Foraging on and consumption of two species of papaya pest mites, Tetranychus kanzawai and Panonychus citri (Acari: tetranychidae) by Mallada basalis (Neuroptera: Chrysopidae)

Authors: CHENG, LING LAN - Kansas State University; NECHOLS, JAMES - Kansas State University; MARGOLIES, DAVID - Kansas State University; Campbell, James - Jim; YANG, PING SHIH - National Taiwan University; CHEN, CHIEN CHUNG - Taiwan Agricultural Research Institute; LU, CHIU TUNG - Taiwan Agricultural Research Institute

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2009
Publication Date: 3/1/2009
Citation: Cheng, L., Nechols, J.R., Margolies, D.C., Campbell, J.F., Yang, P., Chen, C., Lu, C. 2009. Foraging on and consumption of two species of papaya pest mites, Tetranychus kanzawai and Panonychus citri (Acari: tetranychidae) by Mallada basalis (Neuroptera: Chrysopidae). Environmental Entomology. 38(3): 715-722. http://dx.doi.org/10.1603/022.038.0323.

Interpretive Summary: Two species of mites are major pests of papaya in Taiwan, and both species can co-occur in screenhouses where papaya is grown. Current management of these pests relies on chemical pesticides, but resistance has developed to many of these pesticides and some alternative pesticides can be toxic to the papaya. The green lacewing is a predator that has been used successfully as a biological control agent, but has not been evaluated for control of these mites. Rate of consumption by predators impacts their ability to suppress pest population growth and is influenced by time spent searching for prey, time spent handling prey after capture, and acceptability of the prey (ability of the predator to feed on the prey), so we determined these variables for different immature stages of the green lacewing using the two important mite pests of papaya. Green lacewings fed on all developmental stages of both mite species. Older immature stages of the green lacewing spent most of their time actively searching for mites and consumed 15 times the mite eggs and 17 times the mite adults of the younger lacewing developmental stage, which also spend approximately 40% of their time at rest. Green lacewings consumed more of one mite species than the other, primarily because it took longer to handle mites after encountering the mite. These results suggest that release of green lacewings within screenhouses where papaya is grown has potential as a management tool.

Technical Abstract: Tetranychus kanzawai Kishida and Panonychus citri (McGregor) are two major acarine pests of the principal papaya variety in Taiwan, and they often co-occur in the same papaya screenhouses. This study measured prey acceptability, foraging schedule, short-term consumption rate, and handling time of larvae of a domesticated line of the green lacewing, Mallada basalis (Walker), in no-choice tests with different life stages of these two mite pests. After a period of prey deprivation, all three larval instars of M. basalis exhibited a high rate of acceptance of all life stages of both T. kanzawai and P. citri. In 2-h trials, second- and third-instar predators foraged actively most of the time, whereas first instars spent about 40% of the time at rest. Consumption increased and prey handling time decreased as predator life stage advanced and prey stage decreased. Third-instar lacewings consumed an average of 311.4 T. kanzawai eggs (handling time: 6.7 s/egg) and 68.2 adults (handling time: 58.8 s/adult), whereas first instars consumed 19.6 eggs (handling time: 23.6 s/egg) and 4.0 adults (handling time: 633.4 s/adult). M. basalis generally consumed more P. citri than T. kanzawai. Except for prey eggs, handling times of T. kanzawai was generally longer than those of P. citri by all M. basalis instars. Handling times were shorter, and consumption were greater, at the higher P. citri density than at the lower one, whereas there were generally no significant differences in prey acceptability and foraging time between those two densities. This study suggests that M. basalis larvae may have high potential for augmentative biological control of mites on papayas.