Quantitative PCR assay for detection of Bois noir phytoplasmas in grape and insect tissue

In Europe's vineyards "Bois noir" (BN) is an expanding yellows disease on Vitis vinifera. It is associated with phytoplasmas of the stolbur group (16SrXII-A). Two subtypes are important, one is associated with Urtica dioica and one with Convolvulus arvensis. Both phytoplasma types are transmitted by the insect Hyalesthes obsoletus. A nucleic acid extraction method for V. vinifera and H. obsoletus was developed together with a real time PCR (qPCR) assay based on a polymorphic sequence with homology to a putative dimethyladenosine transferase. The comparison of the conventional detection method with the qPCR assay of 40 insect and 40 V. vinifera samples showed a 10 % higher sensitivity of qPCR in plant samples. The titer of phytoplasmas in H. obsoletus was 2643-fold increased in the strongest infected samples compared to the lowest ones. The results suggest this real-time PCR as a valid and fast alternative procedure for the detection and quantification of BN phytoplasmas. The assay allows to discriminate the two phytoplasma types and to quantify phytoplasmas in H. obsoletus.

First European leaf-feeding grape phylloxera (Daktulosphaira vitifoliae Fitch) survey in Swiss and German commercial vineyards

Recent observations report the worldwide incidence of leaf-feeding grape phylloxera in formerly resistant scions of commercial vineyards. To analyze the genetic structure of leaf-feeding phylloxera, we performed an extensive sampling of leaf-feeding phylloxera populations in seven regions (“cantons”) in Switzerland and Germany. The use of polymorphic microsatellite markers revealed presence of 203 unique grape phylloxera multilocus genotypes. Genetic structure analyses showed a high genetic similitude of these European samples with phylloxera samples from its native habitat on Vitis riparia (northeastern America). Nevertheless, no genetic structure within the European samples was observed, and neither host, geography nor sampling date factors caused clear effects on phylloxera genetic stratification. Clonality was high in commercial vineyards and leaf-feeding grape phylloxera strains were found to be present in scion leaves and rootstock roots in the same vineyard, potentially indicating migration between both habitats. We found indications of sexual reproduction, as shown by high degrees of genetic variation among collection sites

Corrigendum

Quantitative PCR assay for detection of Bois noir phytoplasmas in and insect tissueVitis 52 (2), 85-89 (2013

First European leaf-feeding grape phylloxera (Daktulosphaira vitifoliae Fitch) survey in Swiss and German commercial vineyards

International audienceRecent observations report the worldwide incidence of leaf-feeding grape phylloxera in formerly resistant scions of commercial vineyards. To analyze the genetic structure of leaf-feeding phylloxera, we performed an extensive sampling of leaf-feeding phylloxera populations in seven regions ("cantons") in Switzerland and Germany. The use of polymorphic microsatellite markers revealed presence of 203 unique grape phylloxera multilocus genotypes. Genetic structure analyses showed a high genetic similitude of these European samples with phylloxera samples from its native habitat on Vitis riparia (northeastern America). Nevertheless, no genetic structure within the European samples was observed, and neither host, geography nor sampling date factors caused clear effects on phylloxera genetic stratification. Clonality was high in commercial vineyards and leaf-feeding grape phylloxera strains were found to be present in scion leaves and rootstock roots in the same vineyard, potentially indicating migration between both habitats. We found indications of sexual reproduction, as shown by high degrees of genetic variation among collection sites

First European leaf-feeding grape phylloxera (Daktulosphaira vitifoliae Fitch) survey in Swiss and German commercial vineyards

Recent observations report the worldwide incidence of leaf-feeding grape phylloxera in formerly resistant scions of commercial vineyards. To analyze the genetic structure of leaf-feeding phylloxera, we performed an extensive sampling of leaf-feeding phylloxera populations in seven regions (“cantons”) in Switzerland and Germany. The use of polymorphic microsatellite markers revealed presence of 203 unique grape phylloxera multilocus genotypes. Genetic structure analyses showed a high genetic similitude of these European samples with phylloxera samples from its native habitat on Vitis riparia (northeastern America). Nevertheless, no genetic structure within the European samples was observed, and neither host, geography nor sampling date factors caused clear effects on phylloxera genetic stratification. Clonality was high in commercial vineyards and leaf-feeding grape phylloxera strains were found to be present in scion leaves and rootstock roots in the same vineyard, potentially indicating migration between both habitats. We found indications of sexual reproduction, as shown by high degrees of genetic variation among collection sites

Automated airborne pest monitoring – a novel technological approach to monitor Drosophila suzukii

Spotted wing drosophila (SWD, Drosophila suzukii) has become a serious pest in Europe attacking many soft-skinned crops such as several berry species and grapevine since its spread in 2008 to Spain and Italy. An efficient and accurate monitoring system to identify the presence of SWD in crops and their surroundings is essential for the prevention of damage to economically valuable fruit crops. Existing methods for monitoring SWD are costly, time and labour-intensive, prone to errors, and typically conducted at a low spatial resolution. To overcome current monitoring limitations, we are developing a novel system consisting of photographable traps, which are monitored by means of unmanned aerial vehicles (UAVs) and an image processing pipeline that automatically identifies and counts the number of SWD per trap location. To this end, we are currently testing the approach using high-resolution RGB imagery of SWD traps taken from both a static position (tripod) and from a UAV. These are then used as input to train deep learning models. Preliminary results show that a large part of the SWD can be correctly identified using a ResNet-18-based model. An autonomous UAV platform will be programmed to capture imagery of the traps under field conditions. The collected imagery will be transferred directly to cloud-based storage for subsequent processing and analysis to identify the presence and count of SWD in near real time. This data will be used as input to a decision support system (DSS) to provide valuable information for farmers

AAPM : automated airborne pest monitoring

www.aapmproject.eu

AAPM : automated airborne pest monitoring

Spotted wing drosophila (SWD) is a fruit fly attacking soft berry fruits. To measure the success of control measures against SWD, accurate and frequent monitoring of its presence is required. The AAPM project develops a system based on planar, photographable such as sticky traps that are monitored with high-resolution airborne imagery. The images are analyzed with deep learning methods and target insects are counted. Currently, we selected the best performing trap to catch SWD. Some hundred traps with SWD were used to train detection and counting algorithms. The next part of the project will focus on airborne image acquisition and integration of SWD counts into decision support systems providing information for IPM strategies