EFFECT OF SOPHONIA RUFOFASCIA (HOMOPTERA, CICADELLIDAE) ON GUAVA PRODUCTION IN HAWAII

Yield studies and polymerase chain reaction (PCR) examination of guava , Psidium guajava L., were performed to determine whether feeding by t he leafhopper Sophonia rufofascia Kuoh and Kuoh or the presence of phy toplasmas were responsible for chlorosis. Insecticide treatments reduc ed leafhopper densities and chlorosis and increased yield 23% compared with untreated control trees. Treatment with the antibiotic oxytetrac ycline had no effect on symptom expression nor on yield of the trees. PCR using primers specific to sequences in the 16S ribosomal RNA of ph ytoplasmas did not reveal any phytoplasma involvement in trees showing chlorosis. Leafhopper feeding was not shown to affect guava juice pH or degrees brix (total soluble solids).