SCOUT YOUR FIELDS OFTEN! YOU NEVER KNOW WHAT BUG MAY SHOW UP AND WHEN YOU WILL NEED TO SPRAY.

This article will detail some mid- to late-season insects to watch out for this summer and how to get them under control; but before I give you a big list of bugs, let me also say that economic thresholds have almost never been so low.

The economic threshold is the amount of insects you must have in your field to breakeven from an insecticide treatment. This varies based on potential yield loss, the price of the crop per bushel, and your total cost of application.

If you are already out spraying something else like a herbicide or fungicide, your cost could be less than $2 per acre, since many pyrethroids are that cheap. On the other hand, if let’s say you need to use an expensive miticide for $10 and you have to call in a plane for another $10 or $20 in total, more yield would be needed to offset the expense.

Western bean cutworm late season, corn leaf aphids on the tassel, grasshoppers at any point, adult corn rootworm beetles clipping silks, European corn borer for the rest of the summer, and spider mites (not an insect but a definite threat, especially if they are damaging the ear leaf).

Gall midge larvae (on your endrows, look for holes in the lower portion of the stalk for the rest of this summer), soybean aphids (don’t believe the 250 threshold; I can promise you it doesn’t take that many aphids to hurt your yield in June or July), bean leaf beetles (look for a black triangle on the back right behind the head), painted lady butterflies and their larvae at any time, adult corn rootworm beetles (control them as soon as you see them and you will have fewer rootworm issues in your corn next year), stinkbugs and spider mites at any time, Dectes stem borer, thrips, whiteflies, leafhoppers, and many others!

Aphids, grasshoppers, mites, wheat stem sawfly, armyworms, Hessian fly, and cereal leaf beetles.

GROUP 1A – CARBAMATE: Lannate ($6 to $12/acre) or Sevin XLR Plus ($22 to $43/acre) – good on worms, beetles, and aphids.
GROUP 1B – ORGANOPHOSPHATE: Lorsban ($7/acre) or Dimethoate ($9/acre).
GROUP 3A – PYRETHROIDS: Silencer – $2/acre; Bifenthrin – $4/acre.
GROUP 4A – NEONICOTINOIDS: We suggest using only as a seed treatment due to bee kills from foliar applications.
GROUP 4C – TRANSFORM: $7 to $9/acre – aphids, leafhoppers, whiteflies, thrips, plant bugs, easy on beneficials.
GROUP 4D – SIVANTO PRIME: $19/acre – aphids, leafhoppers, whiteflies, thrips, plant bugs, easy on beneficials.
GROUP 5 – RADIANT: $16/acre – loopers, armyworms, thrips, leafminers, potato beetles.
GROUP 9D – SEFINA: $8/acre – aphids, leafhoppers, whiteflies, easy on beneficials.
GROUP 22A – STEWARD: $8 to $11/acre – adult corn rootworm beetles, grasshoppers, and most worm species including alfalfa weevil larvae.
GROUP 28 – CORAGEN EVO: $6 to $14/acre – worm species and grasshoppers, easy on beneficials.
GROUP 30 – VERTENTO: $13 to $23/acre – spider mites, bean leaf beetles, stinkbugs.

Not all the products listed on the left are labeled in every crop, but I just wanted you to see that we have lots of different chemical families; so while I am always concerned about resistance issues, there are often several choices for controlling resistant bugs. That said, when you look up and down this list, there is only one chemical family in the $2 to $4 range – the pyrethroids. There are only a couple choices that say $6 or $7. Otherwise, you’re talking $8 per acre or more. In addition to this list, there are many combination products we love, including Ridgeback (Bifenthrin plus Transform). Plus, I did not include miticides (other than the insecticides with mite activity, namely Lorsban, Dimethoate, Bifenthrin, and Vertento), since mites aren’t considered insects. The common miticides include Zeal, Abamectin, Onager, Comite, and Oberon, but we also see slight suppression of spider mites out of Liberty herbicide.

THE KEY TO EVERYTHING IS TO KEEP SCOUTING YOUR FIELDS ON A REGULAR BASIS.