Page 19 - Griffin Gazette Issue 3 - 2019

Two spotted spider mites Thrips

How to ID: Adults white to pale yellow with two How to ID: Larvae and adults found on foliage
black spots mid body. Adults are oval shaped and flowers, visible to the naked eye. Elongated
with eight legs, visible with naked eye, but best white to creamy yellow larval stages feed on
viewed with hand lens. Eggs clear and spherical. leaves. Dark, narrow bodied adults with fringed
May produce fine webbing. wings held close to body prefer young tissue and

Two spotted spider mites are probably the most common flowers. Larvae and adults found with beat tests.
pest of hemp and cannabis. Their populations can explode Adults captured on sticky cards.
rapidly. Their piercing/sucking feeding causes stippled Thrips have a relatively complex life-cycle that involves a
damage on leaves. Webbing indicates heavy infestations. pupal stage, often in the media. Eggs are laid within the
Two spotted spider mites are one of the few pests for leaf tissue and not visible during scouting. Common in
which BCAs can be used curatively. Treat with Phytoseiulus hemp and cannabis, thrips can be controlled with vigilance
persimilis for curative action. Use Hot Shot vials to treat and proactive treatments. As with all pests, control starts
flowers without transferring vermiculite carrier. Create a with good sanitation: quarantine inbound plants and scout
preventative shield over the crop by using Amblyseius thoroughly. Take care to avoid propagation from infested
andersoni from the very start of the crop. Replace andersoni moms. Scouting is highly effective at detecting thrips. Inspect
sachets every four weeks. When chemicals are allowed, plants for signs and symptoms and use sticky cards to
focus on horticultural oil products that work by suffocating monitor the crop.
the pests, e.g. Suffoil-X, EcoTec Plus. Allow a few days BCAs are effective against thrips, with a multi-layered
between spray and release of predatory mites. approach working best. Start with Amblyseius cucumeris
as a foundation on the crop. Replace sachets every four
weeks. A. cucumeris attacks the larval stages only, so add
a layer to target the pupae, too. Best options for media
treatment include beneficial nematodes (Steinernema feltiae),
Hypoaspis miles and Atheta coriaria. Finally, if pressure
persists, add Orius insidiosus, a predatory bug that feeds
on adult thrips and other soft bodied pests. When allowed,
treatments with Azatin O, AzaGuard, Botanigard WP, EcoTec
Plus, Grandevo CG and Suffoil-X may be effective.

It is the grower’s responsibility to understand federal, state and local regulations regarding pesticide use on hemp and
cannabis crops. Some pesticides are approved by some states and not by others. Applicators must read the entire pesticide
label. It is the responsibility of the applicator to read and follow all label directions. Labels do change without notice. Pesticides
other than those listed may be safe, legal and effective. The label is the law.

GRIFFIN GAZETTE 2019 | 19