As an update to our March 16 Thrips and Aphids message, some growers are reporting great success in early season control of Western Flower Thrips using sachets of Neoseiulus cucumeris. These packets of beneficial mites contain bran, bran mites which feed on the bran, and N. cucumeris, which feed on the bran mites while in the packet, but will prey on thrips once they move out and onto the crop. The sachets are replaced every 4-6 weeks to maintain a high population of N. cucumeris in the greenhouse.
Biocontrol of greenhouse pests is not effective as a curative measure - the predator mites must be present prior to an outbreak in order to prevent it. Successful use of biological controls requires careful planning and diligence. For more information on using predator mites for thrips management in the greenhouse, please see https://ag.umass.edu/greenhouse-floriculture/fact-sheets/biological-control-in-greenhouses-preparing-for-spring-crops and https://ag.umass.edu/greenhouse-floriculture/greenhouse-updates-jan-28-2019
- Dr. Angela Madeiras, UMass Extension Plant Diagnostic Lab with Jim Mussoni, Private IPM Scout