Contribution for the development of a degree-day model for the olive moth, Prays oleae (Bernard)

Abstract

The olive tree is a traditional crop of great economic importance in the Mediterranean countries. Nowadays, it faces several crop protections problems that reduce their productivity and quality and force farmers to intervene, often using pesticides. Among these problems, the moth Prays oleae (Bern.) is a key pest in the Dão region, which in some years causes severe losses. The development of control measures against olive moth, that might constitute an alternative to the use of pesticides or that allow the reduction of its use, is in the best interest for the environment and human health as well as to reduce costs and improve the quality of olives and olive oil. The present study aimed to contribute to the establishment and validation of a degree-day model for the olive moth in the Dão region that helps establishing the biological cycle and risk periods of this pest. Based on this prevision the moments for applying the control measures can be determined with more precision, contributing to reduce the number of pesticide applications. During 2014, the olive moth was monitored (eggs, larvae, adults), through visual observation and capture of males using sex traps, at the experimental farm belonging to regional services (Advisory services). Simultaneously, temperature and male captures from 12 years (2003-2014) were analysed. Based on these data, it was possible to establish the flight beginning and peaks for the three generations of the pest and to contribute to the establishment of a regional model to predict the development of the olive moth, based on the modified degree-day model: first generation from 169 to 389 degree-days; second generation from 436 to 778 degree-days and third generation from 1334 to 2128 degree-days.