Intra-plant spatial distribution of Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae) on Eucalyptus grandis plants

Abstract

The bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae), which is native to Australia, damages eucalyptus plantations. In Brazil, this insect was recently introduced, but its distribution on eucalyptus plants remains to be studied. The best sample collection points of T. peregrinus are important to determine infestations of adults, nymphs and eggs on eucalyptus canopy. This study was conducted with Eucalyptus grandis (Myrtaceae). Ten leaves per branch of the prospected trees were collected and the number of T. peregrinus adults, nymphs and eggs on each was counted. Leaves sampled in the middle one-third of the canopy of E. grandis yielded representative data for the T. peregrinus biological cycle. This insect showed vertical intra-plant distribution of 58.28, 46.66 and 49.19 % of adults, nymphs and eggs, respectively, in this stratum. The horizontal distribution of T. peregrinus was 35, 46 and 41 % of adults, nymphs, and eggs in the east, west, and south quadrants, respectively. Thus, Thaumastocoris peregrinus should be sampled on leaves of the middle one-third part of E. grandis.