Do irrigation practices and the olive fruit curculio (Rhodocyrtus cribripennis (Desbrochers, 1869.)) influence the maturity index of olive cultivar ‘Coratina’?

Abstract

Olive ( Olea europaea L.) is a Mediterranean fruit crop that requires irrigation to achieve optimal yield and quality. Irrigation practices and damage of olive fruit curculio ( Rhodocyrtus cribripennis (Desbrochers, 1869)), a pest of olive fruit, may be an important factor in determining the stage of fruit maturity, one of the main indicator of of fruit quality. The aim of this paper is to determine how different practices, through the amount and frequency of irrigation, with presence of olive fruit curculio, affect the maturity index of olive, variety ‘Coratina’. The research was conducted on 24 olive trees at two locations in Zadar County: Žman (Dugi otok) and Novigrad. Irrigation was performed with a drip system with four variants in three replicates: K (0%) rainfed olives; T1 (PP) irrigation set according to grower experience; T2 (SAN) irrigation set according to evapotranspiration and olive phenology, at up to 80% of field capacity and T3 (100%) where 100% of calculated evapotranspiration was added. Soil analysis determined the field capacity, and evapotranspiration was read from the Pinova™ meteorological station. Harvests was conducted in October 2020 and 2021. For determination of olive fruit curculio infestation and maturity index, 100 fruits per sample were harvested. By processing the data with one-way analysis of variance (ANOVA) and return test (Tukey), the significant effect of irrigation practices on the olive fruit maturity index by treatments, years and locations, single and interdependent, was determined. No effect was found between the presence of olive fruit curculio and the maturity index.