Diapause Attributes and Seasonal Occurrences of Two Populations of the Citrus Red Mite, Panonychus citri (McGregor) on Pear (Acarina: Tetranychidae)

Abstract

Diapause attributes and seasonal occurrences were studied on the two populations of the citrus red mite, Panonychus citri (McGregor) occurring in two pear orchards (Sairyuji and Momoezuki) in the southern part of Okayama Prefecture. Both of the populations consisted of a mixture of diapausing and non-diapausing individuals in autumn but the proportion of each was different. The Momoezuki population started with eggs which overwintered within the orchard. The population increased during the summer reaching a peak in mid-August, but the density in autumn was low. The majority of the individuals in this population were diapausing. In contrast, no mites occurred in Sairyuji until the end of August but then the population rapidly increased to a peak in mid-October. The initial population in this orchard started with non-diapausing individuals which were likely immigrants from the neighboring citrus orchard, and the majority of the individuals of this population were non-diapausing. © 1983, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.