A novel approach for exploring climatic factors limiting current pest distributions: A case study of Bemisia tabaci in north-west Europe and assessment of potential future establishment in the United Kingdom under climate change

Abstract

Bemisia tabaci (the tobacco whitefly) is an important agricultural pest of global significance primarily because of its ability to transmit multiple damaging plant viruses. To date, UK outbreaks of the whitefly have been restricted to glasshouses and there are no records of the whitefly establishing outdoors during the summer. This is despite the fact that annual degree-day models (that estimate accumulated warmth over the year above the development threshold), indicate that B . tabaci has the thermal potential for multiple summer generations in the UK. A set of 49 climate indices calculated using the present day climate (1986–2015) were therefore compared between the UK and the south of France, where B . tabaci is able to establish outdoors, to identify the factors limiting its establishment. The number of cold days and nights in summer, as well as the time spent within the whitefly’s optimum temperature range, were most significantly different between the two areas. These indices may impact the development of B . tabaci and offer an explanation for the absence of the whitefly outdoors in the UK during the summer. Further analyses undertaken with climate projections suggest that in a 2–4°C warmer world this pest could pose a risk to outdoor UK crops in July and August. A clear south-north gradient can be demonstrated for these indices. Linking any possible northwards spread of B . tabaci populations outdoors in France with changes in these indices could therefore provide an important indicator of any change in the risks of outdoor populations of this species developing in the UK. The effectiveness of climate indices in pest risk analysis is compellingly demonstrated, and it is recommended that in-depth comparisons of climatic indices between areas of pest presence and absence are conducted in other situations where forecasting the risks of pest establishment are complex and challenging.

Distribution and Genetic Variability of Bemisia tabaci Cryptic Species (Hemiptera: Aleyrodidae) in Italy

“…The adaptative process could have been favoured not only by the high genetic plasticity of the MED species but also by the increase in both winter and summer temperatures which recently occurred in the Mediterranean area. Indeed, several prediction models simulating the potential distribution of the B. tabaci species under temperature changes have proved that global climate warming would expand the northern boundaries of the open-field populations in Europe [63,64].…”

Household perception and infestation dynamics of bedbugs among residential communities and its potential distribution in Africa

“…Elevation was selected as variable because it greatly influences species' occurrence and dispersal by affecting the temperature, precipitation, vegetation, and sun characteristics (direction, intensity, etc.) on the earth's surface 54 – 56 . The study variables had different resolutions and were therefore, resampled to 1 km.…”

Commodity risk assessment of Ligustrum delavayanum topiary plants grafted on Ligustrum japonicum from the UK

“…From 1998-2015 there were between 7-35 outbreaks per year of B. tabaci in the UK and all the findings were subject to eradication. The UK outbreaks of B. tabaci have been restricted to greenhouses and there are no records of the whitefly establishing outdoors during summer (Cuthbertson and V € anninen, 2015;Bradshaw et al, 2019).…”

“…Bemisia tabaci (European populations) is present in the UK with few occurrences (location not specified) (CABI, online; EPPO, online_c) and is continuously intercepted in the UK. The UK outbreaks of B. tabaci have been restricted to glasshouses and there are no records of B. tabaci establishing outdoors during summer(Cuthbertson and V € anninen, 2015;Bradshaw et al, 2019). Bradshaw et al…”