Thursday, April 18, 2019

Hemp Russet Mites: Scouting and Control Tips

Hemp Russet Mite (HRM) is an eriophyid mite that can severely damage flowers and decrease THC and CBD in cannabis production. Eriophyid mites are small, cigar-shaped pests; they’re capable of reproducing profusely. They infest many horticultural crops.

The eriophyid mite that occurs in cannabis is called Aculops cannabicola. It’s known to occur on cannabis, as well as hops and hackberry.

HRM can infest indoor production facilities throughout the year. These mites are carried on incoming plant material, on staff and tools. They can also move readily on wind currents.

Hemp Russet Mites on cannabis

HRM scouting tips

HRM detection should be part of the weekly scouting protocol that goes with yellow sticky card and whole-plant inspections. HRM should be addressed as quickly as possible.

When scouting, growers should look for leaf curling and carefully inspect leaves with a 20X hand lens or greater magnification. Scout crop edges and, since HRM are known to spread on wind currents, look near fans, too.

Inward leaf curling is another sign of infestation. If leaf curling is observed, sample the leaves and look in the nooks and crannies of the leaves for HRM.

HRM control options

Control options in cannabis are limited. Beneficial insects are a great option for early HRM infestations, but they’re not known to completely eradicate HRM populations. Release BCAs preventively for best control of HRM.

Horticultural oil sprays are effective at reducing populations. Applicators must read and follow the label instructions, and also follow all state and local regulations regarding chemical application to cannabis crops. All products listed below may not be approved for use in all states. Products other than those listed may be safe, effective and legal.


Featured products

Product Name
Item Number
Ecotec Plus 17%
2.5 gal, OMRI-listed
SuffOil-X Spray Oil 80%
2.5 gal, OMRI-listed
Amblyseius andersoni
62,500 BI 250 mini sachets w/hook
Amblyseius andersoni
Mini sachets on sticks, 1000/CS
Anderline aa
A. andersoni, 125K 5 liter bag SB
Anderline aa
A. andersoni 200 mini sachets SB
Amblyline cal
A californicus 200 mini sachets w/hooks SB
Amblyseius californicus, 2000/bottle SB

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