Seleção de introduções do gênero Brachiaria (Griseb) resistentes à cigarrinha Zulia entreriana (Berg) (Homoptera: Cercopidae)

Abstract

Spittlebugs are the most damaging pasture pests in tropical America where extensive monocultures of Brachiaria decumbens cv. Basilisk have favoured the buildup of spittlebug populations. Under severe spittlebug attack, the entire above-ground portion of the plant appears dry and dead, reducing the stocking rates of damaged pastures. Host plant resistance is a low-cost method of controlling spittlebugs, which farmers can easily adopt. High level of spittlebug resistance is found in the cultivar B. brizantha cv. Marandu, but it requires more fertile soils. A Brachiaria germplasm provided by the International Center for Tropical Agriculture and available at the National Center for Beef Cattle Research (CNPGC) has been screened for spittlebug resistance. In the present study 30 introductions of Brachiaria were evaluated for resistance to the spittlebug Zulia entreriana (Berg), based on nynphal survival and period. Three introductions (BRA 1945, BRA 3115 and BRA 3425), all B. brizantha, were selected as resistant. Given the great number of available introductions and even hibrids resulting from the breeding program, this test has been done routinely at the CNPGC in the search for sources of resistance. Complementary evaluations aiming the releasing of new spittlebug resistant Brachiaria cultivars are in progress.