Journal of Insect Science (2008) 8 (4), 11-12
Javier Calvo, Karel Bolckmans and José E. Belda (2008)
Controlling the tobacco whitefly Bemisia tabaci (Genn.) (Hom.: Aleyrodidae) in horticultural crops with the predatory mite Amblyseius swirskii (Athias-Henriot)
Journal of Insect Science 8 (4), 11-12
in P. A. Stansly and C.L. McKenzie, organizers: Fourth International Bemisia Workshop - International Whitefly Genomics Workshop, December 3-8, 2006, Duck Key, Florida, USA
Abstract: The predatory mite Amblyseius swirskii has demonstrated the potential to become a key biological control agent in several horticultural crops in southern Spain. However, actual implementation of A. swirskii required clarification of such critical parameters such as optimal release rates, and introduction times, response of pest populations, adaptability to various crops, and compatibility with different natural enemies. The experiments described below were intended to provide this information under simulated field conditions in sweet pepper, cucumber and eggplant. Trials were conducted in a 40 x 10 m greenhouse located in Aguilas (Murcia, Spain). The greenhouse was divided into 36 cages of 4 x 2 m, 12 of which were used for two studies on sweet pepper. The focus of the first experiment was to compare two widely divergent release rates for A. swirskii in sweet pepper 25 and 100 mites/m2 with an untreated control. Plants were infested by releasing 8 adult whitefly per plant over a 3 week period with the mites released the 3rd week. The second experiment compared the efficacy of single species and combinations of several biological control agents: EM (Eretmocerus mundus alone), NT (E. mundus + Nesidicoris tenuis), AS (E. mundus + A. swirskii) and MIX (E. mundus + N. tenuis + A. swirskii). Plants were infested by releasing 50 adults of Bemisia tabaci per plant over 4 weeks in all the treatments. In the first experiment both release rates of A. swirskii (25 and 100 mites/m2) virtually eliminated whitefly nymphs from the plants. The second experiment demonstrated that the combination of A. swirskii and E. mundus was most efficacious against whitefly in sweet pepper. The same procedures and treatments (EM, NT, AS, and MIX) were applied to eggplant except that plants were infested by releasing a total of 30 B. tabaci adults in each of the 12 cages. The whitefly population was significantly suppressed by treatments (AS and MIX) that included A. swirskii was released compared with the remaining treatments. Furthermore, the addition of N. tenuis did not contribute significantly to whitefly control (NT and EM). Thus, the best biological control strategy for B. tabaci in eggplant was the combination of A. swirskii and E. mundus. Two trials were conducted in cucumber using 12 and 15 cages respectively, the first focusing on release rates for A. swirskii against whitefly and the second, on the relative effectiveness against whitefly and thrips, In the first experiment, infestation was initiated by releasing 35 adults of B. tabaci per plant and 4 release rates of A. swirskii were compared (0, 25, 50 and 75 mites/m2). In the second, 5 treatments were compared: WFC (35 B. tabaci/plant), FOC (15 Frankliniella occidentalis/plant), ASWF (35 B. tabaci/plant + 75 A. swirskii/m2), ASFO (15 F. occidentalis/plant + 75 A. swirskii/m2), MIX (35 B. tabaci/plant + 15 F. occidentalis/plant + 75 A. swirskii/m2). Significant whitefly control was again observed over the entire range of release rates in the first experiment, although greater suppression was achieved at the higher release rates. The second experiment showed that, A. swirskii, was able to provide efficient control of B. tabaci in cucumber, and further that F. occidentalis could also be controlled, even when both pests appeared simultaneously in the crop. As a general conclusion, A. swirskii has demonstrated excellent potential as a biological control agent of B. tabaci for horticultural crops in Southern Spain and similar areas. Its implementation enables the use of IPM programs for these crops by controlling B. tabaci biologically in many situations, avoiding the necessity of insecticides. Due to its efficacy against whitefly and thrips, it has recently been implemented as a key component in the IPM programs for these crops.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Francisco Javier Calvo
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
inundative/inoculative release
application technology
