Effect of Temperature on Prey Consumption Rate of the Green Lacewing Mallada basalis (Walker) (Neuroptera: Chrysopidae) to Two Species of Pest Mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor) (Acari: Tetranychidae)

Abstract

The green lacewing, Mallada basalis, has been shown to have high potential as a biological control agent against two mite species of economic importance on papaya: the Kanzawa mite, Tetranychus kanzawai, and the citrus mite, Panonychus citri. However, the impact that this predator can have on mite populations is dependent on prevailing environmental temperatures, which influence predator-prey dynamics by affecting developmental rate, survival, reproduction, and longevity. Another effect of temperature, which this study investigated, is predator consumption rate. We measured the consumption rates of 2nd instar M. basalis on T. kanzawai and P. citri at five temperatures (15, 20, 25, 30, and 35°C) in the laboratory. Results indicated that prey consumption by 2nd instar lacewings was temperature-dependent, increasing between 15 and 30°C for both mite species; however, consumption declined at 35°C. Numbers of T. kanzawai nymphs consumed in a 30-min trial ranged from 16.3 ± 1.0 at 15°C to 45.7 ± 2.5 at 30°C. On P. citri, predators consumed 26.4 ± 1.8 nymphs at 15°C and 48.0 ± 3.3 at 30°C. There were slightly different trends in the consumption rate of the lacewing in response to the five temperatures between the two mites, and this might be the result of the different spatial distribution patterns of the two mites as well as different handling times of the lacewing for the two mites. High prey consumption rates across a wide temperature range, including temperatures as low as 15°C, suggest that M. basalis may be suitable for year-round application in Taiwan against both T. kanzawai and P. citri. However, further investigations on the effect of temperature on the predatory potential of M. basalis under field conditions are needed for effective application of this lacewing in papaya mite management programs.