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Submitted to: Biopesticides International
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/23/2013 Publication Date: 12/1/2013 Citation: Rojas, M.G., Morales Ramos, J.A., Riddick, E.W. 2013. Determining an optimal temperature range for reproduction of Phytoseiulus persimilis, a predator of the two-spotted spider mite, Tetranychus urticae. Biopesticides International. 9:101-112. Interpretive Summary: The predatory mite Phytoseiulus persimilis is the most important predator of the two-spotted spider mite. This predatory mite is mass produced and commercially available in the United States and sold for controlling spider mite infestations in many crops including open field and greenhouse strawberries, greenhouse tomatoes, and ornamentals. Improving the production of this predatory mite could reduce the costs of producing it and make it more affordable to use in other crops such as red beans, lima beans, and soybeans where spider mites are important pests. Our research contributed to improving the mass production by determining the optimal temperature for development and reproduction of the predatory mite. Our results showed that the P. persimilis will multiply the best at a range between 25 and 27ºC. The optimal temperature for reproduction was 26ºC. Temperatures higher than 27ºC and lower than 25ºC were detrimental to the predatory mite growth and reproduction. This information will enable producers of this predatory mite to optimize the mass production environment to obtain the highest yield with minimal losses by mortality of immature stages. These improvements may result in the reduction of production costs and increase the profitability of this fragile industry of biological control. Technical Abstract: Minor changes in temperature can have profound effects on the population growth of predaceous arthropods. In this study, we tested the hypothesis that a restricted range of temperatures is optimum for the population growth of Phytoseiulus persimilis Athias-Henriot in culture. When we compared mites reared at 6 alternating temperatures, immature survival was significantly lower at 29 and 31ºC, but significant differences in survival were not observed among mites developing at 21, 23, 25, and 27ºC. Development time decreased significantly as temperature increased. When subjecting mites to a more restricted range of temperatures (24 – 27ºC), development time was significantly shorter at 27ºC, but fecundity was significantly higher at 26ºC. No difference was observed in immature survival among the 4 temperatures. Although temperature fluctuated from 26 to 27ºC between the photophase and scotophase cycles in our system, doubling time was significantly shorter at 26ºC, suggesting that this temperature was most optimal for P.persimilis population growth. This study expands our knowledge of the temperature requirements for maximizing the production of predatory mites. |
