Influence of temperature and leaf wetness period (LWP) on the incidence and severity of gala leaf spot (Colletotrichum spp.)

Abstract

To understand the life cycle of the causal agent of gala-leaf-spot (GLS), potted apple plants cultivar
Gala were inoculated using spore suspension of C. gloeosporioides and submitted to different leaf wetness periods (LWP) at temperatures of 12 and 16oC. At 12oC, the symptoms appeared later and it required longer LWP than at 16oC (after eight days with 72 hours LWP, and after six days with 24 hours LWP, respectively). According to the
results temperature of 12oC is marginal to GLS infection, as in this temperature the fungus is able to establish on apple leaf but did not manifest symptoms until the occurrence of higher temperatures.