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Wednesday, August 4, 2010

What to Watch For - Caterpillars in blueberries

Yellow necked caterpillar damage on a blueberry bush. Photo: HJB

Last fall, I posted about blueberry feeding caterpillars. Several caterpillars species in the genus Datana feed on NC blueberries and are generally called yellow necked caterpillars. More information on this group can be found here. Yesterday, I visited Vollmer Farms near Bunn, NC to discuss organic blackberry management (this is their first year growing blackberries) and took a look at their blueberries as well. There was some light Japanese beetle injury on a few bushes, but one plant was fairly defoliated. A few yellow necked caterpillars were still present on this plant, but most were close to pupation. I did not start getting calls about these insects until September last year, so like many other things this summer, it appears the caterpillars are also earlier than normal.

Yellow necked caterpillar larva on blueberry bush. Photo: HJB

These caterpillars are gregarious, meaning they feed in large groups, often on a single plant. This grouping also means that yellow necked caterpillars can readily defoliate bushes. This time of year, blueberry bushes develop flower buds for next year and severe defoliation could impact fruit set for next year. Fortunately, only one of the bushes at Vollmer's Farm was damaged.

Nearly mature yellow necked caterpillar and young caterpillar. Photo: HJB

If yellow necked caterpillars are observed early on blueberry plantings, they can be easily managed with both conventional and organic materials (a note of on pesticide recommendations). In addition to the caterpillars, we found a surprise, a large female praying mantis. One caterpillar on the bush had clearly been killed by the mantis, but that didn't seem to deter another from tempting fate by climbing onto the same branch she was on.

A brave caterpillar. Photo: HJB

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