Etiology and Population Genetics of Colletotrichum spp. Causing Crown and Fruit Rot of Strawberry.

ABSTRACT Isolates of Colletotrichum spp. from diseased strawberry fruit and crowns were evaluated to determine their genetic diversity and the etiology of the diseases. Isolates were identified to species using polymerase chain reaction primers for a ribosomal internal transcribed spacer region and their pathogenicity was evaluated in bioassays.

Selection for Pathogenicity to Strawberry in Populations of Colletotrichum gloeosporioides from Native Plants.

ABSTRACT Colletotrichum gloeosporioides causes a serious crown rot of strawberry and some isolates from native plants are pathogenic to strawberry. C. gloeosporioides from lesions on wild grape and oak were sampled at two sites adjacent to commercial strawberry fields in Florida and two distant sites.

Genetic and Pathogenic Analyses of Colletotrichum gloeosporioides Isolates from Strawberry and Noncultivated Hosts.

ABSTRACT Colletotrichum crown rot of strawberry in Florida is caused primarily by Colletotrichum gloeosporioides. To determine potential inoculum sources, isolates of Colletotrichum spp. from strawberry and various noncultivated plants growing in the areas adjacent to strawberry fields were collected from different sites.

Resistance of Strawberry Cultivars to Crown Rot Caused by Colletotrichum gloeosporioides Isolates from Florida Is Nonspecific.

Isolates of Colletotrichum gloeosporioides from strawberry (Fragaria × ananassa) and native grape were tested for virulence on strawberry cultivars in field experiments for three seasons. Isolate aggressiveness and cultivar resistance were determined by the proportion of plants killed at a defined time. Each year, four to six isolates were inoculated on four to seven different cultivars, with a subset of isolates and cultivars evaluated again the next season.

Development of a Reduced Use Fungicide Program for Control of Botrytis Fruit Rot on Annual Winter Strawberry.

Crop phenology and epidemiological information were used to design a reduced use fungicide program for control of Botrytis fruit rot in winter annual strawberry. Fungicide spray programs during early and late periods of the season using high and low rates of captan were evaluated with or without second peak bloom applications of fenhexamid during the 1999-2000 and 2000-2001 seasons. During the early harvest period, low rates of captan were as effective as high rates for controlling Botrytis fruit rot and maintaining yield.