Diferenças na intensidade e na expansão da pústula da ferrugem do cafeeiro em dois acessos de Hemileia vastatrix

Abstract

The aim of this work was to study, under controlled environment, the differences in the disease intensity and pustule expansion of two Hemileia vastatrix accesses, sampled in cultivar Catuai coffee (Coffea arabica L.) plants from Coromandel (COR2) and Ijaci (IIJ1), towns located respectively in the West and South of Minas Gerais State. The inoculated plants were submitted to three temperatures (15, 20 and 25ºC) and three leaf wetness durations (24, 48 e and 72 hours) in a factorial scheme with three replicates. Both accesses presented a higher disease severity when submitted to 24h leaf wetness duration after inoculation. The higher infection frequency for IIJ1 was at 15ºC, while the temperature did not influence this variable for COR2. There was a higher severity for COR2 inoculated plants when incubated at 25ºC. The higher pustule expansion, for leaves inoculated with IIJ1 was at 15ºC with 7.59cm2 and a lower at 25ºC, with 5.37cm2, while for COR2 when temperature raised from 15 to 25ºC, there was an increase in the pustule expansion from 1.44 to 6.62 cm2, respectively. Fungal lines from Ijaci and from Coromandel presented differences in the intensity and pustule expansion of rust, under controlled environment.