First record of Polyphagotarsonemus latus (Banks 1904) (Αcari: Tarsonemidae) on greenhouse peppers in Crete

Abstract

The broad mite, Polyphagotarsonemus latus Banks (Acari: Tarsonemidae), was first noticed on greenhouse pepper cv Cleopatra and Sonar in Ierapetra (Southeastern Crete) in 1984. During 1984 there were scattered mite infestations in a few greenhouses but in the following years it has become an increasingly important pest of peppers. The mite has been also found on cucumber cv Cnossos, aubergine cv Flaska and Solanum aviculare (indigenous of Amazonios) in the greenhouses of the Ierapetra Experimental Station. It atta­cks the growing points, young foliage, stem flowers and fruits. The growing points and bud are distorted, the young leaf margins down curl, the apical leaves crinkle, the leaf veins fuse and distort and the color changes to dark green, the fruits and stem crack and turn russet, mis-shape resembling like a fruit or stem scab and finally the small leaves and flowers fall off. Severely affected plants have little or no young growth, remain stunt and all fruitlets are aborted. The general look of the infested plants is similar to those affected by hormone weedkiller. Affected plants could not recover easily and the symptoms persisted for many weeks in spite of the acaricide treatments applied by the growers. In an artificial infestation of young pepper plants cv Sonar by 100-200 individuals, the symptoms of broad mite damage appeared in eight to ten days under growth chamber conditions (24±0.5°C, 60±5% R.H., 12.000 Lux for 16 hours daily).In Greece, the broad mite was first recorded on cotton leaves in 1969 and later on citrus trees. In Britain, it causes serious problems since 1978. It has been also noticed in several other countries of Europe. The spread of P. latus in many greenhouse plants in Britain was caused by the absence of acaricide treatments in green­houses where biological control against the two spotted spider mite Tetranychus urticae was ap­plied and the predator Phytoseilus persimilis was introduced by French bean leaves which was a recorded host of broad mite. The female longevity varies between 7-18 days depending mainly on temperature. The mean number of eggs/female is 40-50. The life cycle of broad mite is completed in 441, 205 and 98 hours at 14, 24 and 30°C, respectively. The developmental rate of various stages of the mite increased with the temperature but declined at about 35°C. The broad mite has been recorded on a wide range of hosts: tea plant, beans, tomatoes, cucumber, pep­pers, aubergines, citrus, zerbera, fuchsia, jasmin­um, magnolia, cotton, jute, coffee, avocado etc.