Redescription of Dolichotetranychus australianus (Trombidiformes: Tenuipalpidae), a pest of bermudagrass Cynodon dactylon (Poaceae)

摘要

The flat mite Dolichotetranychus australianus (Womersley, 1943) - a significant pest of Cynodon turfgrasses in Australia and Africa - is redescribed on the basis of new Australian material collected from C. dactylon (bermudagrass, green couchgrass) and its hybrid C. dactylon x transvaalensis. All active life stages are described, leg chaetotaxy is provided, anomalous features are noted and the specimens compared with type material. The species is widespread in Queensland and is probably present anywhere that C. dactylon is grown in Australia, as indicated from its presence in other states. Photographs of its colonies and damage to turfgrass are presented, and damage symptoms are compared with similar damage caused by Aceria cynodoniensis (Trombidiformes: Eriophyidae). Dolichotetranychus summers Pritchard and Baker, 1952 known from C. dactylon in California, is redescribed from type material and confirmed as a species distinct from D. australianus, with both sexes of D. summersi lacking genital setae g2, coxal seta 2b and the subcapitular seta m. Male D. summersi also have two solenidia on tarsi I-II and have an aedeagus approximately one-third the length (65m) that of D. australianus (ca. 200m). The species Dolichotetranychus riyadhensis Alatawi and Kamran, 2015 is considered a junior synonym of D. australianus, and ontogenetic leg chaetotaxy of Dolichotetranychus zoysiae Ehara, 2004 is provided and corrected.