Copper Fungicides Research Articles

Effective Control of Neofusicoccum parvum in Grapevines: Combining Trichoderma spp. with Chemical Fungicides

Vitis vinifera is highly susceptible to grapevine trunk diseases, with Neofusicoccum parvum recognized as a highly destructive pathogen. This study investigates the biocontrol potential of five Trichoderma species (T. harzianum, T. viride, T. asperellum, and T. virens) against N. parvum, evaluating multiple biocontrol mechanisms (mycoparasitism, competition for nutrients, production of volatile organic compounds (VOCs), and antibiosis) as well as their compatibility with the fungicides copper oxychloride and sulfur. Results demonstrated that (1) Trichoderma harzianum effectively suppressed N. parvum through VOC production, mycoparasitism, and nutrient competition, significantly reducing pathogen growth in planta while showing compatibility with both fungicides, highlighting its suitability for integrated disease management; (2) Trichoderma viride showed high inhibition of N. parvum in vitro, but its phytotoxicity in planta limits its field application. These findings support T. harzianum as a promising agent within integrated disease management strategies, offering a sustainable alternative to reduce chemical fungicide reliance in controlling grapevine trunk pathogens.

Ten-Year Trends in Aerial Stem Rot Management: Evaluating Copper-Based Solutions for Sustainable Potato Cultivation

Aerial stem rot (ASR) is an important disease of potato worldwide and is predominantly caused by the soft rot bacteria Pectobacterium carotovorum. It differs from black leg (caused by P. atrosepticum) as it is found later in the season after row closure. The pathogen enters through wounds in the stem and expands outward leaving a distinct black lesion. Lesions spread down the stem as opposed to black leg lesions which spread up the stem from diseased tubers. Ten years of field trials were conducted using a susceptible variety in a randomized complete block design. Treatments consisted of different formulations of copper fungicides starting at row closure and continuing on a seven-day schedule until vine kill. Disease incidence and severity was rated visually, and results were used to calculate the Relative Area Under the Disease Progress Curve (RAUDPC), showing the rate of disease progress. Results showed that the RAUDPC was consistently higher in the untreated check compared to fungicide-treated plots, suggesting these products significantly reduced both disease incidence and severity. However, while the fungicides reduced disease, this did not always translate into higher yields. Nevertheless, factorial analysis of variance of yield by treatment showed significant differences in total yields with fungicide-treated plots outperforming the untreated check with yields at least 3 tonnes/ha higher. There have been few studies on the efficacy of copper fungicides for control of ASR. The findings of this ten-year study should provide growers with the data necessary to make informed decisions on the management of ASR.

Organic matter mitigates biotic impact of copper in fruit orchard soil

Inorganic copper (Cu) fungicides and bactericides are widely used to control disease in fruit and vegetable crops and has led to widespread accumulation of the metal in soil beyond regulatory thresholds. We aimed to elucidate the impacts of Cu on soil health within cherry orchard soils in New Zealand, focusing on three biological indicators: earthworm behaviour, soil respiration, and plant growth. We sampled soils from four blocks of different ages within a single orchard, varying in amounts of accumulated soil Cu (7–263 mg kg−1) but also in Soil Organic Matter (SOM) content (3–10 %). Experimental work was designed to isolate the impacts of both Cu and SOM on three critical biological descriptors: earthworm behaviour, soil respiration and root growth. Soils were amended to standardise both variables in laboratory and glasshouse experiments. The results demonstrated a pronounced inhibition of soil respiration and root development, as well as adverse effects on earthworm behaviour, with increasing Cu concentrations. SOM played a mitigating role, reducing the bioavailability and toxicity of Cu to soil organisms. However, the buffering capacity of SOM is limited and long-term reliance on SOM to mitigate Cu toxicity is not sustainable. Currently Cu continues to accumulate in most orchard soils. This study highlights the importance of assessing Cu bioavailability and soil health in the context of orchard management.

Strategies for identification of elite Hevea brasiliensis genotypes tolerant to ALF disease from half-sib and full-sib population

Natural Rubber (NR) from Hevea brasiliensis tree is an important commercial commodity worldwide. In general, many Hevea cultivars are vulnerable to abnormal leaf fall (ALF) disease caused by Phytophthora spp., which can lead to considerable reduction in crop production. Chemical control of ALF by spraying mineral oil-based copper fungicides is the conventional approach which is harmful to the ecosystem. Development of ALF tolerant varieties of Hevea through conventional breeding is the major objectives of this study. We evaluated the primary agronomy traits and ALF tolerance level of the newly developed Hevea clones using in vitro leaf disc bioassay as well as field screening for disease incidence consecutively for three years. Variation in disease infestation was observed among genotypes. Based on field screening, the clones which showed better field tolerance against ALF than the parental clones were selected. Clone 683 was identified as one of the most desirable genotypes which had vigorous growth as well as high crop yield in addition to ALF tolerance. The study also confirms the reliability of in vitro leaf disc bioassay technique for screening against ALF across genotypes for its inherent variability. This technique is rapid and easier and can be completed within 96 hours. This approach could reduce the burden of screening larger breeding population to a manageable size to enhance the efficiency of selection in ALF disease resistance breeding programs. Selected fast growing, high yielding ALF tolerant clones, could be further evaluated in on farm trials for recommending to the growers in the traditional region of rubber growing tracts.

Adsorption of herbicide iron chelate EDDHA 6 % and fungicide copper oxychloride in drainage water on activated carbon derived from carob pods

The study addresses a significant environmental issue regarding the removal of harmful agricultural chemicals from wastewater. Specifically, it investigates the potential of activated carbon produced from carob pods (CAC) as an effective adsorbent for removing the fungicide copper oxychloride and the herbicide iron chelate EDDHA 6 % from drainage water. The research highlights the importance of finding sustainable and cost-effective methods for treating agricultural runoff, which often contains toxic substances detrimental to ecosystems and human health. CAC was obtained using a saline solution (0.9 % NaCl). The CAC had a surface area of 441.15 m2/g and a pore diameter of 1.18 nm. Adsorption equilibrium for each product was reached in 180 min. The results showed that the adsorption processes followed the pseudo-first-order model perfectly. Moreover, the adsorption of these products onto the CAC was affected by the initial pH of the drainage water. Furthermore, the adsorption isotherm data showed a closer fit to the Langmuir model, suggesting monolayer adsorption occurring on a uniform surface. The maximum Langmuir adsorption capacities obtained were 16.72 and 45.99 mg/g for copper oxychloride and iron chelate, respectively. The thermodynamic parameters showed that adsorption was spontaneous, favorable and exothermic. Considering its commendable adsorption capacity, the adsorbent formulated in this study demonstrates promising potential for the treatment of phytosanitary products wastewater within practical applications.

Essential Oils for Managing Anthracnose in Mango (Mangifera indica): Laboratory Results Do Not Translate into Field Efficacy.

Essential oil-based products with broad plant disease control claims are commercially available and may be a practical alternative to copper fungicides for crop protection in organic mango orchards. We evaluated the disease control efficacy and crop safety of thyme oil, savory oil, and tree tea oil through replicated in vitro, in vivo (detached leaf and potted trees), and field assays. Three Colletotrichum species associated with mango anthracnose were tested in vitro, whereas only C. siamense was used for in vivo assays. Within the range of concentrations tested in vitro (62.5 to 2,000 μl active ingredient [a.i.]/liter), thyme and savory oil displayed fungicidal activity, whereas no fungistatic or fungicidal activity was observed with tea tree oil. In the in vivo assays, none of the treatments based on a preventive application rate of thyme (1,150 μl a.i./liter), savory (2,000 μl a.i./liter), or tea tree oil (342 μl a.i./liter) were effective in preventing the development of anthracnose on wounded and artificially inoculated leaves. Although field applications of thyme or tea tree oil did not result in phytotoxicity or negative impacts on fruit yield, they were ineffective in reducing the incidence and severity of naturally occurring anthracnose. Applications of copper hydroxide approved for organic agriculture were effective in controlling anthracnose in the field, and no added benefits were found by premixing this compound with thyme oil. Results indicate that essential oil products based on thyme or tea tree oil are inefficient at controlling anthracnose in mangoes.

The Potential Impact of Long-Term Copper Fungicide Sprays on Soil Health in Avocado Orchards

The long-term use of copper (Cu)-based fungicide sprays in orchards is associated with changes in soil Cu levels. However, there is a gap in knowledge regarding the potential accumulation of Cu in orchards and the associated impacts on the soil microbial structure. This study assessed the possibility of Cu accumulation in different avocado orchard farms and further evaluated the potential effect on soil microbial activities. Soil Cu levels were quantified in Tauranga and Northland, and three avocado orchards were analysed in each experimental location. All avocado farms in both sites received Cu-based fungicide sprays for over eight years. Soil samples were collected at a 0–20 cm depth from all six orchards. The soil total and bioavailable Cu, changes in soil chemical properties, microbial biomass, dehydrogenase activity, alkaline phosphatase activity, and acid phosphatase activity were measured. The results revealed that the total Cu and bioavailable Cu concentrations in Tauranga orchards were 81.3 and 0.32, 196.7 and 0.82, and 33.6 and 0.31 mg Cu kg−1 in Farms 1, 2, and 3, respectively. In Northland orchards, the total Cu and bioavailable Cu were 54.5 and 0.06, 18.4 and 0.77, and 46 and 0.34 mg Cu kg−1 in Farm 1, 2, and 3, respectively. Five out of six of the avocado orchard farms assessed in this study had total Cu concentrations greater than 30 mg Cu kg−1 reported in New Zealand native land. The magnitude of Cu accumulation was linked with soil pH and C content. No clear trend was observed between soil Cu concentrations and the soil microbial activity. Our study results demonstrated that the long-term use of Cu-based fungicide sprays can elevate Cu concentrations in orchard soils. Mitigation strategies need to be explored to abate the accumulation of Cu in orchard soils.

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity.

Herein, a series of chitosan oligosaccharide copper complexes modified with pyridine groups (CPSx-Cu complexes) were successfully prepared via the Schiff base reaction and ion complexation reaction for slow-release fungicide. The structures of the synthesized derivatives were characterized via Fourier transform infrared spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy, and the unit configuration of the complexes was calculated using Gaussian software. The slow-release performance experiment demonstrated that the cumulative copper ion release rate of CPSx-Cu complexes was dependent on the type of substituents on the pyridine ring. Furthermore, the in vitro and in vivo antifungal activities of the CPSx-Cu complexes were investigated. At a concentration of 0.4 mg/mL, CPSx-Cu complexes completely inhibited the growth of Pythium vexans and Phytophthora capsici. Results indicated that CPSx-Cu complexes with slow-release ability exhibited better antifungal activity than thiodiazole-copper and copper sulfate basic. This study confirmed that combining chitosan oligosaccharide with bioactive pyridine groups and copper ions is an effective approach to further developing slow-release copper fungicides, providing new possibilities for the application of copper fungicides in green agriculture. This study lays the foundation for further studies on biogreen copper fungicides.

Fungicidal activities of chitosan-stabilized copper nanoparticles on Magnaporthe oryzae, Rhizoctonia solani, and Phytophthora capsica

Pathogenic fungi are the most common causes of economic loss in crop production. Until now, synthetic fungicides are the most effective tools for management in agriculture, but they cause a severe impact on the environment as well as several side effects for human health. The use of synthetic fungicides is prohibited in organic agriculture; however, sulfur and copper fungicides are still permitted in organic farming. In this study, chitosan-stabilized copper chitosan nanoparticles (CS-CuNPs) were synthesized and characterized via UV-Vis analysis and scanning electron microscopy (SEM). Moreover, fungicidal activities of CS-CuNPs in the range of concentrations (00, 500, and 1000 mg/L) against several plant pathogenic fungi, including Magnaporthe oryzae, Rhizoctonia solani, and Phytophthora capsici, have been assessed via filamentous fugal growth inhibition. The results indicated that the size of CS-CuNPs ranged from 70 to 74 nm with the plasmon absorption peak at 600 nm, which implied the CS-CuNPs were successfully synthesized. Furthermore, CS-CuNPs effectively inhibited the growth of all three fungi at a concentration 1000 mg/L. Among the three species, Rhizoctonia solani was the most susceptible to CS-CuNPs, with the growth inhibitory effect at 100 mg/L. In conclusion, CS-CuNPs demonstrated a strong potential for the elimination of plant pathogenic fungi and further applications in agriculture.

Further Limitations of Synthetic Fungicide Use and Expansion of Organic Agriculture in Europe Will Increase the Environmental and Health Risks of Chemical Crop Protection Caused by Copper-Containing Fungicides.

Copper-containing fungicides have been used in agriculture since 1885. The divalent copper ion is a nonbiodegradable multisite inhibitor that has a strictly protective, nonsystemic effect on plants. Copper-containing plant protection products currently approved in Germany contain copper oxychloride, copper hydroxide, and tribasic copper sulfate. Copper is primarily used to control oomycete pathogens in grapevine, hop, potato, and fungal diseases in fruit production. In the environment, copper is highly persistent and toxic to nontarget organisms. The latter applies for terrestric and aquatic organisms such as earthworms, insects, birds, fish, Daphnia, and algae. Hence, copper fungicides are currently classified in the European Union as candidates for substitution. Pertinently, copper also exhibits significant mammalian toxicity (median lethal dose oral = 300-2500 mg/kg body wt in rats). To date, organic production still profoundly relies on the use of copper fungicides. Attempts to reduce doses of copper applications and the search for copper substitutes have not been successful. Copper compounds compared with modern synthetic fungicides with similar areas of use display significantly higher risks for honey bees (3- to 20-fold), beneficial insects (6- to 2000-fold), birds (2- to 13-fold), and mammals (up to 17-fold). These data contradict current views that crop protection in organic farming is associated with lower environmental or health risks. Further limitations in the range and use of modern single-site fungicides may force conventional production to fill the gaps with copper fungicides to counteract fungicide resistance. In contrast to the European Union Green Deal goals, the intended expansion of organic farming in Europe would further enhance the use of copper fungicides and hence increase the overall risks of chemical crop protection in Europe. Environ Toxicol Chem 2024;43:19-30. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Use of Biological and Chemical Compounds for the Integrated Management of Apricot Powdery Mildew in Egypt

This study aims to evaluate an integrated management program for powdery mildew caused by Sphaerotheca pannosa in apricot trees Prunus armeniaca, where four fungicides Copper, Carbendazim, Praiz and Topas) and three biocides ( Bio Z , Bio Arc and Activator Yeasts ) were evaluated in the first season 2020 in Ismailia and Beheira governorates in the regions of South Tahrir and Nubariya. All compounds significantly reduced the percentage of disease severity on leaves and flowers compared to the control, and the activator yeasts was among the best treatments, as it recorded in the last spraying a percentage of disease severity on leaves and flower 28.5% and 27.6% respectively compared with control 52.7 %and 56.2%, followed by the biocides Bio Z and Bio Arc.In the second season 2021, the compounds were evaluated during the flowering period, which led to their precipitation and the occurrence of plant toxicity for flowers at their highest rates with copper. As for the biocides compounds, they were completely safe.From here, an integrated control program was designed for two seasons 2022 and 2023 that combines fungicides and biocides. It is applied early before flowering. It gave excellent results, reduced the rate of fungicide use, and was safer and cost-saving.

Design and evaluation of microencapsulation technology to reduce the environmental impact of copper fungicides in vineyards

Grapevine is a relevant crop in the European area, that has been traditionally linked to the use of copper fungicides for downy mildew control (Plasmopara viticola). The continued use among the years of this type of copper fungicides has caused an environmental impact, mainly accumulating copper ions in the soil and also resulting in surface and groundwater pollution. To reduce the amount of copper used in vineyard crop protection strategies, and for instance, the contamination, a microencapsulated copper product has been developed. Deposition trials in artificial vegetation were assessed in order to define the optimal formulation characteristics linked with leaf deposit. Also, field trials in real conditions were performed to compare the newly developed copper product with a conventional one. These studies were completed with an evaluation of the microencapsulated product behaviour into two different soil types and its leaching that can consequently be potential groundwater contamination. Microencapsulated formulation resulted in higher deposition compared to the reference product. The obtained results are a relevant drawing up on a way to reduce the amount of copper used, due to the microencapsulated product having the potential to reduce the amount of copper used in vineyard crop protection and the environmental impact they cause.

Assessing the toxicity of selected pesticides to Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) pupae as a first step in the development of a potential novel deployment programme

ABSTRACT Trichogramma spp. have been used or have been proposed for use in biological control programmes of lepidopteran pests, including the European corn borer, Ostrinia nubilalis, the cotton bollworm, Helicoverpa armigera, and the spruce budworm, Choristoneura fumiferana. Releases are typically made by placing cards with parasitised eggs at set points in the field. However, this method can be cost-prohibitive due to its laborious nature. As a result, labour-saving mechanised release programmes have been developed, including distribution by spray equipment. However, few have investigated applying Trichogramma with a standard pesticide application (i.e. ‘tank mix’). As a first step to ascertain the feasibility of such a system, we observed the effect of immersion of T. ostriniae pupae in field-relevant concentrations of eight herbicides (bentazon, clethodim, fomesafen, quizalofop, Glacial acetic acid, glyphosate, imazamox, imazethapyr), three fungicides (Copper Hydroxide, flutriafol, and penthiopyrad), one insecticide (K+ salt of fatty acid), and five adjuvants (Ammonium Sulfate, Crop Oil Concentrate, Methylated seed oil, Non-ionic surfactant, and Urea-Ammonium Nitrate) on the emergence of T. ostriniae adults. The herbicides GAA and clethodim; the fungicides copper hydroxide, flutriafol, and penthiopyrad; and the adjuvants COC, MSO, and NIS all reduced T. ostriniae emergence compared to a water control. No emergence was observed with exposure to quizalofop, GAA, or K+ salt of fatty acid treatments. Other treatments did not affect emergence compared to water. Thus, deploying Trichogramma with a standard pesticide application may be a feasible labour-saving distribution method that warrants further investigation.

Efficacy of Scabdel and Golden Copper Fungicides on Phytopathogenic Fungi Isolated from Guava Leaves

The objectives of the study identify the fungal species from guava leaves symptomatic with leaf spots. Six fungal species (Alternaria atra, Botryotrichium verrucosum, Cochliobolus specifer, Drechslera halodes, Humicola grisea and Stachybotrys chartarum) were isolated from infected guava leaves by the direct plate method on PDA medium at 28°C. Pathogenicity test illustrated that only two species were pathogenic to guava leaves, and B. verrucosum exhibited moderate virulent ability, but C. specifer was weakly virulent. Half of the fungal species were pathogenic to apple fruits indicating that the species were non-host-specific to the guava plant. Scabdel fungicide completely inhibited the growth of B. verrucosum at 50 ppm, but in the case of C. specifer the inhibition ranged 18.8-33.3% with dose increases. Golden Copper was stimulatory to the growth of tested fungi at 50 -1000 ppm doses.

Response of microbial communities in the phyllosphere ecosystem of tobacco exposed to the broad-spectrum copper hydroxide.

Copper hydroxide is a broad-spectrum copper fungicide, which is often used to control crop fungal and bacterial diseases. In addition to controlling targeted pathogens, copper hydroxide may also affect other non-targeted microorganisms in the phyllosphere ecosystem. At four time points (before spraying, and 5, 10 and 15 days after fungicide application), the response of diseased and healthy tobacco phyllosphere microorganisms to copper hydroxide stress was studied by using Illumina high-throughput sequencing technology, and Biolog tools. The results showed that the microbiome communities of the healthy group were more affected than the disease group, and the fungal community was more sensitive than the bacterial community. The most common genera in the disease group were Alternaria, Boeremia, Cladosporium, Pantoea, Ralstonia, Pseudomonas, and Sphingomonas; while in the healthy group, these were Alternaria, Cladosporium, Symmetrospora, Ralstonia, and Pantoea. After spraying, the alpha diversity of the fungal community decreased at 5 days for both healthy and diseased groups, and then showed an increasing trend, with a significant increase at 15 days for the healthy group. The alpha diversity of bacterial community in healthy and diseased groups increased at 15 days, and the healthy group had a significant difference. The relative abundance of Alternaria and Cladosporium decreased while that of Boeremia, Stagonosporopsis, Symmetrospora, Epicoccum and Phoma increased in the fungal communities of healthy and diseased leaves. The relative abundance of Pantoea decreased first and then increased, while that of Ralstonia, Pseudomonas and Sphingomonas increased first and then decreased in the bacterial communities of healthy and diseased leaves. While copper hydroxide reduced the relative abundance of pathogenic fungi Alternaria and Cladosporium, it also resulted in the decrease of beneficial bacteria such as Actinomycetes and Pantoea, and the increase of potential pathogens such as Boeremia and Stagonosporopsis. After treatment with copper hydroxide, the metabolic capacity of the diseased group improved, while that of the healthy group was significantly suppressed, with a gradual recovery of metabolic activity as the application time extended. The results revealed changes in microbial community composition and metabolic function of healthy and diseased tobacco under copper hydroxide stress, providing a theoretical basis for future studies on microecological protection of phyllosphere.

Toxic Effects of Copper Fungicides on the Development and Behavior of Zebrafish in Early-Life Stages.

Copper-based fungicides have been used to control various plant diseases for more than one hundred years and play very important roles in agriculture. Accumulation of copper in freshwater and environment pose severe threats to human health and the environment. The current study evaluated the developmental and behavioral toxicity of PEG@Cu NCs (copper nanoclusters), Kocide® 3000 (copper hydroxide), and Cu(CH3COO)2 (copper acetate) to zebrafish in early-life stages. The developmental toxicity was evaluated according to the parameters of mortality, hatching rate, autonomous movement and heartbeat of embryos, and body length of larvae. The 9 dpf (days postfertilization)-LC50 (50% lethal concentration) of embryonic mortality was 0.077, 0.174 or 0.088 mg/L, and the 9 dpf-EC50 (effective concentration of 50% embryos hatching) of hatching rate was 0.079 mg/L, 0.21 mg/L and 0.092 mg/L when the embryos were exposed to PEG@Cu NCs, Kocide® 3000 or Cu(CH3COO)2, respectively. Kocide® 3000 and Cu(CH3COO)2 obviously decreased the spontaneous movements, while PEG@Cu NCs had no adverse effects on that of embryos. The reduced heartbeat can return to normal after exposure to PEG@Cu NCs for 96 h, while it cannot recover from Kocide® 3000. In addition, Kocide® 3000 (≥0.2 mg/L), PEG@Cu NCs and Cu(CH3COO)2 with 0.05 mg/L or higher concentration exhibited obvious behavioral toxicity to zebrafish larvae according to the parameters of movement distance, average velocity, absolute sinuosity, absolute turn angle and absolute angular velocity.

Patterns of Copper Bioaccumulation and Translocation in Grapevine Grafts Depending on Rootstocks

The long-term use of copper (Cu) fungicides in viticulture in Europe has led to Cu accumulation in vineyard top soils. However, less is known about the accumulation of Cu in grapevine grafts after the callusing process/before planting in the nursery. This paper presents the capacity of 5BB and SO4 rootstocks to accumulate Cu, as well as the patterns of translocation in the grafts. After heat forcing (callusing), the grapevine grafts of Sauvignon Blanc on 5BB and SO4 rootstocks were grown in pots for six months in a glasshouse and exposed to various Cu formulations (Cu-oxychloride, Cu-gluconate) and concentrations in peat (50, 150, 500, and 1000 mg Cu of dry weight (DW)). In addition to monitoring the shoot growth dynamics and analyzing the copper content in graft organs, bioaccumulation (BAFs) and translocation factors (TFs) of Cu were calculated. The mean Cu concentrations were ranked as follows: roots (15–164) > rootstock trunks (8–38) > canes (5–21) mg kg−1 DW. The Cu concentrations depended on the Cu formulation and concentration in the substrate. Higher Cu content was found in the roots of both rootstocks (5BB and SO4, 23–155 and 15–164 mg kg−1 DW, respectively) and the lowest in the canes (less than 10 mg kg−1 DW) of grafts grown in Cu-oxychloride-treated peat. Based on the BAFs and TFs, both rootstocks could be considered as Cu exclusive. A higher translocation rate was determined in systemic Cu-gluconate and SO4 rootstock. With shoot length measurements, the significant inhibitory effects of Cu on grapevine grafts growth could not be confirmed, despite the inhibitory effects that were clearly expressed in the first two months of growth. Soils containing more than 500 mg Cu/kg−1 are less suitable for growing vine grafts.

Combining Trichoderma koningiopsis and chitosan as a synergistic biocontrol and biostimulating complex to reduce copper rates for downy mildew control on grapevine

Plasmopara viticola, causal agent of downy mildew and one of the most severe grapevine diseases, is commonly controlled by multiple fungicide applications, primarily based on copper compounds in organic viticulture. Biostimulants and biocontrol agents could make a major contribution to pesticide reduction. A synergistic biocontrol and biostimulating complex consisting of Trichoderma sp. and chitosan was investigated to achieve copper fungicide reduction in the control of P. viticola. To ensure complex efficacy, the interactions and effects of all agents need to be investigated at the tri-trophic level of grapevine, downy mildew, and biocontrol and biostimulating complex. To guarantee the compatibility of Trichoderma sp. and chitosan, the chitosan tolerance of different copper-tolerant Trichoderma isolates was investigated in mycelial growth and germination tests. A T. koningiopsis isolate proved to be highly chitosan-tolerant was identified for further studies. The timing of spray application with T. koningiopsis and various chitosans was evaluated for efficacy against P. viticola. In the period 0 to 1 day before inoculation with the pathogen, the formation of the sporangia number was significantly reduced by the tested agents. To further describe the mode of action and efficacy of T. koningiopsis and chitosan against P. viticola, the application of single agents on upper and lower grapevine leaves inoculated with the pathogen in comparison to resistance inducers and copper fungicide were tested. Moreover, the combination of T. koningiopsis with different chitosans and a reduced copper rate was investigated on the respective leaf sides of greenhouse plants. Both, a direct and indirect mode of action against downy mildew was demonstrated. Regardless of the treated leaf side, sporulation of downy mildew was clearly inhibited compared to the untreated control. Moreover, microscopic images showed successful establishment of T. koningiopsis and uniform distribution of chitosan on leaves. The tested biocontrol and biostimulating complex might show a promising combatting tool against P. viticola while simultaneously reducing copper rate.

Effect of direct tea plant covering on the incidence of anthracnose

Considering the growing global demand for matcha, the Shizuoka prefectural government is promoting the export of matcha prepared from cover-cultured tea. To improve matcha production, it is important to investigate the characteristics of pest incidence under covering culture and develop suitable pest management strategies. In this study, we investigated the effects of direct tea plant covering and copper fungicide application to curb the incidence of tea anthracnose (Discula theae-sinensis (I. Miyake) Moriwaki & Toy. Sato), the most serious tea disease that occurs primarily during or after the second tea season. Our results indicated that the incidence of tea anthracnose decreased when cover culture treatment was used compared to that with no-cover treatment during the second tea season. In addition, the tea plants grown under cover and pre-treated with a copper fungicide showed less anthracnose symptoms during the sprouting period than those not treated with the fungicide. These findings suggest that tea anthracnose can be effectively controlled using covering culture after the application of copper fungicide.

Control of sesame bacterial leaf spot with copper fungicides

In recent years, Mie Prefecture has been working to establish a domestic production area for sesame (Sesamum indicum L.), and the cultivation area has been increasing. Meanwhile, there is a wide incidence of sesame bacterial leaf spot (caused by Pseudomonas syringae pv. sesami Young, Dye & Wilkie, Acidovorax valerianellae Gardan, Stead, Dauga & Gillis, and Xanthomonas sp.), contributing to yield loss. No pesticides against the disease are currently registered in Japan, and no control measures have been established. We evaluated three copper fungicides (basic copper sulfate, sodium bicarbonate/anhydrous copper sulfate, and basic copper chloride/sulfur) in pot and field tests. Our results demonstrated that all fungicides could suppress the disease when applied before its onset or in its early stage.