Fungicide Sprays Research Articles

Evaluation of fungicides against false smut disease of rice (Oryza sativa L.)

False smut of rice caused by Ustilaginoidea virens is a worldwide serious disease of rice. Seven fungicides were evaluated against false smut disease of rice during kharif, 2019 and 2020 at two locations. The ready mix fungicide azoxystrobin 18.2 % + difenoconazole 11.4% w/w SC was used in three doses where as other fungicides were used in single dose. Total two fungicidal sprays were given, first at 50% flowering and second at 100% flowering stage. The results showed that tebuconazole 50% + trifloxystrobin 25% WG at 0.8 g/L and picoxystrobin 7.05% + propiconazole 11.7% SC at 2.0 ml/L were found best in order of efficacy against false smut. These treatments recorded minimum per cent infected panicles/ sq m (3.57 and 4.31, respectively), per cent infected spikelets/ panicle (4.58 and 4.66, respectively) and maximum grain (7114 and 7043 kg/ha, respectively) and straw yield (10942 and 10984 kg/ha, respectively). The next best performance was recorded in azoxystrobin 18.2 % + difenoconazole 11.4% w/w SC at 1.25 ml/L where per cent infected panicle/ sq m was 6.50, per cent infected spikelets/ panicle was 8.22, where as the grain and straw yield was 6410 and 10551 kg/ha, respectively.

Re-Fining Citrus Leaf and Fruit Spot Disease Control Options in Northern Uganda

Citrus leaf and fruit spot disease, caused by Pseudocercospora angolensis has, since 2010, come about as the most dreadful disease of citrus in Northern Uganda. Over the last few years, feedback from citrus farmers has helped in re-fining management strategies. In the first years of citrus leaf and fruit spot disease outbreak in Northern Uganda, chemical treatment was promoted as part of a control package, in addition to the destruction of heavily diseased plants and buckthorn to remove inoculum. Buck horning and destruction of diseased plants is labour-intensive and time-consuming, especially when many infected citrus trees have to be taken out, or buck horned. Research findings indicate citrus leaf and fruit spot disease fungus can be weakened with fungicide sprays to the extent that even when disease symptoms are present on leaves, it does not automatically lead to infection of fruits. This gave rise to a new control strategy where only infected plants in an orchard are pruned, and all the citrus trees in the orchard are treated with fungicides. The pruning of visibly infected plants in an orchard will lessen the inoculum load, and the fungicide sprays will stop pathogen replication. This method is not labour intensive and takes less time when equated to severe buck horning of all the trees in the orchard. However, pruning and fungicide treatment need to move together with the control of new infections that can happen via unrestricted entry during harvesting

Biocontrol Potential of Trichoderma asperellum CMT10 against Strawberry Root Rot Disease

Strawberry root rot caused by Neopestalotiopsis clavispora is one of the main diseases of strawberries and significantly impacts the yield and quality of strawberry fruit. Currently, the only accessible control methods are fungicide sprays, which could have an adverse effect on the consumers of the strawberries. Biological control is becoming an alternative method for the control of plant diseases to replace or decrease the application of traditional synthetic chemical fungicides. Trichoderma spp. are frequently used as biological agents to prevent root rot in strawberries. In order to provide highly effective biocontrol resources for controlling strawberry root rot caused by Neopestalotiopsis clavispora, the biocontrol mechanism, the control effects of T. asperellum CMT10 against strawberry root rot, and the growth-promoting effects on strawberry seedlings were investigated using plate culture, microscopy observation, and root drenching methods. The results showed that CMT10 had obvious competitive, antimycotic, and hyperparasitic effects on N. clavispora CMGF3. The CMT10 could quickly occupy nutritional space, and the inhibition rate of CMT10 against CMGF3 was 65.49% 7 d after co-culture. The inhibition rates of volatile metabolites and fermentation metabolites produced by CMT10 were 79.67% and 69.84% against CMGF3, respectively. The mycelium of CMT10 can act as a hyperparasite by contacting, winding, and penetrating the hyphae of CMGF3. Pot experiment showed that the biocontrol efficiency of CMT10 on strawberry root rot caused by Neopestalotiopsis clavispora was 63.09%. CMT10 promoted strawberry growth, plant height, root length, total fresh weight, root fresh weight, stem fresh weight, and root dry weight by 20.09%, 22.39%, 87.11%, 101.58%, 79.82%, and 72.33%, respectively. Overall, this study showed the ability of T. asperellum CMT10 to control strawberry root rot and its potential to be developed as a novel biocontrol agent to replace chemical fungicides for eco-friendly and sustainable agriculture.

Impact of Foliar Fungicide Application on the Culturable Fungal Endophyte Community of Soybean Seed in the Midwest United States.

The purpose of our study was to determine whether the application of quinone outside inhibitor (QoI) and pyrazole-carboxamide fungicides as a tank mix would impact the endophyte community of soybean seed. Field trials during 2018 in Iowa, South Dakota, and Wisconsin, U.S.A., investigated the impact of a single combination fungicide spray at early pod set in soybeans. The composition of culturable endophytic fungi in mature soybean seed was assessed on three cultivars per state, with maturity groups (MGs) ranging from 1.1 to 4.7. An unusually wet 2018 season delayed harvest, which led to a high level of fungal growth in grain. The survey included 1,080 asymptomatic seeds that were disinfested and individually placed on 5-cm-diameter Petri plates of acidified water agar. The survey yielded 721 fungal isolates belonging to 24 putative species in seven genera; taxa were grouped into genera based on a combination of morphological and molecular evidence. The dominant genera encountered in the survey were Alternaria, Diaporthe, and Fusarium. The study showed that the fungicide treatment reduced the incidence of Fusarium in Wisconsin seed, increased the incidence of Diaporthe in seed from all states, and had no impact on the incidence of Alternaria. This is one of the first attempts to characterize the diversity of seed endophytes in soybean and the first to characterize the impacts of fungicide spraying on these endophyte communities across three states. Our study provides evidence that the impact of a fungicide spray on soybean seed endophyte communities may be influenced by site, weather, and cultivar maturity group.

Identification of Resistance to Target Spot of Tomato Caused by Corynespora cassiicola in Wild Tomato Accessions

Tomato (Solanum lycopersicum) is an important vegetable crop and a valuable source of nutrients for the human diet. The southeast is the main fresh market tomato producer of the United States, with much of the production concentrated in Florida. However, production in this region is threatened by plant diseases such as target spot of tomato (TS) caused by Corynespora cassiicola, a multitrophic fungus widely distributed in tropical and subtropical areas. TS can infect foliage and fruit, often resulting in significant yield losses in conductive environments. There are no known TS-resistant cultivars, and control relies entirely on fungicidal sprays. However, several studies have demonstrated that the fungus is developing resistance to commonly used fungicides which further complicates disease management. The objective of this work was to identify sources of resistance to TS from wild Solanum accessions. Initial screens of 83 accessions informed the selection of 24 accessions for a more robust screening in which six diverse C. cassiicola isolates were used for single-isolate inoculation experiments. The results from a broad-sense mixed-model analysis including data from all six experiments demonstrated that all 24 accessions had significantly lower disease severities compared with the susceptible controls, suggesting that all accessions potentially harbor resistance quantitative trait loci (QTLs). Solanum cheesmaniae accession LA0524, S. galapagense accessions LA0483 and LA0532, and S. pimpinellifolium accession LA2093 were among the most resistant accessions tested and may be particularly useful for introgression of resistance into cultivated germplasm and for mapping of TS resistance QTLs.

Compatibility Studies on Selective Insecticides, Fungicides and Water-Soluble Fertilizer Mixtures in Soybean

In present context, there is a demand for combination spray of insecticides and fungicides to manage both insect pests and diseases simultaneously in a crop season. However, tank mixing of incompatible combinations can reduce the effectiveness of the chemicals, cause phytotoxicity or development of insecticide resistance in pests. Hence, a laboratory experiment was conducted at Agricultural Research Station (UAS, Dharwad), Sankeshwar, Karnataka to study the physical, chemical and phytotoxic compatibility of selective insecticides, fungicides and water-soluble fertilizer mixtures at their recommended dose in soybean by jar compatibility method. Out of eighteen different combinations tested emamectin benzoate 5 SG (0.3 g l-1) in combination with propiconazole 25 EC (1 ml l-1) and 19:19:19 (N:P:K @ 5 g l-1), as well as lambda cyhalothrin 4.6 + chlorantraniliprole 9.3 ZC (0.4 ml l-1) in combination with propiconazole 25 EC (1 ml l-1) and 19:19:19 (5 g l-1) exhibited sedimentation levels of 1 ml l-1 which was less than the limits of 2 ml 100 ml-1 as specified in 1973 by Indian Standard Institute. The pH of agrochemicals both alone and combinations in all solutions test ranged from 6.02 to 8.39 and none of the solutions found extremely acidic nor alkaline. No phytotoxic symptoms were observed in combination treatments at 5 and 10 days after spraying. All test combinations were physically, chemically and biologically compatible hence, tank mixing of these chemicals can be recommended in soybean for managing of insect pest and diseases.

Fungicide ingestion reduces net energy gain and microbiome diversity of the solitary mason bee

Fungicides are frequently used during tree fruit bloom and can threaten insect pollinators. However, little is known about how non-honey bee pollinators such as the solitary bee, Osmia cornifrons, respond to contact and systemic fungicides commonly used in apple production during bloom. This knowledge gap limits regulatory decisions that determine safe concentrations and timing for fungicide spraying. We evaluated the effects of two contact fungicides (captan and mancozeb) and four translaminar/plant systemic fungicides (cyprodinil, myclobutanil, penthiopyrad, and trifloxystrobin) on larval weight gain, survival, sex ratio, and bacterial diversity. This assessment was carried out using chronic oral ingestion bioassays where pollen provisions were treated with three doses based on the currently recommended field use dose (1X), half dose (0.5X), and low dose (0.1X). Mancozeb and penthiopyrad significantly reduced larval weight and survival at all doses. We then sequenced the 16S gene to characterize the larvae bacteriome of mancozeb, the fungicide that caused the highest mortality. We found that larvae fed on mancozeb-treated pollen carried significantly lower bacterial diversity and abundance. Our laboratory results suggest that some of these fungicides can be particularly harmful to the health of O. cornifrons when sprayed during bloom. This information is relevant for future management decisions about the sustainable use of fruit tree crop protection products and informing regulatory processes that aim to protect pollinators.

Fungicide strategies for Ramularia Leaf Spot control recommended in Uruguay and its residues in barley grains

Ramularia leaf spot (RLS) is primarily managed by foliar fungicide spraying, which can result in residues in the grain. In recent years, increasing attention has been paid to the risks these residues pose to consumers. This study aimed to evaluate the efficacy of fungicide management used for RLS control and their fungicide residues in barley grain. Four different alternatives of fungicide mixtures: fluxapyroxad + pyraclostrobin + epoxiconazole; pyraclostrobin + epoxiconazole + chlorothalonil; prothioconazole + trifloxystrobin, and isopyrazam + azoxystrobin, in three spray timings: GS33, GS47 and GS33+GS47, were evaluated in five field experiments. An untreated and a fully protected treatment were included. Fungicide residues, disease severity, control efficacy, area under the disease progress curve, and plump grain yield were calculated. All fungicide strategies adhered to food safety, complying with the Maximum Residue Limits established by Codex and the European Union. Effectiveness varied based on RLS development, application time, and number of applications. Fungicide treatments applied at GS33+GS47 were the most effective as the highest severity levels were observed at the stage after GS47 under the conditions studied. Plump grain yield only showed minimal differences in the late epidemic. The study emphasized the low risk of fungicide presence in grains, favoring efficacy when selecting RLS management options. Any changes in management or regulations should be carefully reviewed to maintain findings. The research underscored the compatibility of recommended fungicide treatments with food safety standards, highlighting the balance between disease control efficacy and consumer safety.

Reevaluation of Sensitivity of Monilinia fructicola Isolates to the DMI Fungicide Propiconazole in the Southeastern United States and Investigation of the Genetic Element Mona.

Sterol demethylation inhibitor (DMI) fungicides continue to be essential components for the control of brown rot of peach caused by Monilinia fructicola in the United States and worldwide. In the southeastern United States, resistance to DMIs had been associated with overexpression of the cytochrome P450 14α-demethylase gene MfCYP51 as well as the genetic element Mona, a 65 bp in length nucleotide sequence located upstream of MfCYP51 in resistant isolates. About 20 years after the first survey, we reevaluated sensitivity of M. fructicola from South Carolina and Georgia to propiconazole and also evaluated isolates from Alabama for the first time. A total of 238 M. fructicola isolates were collected from various commercial and two experimental orchards, and sensitivity to propiconazole was determined based on a discriminatory dose of 0.3 μg/ml. Results indicated 16.2, 89.2, and 72.4% of isolates from Alabama, Georgia, and South Carolina, respectively, were resistant to propiconazole. The detection of resistance in Alabama is the first report for the state. All resistant isolates contained Mona, but it was absent from most sensitive isolates. It was unclear if the resistance frequency had increased in South Carolina and Georgia. However, the resistance levels (as assessed by the isolate frequency in discriminatory dose-based relative growth categories) did not change notably, and no evidence of other resistance genotypes was found. Analysis of the upstream MfCYP51 gene region in the resistant isolate CF010 revealed an insertion sequence described for the first time in this report. Our study suggests that current fungicide spray programs have been effective against increasing resistance levels in populations of M. fructicola and suppressing development of new resistant genotypes of the pathogen.

In vitro and in vivo evaluation of fungicides against anthracnose disease on pomegranate (Punica granatum L.) caused by Colletotrichum gloeosporioides

Successful cultivation of pomegranate in India has faced many challenges, with diseases and pests being the major constraints. Many pathogens affect pomegranate leaves and fruits, and anthracnose, which can cause significant damage to the pomegranate crop. The spraying of fungicides with varying modes of action is a successful disease management approach. Hence, the present work was aimed to characterize the pathogen and evaluate the different fungicides for the effective control of the disease under field conditions. The pathogen was identified as Colletotrichum gloeosporioides through morphological features and sequencing of ITS 1 and ITS 4 regions. Fifteen fungicides were then tested in vitro against C. gloeosporioides using the poison food technique at various concentrations. Out of the five contact fungicides evaluated, copper oxychloride was found to be the most effective against C. gloeosporioides. On the other hand, all three concentrations of pyraclostrobin, thiophanate methyl, tebuconazole, hexaconazole, and propiconazole showed 100 % inhibition. Among the five combination products tested, propiconazole + difenconazole, tebuconazole + trifloxystrobin, and pyraclostrobin + epoxiconazole showed 100 % inhibition. After the in vitro results, the field evaluation was further studied to find the most effective fungicides. The trifloxystrobin + tebuconazole fungicide was found to have a percent disease index of 4.50, which was significantly lower than all other treatments. The plots treated with this fungicide produced the highest yield of 10.92 t/ha, followed by Pyraclostrobin + Epoxiconazole at 9.89 t/ha. The control plot had the lowest yield, producing only 3.02 t/ha. Based on field evaluations, Tebuconazole + Trifloxystrobin is recommended as a preventative measure against anthracnose disease in pomegranates.

Effect of fungicide sprays on spiders in vineyards

Effect of fungicide sprays on spiders in vineyards

Grapevine Leaf Epiphytic Fungal and Bacterial Communities Are Influenced More by Spatial and Temporal Factors than by Powdery Mildew Fungicide Spray Programs

Synthetic fungicide treatments for managing grapevine powdery mildew have been widely applied in vineyards for decades, yet their ecological impacts on microorganisms in the phyllosphere have not been sufficiently studied. To investigate the impact of fungicide sprays on the grapevine leaf microbiota, grapevine leaf epiphytes were collected throughout the growing season from two California vineyards, each treated with identical spray programs. Each spray program was designed to control grapevine powdery mildew and contained five rotating synthetic fungicides. Leaf samples were collected before the first spray and between subsequent spray applications. Amplicon sequencing of ITS2 and 16S rRNA V4 regions was used to compare leaf epiphytic fungal and bacterial/archaeal diversities, taxonomic compositions, and differential abundances of taxa among treatments, locations, and sampling time points. Location (vineyard) and time significantly affected bacterial and fungal community compositions, whereas spray treatment did not. Plant-pathogenic fungi were the dominant fungal guild in both locations, and, in one location, their dominance increased significantly as the season progressed. Botrytis, an important postharvest pathogen in grapes, was significantly higher in relative abundance in one of the locations in the late season and acted as a hub genus in a co-occurrence network. In summary, the overall impact of the different spray programs on microbial community compositions was not significant, suggesting that the shifts of grapevine foliar microbial communities may be driven mainly by spatial and temporal factors rather than specific fungicide applications. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Streptomyces rapamycinicus HCD1–10: An effective biocontrol actinomycetes against postharvest Chinese flat peach brown rot caused by Monilinia fructicola

Monilinia spp. causing brown rot are fungal pathogens producing severe losses in worldwide stone fruit production, with high economic relevance (M€ 1.7/year). There are three main fungal species: Monilinia laxa, M. fructigena and M. fructicola. The pathogen infects aerial parts of host plants with a variety of symptoms, including blighting of blossoms, cankers on woody tissues and rotting of fruits, although the prevalent fruit losses are in the postharvest phase. Fungicide sprays in pre- and postharvest periods are usually used to control Monilinia spp. but, in Europe, no fungicide fruit treatments are allowed after harvest. Many studies conducted in recent years have defined three main research fields within the alternative methods for postharvest brown rot control: (1) biological control sensu strictum with microbial antagonists; (2) use of natural bioactive compounds; and (3) use of physicochemical methods. Although the reviewed results have reported a significant reduction of pesticide use, a multidisciplinary approach is recommended in the future, where biological products will be combined with low-risk chemical fungicides, natural antimicrobial substances and other physical means for an integrated strategy to control brown rot.

Phenotyping, genetics, and "-omics" approaches to unravel and introgress enhanced resistance against apple scab (Venturia inaequalis) in apple cultivars (Malus × domestica).

Apple scab disease, caused by the fungus Venturia inaequalis, endangers commercial apple production globally. It is predominantly managed by frequent fungicide sprays that can harm the environment and promote the development of fungicide-resistant strains. Cultivation of scab-resistant cultivars harboring diverse qualitative Rvi resistance loci and quantitative trait loci associated with scab resistance could reduce the chemical footprint. A comprehensive understanding of the host-pathogen interaction is, however, needed to efficiently breed cultivars with enhanced resistance against a variety of pathogenic strains. Breeding efforts should not only encompass pyramiding of Rvi loci and their corresponding resistance alleles that directly or indirectly recognize pathogen effectors, but should also integrate genes that contribute to effective downstream defense mechanisms. This review provides an overview of the phenotypic and genetic aspects of apple scab resistance, and currently known corresponding defense mechanisms. Implementation of recent "-omics" approaches has provided insights into the complex network of physiological, molecular, and signaling processes that occur before and upon scab infection, thereby revealing the importance of both constitutive and induced defense mechanisms. Based on the current knowledge, we outline advances toward more efficient introgression of enhanced scab resistance into novel apple cultivars by conventional breeding or genetic modification techniques. However, additional studies integrating different "-omics" approaches combined with functional studies will be necessary to unravel effective defense mechanisms as well as key regulatory genes underpinning scab resistance in apple. This crucial information will set the stage for successful knowledge-based breeding for enhanced scab resistance.

Agronomic and disease responses of three watermelon (citrilus lanatus l.) varieties to fungicide spraying regimes in a tropical environment

usarium wilt disease is a major biotic factor limiting watermelon production in the derived savanna agroecology of southeast Nigeria. The study hypothesized that variety could interact with the fungicide spraying regime to improve the agronomic performance of watermelon (Citrulus lanatus (Thunb) Matsum and Nakai). The objectives of the study were: to assess the effect of fungicide spraying regimes on disease incidence, severity, and agronomic performance of three watermelon varieties; and to identify and characterize the fungal causal organism of Fusarium wilt of watermelon in the derived savanna agroecology of southeast Nigeria. Three varieties of watermelon (Jubaly, red diamond, and sweet sangaria) and four fungicide spraying regimes (No spray, weekly, bi-weekly, and tri-weekly spray) were evaluated for agronomic performance, and disease incidence and severity in a 3 × 4 factorial in a randomized complete block design replicated thrice. Data were collected on phenological, growth and yield indices, and disease incidence and severity. Analysis of variance was done using Genstat 16th edition and GraphPad Prism 9 was used to construct the graphs. Variety significantly affected agronomic traits as well as disease incidence and severity. The Jubaly variety performed better than other varieties in most of the growth and yield parameters measured despite recording higher disease incidence and severity scores. Weekly application of fungiforce recorded the lowest disease incidence (16.67, 16.67, and 50%) and severity (6.7, 6.7, and 10%) at 9, 10, and 11 weeks after planting, respectively. The interaction effect of the Jubaly variety and weekly spray was consistently higher in vine length, node number, fruit number, and fruit yield. Morphological isolation and identification of the fungal causal organism showed the presence of Fusarium species. Further molecular characterization by DNA extraction from the Fusarium isolate and sequencing using the Sanger sequencing method confirmed the presence of Fusarium equiseti. The basic local alignment search tool result showed 94–100% similarity with F. equiseti strain WZ-98 from the NCBI Gene bank. The organism was identified as F. equiseti based on the Phylogeny.

Impact of managing yellow rust (Puccinia striiformis f.sp. tritici) by the use of fungicide sprays and resistant varieties on the physiochemical qualities of bread wheat

AbstractYellow rust disease caused by Puccinia striiformis f. sp. tritici is one of the major threats to wheat production in Ethiopia. In this paper, the impact of yellow rust on the physical qualities of bread wheat was studied. For this purpose, combinations of four bread wheat varieties (Digalu, Hidase, Danda'a, and Honkolo) and two fungicides (Nativo SC 300 and Tilt® 250E.C.) were tested at two different hotspot areas (Albazar and Alicho) in the Silte Zone, Southern Ethiopia, under natural epidemics of the disease during the 2018 growing season. A randomized complete block design in factorial arrangement with three replications was used to set up the experiment. A significant (p < .01) increase in hectoliters weight and wet gluten content were observed due to the application of Nativo SC 300; however, grain protein content did not respond significantly (p > .01) at both locations. Wheat varieties with high yellow rust severity exhibited maximum values of area under the disease progress curve and physical quality loss percentage (%). The highly susceptible wheat variety Digalu exhibited the highest values of hectoliter weight losses (%), and the actual losses ranged from 5.5% to 29.5%. Except for grain protein content, there was a significant negative correlation between the values of terminal rust severity, average coefficient infection, and area under the disease progress curve and that of hectoliters weight and wet gluten content, with correlation coefficients ranging from −0.85** to −0.33**. It is possible to improve the physiochemical properties of bread wheat through the application of foliar fungicides by selecting the appropriate genotypes that have an acceptable level of resistance to yellow rust.

Controlling of Maize Grey Leaf Spot by Interacting Host Resistance and Fungicide Spray Frequency at Bako, Ethiopia

Controlling of Maize Grey Leaf Spot by Interacting Host Resistance and Fungicide Spray Frequency at Bako, Ethiopia

Soybean and grapevine rusts accelerate the defoliation rates of host plants

AbstractGrapevine leaf rust (GLR) and soybean rust (SBR), caused by Neophysopella tropicalis and Phakopsora pachyrhizi, respectively, may lead to early defoliation of the host, depending on disease severity level. The rate of defoliation is an important parameter in mechanistic models aimed at simulating yield loss, but such knowledge is not available for these rust diseases. This work aimed to (i) relate the temporal dynamics of GLR and SBR to defoliation; and (ii) estimate the relative rates of defoliation and model their relationship with rust severities. Grapevine and soybean plants were inoculated in the field at increasing concentrations of urediniospore suspensions of the respective causal agent. Control plots of the vineyard and the soybean field were protected with sequential fungicide sprays to evaluate natural defoliation. Rust severity (proportion of area affected) of each leaf or leaflet was evaluated every three or four days on 1323 grapevine leaves and 655 soybean leaflets, respectively. The relative rates of defoliation were estimated as the slope parameters of linear regression of the Napierian logarithm of the number of alive leaves or leaflets over time. Defoliation rates in grapevine and soybean incremented logarithmically with the increase of rust severity. Defoliation rates on symptomless grapevine and soybean leaves were 0.018 and 0.05 day−1, respectively, while they averaged 0.033 day−1 on diseased grapevine leaves (rust severity between 5% and 12%), and 0.12 day−1 on diseased soybean leaflets (rust severity between 25% and 60%). Thus, a quantitative relationship was established between rust severity and defoliation on grapevine and soybean.

Influence of production situation on the incidence of brown spot of rice (Oryza sativa) caused by Bipolaris oryzae in the Philippines

AbstractBrown spot, caused by Bipolaris oryzae, is becoming more prevalent and important in the Philippines but risk assessment is limited. Surveys of 2186 farmers' fields were conducted in the major rice‐growing areas in the country from 2015 to 2018 to analyse the components of production situation (PS) that contribute to the area under the progress curve of brown spot incidence (aBS). Based on lasso regression, the components of PS that influence aBS, in decreasing order, are ecosystem (irrigated vs. rainfed), crop establishment method (direct seeding vs. transplanting), variety type (hybrid vs. inbred), rate of phosphorus fertilizer, rate of potassium fertilizer, application of organic fertilizer (with vs. without organic fertilizer) and frequency of fungicide application. Pairwise comparisons showed that aBS is positively associated with direct‐seeded rice, rainfed ecosystem, hybrid rice, moderate to high P and K rates and spraying of fungicide. Correspondence analysis and chi‐squared tests showed that the class with highest aBS is closely associated with the production situation characterized by rainfed ecosystem, direct‐seeded rice, fungicide application, moderate nitrogen and moderate to high phosphorus and potassium rates; and weather pattern (temperature, relative humidity, solar radiation, rainfall and wind speed) that occurs during the wet season. These results confirm previous studies showing that increased adoption of water‐saving technologies and direct seeding for adaptation and mitigation to climate change and reduction of agricultural labour, will most probably favour brown spot. Strategies to manage the disease under these production situations should be implemented in government programmes and considered in future research agendas.

Management of Charcoal Rot (Macrophomina phaseolina) of Fenugreek in Rajasthan

Background: Charcoal rot of fenugreek caused by Macrophomina phaseolina is destructive disease of all fenugreek growing areas of Rajasthan, The disease is wide occurrence in sandy soil of Rajasthan, where the climatic conditions are dry and temperature remains high. Under severe infestation it cause 35.00-42.56% losses in yield. In the present investigation, our main emphasis was to find out some new fungicides alone and combination with bio-agent for management of charcoal rot of fenugreek. Methods: Eight fungicides viz., captan 70%+ hexaconazole 5% WP, azoxystrobin 18.2% + difenaconazole 1.4% SC, chlorothalonil 75% WP, carbendazim 12% + mancozeb 63% WP, tebuconazole 50% + trifloxystrobin 25% WG, carboxin 37.5% + thiram 37.5% WP, copper oxychloride 50% WP and captan 70% WP were tested at different concentration of 100, 200, 300, 400 and 500 ppm against M. phaseolina using Poisoned Food Technique in vitro. The in vivo study was taken to evaluate the effect of one fungal and one bacterial bio-agent viz., T. harzianum, P. fluorescens was applied as seed treatment, soil dressing and soil application @ 5+5g/kg and @ 10 kg/ha respectively and fungicides viz., tebuconazole 50%+ trifloxystrobin 25% @ 1.5 g/kg, carbendazim 12% + mancozeb 63% @ 2 g/kg and azoxystrobin 18.2% + difenaconazole 11.4% 2 ml/kg seed were used in different treatments. The experiment was conducted at Experimental farm COA, SKRAU, Bikaner during Rabi 2020-21 on most popular cv. Rmt-305 in RBD design with the application of seed treatment, soil dressing and foliar spray of different fungicides with bioagents at different concentrations against Charcoal Rot disease and compared with an untreated control. Result: Among all the tested fungicides used in the present investigation, tebuconazole 50% + trifloxystrobin 25% WG found most effective in controlling the mycelium growth of pathogen. In field condition, it gave maximum disease control (85.72%) with highest grain yield (19.83 q/ha) when applied as seed treatment with tebuconazole 50% + trifloxystrobin 25% WG @ 1.5 g/kg seed + soil application of T. harzianum @ 10 kg/ha + SD with tebuconazole 50% + trifloxystrobin 25% WG. These treatments can provide an effective management of charcoal rot disease for fenugreek cultivators.