Incidence of arthropods found in packed nectarine fruit in central California

About 18,000 fruit of each of six cultivars of nectarine, Prunus persica (L.) Batsch v. nucipersica , fruits were sampled (326,625 packed nectarines) yearly for three years and examined individually for the presence of arthropods. Twenty-three different species representing 2 classes, 11 orders and 16 families of insects, mites, and spiders were found. Pests of economic significance were represented by seven lepidopterous species, five species of Homoptera, and one species each of Thysanoptera, Heteroptera, Neuroptera, Coleoptera, and Acari. Of the 17 species identified, 12 were found to be recorded on nectarine as a host in a comprehensive survey of literature and of California state records for arthropods. Species with relatively high incidence (10-60/100,000 fruit) included omnivorous leafroller, Platynota stultana (Walsingham); oriental fruit moth, Grapholita molesta (Busck); walnut scale, Quadraspidiotus juglandsregiae (Comstock); San Jose scale, Q. perniciosus (Comstock); Chrysopa sp.; and Pacific spider mite, Tetranychus pacificus McGregor.