Black Cutworms and Armyworms Continue to Arrive
The NWNY region has reached the 300-degree days for the flights that came in on April 24, May 1 and May 7 and will hit that mark for the May 14 flight this weekend. We will not continue to track degree days going forward. Cutworms are big enough to do some significant plant damage and all fields should be scouted. Unfortunately, we had another significant BCW and CAW flight again this week. Scout all corn until it reaches the V6 growth stage (6 leaves with visible collars). At this stage the stem is too thick for the cutworms to completely cut plants.
I still have not had a report of armyworms in grass or small grains yet. Keep looking for the blackbirds!
Watch for Alfalfa Weevil Larvae and Potato Leaf Hopper in Second Cut Regrowth
A lot of alfalfa hit the ground in the last ten days. As we mentioned earlier, there were a high number of fields that were at or exceeded the economic threshold for injury. I’m sure there were some cutter bars loaded with weevil larvae! Many of these larvae were not at the final instar where they do 80% of their feeding. The second cut regrowth really needs to be monitored. If you feel the alfalfa is not growing and just standing still, you better take a closer look. Treatment threshold is 50% tip feeding. Randomly pick 50 stems and count the number with feeding damage. You do not have to actually look for the larvae. If 25 of those 50 stems are positive for damage, you are at 50% injury and an insecticide application is warranted.
We have also received the first reports of Potato Leaf Hopper (PLH) in alfalfa fields in western NY. They usually arrive around Memorial Day, so it is not a surprise. Time to get the sweep nets out and start monitoring the regrowth on second cut. I will write more on thresholds and proper sampling next week.
Winter Wheat Update
Wheat continues to flower across the region. Many fields have already had a flowering fungicide application while some fields are just beginning to flower. The Fusarium Risk Model (http://www.wheatscab.psu.edu/ ), shows that the northern part of NWNY is still at high risk for infection the next couple of days. It looks like it will decrease to medium risk in the next 4 to 6 days.
Stripe rust will continue to be a risk with the cooler wetter conditions most of the week. This is a crucial time to have the flag leaf clean as the heads begin to fill. Again, any of the products sprayed to protect the flowers should also protect the flag leaf.
I can still easily find cereal leaf beetle adults and larvae. At this point, we are looking for larval feeding injury on the flag leaf. Threshold is one larva per flag leaf.
Next report will be June 5.
