Domesticated lettuce varieties encompass much morphological variation across a range of crop type groups, with large collections of cultivars and landrace accessions maintained in genebanks. Additional variation not captured during domestication, present in ancestral wild relatives, represents a potentially rich source of alleles that can deliver to sustainable crop production. However, these large collections are difficult and costly to screen for many agronomically important traits. In this paper, we describe the generation of a diversity collection of 96 lettuce and wild species accessions that are amenable to routine phenotypic analysis and their genotypic characterization with a panel of 682 newly developed expressed sequence tag (EST)-linked KASP™ single nucleotide polymorphism (SNP) markers that are anchored to the draft Lactuca sativa genome assembly. To exemplify the utility of these resources, we screened the collection for putative sources of resistance to currant-lettuce aphid (Nasonovia ribisnigri) and carried out association analyses to look for potential SNPs linked to resistance.Electronic supplementary materialThe online version of this article (doi:10.1007/s11032-016-0606-4) contains supplementary material, which is available to authorized users.

In the UK, severe infestations by Plutella xylostella occur sporadically and are due mainly to the immigration of moths. The aim of this study was to develop a more detailed understanding of the phenology of P. xylostella in the UK and investigate methods of monitoring moth activity, with the aim of providing warnings to growers. Plutella xylostella was monitored using pheromone traps, by counting immature stages on plants, and by accessing citizen science data (records of sightings of moths) from websites and Twitter. The likely origin of migrant moths was investigated by analysing historical weather data. The study confirmed that P. xylostella is a sporadic but important pest, and that very large numbers of moths can arrive suddenly, most often in early summer. Their immediate sources are countries in the western part of continental Europe. A network of pheromone traps, each containing a small camera sending images to a website, to monitor P. xylostella remotely provided accessible and timely information, but the particular system tested did not appear to catch many moths. In another approach, sightings by citizen scientists were summarised on a web page. These were accessed regularly by growers and, at present, this approach appears to be the most effective way of providing timely warnings.

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The overwintering stages of the carrot fly (Psila rosae (Fabricius)) were sampled at Wellesbourne, Warwickshire, during the winters of 1987, 1988, 1989 and 1990. Between 20% and 55% of the insects overwintered as pupae in diapause. The remaining insects stayed in the larval stage during the winter period and gave rise to non-diapausing pupae in the early spring. In May, adults emerged earlier, and over a shorter period, from insects that overwintered as larvae than those that overwintered as pupae. Diapause was most intense during late December and early January. In the laboratory, diapause was completed at temperatures of 5°C and above but was not completed at 0°C. When the overwintering stages were sampled in early February and maintained at constant temperatures in the laboratory, the overwintering pupae required from 114 days at 9°C to 44 days at 21.5°C to give rise to adults. In contrast, the overwintering larvae required only 91 days (9°C) and 27 days (21.5°C), respectively. Populations of overwintering P. rosae collected from Warwickshire and Norfolk had similar requirements for spring emergence but diapause pupae collected in Lancashire emerged over a longer period of time than those collected in Warwickshire. Comparisons with published data indicated that North American and European pupae had different requirements for the completion of diapause. Accumulation of weather data for a P. rosae forecast should start when temperatures are low and any date in early February would be suitable.