What is in this article?:
- Cutworms building in Florida peanut crop
- Florida recommendations
• I could find a few earworms, and we are also seeing some armyworms in sorghum fields, but my main concern, and I suspect that something we will be hearing more about very soon, was finding threshold levels of granulate cutworms (cutworm) in several peanut fields.
EARLY FEEDING of cutworms on peanut leaves on June 15, 2013. This was the isolated incidence I observed of significant feeding even with cutworm populations as high as 5 per foot in other fields on this date.
The University of Florida recommendation is loss of 20 percent of the peanut canopy. Although these caterpillars are easier to find at night, I feel comfortable scouting during the day, and will raise a red flag when finding 3-5 per foot of row.
If you can find feeding, but not find the caterpillars you might come back after dark and search with a flashlight. I could find 3-5 cutworms per foot in some fields and none in others this past weekend, so these are definitely an insect where scouting pays compared to blanket applications.
In those fields, I only found one with significant levels of canopy feeding. But, I was obviously on the front end of the cycle, finding primarily small caterpillars.
My experience in 2011 was I could find up to 10 caterpillars per foot of row, but almost a week went by before they begin to consume the peanut canopy to a measurable extent.
Most farmers will go ahead and treat when they find the high populations instead of scouting at frequent intervals to assess canopy damage. One thing we saw in 2011 was consistent with Sprenkel’s comment that they can consume a lot of foliage rapidly when the time comes that they move away into the peanut canopy.
The UGA Peanut Insect Control Guide shows pyrethroids, plus Lannate, Steward, and Belt for control. However, the reports I heard in 2011 was spraying multiple times because of lack of control by pyrethroids. My experience was that we had excellent control with Belt at 2 ounces per acre. We haven’t made any treatments yet for this cycle of caterpillars.
On a related note, it is about the time of year peanut growers start getting excited about the lesser corn stalk borer (LCSB). This is a pest that summer rainfall patterns usually solve without our involvement.
The IFAS recommendation is control when larvae are found with 15 percent of the plants at pegging. So for 6 plants per foot, that is roughly one larvae per foot.
I found LCSB in every field I surveyed. However, I was not concerned about the populations I found in any field. I suppose we are getting enough rain that the natural fungus and mechanical action of rainfall are keeping populations in check as we see most years.
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