Establishment Probability of Anastrepha grandis and Zeugodacus cucurbitae (Diptera: Tephritidae) in Brazilian Semiarid Based on Thermal Requirements.

Abstract

The quarantine pests, Anastrepha grandis (Macquart) and Zeugodacus cucurbitae (Coquillett), are economically important for the fruit fly-free area in Brazilian semiarid, an area in which they are not yet present. Therefore, the objective of this study was to assess the probability of establishment of A. grandis and Z. cucurbitae based on the estimate number of generations in different climatic regions of the Brazilian semiarid. For scenarios of future projections, it was estimated the number of generations with increase of 1°C (low radiative forcing scenario) and 4°C (high radiative forcing scenario) in the air temperature. Finally, we also estimate the quarantine period to eliminate the invading population of cucurbit fruit flies in Brazilian semiarid. For this, the average historical air temperature of 32 semiarid municipalities was used and the biology data of fruit flies (thermal threshold of development and thermal constant) were used. The fruit flies are able to present several generations per year in Brazilian semiarid. Anastrepha grandis can present from 7.99 (Sergipe) to 9.66 (Piauí) generations. The melon fly Z. cucurbitae may present from 31.25 (Sergipe) to 40.66 (Piauí) generations. The estimation of species multiplication is accentuated in any season, with greater amplitude in spring and summer. The municipalities of Piauí, Ceará, and Rio Grande do Norte presented the highest estimates of fruit fly generations. The increase of air temperature in a future scenario may favor the quarantine pests, A. grandis and Z. cucurbitae, in Brazilian semiarid. In conclusion, the species A. grandis and Z. cucurbitae can be established in Brazilian semiarid, with particular concern for the fruit fly-free area.