Efeito de Densidades Populacionais de Pratylenchus brachyurus No Crescimento de Plantulas de Coffea arabica cv. Mundo Novo e C. canephora cv. Apoata

Abstract

The effect of initial population densities (Pi) of Pratylenchus brachyurus on the growth of Coffea arabica cv. Mundo Novo and C. canephora cv. Apoata seedlings was studied under greenhouse conditions. The initial population density of P. brachyurus consisted of 0, 2, 6, 18, or 54 nematodes/cm of soil. Plant height, fresh root weight, top dry weight, and reproduction factor (RF) were evaluated 90 days later. The data for plant height, fresh root weight, and top dry weight were fitted to the Seinhorst nonlinear model y = m + (1 - m). z . The tolerance limit (T) was zero for the three parameters, showing that growth of coffee plants was reduced by even low Pi of P. brachyurus. However, the reproductive rate was low (RF 1), indicating that C. arabica cv. Mundo Novo and C. canephora cv. Apoata were intolerant hosts for the nematode.