Leafhopper, Armyworm, and European Corn Borer

Our Scouts have been hard at work identifying some of the pests that have been making your crop fields their home this season. Here’s what we’ve been seeing across NYS over the last few weeks.

Potato Leafhopper

Now that 2^nd cut is over, it’s time to get out in your alfalfa fields with a sweep net (a hat works, too, in a crunch) and check for the presence of leafhopper. We have been seeing leafhopper in fields that are above threshold in NYS. If your alfalfa fields look pale and the tips are turning yellow in a V shape – it’s likely Potato Leafhopper and needs to be scouted ASAP! PLH reduce crude protein content, carbohydrate reserves in the taproot, and plant regrowth. There are insecticide options for the PLH, but if far enough along, early harvest is also an option. Remember – Potato Leafhopper damage becomes more severe in hot, dry weather and economic thresholds can even be halved in this type of weather.

True Armyworm

Keep an eye on your grass hay fields for True Armyworm. There have been reports across the state of these pests – most likely coming up from storms from the south. Remember, while the larvae look small now – the only way they get bigger is to eat! Be sure to check corn, grasses, and small grains – this pest will feed on it all. Check out the Cornell economic threshold below:

Recommended economic thresholds for corn:

• seedling: 10 percent or more plants show damage and larvae are still present.
• whorl-stage: apply an insecticide when there are three or more larvae per plant.
• Tall corn seldom needs treatment unless the leaves above the ear are also damaged.

Recommended economic thresholds for small grains:

• Wheat/small grains – 5 or more larvae per linear ft of row, larvae less than 1.25 inches and not parasitized, watch for flag leaf reduction or if grain heads clipped off – yield losses, a spray before soft dough to save the remaining 3 upper leaves is generally beneficial since these tissues are still important to grain filling

 

Recommended economic thresholds for grasses:

• Grasses – no specific guidelines available, need for treatment based on the level of damage observed in relation to the expected value of grass harvest

European Corn Borer

The use of GMO – BT corn has reduced European Corn Borer populations, but as we see an increase in Non – GMO corn, we’re seeing more ECB – and are likely to see an increase over the next few years. ECB may cause a decrease in yield, lodging, dropped ears, and an increase in stalk and ear rots. Some signs to look out for are holes in stalks and ears, sawdust – like frass, and broken leaf midribs. Make sure to get out in your fields and look for any abnormal signs that may save you a headache in the fall. As always, any questions call your local CaroVail location for assistance.