Insect Pests of Industrial Hemp in NYS

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Matt Chartrand (, Entomology, Shields Lab, Summer 2018.

Photos, unless where noted, were taken by the author.

Tarnished Plant Bugs (Lygus lineolaris)

Also commonly referred to as Lygus bugs, this species is found on many field crops throughout NYS. These bugs feed by sucking fluids from the plant destroying cells pictured in the leaf sample below, collected from Cortland County, NY. While the effects of the Lygus bug seem to be minimal, the feeding is concentrated on new, young plant tissue and flower distortion/deformities in seed may occur.

A Tarnished Plant Bug
Damage to a hemp leaf caused by a Tarnished Plant Bug

Adult European Corn Borer on a Leaf. Photograph courtesy of David Shetlar, The Ohio State University.
A European Corn Borer tunneling in a plant stem. Photo courtesy of David Keith, University of Nebraska.

European Corn Borer (Ostrinia nubilalis)

The European Corn Borer has only been found in Orange County this 2018 season. This does not mean this pest won’t become a problem in the near future. The developing stage larvae bore into the stems tunneling through the inner layer known as hurd resulting in structural weakening that may cause damage and reduce growth.

Western Black Flea Beetles (Phyllotreta pusilla)

Western Black Flea Beetles have chewing mouthparts that create the small pin-size holes in the photo below. These tiny, black beetles don’t seem to cause enough harm to well-established plants to stunt growth but have the potential to harm seedlings. Even in high population environments, the flea beetle will not be much of a concern if seedlings are protected to form enough vegetation.

Adult Western Flea Beetles. Photo courtesy of Whitney Cranshaw, Colorado State University.
Western Flea Beetle damage on a hemp leaf. Photo courtesy of Whitney Cranshaw, Colorado State University.

An adult Japanese Beetle on a hemp leaf.
A hemp leaf damaged by Japanese Beetles.

Japanese Beetles (Popillia japonica)

Japanese Beetles can be devastating pests for many commonly grown crops in NYS. While a noticeable number of adults have been spotted in fields this year, the populations are remaining low enough to not cause damage. The image of the second leaf on the left shows the damage the chewing mouthparts of these beetles can cause. The leaf was collected in Jefferson County, NY, during this season.

Want to learn more about the insect pests found in Industrial Hemp in NYS? Check out my blog and see what was found as I worked with the Cornell Cooperative Extension and traveled across NYS:

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