Submitted to: International Whitefly Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/11/2013
Publication Date: 5/20/2013
Citation: Oetting, R., McKenzie, C.L., Townsend, M. 2013. Efficacy of insecticide rotations and their impact on populations of the ‘B’ and ‘Q’ biotypes of Bemisia tabaci. In: Proceedings of the First International Whitefly Symposium, Kolybari, Crete, Greece. T8.P-02:229. Interpretive Summary: 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.
Technical Abstract: In our trial, we tested rotations of different chemistries in controlling ‘B’ and ‘Q’ whiteflies in a caged environment. Three main objectives were studied during the trial. The first: to determine efficacy of different treatment rotations on a mixed population of Bemisia. Second, to determine the selective efficacy against either ‘B’ or ‘Q’ biotype in the treatments and the final objective was to observe the ratio of B/Q biotype resulting from the rotation programs. Poinsettia cuttings were placed in potting medium and six plants placed into each cage. Two introductions at 2 week intervals of 25 ‘B’ and 25 ‘Q’ biotypes were added to each cage. All insecticide treatments were applied as foliar sprays and data were collected every seven days. At least 10 adults were collected weekly in 95% ethanol and sent to Dr. Cindy McKenzie for DNA analysis to determine the ratio of B/Q biotypes. All treatment rotations managed the total population of whiteflies. All rotations did manage the ‘B’ biotype better resulting in higher ‘Q’ populations at the end of the trial. Water checks have a ‘steady’ population which indicates that in the absence of insecticide neither ‘B’ nor ‘Q’ will outcompete the other.