Beneficial Insects for Thrips in Cannabis Production

Beneficial Insects for Thrips in Cannabis Production
Professor DeBacco
Research Article
GRAMMENOS, G., KOUNELI, V., MAVROEIDIS, A., ROUSSIS, I., KAKABOUKI, I., TATARIDAS, A., & BILALIS, D. (2021). Beneficial Insects for Biological Pest Control in Greenhouse Cannabis Production.
http://journals.usamvcluj.ro/index.ph...

Insect Challenges in Greenhouse Production
In greenhouse cannabis cultivation an insect infestation can be the cause of many losses.
Synthetic chemical insecticides have been the go to option, however in medical cannabis cultivation, there are strict legislations and restrictions in pesticides use which is the driving force toward the development of new environmentally friendly and profitable methods for pest control.
Greenhouse Study
A greenhouse experiment was conducted in the Agriculture University of Athens.
Cannabis plants were grown in two different greenhouses.
Beneficial insects were released only in one greenhouse (treatment).
Νο additional pesticides were used during the cultivation.
The cultivar used was Futura 75, a monoeicus variety.
Greenhouse temperature and humidity fluctuation were estimated, at about, 13°C and 25% the lowest, while the greatest values were 43°C and 90%, respectively.

Beneficial Insect Release Date
Three weeks after transplantation, beneficial insects were released in the treatment greenhouse in order to assess the efficacy of biological pest management.
Thrips Identified
The main pests identified in the greenhouse included…
Thrips (Frankliniella occidentalis)
Basic Measurements
Measurements included the visual estimation of infestation, the recording of pest species and populations, and the comparison of infestations between the two greenhouses.
Only the nymphs and adult stages of pests were counted (no egg stage).

Pest Population Determination
The measurements of the pest population were taken in the third, fifth, seventh and ninth week.
The number of pests (thrips) was counted with hand-held digital 1600X microscope in order to quantify the efficiency of beneficial insects.
The average pest populations were measured on ten plants (4 leaves per plant) per greenhouse.

Thrips Life Cycle and Identification
Beneficial Insects that Target Thrips: Amblyseius swirskii
Predatory mites pierce their prey with their sucking mouthparts and suck out the contents.
Beneficial Insects that Target Thrips: Orius laevigatus
Thrip Control
Application Methods
Predatory mites were applied by hanging slow-release sachets (each sachet with hook contains 250 predatory mites and storage mites) of A. swirskii on cannabis plants.

Predatory bug O. laevigatus was applied by spreading evenly, the bottle materials on leaves and in Diboxes.
Thrip Numbers Over Time
Gradual reduction in thrip numbers over the weeks studied.
On week 9 the numbers were as low as only about 2.6 thrips per plant treated with beneficial insects compared to over 40 in control plants.
Average Number of Pest Populations
Numbers are weeks
A continuous reduction of all pest populations was observed throughout the experiment, approaching zero value per plant

Are Beneficial Insect Worth the Effort?
In short… YES!
Study results indicate that beneficial insects could control pest populations up to 100%.
Pest management with natural enemies is a promising, very effective, safe method for plant protection.


Growers Need to Keep In-Mind
Proper pest identification is very important since this will determine the exact beneficial insect to be used.
This requires frequent scouting.
Timing and rate of beneficial additions are important.

Link to Lecture Slides: https://drive.google.com/file/d/1iDGq...

*Due to the description character limit the full work cited for "Beneficial Insects for Thrips in Cannabis Production" can be viewed at... https://docs.google.com/document/d/1g...