US: White flies enter greenhouse via poinsettia cuttings at two locations

According to a weekly report by the extension of the University of Maryland, two major growers who received white fly contaminated poinsettias cuttings in the Spring from the West Coast. One shipment came in late March for stock plant production. The other greenhouse operation received plants in April to produce tree poinsettias. In both cases the plants came in with small populations of whitefly. In hindsight, they should have refused the infested plants, but it was a busy Spring.

In both cases they treated with imidacloprid and then ignored the plants through the Spring bedding plant season. The grower that introduced the plants in late March ended up applying Avid, Azatin, Azatin, BotaniGard, Sanmite, Safari, Distance, TriStar and finally, Kontos. He just obtained a reasonable control in early August since he applied the Kontos, but it took several weeks for the Kontos to really show an impact.

The second grower’s greenhouse operation treated plants May through August with wet sprays of Aria, Talus, Judo, 1% oil, Sanmite, NoFly, Endeavor, Marathon II, and Azatin. They were applying the foliar applications once a week. The whitefly population kept increasing. Two weeks ago they applied a Kontos drench. Since they applied the Kontos drench the newer foliage was pretty clean, but still found several viable 2nd and 3rd instars and a couple of adults with their mouthparts still inserted into the foliage and

Click here to read the report.