Although the invasive pest Thrips parvispinus continues to threaten tropical ornamental crops, the good news is that the sky isn’t falling. Producing crops like mandevilla, schefflera and hoya is still possible, at least in a closed greenhouse setting.
Although developing a reliable biological control program for this pest is probably a few years off, a suite of pesticides is available in the U.S. and Canada to successfully manage T. parvispinus.
This post covers these pesticides, their relative efficacy and demonstrates outcomes when used in an 8-month on-farm trial in mandevilla.
Lab Testing of Pesticides: An Important First Step
Dr. Alexandra Revynthi from the University of Florida Tropical Research and Education Centre has done the important first step of screening pesticides against T. parvispinus in 24-48 hour lab tests. This involves spraying label rates of pesticides on the leaf discs, which thrips then feed on, and seeing how many survive. She also quantified feeding damage on these leaf discs compared to untreated control.
Her work found several pesticides that are already registered in the U.S. and Canada that cause high levels of mortality of various T. parvispinus life stages (Table 1, below) and also reduced feeding damage.
Some of these products are not registered for thrips specifically but could be used as part of a total pest management program for other pests of tropical plants, including whitefly and spider mites.
Read more at onfloriculture.com