European grapevine moth in the Douro region: voltinism and climatic scenarios

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.

European Grapevine Moth and Vitis vinifera L. Phenology in the Douro Region: (A)synchrony and Climate Scenarios

“…The earliness of LB flights in this climate scenario is in line with other previous studies [2,23,57]. According to Reis et al [22], it was observed that LB phenology advances in the locations evaluated in the DDR. The earliness observed in the three flights in the 2021-2080 period was 7 to 12 days, under RCP4.5, and 15 to 24 days, under RCP8.5, when compared to the historic period (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019).…”

“…For our purpose, the combinations used (GCM-RCM chains) were CNRMALADIN, ICHECDMI, IPSLINERIS and MPICLM. More details can be found in Reis et al [22]. Daily T G , T N and T X were extracted from these climate model experiments.…”

“…However, early spring temperatures might have a positive effect on the pest [20]. Another aspect, warmer conditions, may accelerate the rate of development, as heat units accumulate earlier and faster, and thus increase voltinism [1,[21][22][23]. Lastly, future warmer temperatures will not only individually affect the phenology of the grapevine and grape moth, but also the biological interactions between them [24].…”

“…In terms of the impact of climate change in the DDR, a warming and drought trend is projected in the coming decades [26], reflected in the earliness of the phenological stages of the grapevine [5,27]. Furthermore, a recent study indicates an earlier three LB flights (beginning and peak of flight) in future climate scenarios, with a fourth complete flight more likely to happen [22].…”

Exploring the Use of Entomopathogenic Nematodes and the Natural Products Derived from Their Symbiotic Bacteria to Control the Grapevine Moth, Lobesia botrana (Lepidoptera: Tortricidae)

“…First, all of the suitable areas for Vitis vinifera are at risk of EGVM pest presence [10,11]. On the other hand, warming-derived phenological shifts imply a higher impact of first-generation EGVM and increased voltinism [12,13], increasing the land range EGVM's damaging effects. The first larval generation of the season usually attacks inflorescence, while later generations cause damage to the fruits.…”