The gall maker Neopelma baccharidis Burck. (Homoptera:Psyllidae) on Baccharis dracunculifolia DC. (Asteraceae): individual, local, and regional patterns

Abstract

Baccharis dracunculifolia, the host plant of the gall maker Neopelma baccharidis Burck., is locally distributed in delimited patches. The effects of the host plant individual (plant height, crown diameter, and crown volume), local (host plant patch), and regional (locality) characteristics on the number of galls were analyzed, in Viçosa (three patches) and in Rio Doce State Park, Marliéria (two patches), Minas Gerais State (20°45'S, 42°50'W; and 19°50'S, 42°30'W, respectively). The number of galls/individual plant increased homogenousliy with plant dimensions on local and regional scale. Gall load was also homogenous, but the proportion of galled plants differed on a local scale. The differences were related to local plant size differences, and not to host plant patch size. Plants without galls presented different frequency distributions of plant dimensions than galled plants, with greater number of little plants, which indicated a minimum plant size to be gall maker prone. Local factors prevailed over regional factors in determining the number of N. baccharidis galls on 5. dracunculifolia, affecting the size of individual plants and suitability to the gall maker, without modifying the relationship between gall load and plant dimensions.