Alternative Fungicide Research Articles

Reduction of peduncle detachment surface discoloration in Ananas comosus L. By pre-harvest spraying with potassium phosphite

Peduncle detachment surface discoloration (PDSD) in fresh pineapple fruit has rendered serious economic losses in pineapple exports from Taiwan. This experiment was conducted to investigate the post-harvest PDSD process and to evaluate the effect of potassium phosphite (KPhi) solution on pineapple PDSD and fruit quality. PDSD often start to appear in pineapple fruit, especially at room temperature (25 °C), quickly between 3 and 4 days after harvest. To evaluate its efficacy in controlling pineapple PDSD, KPhi was sprayed on pineapple leaves at the pre-harvest stage, at four concentrations: 0 (control), 2 g·L−1, 4 g·L−1, and 10 g·L−1. All treated fruits were stored at 18℃ and 80–90 % relative humidity for 1 week and then shift to room temperature (25℃) for 4 days to simulate the transportation and shelf-life conditions of exported pineapples. The results showed that KPhi treatment significantly reduced the severity of PDSD compared to that of control (water-only spray). All the KPhi treatments did not affect the total soluble solid content significantly. A pre-harvest spray of 10 g·L−1 resulted in better skin color but yielded the worst crown leaf condition and shell appearance of the just-harvested fruit, however, with no significant difference from the control in skin color or shell appearance after the export condition simulation. Most of the fruit characteristics for the other two KPhi treatments were better than those of the control and 10 g·L−1 treatments. The results indicate that pre-harvest KPhi spraying at 4 g·L−1 is well expected and suggested as a good alternative fungicide treatment to maintain and ensure good pineapple fruit quality for export.

Efficacy evaluation of different foliar fungicides for the management of wheat strip rust (Puccinia striiformis) in West Shoa Zone, Oromia, Ethiopia

Rust is one of the most widespread and devastating disease of cereal crop all over the world. This study was conducted to evaluate the efficacy of different fungicide against strip rust of wheat (Puccinia striiformis) at Toke Kutaye District, West Showa Zone of Oromia region, Ethiopia. The experiment was laid out in Randomized Complete Block Design (RCBD) in three replications and contains five treatments. Disease parameters like incidence, severity, Area under Disease Progress curve (AUDPC), and yield loss (dry biomass, grain yield, and thousands grain weight) were used to evaluate the treatments. The fungicides showed significant differences (P<0.05) in reducing incidence, severity, AUDPC and yield losses compared to the control treatment. There also significant differences between Zantara EC 216 and Rex®Duo fungicide in reducing disease incidence and also between Zantara EC 216 and Tilt 250 EC in reducing the disease severity. Zantara EC 216 fungicide reduced strip rust severity by 94.2% compared to the control treatment. The analysis of variance also revealed significant difference among Zantara EC 216 and Rex®Duo, Tilt 250 EC and Progress fungicides in reducing grain yield loss and thousand grain weights loss. Zantara EC 216 fungicide increased grain yield by 32.2% compared to the control. However, for the most parameters, there was no significant difference among Rex®Duo, Tilt 250 EC and Progress fungicides. Hence, Zantara EC 216 which is newly introduced to Ethiopian country was very effective and can be recommended as alternative fungicide for the management of strip rust of wheat in west showa zone of Ethiopia and areas of similar agro-ecological conditions.Keywords: Fungicides efficacy, Wheat, Severity, Zantara EC 216

Labeling of dsRNA for Fungal Uptake Detection Analysis.

Double-stranded RNA (dsRNA) plays an essential role in many biological processes and has a great potential for agronomic applications in disease and pest control. A simple and effective method to monitor dsRNA uptake by fungi is crucial for the use of dsRNA as alternative fungicide. The protocol reported in this chapter describes an efficient method to detect and localize labeled dsRNA in fungal hyphae. We use the fungal Verticillium longisporum, a fungal plant pathogen that commonly infects rapeseed and other Brassica species, to explain the procedure, though we have validated the method in a broad spectrum of fungi. Hereafter we elucidate step-by-step the production, fluorescence labeling, as well as detection of dsRNA via fluorescence microscopy in fungal mycelium.

Suppressive effect of compost /pomegranate peel tea combination against Fusarium oxysporum f. sp. lupini, and Rhizoctonia solani as an alternative synthetic fungicide

Plant diseases continue to cause severe damage to most agricultural crops resulting in heavy losses of both yield and quality. In addition the agricultural wastes cause real problems to get rid of them. Therefore, intensive concern was directed toward compost utilization, as they are available for no cost no side effect. So, in this study different suggested formulations of aerated compost tea in combination with pomegranate peel powder were evaluated for the possibility of using them as an environmentally safe alternative to fungicides. In vitro antifungal activity as well as, the in vivo probability of these combinations to suppress damping-off and wilt diseases caused by R. solani and F. oxysporum was done. Pathogens were isolated from diseased lupine plants with root rot and wilt symptoms. In vitro experiment results illustrated that high inhibition linear growth was obtained by compost/sour pomegranate tea prepared using alkaline water by up to 60% and 70% for F. oxysporum and R. solani respectively. Meanwhile, under field condition all tested combinations showed significant reduction in disease severity over un-composted control, indicated by low wilting and high survival % of lupine plants, no significant differences were detected between treatments. All compost treatments, in the field experiment, performed significantly better than the un-composted control in terms of growth parameters, NPK accumulation, yield and its components with no significant differences. Findings of this study suggest that mixture of pomegranate (Punica granatum L.) peels extract with compost tea might be a promising combination for controlling phytopathogenic fungi and can be used as effective natural fungicide against two of the most dangerous soil-borne fungi looking for reducing the dependence on the chemical fungicides.

Evaluation of bio-efficacy and phytotoxicity of BAS 751 01 F SC against early blight disease of tomato

Early blight disease in tomato is destructive in nature and reduces fruit yield. Fungicides were used to control early blight disease but still early blight disease occurs. Hence, for in search of good alternative fungicide to control early blight disease, field experiment on efficacy of BAS 751 01 F SC against early blight disease was conducted in kharif season of 2017-18 and 2018-19. There were 7 treatments with six fungicides and control. Observations on per cent disease index (PDI), fruit yield and phytotoxicity of fungicides on tomato were recorded. In both 2017-18 and 2018-19, BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water was found superior in reducing disease severity (22.12 % mean PDI) over other fungicides used. In 2017-18 and 2018-19, BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water treated plants produced higher yield of tomato fruits (19.41 t/ha, 19.80 t/ha) over other fungicides. BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water were not toxic to tomato plant in kharif season of 2017-18 and 2018-19. The results concluded that use of BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water resulted in reducing disease severity and improved yield.

A bioactivity and biochemical analysis of iminoctadine tris (albesilate) as a fungicide against Corynespora cassiicola

Iminoctadine tris (albesilate) is a bis-guazatine fungicide, and its specific modes of action and efficacy against C. cassiicola are not yet clear. In this study, baseline sensitivity data for mycelial growth showed that the frequency distribution curve of iminoctadine tris (albesilate) EC50 values is unimodal. The EC50 values ranged from 0.1151 to 1.2101 μg/mL, with a mean of 0.5775 ± 0.2677 μg/mL. Iminoctadine tris (albesilate) affected the morphological development of C. cassiicola, causing increased branching of the mycelium. The significant increase in membrane permeability and malondialdehyde content after iminoctadine tris (albesilate) treatment indicated that this fungicide caused severe damage to the membrane structure. Furthermore, 0.4 μg/mL iminoctadine tris (albesilate) could decrease the spore density of C. cassiicola from 2.6200 × 104 to 1.4967 × 104/cm2 on average in vitro, indicating that the fungicide had great potential to reduce secondary infection with C. cassiicola in the field. Additionally, 120 μg/mL iminoctadine tris (albesilate) provided over 95% curative efficacy and 81.17% preventative efficacy on detached cucumber leaves inoculated with C. cassiicola. In field trials, iminoctadine tris (albesilate) at a dose of 120 g a.i./ha exhibited 72.92% and 80.92% control efficacy in 2017 and 2018, respectively. However, the efficacy supplied by the reference fungicide azoxystrobin at 250 g a.i./ha was only approximately 50% due to the development of fungicide resistance in C. cassiicola. Taken together, the findings above provide a solid foundation for the exploration of the action mechanisms of iminoctadine tris (albesilate) against C. cassiicola and provide overwhelming evidence for the use of iminoctadine tris (albesilate) as an excellent potential alternative fungicide in the management of cucumber Corynespora leaf spot.

Baseline sensitivity of isopyrazam against Sclerotinia sclerotiorum and its efficacy for the control of Sclerotinia stem rot in vegetables

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is a devastating fungal disease that infects a wide range of agriculturally important crops. An important approach to manage Sclerotinia stem rot is the use of fungicides. This study was conducted to determine the efficacy of isopyrazam in controlling Sclerotinia stem rot in vegetables. The baseline sensitivity of S. sclerotiorum to isopyrazam was established using 178 isolates collected from different vegetable crops during 2016 and 2017 in China. The results showed that the frequency distribution of the EC50 values of isopyrazam was a unimodal curve with a mean EC50 value of 0.039 ± 0.002 μg ml−1, which could be used in the future to detect changes in S. sclerotiorum population sensitivity to isopyrazam. Furthermore, sclerotial production and germination were strongly inhibited by isopyrazam. On detached eggplant leaves, the preventative and curative performance of 40 μg ml−1 isopyrazam against S. sclerotiorum was 100% and 87.78%, respectively. In polytunnel trials, the disease incidence of S. sclerotiorum significantly decreased when isopyrazam was applied at a concentration of 200 g a.i. ha−1. These results suggest that isopyrazam is very effective in managing S. sclerotiorum and could serve as an alternative fungicide to control the Sclerotinia stem rot of vegetables in the future.

Improved the Shelf Life of Guava Fruits by Salicylic Acid against Postharvest Black Spot Disease

Guava fruit (Psidium guajava L.) is one of the most important popular fruits in the tropical and subtropical zones. It is a perishable and has a short postharvest shelf life at environment temperature due to climacteric ripening with changes in physicochemical properties; However, the most serious microorganisms attacked guava fruits are the fungi. Guava black spot (GBS) is a latent infection disease caused by the ascomycete fungal Phyllosticta capitalensis, that infect immature guava in the field. This postharvest decay can lead to significant economic losses. Since the commercial application of fungicides to control postharvest diseases found harmful to human and the ecosystems. Therefore, the search of finding alternative fungicides, safety and environmentally friendly strategy is a major aim of the researchers worldwide. Salicylic acid (SA) is one of the safe, natural compounds applied in the postharvest treatment of fruit. The present investigation aimed to evaluate the effect of different concentrations of SA on fungal growth in vitro and postharvest treatment of infected fruit to improve the shelf life of guava fruits. Guava fruit collected from local supermarket and measurement of disease incidence and severity (DI & DS%) carried out in the three seasons (2015-2017). SA at different concentrations assessed on mycelial linear growth inhibition (MLGI%) of P. capitalensis in vitro. Exogenous postharvest treatment of guava fruit with SA tested at five concentrations, three times of immersion and kept for three periods time of shelf life. DS% evaluated after three period time. Total soluble solids (TSS) and weight loss (WL) evaluated after three period time. SA concentrations at 6 mmol/L significant on MLGI of P. capitalensis in vitro. Postharvest treatment with SA at 3 mmol/L significantly reduced DS% on guava fruit, at three immersion time and after three periods of shelf life, compared to control. SA with a concentration at 4 mmol/L decreased TSS and WL after three periods of shelf life. Postharvest treatment with SA solutions had an overall positive effect on fruit quality of guava during shelf life. A decay incidence decreased, TSS and weight loss noticed in treated guava fruit compared to control. The present study demonstrated the efficacy and potential of SA solutions in preserving the shelf life of a highly perishable like guava fruits.

Antifungal Activity and Action Mechanism of the Natural Product Cinnamic Acid Against Sclerotinia sclerotiorum.

Sclerotinia stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary spreads worldwide and causes serious economic losses. Considering the development of fungicide resistance and chemical residues, it is urgently necessary to explore alternative fungicides. In this study, the activity of the natural product cinnamic acid was assessed. The EC50 values for cinnamic acid inhibition of mycelial growth of 103 S. sclerotiorum strains ranged from 9.37 to 42.54 µg/ml with an average EC50 value of 18.77 (±3.39) µg/ml. No cross-resistance was detected between cinnamic acid and the commonly used fungicides carbendazim or dimethachlon. After treatment with cinnamic acid, mycelia distorted with more branches, no sclerotia developed, and the oxalic acid content decreased, whereas cell membrane permeability increased significantly. In pot experiments, cinnamic acid at 2,000 µg/ml provided over 95% efficacy against both carbendazim-sensitive and carbendazim-resistant strains of S. sclerotiorum. The expression of the sclerotia development-correlated genes Sac1, Pac1, Smk1, and Pka1 decreased, whereas the Cna1 gene expression increased. Altogether, cinnamic acid shows potential to be a natural alternative to commercial fungicides or a lead compound to develop new fungicides for the control of Sclerotinia stem rot. The biological characteristics contribute to the understanding of the action mechanism of cinnamic acid against S. sclerotiorum.

Control Effect of Alternative Fungicide Spraying System on Powdery Mildew Caused by <i>Podosphaera xanthii</i> on Greenhouse Cucumber

Control Effect of Alternative Fungicide Spraying System on Powdery Mildew Caused by <i>Podosphaera xanthii</i> on Greenhouse Cucumber

Effect of Integrated Control Program of Powdery Mildew Disease on Growth and Productivity of Apple

Disease incidence % and disease severity % of the powdery mildew fungus(Podosphaera leucotricha) were assessed on Anna apple trees (Malus domestica, Borkh) budded on MM106 rootstock during 2016-2017 seasons in three different locations in Egypt. The disease occurrence was more prevailing in Qalyoubia governorate than the two orchard sites in Behaira (Kafr El Dawar and Noubaria). The efficacy of eleven foliar spray programs for management apple powdery mildew and on vegetative growth, fruiting parameters and fruit quality of Anna apple trees was evaluated in experimental farm at El-Qanater El-Khairia Horticultural Research Station in Qalyoubia, Agricultural Research Centre. All treatments reduced the disease severity % of powdery mildew with significant increase to all investigated vegetative growth measurements, fruiting parameters and fruit quality of Anna apple trees in relation to the control. The alternative fungicides in program 4 (Microvit, Punch and Topas) provided protection at an important level against powdery mildew infection and improved parameters and characters as compared with fungicide Microvit (P1), Punch (P2) or Topas (P3) each alone in the two seasons. In addition, alternation sprays among biofungicides in program 8 (Bio Zied , Bio Arc and AQ10) gave more efficiency, both growth and fruiting parameters and fruit characters as compared with those used in a single treatment in P5 (Bio Zied), P6 (Bio Arc) and P7 (AQ10). The effectiveness of Potassium Silicate in (P9) in inhibiting powdery mildew disease led to used it in alternation with Microvit and AQ10 in program10 as an integrated pest management (IPM) program. In general, the effectiveness of the alternative treatments with non-systemic fungicide Microvit, Potassium Silicate and AQ10 in (P10) was similar to that recorded of the systemic fungicides P2 (Punch) and P3 (Topas)) in both seasons. Results show that P10 can be used as alternative method for farmers to have eco-friendly management of powdery mildew with significant increase to the produced growth, productivity and fruit quality.

Natamycin, a New Biofungicide for Managing Crown Rot of Strawberry Caused by QoI-Resistant Colletotrichum acutatum

Anthracnose crown rot of strawberry, caused by Colletotrichum acutatum, is an important disease affecting California nursery and fruit production. Preplant dip treatments of transplants with fludioxonil-cyprodinil or azoxystrobin are industry standards for managing the disease and have been used extensively. Following reports of reduced efficacy of azoxystrobin in the field, high levels of quinone outside inhibitor (QoI) resistance were detected in California isolates of the pathogen. Resistance was associated with the G143A mutation in the cytochrome b gene, similar to a previous report from Florida, and there were no detected fitness penalties in pathogenicity or virulence. Therefore, several alternative fungicides were investigated in laboratory and field studies. Subsequently, the new biofungicide natamycin was identified. Baseline sensitivities of 74 isolates of C. acutatum to natamycin were determined to be unimodal, with a range from 0.526 to 1.996 μg/ml (mean 0.973 μg/ml). Although this toxicity was considerably lower than that of azoxystrobin (using sensitive isolates), fludioxonil, or cyprodinil, dip treatments of transplants with natamycin (at 500 or 1000 mg/liter) were highly effective. Disease severity and plant mortality in field studies with inoculated transplants were reduced to similarly low levels as treatments containing fludioxonil, whereas azoxystrobin failed in inoculations with QoI-resistant isolates of C. acutatum. Fruit yield was also significantly increased by natamycin as compared with the inoculated control. Differences in disease susceptibility were observed among cultivars evaluated, with Monterey and Portola more susceptible than Fronteras. Natamycin has a unique mode of action that is different from other fungicides registered on strawberry and, based on this research, was registered in the United States as a preplant, biofungicide dip treatment of strawberry transplants for management of anthracnose crown rot.

Pseudoperonospora cubensis in China: Its sensitivity to and control by oxathiapiprolin

The novel fungicide oxathiapiprolin has potential for the control of downy mildew of cucumber, which is caused by Pseudoperonospora cubensis. In this study, an in vitro bioassay with detached leaves was used to determine the baseline sensitivity to oxathiapiprolin for 77 Ps. cubensis isolates from 11 provinces in China. The baseline sensitivity curve was continuous, and the average EC50 value was 2.23 × 10−4 μg ml−1. In field trials, the control of downy mildew of cucumber was greater with oxathiapiprolin at 20 or 30 g a.i. ha−1 than with dimethomorph at 262.5 g a.i. ha−1. Oxathiapiprolin was taken up by cucumber roots and transported upwards to stems and leaves. The full length of PscORP1, the gene that encodes the target protein of oxathiapiprolin in Ps. cubensis, was sequenced for the first time. Our results suggested that oxathiapiprolin will be an excellent alternative fungicide for control of cucumber downy mildew. However, as Ps. cubensis is a high-risk pathogen, resistance development to oxathiapiprolin should be monitored and managed.

Screening and Evaluation of Yeast Antagonists for Biological Control of Botrytis cinerea on Strawberry Fruits

Gray mold (Botrytis cinerea) is one of the most common diseases of strawberries (Fragaria × ananassa Duchesne) worldwide. Although many chemical fungicides are used for controlling the growth of B. cinerea, the risk of the fungus developing chemical resistance together with consumer demand for reducing the use of chemical fungicides have necessitated an alternative method to control this pathogen. Various naturally occurring microbes aggressively attack plant pathogens and benefit plants by suppressing diseases; these microbes are referred to as biocontrol agents. However, screening of potent biocontrol agents is essential for their further development and commercialization. In this study, 24 strains of yeast with antagonistic ability against gray mold were isolated, and the antifungal activity of the volatile and diffusible metabolites was evaluated. Putative mechanisms of action associated with the biocontrol capacity of yeast strains against B. cinerea were studied through in vitro and in vivo assays. The volatile organic compounds produced by the Galactomyces candidum JYC1146 could be useful in the biological control of plant pathogens and therefore are potential alternative fungicides with low environmental impact.

Baseline Sensitivity and Control Efficacy of Tetramycin Against Phytophthora capsici Isolates in China.

Tetramycin is a new biopesticide that combines high-level and broad-spectrum fungicidal activity, low toxicity, and environmental safety. In this study, 90 Phytophthora capsici isolates obtained from various regions in southern China were characterized for their baseline sensitivity to tetramycin. The protective and curative activities of tetramycin against P. capsici were determined on leaves of pepper, and the control efficacy of tetramycin in greenhouse experiments was also determined. Compared with mycelial growth, the formation of sporangia and the discharge of zoospores were inhibited by lower concentrations of tetramycin, approximately 5 µg ml-1 on V8 media. The frequency distribution curves for the tetramycin sensitivity were unimodal, with mean values for the fungicide concentration that reduced mycelial growth, sporangia formation, and zoospore discharge by 50% compared with the control of 1.18 ± 0.91, 0.64 ± 0.42, and 0.63 ± 0.30 µg ml-1, respectively. In addition, no correlation was observed between tetramycin and other fungicides tested, including mandipropamid, azoxystrobin, mefenoxam, fluazinam, fluopicolide, and famoxadone. Tetramycin exhibited both protective and curative effects against P. capsici in vitro, and its protective activity was better than its curative activity. In greenhouse experiments, tetramycin concentration of 60 and 90 µg ml-1 provided a protective control efficacy of 47.1 to 56.4% and curative efficacy of 43.3 to 52.7%. These results demonstrated that tetramycin could serve as an excellent alternative fungicide to control Phytophthora blight of pepper.

AKTIVITAS ANTIFUNGI EKSTRAK DAUN PICUNG TERHADAP CENDAWAN Botryodiplodia theobromae PENYEBAB MATI PUCUK BIBIT JABON MERAH Antifungal Activity of Picung Leaf Extracts Against Botryodiplodia theobromae A Dieback Fungus of Jabon Merah Seedling

Invasion of Botryodiplodia theobromae as a dieback fungus on jabon merah (Anthocephalus macrophyllus) seedlings is a crucial issues. This pathogenic fungus needs to be controlled precisely. Phytochemical compounds of plant material is one alternative fungicides. Crude extracts of picung (Pangium edule) leaf in water and methanol solvent known to have antifungal potential. However, its activity against B. theobromae need to be revealed. In vitro assay aimed to measuring antifungal activity of water and methanol extracts of picung leaf on controlling growth of B. theobromae pathogenic fungus. Hot water extraction and maceration in methanol was conducted to obtain crude extract materials. In-vitro antifungal assay of water and methanol extracts of picung leaf was conducted by food poisoning method on Potato Dextrose Agar media. The results showed that water and methanol extracts of pangi leaf be able to suppress the growth of B. theobromae on the first day of observation, with the highest antifungal index reached 100% at concentration of 25mg/mL and 50mg/mL, respectively. This indicates that water and methanol extracts of picung leaf have antifungal activity. Generally, there was a trend of decrease in antifungal index over time.Key words: antifungal activity, Botryodiplodia theobromae, jabon merah, picung

Assessment of the baseline sensitivity and resistance risk of Colletotrichum acutatum to fludioxonil

Anthracnose, which is caused by Colletotrichum acutatum, is a destructive disease of pepper. A preliminary study demonstrated that fludioxonil (a phenylpyrrole fungicide) has good activity against C. acutatum and thus has potential to be used as an alternative fungicide for the management of pepper anthracnose. However, there is no information regarding the baseline sensitivity and resistance risk of C. acutatum to fludioxonil. Thus, the sensitivities of 205 isolates of C. acutatum to fludioxonil were determined. The results showed that the frequency distributions of the EC50 values were unimodal, and the mean EC50 values for the inhibition of mycelial growth and spore germination were 0.031 μg/mL and 0.035 μg/mL, respectively. Three stable mutants with high resistance to fludioxonil were obtained in the laboratory. Two parameters, namely in vitro sporulation and the in vitro and in vivo germination of spores, showed significant difference (P < 0.01) when the mutants were compared to the sensitive isolates. Moreover, the mutants were more sensitive to osmotic stress compared to the parents. No significant differences (P ≥ 0.05) were detected in colony diameter, mycelia weight, pathogenicity or sporulation in vivo between the fludioxonil-resistant mutants and their corresponding parents. Cross-resistance occurred between fludioxonil, iprodione and procymidone. Overall, resistance risk of C. acutatum to fludioxonil was low to medium, and thus resistance management should be considered.

Biotechnical Preparations in Protection of Cucumber against Downy Mildew

Abstract The effectiveness of the preparations PB 500 (extracted from cow dung) and PB 501 (silica fume – 92.8% SiO2) in protection of cucumber against downy mildew was tested during the two-years experiment. PB 500 was used at 2% concentration and PB 501 at 1% concentration. The alternative fungicides recommended by the standard protection program were used as the reference agents. The effectiveness of the preparations PB 501 and PB 500 was lower than the conventional fungicides. It was observed that the infestation of protected plants is lower than the control plants, although not statistically significant. The results indicate a limited possibility of application of the tested formulations for cucumber protection against downy mildew in comparison to the chemical protection.

Managing leaf diseases of carrots with traditional and alternative fungicides including baseline sensitivity studies

Field research was conducted to examine traditional and alternative fungicide options for controlling leaf diseases of carrots caused by powdery mildew and Cercospora. Wet conditions favoured leaf blights caused by Cercospora and dry favoured powdery mildew. Pyraclostrobin, azoxystrobin, and tebuconazole controlled both Cercospora leaf blight and powdery mildew whereas sulphur on its own controlled only powdery mildew compared to untreated plots. Spray oils did not improve powdery mildew control, but when combined with sulphur, improved Cercospora leaf blight control. A baseline sensitivity study indicated a powdery mildew isolate from South Australia, sourced from carrots sprayed with a fungicide containing azoxystrobin over several seasons, was less sensitive to azoxystrobin than an isolate from New South Wales which had not been exposed to the fungicide.

Effects of paraffine oil on leaf and berry mycobiota on two grape varieties

Application of fungicides have advantages and also some direct or indirect disadvantages, such as imbalance and/or fungicide resistance in microbe population. To avoid these problems the development of alternative, eco-friendly methods like mostly spraying with oils are in the focus nowadays. The investigations of the effects of fungicides on microbiota in some cultivations can give a more complex view to this topic and developmental possibilities. In the present study, our aim was testing of the effects of paraffine oil (as alternative fungicide) on microbial properties (CFU and rate of filamentous fungi and yeasts) of Chardonnay and Kékfrankos leaves and berries.&#x0D; Our results from 2014 showed that the application of paraffine oil as sole spray agent can decrease the presence of saprophytic filamentous fungi on the berries of Chardonnay (susceptible for fungal infections). In the case of Kékfrankos berries opposite properties were observed, which may be the result of the absorption of oil by the thick wax layer of this variety. The oil treatment did not affect the yeast population of Chardonnay and Kékfrankos berries contrary to negative effect of the regular pesticide treatment. The selective fungicide effect of paraffine oil against filamentous fungal population caused the accumulation of yeast cells in the mycobiota of grape berries. The careful use of this yeasts in spontaneous fermentation can improve the aroma profile of wines. The year of 2015 did no prefer the growth of fungi, therefore no interesting properties were detected in the mycobiota of grape varieties. The occurence of the harmful saprophytic filamentous fungi predicted to be increased in mild climate agricultures as the result of the climate change.&#x0D; In summary, the paraffine oils are seem to be promising tools for the eco-friendly control of harmful fungi of grapes.