Windshield Splatter: Insect Pest Update

As many have asked, or made note, insect pest numbers seem lower this season. No surprise that the moisture and temperature extremes have had an impact, especially those insects depending on the soil to complete at least a portion of their life cycle.

Japanese beetles have been slow in appearing throughout the state. One report this week from Brad Kohlhagen, Adams County CES, indicated that after a much-needed rain, Japanese beetles began appearing everywhere. The white grubs, turned pupa, await in dry soils for moisture to soften the ground so adults are able to dig out. Hopefully, the whole state will get ample rainfall, without the severe winds, even if that means more beetles! It is always difficult to assess how abundant Japanese beetles are in the state. From my perspective, they seem fewer…still waiting on a soaking rain in west central Indiana. Typically this pest is quite spotty in the state, and soybean defoliation and/or corn silk feeding is noticeable, but hardly justified to treat.

 

Dusty Japanese beetle just emerged from the soil. (Photo Credit: John Obermeyer)

Dusty Japanese beetle just emerged from the soil. (Photo Credit: John Obermeyer)

 

Yesterday, July 7, I saw my first male western corn rootworm beetle in Tippecanoe County. The males emerge a few days before the females. Beetle emergence will go on for weeks, so this is just the beginning. This insect is known as the “silk beetle,” although it has been some years since I have seen them be of concern except in late-market sweet corn. Years of widespread use of Bt-rootworm corn traits and soil moisture extremes, has certainly had an overall impact on this “billion-dollar” insect in Indiana. For those willing to scout fields later this month and into August, to assess for western corn rootworm beetle presence, may find very low numbers. Consider, low beetle numbers equate fewer eggs laid in field for next year’s corn. Is the trait in next year’s corn needed for this pest?

 

Female western corn rootworm beetle emerging from the soil. (Photo Credit: John Obermeyer)

Female western corn rootworm beetle emerging from the soil. (Photo Credit: John Obermeyer)

 

Three weeks ago, our trap cooperators began monitoring for the emergence/flight of the western bean cutworm. This insect spends a considerable amount of time in the soil throughout fall, winter, and spring. Though it is early in the trapping process, catches so far have been very low. The recent catches are reported below. We shall find out if there is a surge after recent rains!

 

Happy Scouting!

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