Poinsettia thrips, also
called impatiens thrips, Echinothrips americanus, and can be a risk to greenhouse and nursery-grown plants. The adult thrips are dark in color with segmentation or banding. When held over their body, the base and tips of the wings are grey with a dark section in the middle. The juveniles are white or beige with red eye spots.
Bermuda, Canada (south), Mexico, USA (most of the eastern states), but
introduced to Europe (Italy, Netherlands, Austria, UK, Czech Republic,
South Bohemia) and also Thailand.
According to information at the University
of Florida MREC website, "In an experiment in Georgia . . . feeding and reproduction was observed on 40
cultivated and 59 native species." Poinsettias,
Irish shamrock, and impatiens are the most common greenhouse-grown hosts in Georgia and have been common on chrysanthemum foliage and flowers and woody ornamentals. The Thrips of California website also lists Dieffenbachia and Syngonium(Araceae), Cardamine hirsuta (Crucifeae), Hibiscus rosa-sinensis (Malvaceae) as host plants.
Biology and behavior
These thrips are generally slow-moving compared to a western flower thrips (WFT). They deposit their eggs inside the leaf tissue. The pre-pupae and pupal stages are on the leaf tissue (versus the soil as is the case for WFT)
Damage to crops can range from minor to extensive, and production may
decrease. This thrips stays lower on the plants, so monitoring cards must
be placed in the canopy. On many foliage crops damage was typical of thrips
damage, but on Alstroemeria damage was similar to be sun scald but on
examination of lower leaf surfaces, colonies of E. americanus were evident.
There can be feeding in the flowers.
Biological control has been limited with this thrips species. Neither Orius insidiosus nor A. cucumeris fed upon this species enough to provide
control in greenhouses. Macrolophus, and A. degenerans have also been
released with no obvious control. Some researchers have had some success
with lacewings. Dr. Lance Osborne, at the University of Florida, MREC, reports some success using Franklinothrips.
Greenhouse populations in Georgia have been reported as susceptible to
most insecticides. There are reports of populations on woody landscape
plants that are more difficult to grow. Some greenhouse growers have had
good success with horticultural oil, insecticidal
soap and Enstar (kinoprene - insect growth hormone) mixed together (check for
local state pesticide registrations and pre-test for phytotoxicity). There are also reports of control with Beauvaria-based microbial insecticides rotated with an insecticide containing the active ingrediant, 3% azadirachtin (Molt-x).
North Carolina State University
and University of Florida MREC's "Insect and Related Pests of Flowers
and Foliage Plants" Echinothrips
University of Minnesota
americanus webpage. Images, biology, and host information are
available at this website.
Thrips of California: Echinothrips
americanus Recognition information at this website.
Anonymous. 2009. National Diagnostic Protocol for Poinsettia
Thrips, Echniothrips americanus. Department of Agriculture, Fisheries and Forestry, Australian Govenerment. Review date November 2012. Accessed 18 March 2014.
risk assessment Australia