POPULATION-DYNAMICS OF HEMISARCOPTES-COCCOPHAGUS MEYER (ASTIGMATA, HEMISARCOPTIDAE) ATTACKING 3 SPECIES OF ARMORED SCALE INSECTS (HOMOPTERA, DIASPIDIDAE)

The parasitic mite Hemisarcoptes coccophagus Meyer (Astigmata: Hemisar coptidae) feeds on armored scale insects (Homoptera: Diaspididae). Thr ee host scales were studied: chaff scale (Parlatoria pergandii Comstoc k and P. cinerea Hadden) infesting citrus (grapefruit and orange) orch ards, latania scale [Hemiberlesia lataniae (Signoret)] and oleander sc ale (Aspidiotus nerii Bouche) occurring on acacia (Acacia cyanophylla) branches and leaves. The overall dynamics of mite populations were si milar on the different scale species, although the level of attack on each sampled diaspidid host was different. Rates of young mite stages were highly variable on all three hosts throughout the sampling period while adult rates were stable, constituting around 20% of all mites. No oviposition by mites occurred in mid-winter on any scale species, o n any plants or parts, at all sampling sites. Of the three diaspidids, highest mite prevalence (parasitization rate) occurred on latania sca le. Mite prevalence on oleander scale infesting mature leaves was high er than on young leaves. H. coccophagus apparently first attacks latan ia scale on branches, it then disperses to the same host inhabiting ma ture leaves, from there to co-occurring oleander scale and finally to oleander scale infesting young leaves. Mite prevalence on chaff scale was influenced by host plants and climatic regions: in the Negev it wa s higher than in the coastal plain, with scales on grapefruit being mo re heavily attacked at the former site but not on coastal plain. Our d ata suggest that H. coccophagus prefers ovipositing scale females. The decreasing order of preference for other scale stages was: young fema les, immature males, 2nd-instar nymphs females.