The potential role of aerial pesticide applications to control landscape-scale outbreaks of pests and diseases in British forestry with a focus on dothistroma needle blight

British forestry is threatened by numerous pests and diseases. This study investigated the potential for re-introduction of aerial pesticide applications for landscape-scale disease management. In North Scotland in 2013 and 2015, copper oxychloride was applied to Pinus sylvestris L. stands infected with Dothistroma septosporum (Dorogin) Morelet. Helicopters distributed ultra-low-volume (ULV) applications of product via Micronair rotary atomisers, following methods used against D. septosporum in P. radiata D. Don stands in New Zealand. Product deposition was quantified on paper catchers and in foliage, soil and water. Catchers 100 m beyond the plot boundaries intercepted 0.5 per cent of within-plot mean deposition. Foliar analysis revealed slightly elevated copper concentrations (+0.07 μg g−1 dw) 250 m outside plot boundaries. Copper in foliage and needle litter remained above background levels for 109 and 157 weeks after application, respectively, longer than recorded during New Zealand operations. Concentrations in the soil increased over 3 years’ monitoring, whilst deposition into water traps resulted in copper concentrations well within limits set by the Scottish Environmental Protection Agency. No deleterious impacts on vascular and non-vascular ground and canopy flora were recorded. Copper fungicide applications significantly reduced foliar infection at both sites but did not affect needle retention. Further ground-based trials will investigate the efficacy of other actives. In Britain, such aerial operations have not occurred for two decades: this study demonstrated aerial and ground teams have the necessary expertise for their re-introduction, whilst highlighting areas needing further optimization.

LEVELS OF REGIONAL PHENOTYPIC ADAPTATION (QST) INDICATE THAT NEUTRALITY HAS SHAPED THE POPULATION STRUCTURE OF THE SOYBEAN-INFECTING PATHOGEN Rhizoctonia solani AG-1 IA

ABSTRACT Populations of the soybean leaf blight pathogen (Rhizoctonia solani AG-1 IA) are highly genetically differentiated along a latitudinal gradient in the major soybean growing regions of Brazil. However, the evolutionary processes leading to regional adaptation are still unknown. The objective of this study was to evaluate the relative importance of neutral genetic variation and natural selection on the divergence and regional adaptation of populations of the soybean-infecting pathogen R. solani AG-1 IA. Therefore, we compared the phenotypic differentiation in quantitative traits (QST) and the neutral genetic differentiation (FST, based on microsatellites data) among three pairs of populations. As measures of phenotypic responses of the fungus (quantitative traits), we estimated the tolerance to temperature stress and the tolerance to a broad-spectrum fungicide (copper oxychloride) under optimal (25 °C) and high temperature conditions (33.5 °C). In general there was an increase in genetic variance with a positive effect on the heritability for tolerance to copper fungicide under temperature stress. The genetic differences among populations were the main determinants of thermal adaptation in R. solani AG-1 IA (h2 > 0.70). The analysis of neutral genetic structure (FST) indicated subdivision between the three pairs of populations. Although population pairwise comparisons between FST and QST values did not follow a single pattern, the majority of QST values did not differ significantly from FST, indicating that, for the quantitative characters studied, neutrality (or neutral evolution) had a major role in the regional adaptation of R. solani AG-1 IA populations.

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of brewing and dry-hopping using hops treated with copper-based fungicides (CBFs) on the final transition metal content of model buffer solutions and pilot-scale systems of wort and beer. Copper levels in model wort and beer solutions were elevated (105.6% and 230.4% increase, respectively) when CBF-treated hops were used. In laboratory-prepared wort, elevated copper concentrations were not observed when CBF-treated hops were used for boiling. Dry hopping of beer using CBF-treated hops led to significant increases in total copper content (ca. 75 µg/kg vs. ca. 40–50 µg/kg in the control-hopped beer) when yeast was absent from the treated beer, but not when yeast was present. It was observed that manganese levels were significantly elevated in all hopped beers (ca. 495–550 µg/kg vs. 90–125 µg/kg in the unhopped control), regardless of hop treatment. A hop varietal thiol, 4-Mercapto-4-methylpentan-2-one, was spiked into treated beers, and the rate of oxidative loss was monitored during aging. Rates of thiol loss in treated beer samples did not differ across CBF treatments but were significantly lower in unhopped controls in the absence of yeast (p < 0.0001) and correlated significantly with total manganese content of the beers (R2 = 0.4228, p = 0.0006). The rate of staling in hopped beers as measured by the rate of 1-hydroxyethyl radical generation did not differ among hop treatments, suggesting that excess copper content contributed from the hops does not negatively impact the oxidative stability of the beers. These findings suggest that brewers can use CBF-treated hops without any negative implications for the shelf stability of their beers and do not contraindicate the use of CBF in hops production when necessary.

New Jersey Farm Soil Copper Levels Resulting from Copper Fungicide Applications

Vegetable growers have expressed concerns regarding the accumulation of copper in soil where copper-based fungicides are used and have requested guidance for copper pesticide applications. Elevated soil copper levels have the potential to become toxic to sensitive crops and impact soil health. In response, total and available soil copper levels were surveyed using soil analysis of samples from 15 New Jersey farms representing organic and conventional production methods. Lettuce (Lactuca sativa) was grown in the sampled soil in a greenhouse trial and evaluated for signs of copper toxicity. We found that all 15 farms were using copper fungicide preventative sprays during the previous 2 years. The soil copper levels of these farms were higher in copper-applied soils than the corresponding noncopper-applied soil. Soil copper levels were not near or in excess of established clean-up limits at any of the locations. Greenhouse-grown lettuce in the sampled soils was not negatively impacted by the copper levels. Due to the increase in the total and soluble soil copper levels, growers should use best management practices to prevent the accumulation of excessive amounts of copper in the soil over time.

Investigation of the Copper Content in Vineyard Soil, Grape, Must and Wine in the Main Vineyards of Romania: a Preliminary Study

The long-term use of copper in viticulture has caused great copper accumulation in vineyard soils, resulting in negative effects on the environment through toxicity to aquatic and soil organisms. The aim of this study was to investigate the copper content in vineyard soils, grapes and wines from Dealu Bujorului, Murfatlar, Tarnave, Iasi and Ştefăneşti vineyards. The ICP-MS method was used for copper determination in vineyard soil, grape must and wine. Copper concentration in red wine samples was significantly higher than in the white wine samples. Values for Transfer Factor and Mobility Ratio indicates that Vitis vinifera L. does not allow the accumulation of copper from vineyard soil in must grape and wine. The copper concentration in grapes, must and wine has been influenced by the copper concentration in soils, by copper fungicide used to protect the vine and by other factors such as the biological specificity of cultivars during growth.

Seasonal microbial dynamics on grapevine leaves under biocontrol and copper fungicide treatments

Winemakers have long used copper as a fungicide on grapevine. However, the potential of copper to accumulate on soil and affect the biota poses a challenge to achieving sustainable agriculture. One recently developed option is the use of biocontrol agents to replace or complement traditional methods. In the present study, a field experiment was conducted in South Africa in which the leaves in two blocks of a vineyard were periodically treated with either copper sulphate or sprayed withLactobacillus plantarumMW-1 as a biocontrol agent. This study evaluated the impact of the two treatments on the bacterial and fungal communities as they changed during the growing season. To do this, NGS was combined with quantitative strain-specific and community qPCRs. The results revealed the progression of the microbial communities throughout the season and how the different treatments affected the microbiota. Bacteria appeared to be relatively stable at the different time points, with the only taxa that systematically changed between treatments beingLactobacillaceae, which included reads from the biocontrol agent. Cells ofLactobacillus plantarumMW-1 were only detected on treated leaves using strain-specific qPCR, with its amount spanning from 103to 105cells/leaves. Conversely the fungal community was largely shaped by a succession of different dominant taxa over the months. Between treatments, only a few fungal taxa appeared to change significantly and the number of ITS copies was also comparable. In this regards, the two treatments seemed to affect the microbial community similarly, revealing the potential of this biocontrol strain as a promising alternative among sustainable fungicide treatments, although further investigation is required.

Application of Copper Fungicide and Row Covers to Control Phytophthora Seedling Blight Disease on Cocoa

Phytophthora seedling blight disease is one of the important diseases in cocoa. The disease is caused by the fungus of Phytophthora palmivora belongs to class Oomycetes. The aim of this research was to determine the effectiveness of the use of row covers and copper oxide fungicide applications to control seedling blight Phytophthora. Covering treatment was to place cocoa seedlings inside bamboo frame covered by transparent plastic in order to avoid from rainfall effect. The research was conducted in the Kaliwining Experimental Station at Indonesian Coffee and Cocoa Research Institute (ICCRI). Experiments were carried out four treatments and repeated 6 times. Each treatment consists of 100 seedlings planted in polybags and placed in the nursery area with a protective paranet. The treatment consisted of (1) row covers, (2) spraying of copper oxide 0.2%, (3) a combination of row covers and copper oxide 0.2% and (4) control (no covers and spray). Observations made 7 days after treatment with an interval of 7 days for 10 weeks. The results showed that row covers able to prolong the incubation period of the disease for 14 days, while the application of row covers + copper oxide 0.2% was able to save cocoa seedlings by 96.2%.