Differences in the infestation level between hosts species of Ceratitis capitata (Diptera: Tephritidae)

DIEGO F. SEGURA; NANCY KAHN; MARÍA T. VERA; JORGE L. CLADERA

Mendoza

Congreso; 4th Meeting of the Working Group on Fruit Flies of the Western Hemisphere; 2001

A study carried out previously along an entire fruit-producing season allowed to find associations between the infestation level of Ceratitis capitata and the dynamics of maturation of different host species, being also preliminary observed that the infestation degree varied according to the hosts species. From this observation new samplings were designed to test for the existence of preference (measure through the infestation level for immature stages) of C. capitata females for egging in some particular host species. On the following season (November 2000 / May 2001), in the two dates with the highest diversity of hosts species with mature fruit, approximately 30 fruits of 50 trees were sampled, distributed homogeneously among the available species. The samples were collected in the EEA of the INTA San Pedro, and the fruits were transported to the INTA Castelar where they were weighed and measured. The number of pupae produced was weekly registered, and they were conditioned until the adult's emergence. The relationship between the hosts and the percentage of infested fruits, the number of pupae per fruit and the number of pupae per kilogram of fruit was analyzed. There were significant differences among hosts for the three variables in both samplings. Also paired comparisons were carried out among all the hosts species. The results indicate - for the first sampling - the existence of differences in the infestation degree between peach and the rest of the present hosts, among which there were not differences. In the second sampling the picture is more complex: asian pear appears as the host with the highest infestation level, then mandarin, fig, orange and lastly, plum. Finally we discuss the differences among the two fruit producing seasons regarding the percentages of infestation of each host species.