Disease Note.

Arthropods as Carriers of Fungal Wood-Rotting Pathogens in Pome and Stone Fruit Orchards. A. W. Helton, Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843. J. B. Johnson, and R. D. Dilbeck. Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843. Plant Dis. 72:1077. Accepted for publication 12 September 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-1077D.

Arthopods were collected six times between bloom and fall frost in Idaho orchards. Propagules of Coriolus versicolor (L. ex Fr.) Quel., C. zonatus (Nees. ex Fr.) Quel. Fl. Myc., Fomitopsis pinicola (Sw. ex Fr.) Karst. Krit. Fin. Basidsv., Ganoderma applanatum (Pers. ex. Wallr.) Pat., and/or Linzities trabea Pers. ex Fr. occurred on 13.2% of 167 ladybird beetles (Hippodamia convergens Guerin-Meneville and Coccinella novemnotata Herbst.), 12.8% of hunting spiders (Microphantidae, Lycosidae, and Salticidae), 19.4% of 36 lygus bugs (Lygus spp.), 23.5% of 34 honeybees (Apis mellifera L.) 32% of 25 March flies (Bibio sp.) and 4.4% of 361 miscellaneous insects. Ladybugs and hunting spiders (15 of each per test) artificially contaminated with F. pinicola were caged on broken spurs, scraped branches, or broken branches of 3-yr old monarch peach (Prunus persica (L.) Batsch) trees. After 251 days, wounds in cages with contaminated ladybugs and spiders had developed advancing internal necroses in 40 and 100, 100 and 80, and 100 and 100% of the three kinds of wounds, respectively; the pathogen was reisolated. Uncontaminated arthropods yielded no infections. These data suggest that orchard arthropod may play an important role in disseminating orchard wood-rot pathogens.