Black Cutworms Continue to Arrive
Much of the NWNY region has reached the 300 degree days for the first significant cutworm flight on May 3rd to be large enough to completely cut corn plants. We have already reported that some corn fields have been significantly injured enough (3-5%) to spray. Unfortunately, we had another significant BCW flight come in again this week. This is five weeks straight! This means that we will have multiple waves potentially attacking corn over the next couple weeks. I would continue to 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.
Armyworm Trap Numbers Still Low
We still are not catching many common armyworms in any of our traps. However, we have had a report of a grass hay field that armyworms were cutting heads. A couple are also showing up in the sweep net in mixed stands. So, let’s not completely let our guard down. Continue scouting those grass, mixed stand and wheat fields and keep an eye on the blackbirds!
Soybean Aphids Migrating to Soybeans
I saw the first winged soybean aphids flying into a soybean field on Friday in Ontario County. They were coming off the buckthorn bushes in the hedgerow where they overwintered as eggs. These adults will immediately give birth to live young which will start feeding on the first emerging trifoliate. They will multiply quickly so soybean scouting should ramp up in the next week. This field had Cruiser treated seed so I hope that will take care of this first flush of aphids. I will be watching this field closely.
Winter Wheat Update
Many wheat fields flowered last week and continue to flower this week. The Fusarium Risk Management site (http://www.wheatscab.psu.edu/ ), is showing no risk right now due to the cool dry conditions. I have had many calls about whether to spray or not. I have cautioned about the many micro-climate factors we have in this region. This includes around lakes, river bottoms, and areas of poor wind drainage surrounded by woods that could still be at risk. Other leaf diseases are also starting to show up unexpectantly. On Friday, I found a field that had severe powdery mildew up on the flag leaf. Gary Bergstrom also reported stripe rust in a couple fields in Yates County. Cereal leaf beetles are still high in some fields. We are almost at the finish line so stay diligent with your normal pest scouting and management routines!
Cereal Leaf Beetles in Oats
I’m now starting to see CLB larvae in oat fields this week. Adults were busy in the wheat and now have made the move. Look for the black larvae up on the top leaves and the associated feeding injury (see picture). Same thresholds as wheat, three or more eggs and larvae per plant of one larva per flag leaf. Unfortunately, most of these fields have already been sprayed for weeds.
- Egg hatch around 90 Degree Days
- Plant cutting around 300 Degree Days
- Degree Day data from Network for Environment and Weather Applications, NEWA
Alfalfa Weevil Damage
Many of our alfalfa fields were harvested 2-3 weeks ago and we are seeing some economic damage of alfalfa weevil feeding across the region. When scouting, select 50 stems and 
if 25 stems out of the 50 stems display significant feeding, then sweep several times across the field to collect some larva and determine their size and life stage. At this point depending on your harvest schedule and scouting results you can either choose to harvest early (if you are within 10 days to remove the food source and larva) or spray with an appropriate insecticide following the labeled instructions. Insecticide table below provided by Jeff Miller.
Pea Aphid
Pea aphids can be green or rose colored, winged or unwinged, large or small, and attached to leaves. Dead individuals are light tan and a result of the beneficial bugs out in the field. The economic threshold is a field average of 100 pea aphids/sweep. Under good growing conditions, spraying may not be necessary, but if the alfalfa is under stress, foliar application may be needed. If you choose to spray check out the table below for the appropriate insecticide. Remember harvesting alfalfa is an excellent cultural control method and few aphids will survive.
Next report will be June 14.
