“I Miss Japanese Beetles,” No One Ever Said

“The Japanese beetle (Popillia japonica) was taken in government bait traps in Indianapolis for the first time. Seventeen beetles were taken, all in an area of less than 45 acres; and it is not unlikely this insect is now established in Indiana and will gradually increase as it has done in most localities where it has become established. The seriousness of this new introduction cannot be under-estimated.” J. J. Davis, Purdue University Agricultural Experiment Station, 1934.


A lonely Japanese beetle. (Photo Credit: John Obermeyer)

A lonely Japanese beetle. (Photo Credit: John Obermeyer)


Starting my college education at the University of Missouri, I took an introductory insect class that changed my life…for a couple reasons. Foremost, I met my future wife in that class, our first “date” was to go insect collecting. I had a vehicle to get us out into the country! As I continued further in my entomology pursuits, classes became more challenging. This included an extensive insect collection, requiring visits to many environments, but also included trading species with classmates. Trading was allowed, but you were required to include their name and location on the label. The professor shared a story of how one student, probably urban legend, failed the course because they had a Japanese beetle in their collection but labeled it from Missouri. Of recent years, catching a Japanese beetle in many states West of Indiana is quite plausible.

My first introduction to Japanese beetle was on the Illinois, Indiana border. Very close to where previous government eradication efforts in 1954 were documented in “Silent Spring” by Rachel Carson. Needless to say, the program taught scientists that indiscriminate use of insecticides wasn’t the answer, as it didn’t eliminate this beetle and was devastating to some non-target organisms. Decades after the area-wide failure, I was consulting with a producer that “hated” Japanese beetle feeding on his soybeans. I attempted with my IPM training to explain the soybean plants ability to compensate for defoliation and that treating wasn’t economic. He wasn’t having any of that!

Finally, to the title of this article! I have noticed a lack of Japanese beetles, and their damage, around my home and local plots this season. Most don’t notice something that isn’t there, right? As you would expect, I haven’t gotten a single call/email from farmers concerned about this pest’s absence. Is it localized because of our droughty conditions that persistent longer that most areas of the state? Fortunately, to my aide are bug trappers for the Western Bean Cutworm Pheromone Trap Report who are scattered throughout the state. So, I asked them to give me their observations with this week’s moth report.

Survey says…overall, most agree with my assessment that Japanese beetle numbers are lower this season. However, two reports from the southern portion of the state and one from the northeast indicate that numbers are higher than normal. What is normal? If one were to have a foot in boiling water, and the other foot on ice, would their overall body temperature be normal? If nothing else, this describes the unpredictability of insects and their damage to crops in any location and year. The insect outbreaks are the ones we notice and become ingrained in our mind for the future. But, when populations are at a low ebb, only entomologists take note, especially when it is the feared Japanese beetle!

Hoping you are experiencing a lower than “normal” insect pest season! Happy scouting!!!

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