Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2013
Publication Date: 1/1/2014
Citation: McKenzie, C.L., Kumar, V., Palmer, C.L., Oetting, R.D., Osborne, L.S. 2014. Chemical class rotations for control of Bemisia tabaci (Hemiptera: Aleyrodidae) on poinsettia and their effect on cryptic species population composition. Pesticide Management Science. 8:49-56. Available online: http://onlinelibrary.wiley.com/doi/10.1002/ps.3736/pdf . Pest Management Science. 8:49-56. Interpretive Summary: Bemisia tabaci feeds upon over 900 host plants and vectors over 111 plant virus species and is considered a major invasive species worldwide. The two most devastating members are MEAM1 and MED (commonly called biotypes B and Q, respectively). After the introduction of MEAM1 into the USA around 1985, unprecedented losses began occurring in the late 1980s in Florida on poinsettia followed by high infestations in field grown tomato crops. MEAM1 rapidly spread across the southern United States to Texas, Arizona and California where extreme field outbreaks occurred during the early 1990s on melons, cotton and vegetable crops. Recently MED was introduced into the U.S. and has already been detected in 26 states. The objectives of these experiments were to 1)determine efficacy of rotating insecticides with different modes of action against the two cryptic species (MEAM1 and MED) infesting poinsettia, 2) determine chemical class rotation effect on cryptic species population composition on poinsettia, and 3)determine cryptic species population composition over time on poinsettia in the absence of insecticide pressure. Results from these experiments will aid in development of Best Management Practices to combat these pests in both greenhouses and nurseries.
Technical Abstract: Bemisia tabaci, a polyphagous insect with over 900 host plants, is an effective vector of more than 100 plant viruses. Being highly fecund, B. tabaci has the potential to develop insecticide resistance rapidly as demonstrated by reports of use failures with MEAM1 and MED cryptic species (commonly known as biotypes B and Q, respectively). Insecticide resistance management is a key component of pest management practices. The research herein studied season-long rotational management programs on poinsettia and their impact on the ratio of MEAM1: MED cryptic species in the surviving treated populations. In all four experiments, only one of the treatments completely eliminated the adult or immature whiteflies, but all significantly reduced the populations. Out of 18 active ingredients tested, dinotefuran (applied as a soil drench) was the most efficacious against both MEAM1 and MED cryptic species compared to the other chemical or bio-rational insecticides evaluated. Reduced susceptibility of MED was reported against a variety of treatment regimes. Rotations can be used to manage MEAM1 and MED cryptic species and maintain a very low population level or completely eliminate Bemisia on poinsettia. It is imperative to continue to emphasize the importance of rotating among different modes of action in our pest management programs in order to retain effective chemistries for as long as possible in the market place.