Whiteflies on Poinsettias - Late Season Control
Wednesday, 12 October 2005 10:29
Last week's message stirred interest about managing whiteflies. Some growers reported that early varieties were already beginning to transition to color. Applications of pesticides to poinsettia with bracts is risky since there are so many variables. Differences in cultivars, culture and environmental conditions may increase or decrease bract sensitivity to pesticides. If you are inexperienced with a particular pesticide, always test a small portion of your crop before treating your entire crop. Whiteflies also tend to be localized in hot spots, and may be more prevalent on certain varieties or in certain houses. If that's the case then spot treating may be best.
After bracts color, foliar sprays of Sanmite, or Azatin + Decathlon have been reported to be effective. It is recommended to use the surfactant CapSil when using Sanmite (wettable powder) to minimize visible residue. Note that it has also been recommended to use only one application of CapSil in a week on the same plants. Marathon II has also been used on bracts, however, growers have reported slow results with a late season application. Other nicotinoids, such as Flagship, Safari and TriStar are also labeled safe on bracts as well as the insect growth regulator, Talus. When in doubt about pesticide safety on bracts, contact the technical representative for the product you plan to use.
Article in Greenhouse Product News, October 2004 issue. "Late Season Whitefly Control" by Daniel Gilrein, Cornell University
Tina Smith and Leanne Pundt
