Biology and control of the broad mite,Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae)

The broad mite,Polyphagotarsonemus latus (Acari: Tarsonemidae), is an important, and in some cases recent, pest of diverse crops in tropical and subtropical regions. Infested leaves become bronzed with down-curling margins, buds are aborted and flowers distorted, shoots grow twisted and fruit may be misshapen and russeted. Injuries, presumably due to toxins, occur even after the broad mite is killed by pesticides. There is no evidence thatP. latus transmits plant viruses, but injury may be mistaken for virus or herbicide damage. The mite infests plants referable to ca 55 dicotyledone and two monocotyledone families as well as to the Cupressaceae. Changes in horticultural practices, including control measures, could have caused recent pest outbreaks. The mite may raise a generation in 1 week under optimal conditions (ca 25°C and high relative humidities) and deposit ca. 40 eggs/ female. The usual sex ratio is 1:4 male: female and reproduction is arrhenotokous. Dispersal is effected through male carriage of pharate females as well as by winds, insects (especially whiteflies) and man. Field sampling is facilitated by the pest's aggregated distribution. Control options comprise plant resistance, pesticides and biocontrol. Areas for future research include the possible emergence of sibling species or feeding strains, better understanding of the mite's reproduction, the effects of host plants on life history parameters, monitoring for pesticide resistance and exploration for additional natural enemies of the broad mite.