Soybean Aphid Scouting

The last three growing seasons have not been big soybean aphid years, which has been great!  However, I saw the winged forms flying off buckthorn three weeks ago.  We are hoping that plants treated with Cruiser will take care of those first aphids. I have not been able to find any established colonies so far.  However, I have two reports (Erie and Niagara County) from consultants that they have found some plants already over the threshold of 250 aphids per plant. These first SBA infestations are hard to locate so here’s a tip.  Look for the ants!  The ants search out these aphids to get their waste products; honeydew. If you see ants on a soybean plant, I guarantee the aphids will be there. We have a video on scouting for SBA by looking for the ants, on our YouTube page. Hopefully, the natural enemies like ladybugs can find the early aphid colonies and keep them in check.

Maximum Corn Growth Stage for Post-emergence Herbicide Application

I was out across the region this week sampling corn for my corn nematode project. Most corn was between the V5 to V7 but a couple early fields were at my shoulder at V8. One thing I noticed was some big weeds that will be hard to control with our post-emerge herbicides. We are getting close to or have surpassed the labeled corn height on some of our corn herbicides. Many herbicide labels state a maximum corn height (ie. atrazine is 12”) or growth stage in leaf collars when a product can be broadcast. Here is a good table from the University of Illinois on Corn Growth Stage and Postemergence Herbicides that includes most of the labeled post-emergence herbicides we use in NY.

Application Deadline for Dicamba on Soybeans

I have looked at some great early planted soybeans this week. It won’t be long until flowering.  I also saw some large lambsquarters, marestail and waterhemp in some fields. Just a reminder that if you plan on applying Dicamba on Dicamba resistant soybeans to control these tough weeds, the deadline is coming quick. The Dicamba products can only be applied to soybean up to and including June 30. So, no applications after June 30, regardless of growth stage. Prior to June 30: Tavium® can be applied up to V4 soybean growth stage; Engenia® and XtendiMax® cannot be applied beyond R1 soybean growth stage.

Winter Wheat Update

We have been getting plenty of pictures of wheat that is turning fast. Some of this early maturing is due to the hot and dry weather. Malting barley fields are being harvested this week. That means some wheat is only 10 days from harvest. Are your bins ready for the new crop? The high winds with some of the storms this week have also left wheat tied in knots and flat on the ground. You should check for fungal foot and root rots in these fields. See last week’s Crop Alert on eyespot identification. As the heads start to mature, the presence of Fusarium Head Scab becomes more noticeable if present.  Look for the whitened kernels usually near the top of the head. I know many growers are using fungicides at flowering, so let’s hope for a low vomitoxin year.

Fun Fact: 

The first fireflies have been visible at night this week. What does this mean?  This first sighting is usually coordinated with the hatch of corn rootworm larvae. The rootworm eggs have overwintered in the soil and they will now feed on corn roots.