The file contains the raw data of the manuscript " Overrepresentation of Alopecurus myosuroides with high levels of resistance towards herbicides applied in spring on heavy clay soils" by Treer S, Scherer K, Pallez-Barthel M, Dam D, Beyer M

Bunch rot caused by Botrytis cinerea is a major fungal disease in grapevines. Under humid climatic conditions, bunch rot development on grapes cannot be completely suppressed and bunch rot control strategies mainly aim to delay the epidemic. In the present study, we investigated the potential of the innovative cultural practice “partial double-pruning after bloom (PDP)” to delay the bunch rot epidemic on Pinot gris and Riesling cultivars over five consecutive seasons (2016-2020) in Remich/Luxembourg. Control vines were pruned at winter to one 10-node fruiting cane per vine, while in PDP, two 10-node fruiting canes per vine were kept; one of the two canes was removed at BBCH 73 (2-3 weeks after bloom). In all the 10 cultivar*year combinations, the bunch rot disease severity at the final assessment date (shortly before harvest) was lower in PDP than in the control. This reduction was significant (P £ 0.05) in 7 of the 10 cultivar*year combinations. PDP significantly delayed the date when 5 % disease severity was reached; in data pooled over the five years this delay ranged between 10.3 (Pinot gris) and 8.3 days (Riesling). The proportion of non-marketable fruit was significantly reduced by 41 % (Pinot gris) and 53 % (Riesling). Total yield per plant was reduced by 10 % (Pinot gris) and 19 % (Riesling), with a significant increase in total soluble solids at harvest in the case of Riesling. An additional evaluation in the year 2020 revealed reduced cluster compactness in PDP for both cultivars. PDP turned out to be an innovative, efficient, reliable and relatively cost-efficient cultural practice to delay the bunch rot epidemic in grapes. It can be integrated as one module into the best practice strategy to control bunch rot and contributes to pesticide reduction in viticulture.

The invasive pest Drosophila suzukii is threatening berry production. It is mainly managed via chemical control, which is associated with consumer and environmental concerns. Here, we tested the efficacy of mineral dusts under field and laboratory conditions in 2019 and 2020. Furthermore, population dynamics were studied in a vineyard and its surroundings. The kaolin products Cutisan and Surround®, as well as the CaCO3 product Carboliq, had neither insecticidal nor repellent effects on Drosophila suzukii adults in laboratory choice tests with grapes at concentrations of up to 2% (w/v). Cutisan and Surround® significantly reduced the number of deposited eggs (−41.9% and −49.3% respectively) while Carboliq had no effect on the oviposition under laboratory conditions. The Surround® treatment significantly reduced the number of flies trapped on 09 September 2020 at a test vineyard. Depending on the assessment date and treatment, between 59% and 84% of the flies in the bait traps were females. The number of eggs found in fruit treated with Carboliq in the field was higher at each assessment date than in the control but this difference was not statistically significant. Fruit treated with Cutisan or Surround® in the field showed an equivalent or lower average number of eggs compared with the control, but this difference was only significant on 24 September 2020. Between May 2015 and October 2020, the highest number of D. suzukii adults was observed around September in the field and a decline of the population occurred in the winter months until July. In epidemic years, temperature – humidity – combinations prior to population peaks were quite stable with low humidity being associated with a high temperature and vice versa. In non‐epidemic years, humidity fluctuated more than in epidemic years and temperatures were lower before population peaks. The effect of global radiation on population maxima seemed to be minor.

In integrated pest management (IPM), pests are controlled when the costs of control correspond with the damage caused by a pest on a monetary scale, implying that low pest levels are left uncontrolled. Several forecast models have been developed in plant pathology to warn farmers before an epidemic occurs to allow timely control. Most of these models do not predict a control threshold (pest level at which action needs to be taken to prevent economic losses at the farm level) directly making an application in precision agriculture where pesticides and other inputs shall be used precisely where and when they are needed, difficult. Here, we quantified the temporal distance between critical rainfall periods and the breaking of the control threshold of Z. tritici on winter wheat, as affected by temperature based on data from 52 field experiments carried out in Luxembourg between 2005 and 2016. The highest frequency of hours with rain (≥ 0.1 mm/h) was observed approximately at 300 h before epidemic outbreaks at about 13 °C, at 350 h at 11.5 °C and at about 475 h at about 7.5 °C. A Q10 value of 2.8 was estimated. The knowledge generated here will be used to construct a model that directly forecasts the time at which the control threshold will be reached and thus, when fungicide use is needed according to the standards of IPM with direct applicability in precision agriculture.

In precision agriculture, pesticides and other inputs shall be used precisely when (and where) they are needed. European Directive 2009/128/EC calls for respecting the principles of integrated pest management (IPM) in the member states. To clarify the question, when, for instance, fungicide use is needed, the well-established economic principle of IPM may be used. This principle says that pests shall be controlled when the costs of control correspond with the damage the pests will cause. Disease levels corresponding with the costs of control are referred to as control thresholds in IPM. Several models have been developed in plant pathology to predict when epidemics will occur, but hardly any of these models predicts a control threshold directly limiting their usefulness for answering the question when pest control is needed according to the principles of IPM. Previously, we quantified the temporal distance between critical rainfall periods and the breaking of the control threshold of Zymoseptoria tritici on winter wheat as being affected by temperature, based on data from 52 field experiments carried out in Luxembourg from 2005 to 2016. This knowledge was used to construct the ShIFT (SeptorIa ForecasT, https://shift.list.lu/ ) model, which has been validated using external data recorded between 2017 and 2019. Within the efficacy period of a systemic fungicide, the model allowed correct predictions in 84.6% of the cases, while 15.4% of the cases were predicted falsely. The average deviation between the observed and predicted dates of epidemic outbreaks was 0.62 ± 2.4 days with a maximum deviation of 19 days. The observed and predicted dates were closely correlated (r = 0.92, P < 0.0001). Apart from outliers, the forecast model tested here was reliable within the period of efficacy of current commercial fungicides.

The European commission directive EC 128/2009 calls for monitoring pests and pathogens of major crops. The monitoring data may be analysed for trends over time, including tests for a potential loss of biodiversity in the domain of plant pests and pathogens. The monitoring programs carried out in Luxembourg since 2007 provided evidence for an increasing role of yellow rust and a decreasing role of brown rust on winter wheat. Vast inter-annual variability was observed at the level of Fusarium head blight and mildew symptoms on winter wheat as well as at the level of Ceutorhynchus counts in oilseed rape, but no trend towards extinction could be demonstrated. Septoria leaf blotch was present in winter wheat at high levels towards the end of all seasons. The maximum number of Brassicogethes aeneus individuals found per main stem and season on oilseed rape increased slightly but significantly between 2007 and 2017. Substantial evidence for highly dynamic changes in the pest populations was found, but no evidence for the vanishing of the monitored species could be demonstrated.

The drosophilid fly Drosophila suzukii is an invasive pest that has recently started threatening fruit production in Europe. In contrast to many other fruit flies, D. suzuk ii is able to lay eggs in ripening and mature fruits where larvae develop, rendering fruits unmarketable. This preference for ripening fruit requires pest control shortly before harvest, implying a high risk of residues on the fruit if synthetic insecticides are used. As the current management practices largely rely on chemical control, the need for alternative solutions has emerged. Here, we review the studies published up to now on the efficacy of natural compounds against D. suzukii. Several natural compounds were identified that act as repellents, contact or ingestion toxicants, fumigants, ovicides or oviposition deterrents. The most promising compounds of each group were (i) essential oils (EOs) such as the EO of thyme or its major ingredient thymol which repelled flies from fresh fruits for at least 24 h; (ii) Leptospermum ericoides and L. scoparium EOs, which expressed contact toxicity at a LD 50 < 1.2 μg/fly; (iii) the combination of erythritol and sucrose, which was a potent ingestion toxicant against adults and (iv) a chitinase from Euphorbia characias against larvae (both of the latter two resulted in 100% mortality); (v) the EO ingredients perilla aldehyde, geranial and neral showed the highest insecticidal activities as fumigants (LC 50 < 1.52 mg/l air for males and 2.6 mg/l air for females) and (vi) powdered sulphur was reported to be the most efficient oviposition deterrent, reducing the number of eggs deposited into the fruits by 76%. To enable a wider use of the natural compounds in sustainable agriculture, more information on (i) potential effects on non-target organisms, (ii) field performance and (iii) life cycle analyses results is currently needed.

Climate change will have several consequences for agro-systems, one of which will concern changes to the development of pathogens. Because of the losses it causes, particularly in organic farming, Monilinia laxa is an important pathogen affecting apricot crops. This study focuses on the consequences of climate change regarding blossom and twig blight (Monilinia laxa) of apricot. To achieve this, a Climatic Index of cumulated Blight risk (CIB) was built, to obtain the weighted sum of blossom blight incidence throughout the blooming period. An epidemiological model to calculate the incidence of blossom blight during every potentially infectious episode and based on biological parameters, was calibrated using a trap pot experiment where trees were placed in orchards and subject to various meteorological conditions. The CIB derived from this model was evaluated on field data, and was shown to be a robust and useful tool to predict the effects of climate change on the development of apricot blight. Then, using the CIB with a phenological model to predict blooming periods in the future, we estimated the risks of apricot blight until 2100 on four contrasted apricot cultivars and in three geographical zones under climate change scenarios RCP 4.5 and 8.5. This study revealed different effects of climate change depending on the cultivar and altitude. Apricot trees would bloom earlier (up to a difference of 50 days between 1950 and 2100) under climate change. Under the combined effects of these shifts of blooming period and changing climatic conditions, late cultivars such as Bergarouge might see a reduction in the risk of blossom blight (down to 31%) because of warmer but dryer blooming periods. Other varieties (e.g.: Bergeron) could experience an increase in this risk by up to 27% with a shift of the blooming period towards rainier conditions at the highest altitudes. The results of this study could be used to anticipate future changes as well as be used at present as a decision-support tool for farmers.