The Bug Front Is Mostly Quiet

JACKSON, TENN.
    April 17, 2012 – Armyworms in Wheat – Unlike some areas to our south, there have been very few calls on armyworms. Granted, many people included an insecticide with their fungicide, but the few reports of those that didn’t indicate that armyworms are not an issue. I have not found armyworms in the wheat at the Jackson experiment station. Dr. Angus Catchot did an excellent podcast about the treatment threshold for armyworms in Mississippi, which is essentially the same as ours (link here). Cereal leaf beetles also appear to be conspicuously absent, but since first posting this article, I’ve had a report of one field exceeding the treatment threshold.
    Stink Bugs in Corn – I‘ve had no reports of stink bugs in Tennessee corn, but some are dangerously close in NW Mississippi. Stink bugs feeding on small plants can cause serious injury, essentially rendering the plant a weed in the worst cases. Stink bugs, often brown stink bugs, will feed at the base of plants into the growing point. This is not commonly a big problem in Tennessee, but I see a few fields with economic damage every year. The suggested treatment threshold is when 10 percent of plants less than 24 inches tall are infested. It requires close inspection as they are deceptively hard to find. Some recommended insecticides include the synthetic pyrethroids or methyl parathion. Many people will specifically use bifenthrin (Brigade, Fanfare or Discipline) as it tends to have better activity on brown stink bugs than the other pyrethroids.
   Sugarcane Beetles in Corn – I had several reports of fairly large numbers of beetles being seen at lights a few weeks back. I also had a report of someone’s sweet corn patch getting “hammered”. However, trap catches in our black light trap have dwindled over the past two weeks. This may just be the result of cooler nights.
   Reminder – Sugarcane beetles feed underground by gnawing on the stem. Damaged plants will often wilt, lay over or outright die. Problems tend to be more common in Cruiser treated seed than with Poncho, but no at-planting treatments are immune from injury. Unfortunately, rescue treatments only rarely provide adequate control.
   Cutworms in Corn – There were a lot of reports of high pre-plant populations of cutworms, but it appears that most folks wisely sprayed a pyrethroid insecticide at or near planting to eliminate the risk. Any fields that were not treated with a pyrethroid within 7-10 days of planting should be scouted to make sure that cutworms are not threatening stands. Heck, you ought to be looking anyway!
   Be careful not to confuse bird feeding with cutworm damage. Birds will sometimes tear off plant tops while digging for seed, but they also often leave peck holes in the soil (and the plant top mostly intact). If cutworms are present, you will typically find some larvae near freshly cut plants or their neighbors. This does require a little digging. Δ
DR. SCOTT STEWART: IPM Extension Specialist, University of Tennessee
  Courtesy of the University of Kentucky
  Sugarcane Beetle
  Cutworm