Due to adventive grapevine pathogens like Plasmopara viticola, variable problems in European viticulture such as yield loss and the high usage of plant protection still occur. For that reason many breeders invest hope in cultivating fungi-resistant varieties using American and Asian wild species as resistance donor in new crosses. Several resistance loci against P. viticola were identified from different working groups so far. By facing the possibility of P. viticola strains to overcome resistances, quantitative trait loci (QTL) analysis was used in this work to screen for new resistance loci in two cross populations. Hereby a major QTL (Rpv10.2) as well as several minor QTLs were detected. The calculation of the QTLs was based on phenotypic data obtained from infections tests and the creation of linkage maps of the cross populations ‘Tigvoasa’ x We 90-06-12 (TVxWe90) und ‘Cabernet Franc’ x ‘Triomphe d‘Alsace’ (CFxTA). Simple sequence repeat (SSR) and RNase H2-dependent amplicon sequencing (rhAmpSeq) markers were used to create the linkage maps. Rpv10.2 was identified as resistance locus by a major QTL on linkage group 09 in the genome of We90. The locus was introgressed by the resistant cultivar We 90-06-12, which derives from the Asian wild grape Vitis amurensis. The area of Rpv10.2 was restricted by the SSR-markers GF09-65 and GF09-47 to approximately 80 kb on the V. vinifera reference genome. This area matches the already identified Rpv10 locus from ‘Solaris’, which also derived from V. amurensis (Schwander et al. 2012). Based on microscopic observation of infected leaf samples, We 90-06-12 and ‘Solaris’ showed similar reaction of resistance to inhibit the growth of P. viticola hyphae. The putative candidate gene RPS5-like is suspected to stay in connections with the Rpv10-mediated resistance ‘Solaris’ (Zyprian et al., in preparation). Due to sequence analysis, the corresponding gene could be verified in We 90-06-12 without any differences. In comparison, a further candidate gene AP2-ERF-like showed a variation in the coding sequence. The variation was observed outside the functional area of the AP2 protein domain. In addition marker analysis repeatedly showed deviating data for We 90-06-12 regarding GF09-46 and GF09-48, which are markers used in breeding since many years to identify new cultivars carrying the Rpv10 locus. The results of this work give evidence for an Rpv10 haplotype defined as Rpv10.2, which can be used for breeding. Rpv10.2 can be distinguished from the Rpv10 locus by the markers GF09-68, GF09-46 and GF09-48. The findings of this work can be used for further characterization of the Rpv10.2 locus in the future. In case of population CFxTA multiple weak QTLs were detected. Those QTLs could only be reproduced for linkage group 12 and 17. The areas of the QTLs on those groups cover long distances on the V. vinifera reference genome. It is necessary to obtain additional marker data to point out if these QTLs are suitable for breeding. It should be mentioned that until now no resistance loci were detected on linkage group 17. In comparison, Rpv6 was detected on linkage group 12 (Marguerit et al. 2009). ‘Riparia Gloire de Montpellier’, a selection of the American wild grape Vitis riparia, was recognized as the origin of this locus. The variety ‘Triomphe d’Alsace’, which represents the resistance donor in case of the cross CFxTA, originates from ‘Riparia Gloire de Montpellier’. If the detected QTL on linkage group 12 is identical to the Rpv6 locus should be verified by further investigations. This work indicates that the resistance level decreases from ‘Riparia Gloire de Montpellier’ to ‘Triomphe d’Alsace’. The hypersensitive response (HR) shown by the cultivar ‘Triomphe d’Alsace’ is weaker compared to ‘Riparia Gloire de Montpellier’ and matches with the identification of multiple weak QTLs in the population CFxTA.

The pollen beetle, Meligethes aeneus (Fabricius) (syn. Brassicogethes aeneus (Fabricius)) is a major pest in the production of oilseed rape, Brassica napus L., in Europe. At high levels of crop infestation, adult beetles can cause severe economic damage by destroying the buds. Chemical control of this pest is biased due to the widely distributed pyrethroid resistance and a decreasing availability of insecticides with different modes of action. Effective insecticides are required not only to avoid yield losses by overwintered pollen beetles but also to minimize the reproduction rate of the beetle, thereby reducing the infestation pressure and the frequency of insecticide treatments in following years. The objectives of the present study were to determine the effects of the systemic neonicotinoid Biscaya (a.i. thiacloprid, 72 g ha-1) and the two contact pyrethroids Mavrik (tau-fluvalinate, 48 g ha-1) and Karate Zeon (lambda-cyhalothrin, 7.5 g ha-1) on population development of pollen beetle. In the years 2013-2015, field trials were established on crops of oilseed rape in the region of Braunschweig (northern Germany) and further locations in Germany. Recommended dose rates of the insecticides were applied at the bud stage, at the beginning of flowering or at full flowering of the crop. The effect of insecticide applications on overwintered pollen beetles was assessed by counting pollen beetles on plants before and up to two weeks after application. Furthermore, the impact of insecticide application at the bud stage on infestation of buds with eggs and larvae was investigated in field trials as well as in greenhouse experiments using plants and pollen beetles collected from untreated and Biscaya- or Mavrik-treated field plots. The effects of insecticides on larval instars and emergence of new generations of pollen beetles were studied in field trials. In addition, the impact of the insecticide treatments on parasitism rates of pollen beetle larvae by Tersilochus heterocerus and Phradis spp. was analysed by collecting samples of larvae from different field trials distributed over Germany. Application of Biscaya and Mavrik during the bud stage significantly reduced the abundance of the overwintered pollen beetles up to seven days after application. In contrast, application of Karate Zeon did not affect beetle numbers on plants. Consequently, the number of buds infested with eggs and larvae was reduced at least for 14 days after application of Biscaya and Mavrik compared to Karate Zeon-treated and untreated plots. Biscaya had a stronger effect on infestation of buds with eggs and larvae than Mavrik. Results of greenhouse experiments indicated that the lower number of infested buds found in Mavrik-treated plots resulted from a reduced number of overwintered pollen beetles, whereas in Biscaya-treated plots in addition to effects on overwintered pollen beetles a further reduction of bud infestation occurred. In all three experimental years the application of Biscaya at the beginning of flowering or full flowering resulted in significantly higher numbers of premature L1-larvae dropping down from the plants to the ground. This effect was only observed in Biscaya-treated plots, with up to 425% more L1-larvae dropping within one week compared to the control. Numbers of mature L2-larvae dropping down for pupation was reduced in plots treated with Mavrik and especially Biscaya. In Karate Zeon-treated plots the number of dropping L2-larvae was even higher than in control plots. In accordance with lower numbers of L2-larvae in Biscaya- and Mavrik-treated plots the number of emerging new generation beetles was reduced. No significant effect of insecticide application on parasitism rates of pollen beetle larvae by T. heterocerus and Phradis spp. was found. The parasitoid T. heterocerus was predominant with parasitized pollen beetle larvae occurring in all field trials and all experimental years, usually not earlier than in BBCH 65. In contrast Phradis spp. larvae were not detected in all field trials in 2015 and not before BBCH 67. Altogether, the results demonstrate that applications of Biscaya and Mavrik cause reductions of pollen beetle population growth. Especially the neonicotinoid Biscaya could form an important part of a resistance management program for controlling populations of pyrethroid resistant pollen beetles. Applications during the bud stage did not only reduce the overwintered pollen beetles, but in addition had sublethal effects on infestation of buds with eggs and larvae. Particularly Biscaya targeted for control of cabbage seedpod weevil or brassica pod midge during flowering has shown long-lasting effects on pollen beetle populations without affecting parasitization of pollen beetle larvae.