3.2.9 Grasses

Abstract

Cultivated grassland ecosystems share a number of characteristics that influence the nature of infestation, damage, and control of eriophyoid populations within them. The extent of host-specificity amongst grassland eriophyoids remains a largely untackled issue, though there is considerable evidence of complexes within current species concepts of Abacarus , Aculodes, and Aceria . They cause economically significant injury to their hosts through direct physical injury, the inducement of growth malformations, or the transmission of plant disease. A number of species within the Aceria tenuis group of grass-infesting eriophyoids colonize graminaceous hosts. Eriophyoids have also been associated with the disorders of bermuda grass, Cynodon dactylon . Extensive damage to bermuda grass may be caused by the bermuda grass stunt-mite, Aceria cynodoniensis . Shortening of the intenodes produces rosetting and tufting, eventually causing lawns to thin as infested plants are killed. However, most notable among the eriophyoids causing economic losses in cultivated grasslands is the cereal rust mite, Abacarus hystrix . This species vectors ryegrass mosaic virus (RMV), a serious disease of temperate grasslands. Abacarus hystrix is also an inefficient vector of agropyron mosaic virus (AMV), a minor disease of wheat and Agropyron repens .