Abstract
The European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae) is considered to be the main pest in the vineyards of the Douro Demarcated Region (DDR) due to the economic losses it can cause. Damage is caused by the larvae of this pest feeding on grape clusters, rendering them susceptible to Botrytis cinerea in mid-season and leading to the development of primary and secondary rot at harvest. Understanding this pest´s behaviour in the region under future climate scenarios is an increasing challenge. Hence, the present study aims to assess the potential effects of two likely climate change scenarios (Representative Concentration Pathways, RCP4.5 and RCP8.5) on Lobesia botrana phenology, particularly at the beginning and at the peak of the three Lobesia botrana flights. Our findings show that the phenological events generally occur earlier in all locations and mostly during the long-term period of 2021–2080, being 7 to 12 days in advance in the RCP4.5 scenario, and 15 to 24 days in advance in RCP8.5, when compared to current values (2000–2019) and regardless of the flight number. These results suggest that a fourth complete flight is likely in the future, and that Lobesia botrana will become a tetravoltine species in the region. The flight (male catches) and infestation of Lobesia botrana over periods with daily temperatures above its upper limit of development (> 33 °C) were also analysed during the period 2000–2019 in the targeted sites. The upward trend in the number of days with maximum temperature above 33 °C tended to be accompanied by a decrease in the total number of male catches during the second and third flights, as well as a decrease in the percentage of attacked bunches by the second and third generations. Overall, climate change is expected to influence the phenology of this pest in the DDR.
Highlights
The European grapevine moth, Lobesia botrana (Denis and Schiffermüller, 1775) (Lepidoptera: Tortricidae) - referred to as LB is one of the most noxious vineyard pests in Europe and the Mediterranean basin (Delbac et al, 2010; Ioriatti et al, 2011; Caffarra et al, 2012)
The temperature increase projected for the climate scenarios (RCP4.5 and RCP8.5) is in line with those already reported (IPCC, 2018); i.e., an increase of 1.5 °C in the period 2030–2052
Our results indicate generally earlier LB flight dates throughout the period 2021–2080 in the two different climatic scenarios RCP4.5 and RCP8.5 compared to the present (2000–2019)
Summary
The European grapevine moth, Lobesia botrana (Denis and Schiffermüller, 1775) (Lepidoptera: Tortricidae) - referred to as LB is one of the most noxious vineyard pests in Europe and the Mediterranean basin (Delbac et al, 2010; Ioriatti et al, 2011; Caffarra et al, 2012). Lobesia larvae damage grapes by feeding on flowers and berries. The greatest economic losses are due to secondary infection provoked by Botrytis cinerea in the feeding sites of LB (Gilligan et al, 2011). LB has a facultative diapause and a variable number of generations per year which depends on two main driving factors: temperature and photoperiod. This moth is trivoltine in Mediterranean latitudes. Voltinism is determined by a conjunction of factors: latitudinal and altitudinal gradients, which largely reflect the thermal forcing conditions of each site (MartínVertedor et al, 2010)
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