beetles on Soybeans

Every year I get questions on Japanese beetles in soybeans. The they are a defoliator but RARELY cause economic losses in soybeans. During the reproductive stage of growth, the beetles can damage up to 20% of the leaf area and still not lose yield. For scouting and threshold information please view the following website: https://extension.umn.edu/soybean-pest-management/japanese-beetle-soybean

This is a photo of Japanese beetles and damage on soybean

Japanese beetles and damage on soybean

Crown Rust on Oats

The have had reports of crown rust on oats. This disease can cause economic losses to oats. There is a good article on “Managing Oat Crown Rust to Prevent Yield Loss” by Michael R. Fulcher, Gary C. Bergstrom, Mark E. Sorrells, and David Benscher. https://blogs.cornell.edu/whatscroppingup/2019/08/26/managing-oat-crown-rust-to-prevent-yield-loss/