Resistance in grasses to the pasture spittlebug

Abstract

The level of resistance of grasses to the spittlebug, Doeis flavopicta (Stal 1854), was tested under field conditions. The most resistant grasses were: Andropogon gayanus cv. Planaltina, Brachiaria brizantha cv. Marandu, Cynodon plectostachyus, Hiparrhenia rufa, and Panicum maximum cv. Tobiatã. The most susceptible were Brachiaria ruziziensis and B. decumbens. Tests to determine the mechanism of resistance and basis for resistance of ten grasses were developed under screened cages and laboratory conditions. The mechanisms of resistance of C. plectostachyus and H. rufa are probably antixenosis and atibiosis; A. gayanus and B. brizantha cv. Marandu display probably antixenosis, antibiosis and tolerance; P. maximum cv. Tobiatã and B. humidicola display tolerance. B. decumbens and B. ruziziensis showed to be the most susceptible of the studied grasses and did not show any mechanism of resistance. Pasture management showed to be an important factor on spittlebug control. Keeping the pastures of susceptible grasses tall during spittlebug season and using the resistant grasses during this time demonstrated to provide the control of the pest.