Susceptibility of guava genotypes to natural infestation by Anastrepha spp. (Diptera: Tephritidae) in the municipality of Monte Alegre do Sul, state of São Paulo, Brazil

Abstract

The infesting species and their infestation indices of fruit flies were determined for eleven guava genotypes (Psidium guajava L.). From March to April 2000, ten mature fruits of each genotype were harvested at weekly intervals from insecticide unsprayed trees located in the municipality of Monte Alegre do Sul, SP, Brazil. Fruits were brought to the laboratory, weighed and placed in individual plastic cups containing sand at the bottom to obtain the tephritid pupae. About 95% of guavas produced fruit fly puparia. Of the 682 Anastrepha females recovered, four species were identified: A. fraterculus (Wied.) (86.5%), A. obliqua (Macquart) (10.8%), A. bistrigata Bezzi (1.8%) and A. sororcula Zucchi (0.9%). Three species of parasitoids Braconidae (Opiinae) were recovered: Doryctobracon areolatus (Szépligeti), Doryctobracon brasiliensis (Szépligeti) and Utetes anastrephae (Viereck). The genotypes differ in level of infestation depend on the collecting time. The genotypes 'L2P4 Vermelha', 'Ruby Suppreme' and 'Webber Suppreme' showed the lowest susceptibility to tephritids in terms of puparia per fruit. The variability of infestation among the guava genotypes and the reasons for increasing fruit fly infestations along the time were discussed.