Insect Pests on Hemp

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Hemp crops really take off in August and so do many arthropods like insects. Not every bug you encounter on your hemp plants is a pest; some are beneficial and are working in your favor! Here are timely resources for identifying and managing summer's abundant arthropods. 

1. Scott Lewins from UVM's Northwest Crops and Soils Team discusses arthropods and control strategies for Northeastern hemp fields in this recorded webinar. Keep in mind that every state has different laws concerning the registration and use of pesticides and Scott's comments concerning products are Vermont-specific. Information about pesticide products for Maine's hemp fields appears in the next section.

2. Colorado State University has a comprehensive Hemp Insect Website. It contains superb images, fact sheets, and more. Their pesticide information is Colorado-specific and may not apply to Maine.

3. Kathy Murray, DACF's IPM expert, is also here to assist. Her hemp presentation highlights the most common pests we see in Maine and is a good primer for understanding when to use pesticides. She can be contacted at 


Pesticides should almost always be used as a last resort. Scientists are just beginning to have access to hemp, which has not been legal to grow until very recently. Few pesticides have been reviewed and approved for hemp. In addition, hemp (CBD) is used in drug manufacture and is a popular health supplement, so the chemicals that are applied to the crop, including natural compounds and inert ingredients, need to be vetted very carefully, especially considering those compounds may be concentrated in the final CBD products, which are administered in multiple ways (oral, dermal, inhalation).

1. Maine Board of Pesticide Control (BPC) has issued a list of pesticide products that are EPA and Maine registered for use on hemp. Some products on the list are not yet fully labeled for use on hemp, but a supplemental label listing hemp as a site was issued. Both the container label and the supplemental label are required and must be followed when making an application. Pesticides must be registered in Maine every year so the list is likely to change. BPC cannot ask companies to register products, but growers can!

2. For pesticide products that do not have to be registered with EPA ("Section 25(b) Minimum Risk Pesticides") but must be registered by the BPC, Maine BPC has a decision tree you can use to determine if the product is not prohibited on hemp. We strongly recommend contacting Mary Tomlinson, Maine BPC, to discuss the material you wish to use to make sure it is not prohibited. Contact her at or 287-7544. Mary also has a presentation on pesticide registration for hemp that is very informative.

3. Kathy Murray, Division of Animal and Plant Health, produced a BMP for pest prevention and management in medical marijuana cultivation, which is relevant to hemp growers.  

4. Finally, growers planning on using any pesticide (including organic or natural products, fungicides, rooting hormones, etc) must be licensed as a pesticide applicator by the Maine Board of Pesticide Control