Net spot (Leandria momordicae) intensity in cucumber plants grown under greenhouse and field conditions

Abstract

Net spot severity in cucumber plants has increased in the Santa Catarina State coastal areas due
to the expansion of the growing season, the use of seedless cultivars and low efficiency of fungicides used to control the pathogen (Leandria momordicae). Trained seedless cucumber plants grown under greenhouse and field
conditions were evaluated to determine the incidence and severity of net spot associated to temperature, relative air humidity and amount of rainy days. The study was carried out during the Fall of 2000 and 2001 and in the FallWinter of 2002. A significant correlation was verified between disease severity and number of rainy days, associated to temperatures ranging from 15 to 21,5oC. Net spot can be successfully controlled by the “umbrella effect” offered by the greenhouse environment.