Passive dispersal of the grape rust mite Calepitrimerus vitis Nalepa 1905 (Acari, Eriophyoidea) in vineyards

Modes of passive dispersal of the grape rust mite Calepitrimeris vitis (Eri ophyoidea) were investigated in a vineyard of South-Western Germany. More t han 200 Eriophyoidea per month were trapped in a wind chamber during summer (32,1 % C. vitis) suggesting long-distance dispersal by air currents. Rain washed part of the adult. C. vitis population from the foliage. SE microgr aphs suggest that quiescent nymphs are affixed to the leaf by a substance o f unknown nature. However, the role of rain in C. vitis colonisation of uni nfested vineyards is still unclear, as is the role of phoretic transport by arthropods. For the first time, evidence of rust mite dispersal by human a ctivity is presented. A large number of C. vitis was found adhering to clot hes and hands of workers carrying out customary cultural practices in the v ineyard. Other arthropods, including Typhlodromus pyri, the main predator o f C. vitis, were also passively transported by wind, rain and human activit y.