Oviposition preference of Bactrocera oleae (Rossi) (Diptera: Tephritidae):influence of cultivar (cvs. Cobrançosa, Madural and Verdeal Transmontana)and maturation process


Abstract: Olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae) is a key pest of olivecrop. In the present study the oviposition preference of olive fly towards three Portugueseolive cultivars (cvs. Cobrançosa, Madural and Verdeal Transmontana) was assessed indifferent oviposition bioassays. Olives at different maturation indices (MI) (MI 2, MI 3, andMI 4) were also assayed to evaluate the impact of maturation in olive fly preference. Onechoiceoviposition bioassays revealed high preference of olive fly by cv. VerdealTransmontana, followed by cv. Madural, being cv. Cobrançosa the less preferred. Nearly 78%of olives from cv. Verdeal Transmontana were infested, while 59% and 45% of olives fromcvs. Madural and Cobrançosa were attacked, respectively. A lower percentage of pupae/adultswere recovered from cv. Cobrançosa olives (51%) while in cvs. Madural and VerdealTransmontana the percentage recovered pass 60%. In the oviposition bioassays to determinethe impact of olives maturation only cvs. Cobrançosa and Madural were tested at MI 4. It wasclear that from MI 2 and MI 3 to MI 4 the number of ovipositions decrease considerably: adecrease of 63% and 36% in cvs. Cobrançosa and Madural, respectively. Clearly olive flyprefer to oviposit in olives at green or reddish color. The present study concluded that olivefly has an oviposition preference to cvs. Verdeal Transmontana and Madural, while cv.Cobrançosa is less preferred. Maturation stage influence olive fly oviposition with highmaturation stages, at MI 4, deterring oviposition. Physical parameters, like olives color, aswell as olives volume and elongation could be attributed to the oviposition preference of olivefly.

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