Likelihood of Extreme Early Flight of Myzus persicae (Hemiptera: Aphididae) Across the UK.

Myzus persicae (Sulzer, Hemiptera: Aphididae) is a major global crop pest; it is the primary aphid vector for many damaging viruses and has developed resistance to most insecticides. In temperate regions, the risk of widespread crop infection and yield loss is heightened following warm winters, which encourage rapid population growth and early flight. Estimates of the frequency and magnitude of warm winters are, therefore, helpful for understanding and managing this risk. However, it is difficult to quantify the statistical distribution of climate events, particularly extremes, because climate observations represent just a small sample of the possible climate variations in a region. The purpose of this study was to establish a large-scale relationship between temperature and M. persicae observations across the UK and apply this to a very large ensemble of climate model simulations, which better sample the variability in climate, to quantify the current likelihood of extreme early M. persicae flight across the UK. The timing of M. persicae flight was shown to be significantly related to January-February mean temperature, where a 1°C warmer/cooler temperature relates to about 12 d earlier/later flight. Climate model simulations predict 40% likelihood of experiencing a year with unprecedented early M. persicae flight during the next decade in the UK. Results from this method can help crop managers assess the long-term viability of crops and management practices across the UK and provide early warning information for targeting pest surveillance activities on the locations and timings at highest risk of early M. persicae flight.

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.

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.

Discovery of an unknown diversity of Leucinodes species damaging Solanaceae fruits in sub-Saharan Africa and moving in trade (Insecta, Lepidoptera, Pyraloidea).

The larvae of the Old World genera Leucinodes Guenée, 1854 and Sceliodes Guenée, 1854 are internal feeders in the fruits of Solanaceae, causing economic damage to cultivated plants like Solanummelongena and Solanumaethiopicum. In sub-Saharan Africa five nominal species of Leucinodes and one of Sceliodes occur. One of these species, the eggplant fruit and shoot borer Leucinodesorbonalis Guenée, 1854, is regarded as regularly intercepted from Africa and Asia in Europe, North and South America and is therefore a quarantine pest on these continents. We investigate the taxonomy of African Leucinodes and Sceliodes based on morphological characters in wing pattern, genitalia and larvae, as well as mitochondrial DNA, providing these data for identification of all life stages. The results suggest that both genera are congeneric, with Sceliodes syn. n. established as junior subjective synonym of Leucinodes. Leucinodesorbonalis is described from Asia and none of the samples investigated from Africa belong to this species. Instead, sub-Saharan Africa harbours a complex of eight endemic Leucinodes species. Among the former nominal species of Leucinodes (and Sceliodes) from Africa, only Leucinodeslaisalis (Walker, 1859), comb. n. (Sceliodes) is confirmed, with Leucinodestranslucidalis Gaede, 1917, syn. n. as a junior subjective synonym. The other African Leucinodes species were unknown to science and are described as new: Leucinodesafricensis sp. n., Leucinodesethiopica sp. n., Leucinodeskenyensis sp. n., Leucinodesmalawiensis sp. n., Leucinodespseudorbonalis sp. n., Leucinodesrimavallis sp. n. and Leucinodesugandensis sp. n. An identification key based on male genitalia is provided for the African Leucinodes species. Most imports of Leucinodes specimens from Africa into Europe refer to Leucinodesafricensis, which has been frequently imported with fruits during the last 50 years. In contrast, Leucinodeslaisalis has been much less frequently recorded, and Leucinodespseudorbonalis as well as Leucinodesrimavallis only very recently in fruit imports from Uganda. Accordingly, interceptions of Leucinodes from Africa into other continents will need to be re-investigated for their species identity and will likely require, at least in parts, revisions of the quarantine regulations. The following African taxa are excluded from Leucinodes: Hyperanalyta Strand, 1918, syn. rev. as revised synonym of Analyta Lederer, 1863; Analytaapicalis (Hampson, 1896), comb. n. (Leucinodes); Lygropiaaureomarginalis (Gaede, 1916), comb. n. (Leucinodes); Sylleptehemichionalis Mabille, 1900, comb. rev., Sylleptehemichionalisidalis Viette, 1958, comb. rev. and Sylleptevagans (Tutt, 1890), comb. n. (Aphytoceros). Deanolisiriocapna (Meyrick, 1938), comb. n. from Indonesia is originally described and misplaced in Sceliodes, and Leucinodescordalis (Doubleday, 1843), comb. n. (Margaritia) from New Zealand, Leucinodesraondry (Viette, 1981), comb. n. (Daraba) from Madagascar as well as Leucinodesgrisealis (Kenrick, 1912), comb. n. (Sceliodes) from New Guinea are transferred from Sceliodes to Leucinodes. While Leucinodes is now revised from Africa, it still needs further revision in Asia.

Population Development of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under Simulated UK Glasshouse Conditions.

Tomato leafminer Tuta absoluta (Meyrick) is a major pest of tomato plants in South America. It was first recorded in the UK in 2009 where it has been subjected to eradication policies. The current work outlines T. absoluta development under various UK glasshouse temperatures. The optimum temperature for Tuta development ranged from 19-23 °C. At 19 °C, there was 52% survival of T. absoluta from egg to adult. As temperature increased (23 °C and above) development time of the moth would appear to decrease. Population development ceases between 7 and 10 °C. Only 17% of eggs hatched at 10 °C but no larvae developed through to adult moths. No eggs hatched when maintained at 7 °C. Under laboratory conditions the total lifespan of the moth was longest (72 days) at 13 °C and shortest (35 days) at both 23 and 25 °C. Development from egg to adult took 58 days at 13 °C; 37 days at 19 °C and 23 days at 25 °C. High mortality of larvae occurred under all temperatures tested. First instar larvae were exposed on the leaf surface for approximately 82 minutes before fully tunnelling into the leaf. Adult longevity was longest at 10 °C with moths living for 40 days and shortest at 19 °C where they survived for 16 days. Generally more males than females were produced. The potential of Tuta absoluta to establish populations within UK protected horticulture is discussed.