The distribution and abundance of Delphacidae (Homoptera) in central Argentina

A 3-year field study has been carried out on the distribution and abundance of Delphacidae in central Argentina. Insects were collected along a 300 km transect of seven equally spaced sampling sites. At each sampling station there was one sticky trap 6 m above the ground and five sticky traps 1.5 m above the ground. The sampling frequency was every 6 to 15 days during the spring and summer months and monthly during the rest of the year. Delphacod es kuscheli (vector of a local strain of the maize rough dwarf virus, MRDV- RC), Delphacodes haywardi, Delphacodes balboae, Toya spp., Dicranotropis ni gricula and Sogatella kolophon meridiana were collected. Among them, D. kus cheli and Toya comprised 67 and 26% of all the delphacid captured. Delphaco des kuscheli showed a geographical gradient in abundance, coincident with t he land management gradient which showed a very heterogeneous landscape tin terms of crop species and (and management) dedicated to grain production i n the north-eastern part of the study area and a less heterogeneous landsca pe dedicated to cattle breeding (with large extensions covered with pasture s where D. kuscheli reproduces and overwinters) in thr south-west. Delphaco des kuscheli showed a high dispersal ability and synchronic dynamics, where as Toya spp. showed a lower dispersal ability with less synchronic dynamics . The implications for the MRDV-RC transmission is discussed.