Some factors affecting the development, survival and prey consumption of Neoseiulus cucumeris (Acari: Phytoseiidae) feeding on Tetranychus urticae eggs (Acari: Tetranychidae)

Biological control of Tetranychus urticae relies mainly on specialist predators that are capable of coping with the dense web of spider mites. The role of generalist predators, however, has been less studied. To evaluate the development and predation of immature Neoseiulus cucumeris on Tetranychus urticae eggs, three experiments were conducted in the laboratory at 25 degrees C. The results showed that only 20-25% N. cucumeris eggs developed into adults when provided with 120 frozen spider mite eggs at the start of the experiment. The rate of predation by predator immatures and their survival increased with prey density. When N. cucumeris were fed 12-24 frozen spider mite eggs every day from larvae, they completed their immature development in 11-14 days and consumed 133-208 spider mite eggs. When the predator was offered 200 fresh spider mite eggs at the start of the experiment, they developed faster when fed every day, with adults emerging in 7 days. It was found that the webbing of spider mite lowered the predation of N. cucumeris. Compared with specialist predators, predation rates by N. cucumeris were much higher. The potential for N. cucumeris to control of T. urticae is discussed.