Purple Blotch Of Onion Research Articles

Effect of Neem Cake, Neem Oil and Plant Extracts on Purple Blotch of Onion (Allium cepa L.) Caused by Alternaria porri (Ellis) Cif.

The present study was conducted to evaluate the Effect of neem cake, plant extracts and neem oil on purple blotch of onion (Allium cepa L.) caused by Alternaria porri (Ellis) Cif. Six different treatments were tested in a randomized block design with 3 replications at the Central Research Field, Department of Plant Pathology, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj during Rabi season of 2023. The results should that the minimum per cent disease intensity was recorded in T1Neem cake + Neem oil (31.72), T5 Neem cake + Eucalyptus leaf extract (37.40). bulb weight of onion (71.13g), bulb diameter (7.13cm), bulb yield per plot (2.106kg), yield (105.317 q/ha) and benefit cost ratio (1: 4.42) were found in T1Neem cake + Neem oil (31.72) when compared to untreated check and other treatments.

Potency of formulated biocontrol agents from lab to field: a sustainable approach for onion purple blotch suppression

Potency of formulated biocontrol agents from lab to field: a sustainable approach for onion purple blotch suppression

Unravelling the synergistic interaction of Thrips tabaci and newly recorded, Thrips parvispinus with Alternaria porri (Ellis.) Cif., inciting onion purple blotch.

Onion purple blotch is the most indispensable foliar disease of crop and has become a major concern for farmers and research fraternity. An attempt to investigate the role of injury in parasitism by Alternaria porri indicated that disease incidence and severity enhance considerably with injury. Thrips injured plants inoculated with A. porri presented 100% incidence and 52-72% severity while mechanically injured plants inoculated with A. porri showed 60-70% incidence and 28-34% severity. The uninjured plants showed considerably less disease incidence (30-40%) and severity (10-16%). Injured inoculated plants presented reduced leaf length and leaf area while the leaf diameter remained unaffected. The lesion number, lesion length and size was substantially enhanced with concomitant infestation of pest and pathogen. Thrips tabaci injury led to more pronounced symptoms of purple blotch compared to Thrips parvispinus injury. There was substantial decrease in photosynthetic rate and chlorophyll content with stress imposed on plant whilst the relative stress injury was enhanced. The induction of injury and inoculation of A. porri had an impact on the concentration of total phenolics, total soluble sugars, total proteins and hydrogen peroxide in onion leaves. A. porri combined with injury caused a more pronounced decrease in total soluble sugars and total protein content while enhancement in total phenolics and hydrogen peroxide content compared to uninjured plants. The dynamic nature of morpho-physiological and biochemical changes owing to stress conditions imposed on onion plant adds an extra layer of complexity in understanding the onion plant physiology and their ability to work out in response to challenging environment conditions.

Physiological studies on Alternaria porri caused purple blotch of onion under In-vitro conditions

The effect of nutrient media, temperature, pH level, carbon and nitrogen ion concentration were studied on mycelial growth and sporulation of Alternaria porri caused purple blotch of onion. The investigations revealed that Potato dextrose agar was the best culture medium for A. porri. The maximum mycelial growth of A. porri was recorded on 30°C temperature (85.74 mm) and pH 7.0 (83.40 mm). A. porri grew significantly better response to the source of carbon nutrient media on mycelial growth and observed the maximum mycelial growth on maltose (88.26 mm) based medium with highest sporulation and potassium nitrate-based media source of nitrogen gave maximum mycelial growth (80.75 mm) and sporulation of A. porri. The present findings are useful for the preparation of inoculums required for resistance breeding and fungicidal evaluation against pathogen A. porri.

Efficacy of plant extracts in growth promotion and onion purple blotch management: Unveiling metabolite fingerprinting of promising neem leaf extracts through GC MS

Efficacy of plant extracts in growth promotion and onion purple blotch management: Unveiling metabolite fingerprinting of promising neem leaf extracts through GC MS

Effect of Purple Blotch Farm Management Practices on Onion Production in Uganda

Onion is one of the most important commercial vegetable crops grown intensively in the world. Purple blotch found in all the growing regions is the most destructive of all onion diseases. Detailed studies on the disease's management practices had not been conducted in Uganda. The objective of this study was to establish the effect of purple blotch disease management practices on onion production. Kabale, Kasese, and Mbale regions were identified as the major onion-growing regions. Five farms/onion varieties/regions were surveyed using a semi-structured questionnaire administered to 52 farm owners who were interviewed. The results revealed the majority were small-scale peasant farmers with mean acreage of 0.64-1.94, which varied significantly p=.000, and Kasese had the highest. Eight onion varieties were recorded: Bombay red, Hazera, Hybrid, Malbec, Red coach, Red creole, S-Zee and Tanzania, with Red creole grown in all the regions. Kabale registered the highest number of farms (40.3%), Kasese district (25.0%), the highest mean production of 6,329.9 kg/season, and Namisindwa (21.1%) the second. The main source of seed was Agro input dealers. The use of artificial fertiliser was highest in Mbale (72.7%) and lowest in Kasese (50%), though it did not vary p>.05 significantly. Only farmers in Kabale and Kasese had access to credit facilities, agricultural extension workers and farmers' groups, with Kasese in the lead. Onion purple blotch disease and thrips were the main problem in all the regions and were controlled using chemicals: 100%, 90.9% and 88.3% in Mbale, Kabale, and Kasese, respectively. Weeding of farms was lowest in Mbale (mean = 3.88) and highest in Kasese (4 .84). In conclusion, growing the right onion variety, farmer groups, access to credit facilities, and genuine farm inputs are necessary for a sustainable onion agribusiness in Uganda

Botanical synthesis of silver nanoparticles (AgNPs) and its antifungal effect against Alternaria porri causing purple blotch of onion: An in vitro and natural epiphytic study

Tulsi (Ocimum sanctum) leaf extract was used to manufacture stable silver nanoparticles. The synthesized AgNPs were characterized by EDX (Energy dispersive X-ray Spectrometry), TEM, and DLR to confirm the size of particles which varied widely within 100 nm and pure. In-vitro analysis was carried out to find the best concentration of AgNPs against Alternaria porri, which showed various levels of inhibition. Maximum inhibition percentage was recorded at 150ppm (91.71%) followed by 125 (91.24%) and 100ppm (87.56%). Similarly, AgNPs was also evaluated against Alternaria porri in natural epiphytic condition. From the result of the field experiment, it has been observed that AgNPs were capable enough to manage the purple blotch disease. The maximum inhibition percentage of purple blotch disease was observed at 100ppm (80.93%), followed by 75ppm (77.17%) under field conditions.

Survey, Occurrence of Major Onion Diseases and Management of Twister Disease of Onion (Allium cepa L.)

Purple blotch of onion caused by the fungus Alternaria porri is a serious disease in kharif season and more yield losses in onion growing areas of Maharashtra. A survey was conducted to assess disease intensity of major diseases in onion growing area in Nashik district during kharif 2020 and 2021 During the survey, small whitish, leaf curling, twisting, chlorosis of leaves, elongation of neck and cylindrical bulb such symptoms of twister disease were observed more severe than purple blotch on onion in kharif 2020. The per cent disease severity ranged from 17.28 to 45.83 per cent and 8.00 to 23.00 per cent in purple blotch of onion and 20.17 to 54.59 per cent and 12.00 to 35.00 per cent twister disease of onion during kharif 2020 and 2021, respectively. The diseased samples were utilized for isolation of pathogen. After isolation and morphological study, it is indicated that twister disease of onion was complex of pathogen caused by Colletotrichum gloeosporioides, Fusarium sp. and nematode. Due to climate change, from the survey concluded that twister disease was found more serious and threatening disease than purple blotch of onion during kharif 2020 and 2021. Considering the yield losses caused by twister disease of onion, the investigation was planned for management of twister disease during kharif 21. The combine application of Trichoderma drenching @ 10 g/l along with two alternate sprays of each Tebuconazole 25.9 EC @ 1 ml/l or Azoxystrobin 23 SC@ 1 ml/l recorded lowest PDI of twister disease (14.33%) of onion than the control treatment (49.11%) and which was found effective maximum per cent disease over control (70.82%) for management of twister disease of onion.

Efficacy of Bio-agents and Neem Oil against Alternaria porri (Ellis) in Onion (Allium cepa L.)

Onion (Allium cepa L.) is one of the important cultivated vegetable crops and can be grown in temperate, tropical and sub-tropical climates. It is the important vegetable and spice crop and known as “Queen of the kitchen”. Area, Production and Productivity on onion in India (2020-21) was 16.54 million ha, 26.92 million Tones and 19.40 t/ha. There are many diseases and pests affecting onion. Among the diseases, majorly purple blotch, downy mildew, Stemphylium blight and basal rot attacks the onion and among the pests, onion thrips, red spider mite, onion fly attacks the onion. Among them, purple blotch of onion is one of the most severe diseases, which is caused by Alternaria porri which causes heavy losses in the onion. The treatments viz., Trichoderma viride, Pseudomonas fluorescens, Bacillus subtilis and neem oil were tested under field conditions against Alternaria porri during Zaid for their efficacy against the growth and disease parameters and an untreated plot will serve as control. At desired interval of days (45,60,75 DAT) readings were taken for growth parameters and disease intensity. Based on single trail, it was observed that among all treatments, seedling treatment with Trichoderma viride + Pseudomonas fluorescens + neem oil @ 5% showed the most significant results with maximum growth parameters and minimum disease intensity results followed by Trichoderma viride + Bacillus subtilis + neem oil @ 5% and the minimum growth parameters and maximum disease intensity was shown in untreated (control) plot.

Major diseases of field and horticultural crops in Northern Bihar region of India

A survey was conducted to determine the status of major diseases of field and horticultural crops grown in Saharsa, Supaul, Madhepura and Khagaria districts of northern Bihar, India. Three blocks in each district and three villages in each block were surveyed through a random field survey method. Per cent disease incidence was recorded on randomly selected plants in a particular field of selected location. The incidence of diseases was observed on the basis of typical field symptoms and later the association was confirmed through microscopic examinations in the laboratory. In view of maximum diseases incidence; foliar blight of wheat, sheath blight of rice, turcicum leaf blight of maize, mungbean yellow mosaic virus, Alternaria blight of mustard were recorded with >50% incidence in these districts. However, dry root rot and wilt of chickpea and lentil, wilt of pigeonpea, powdery mildew of pea, Alternaria leaf spot of linseed, Fusarium wilt and red rot of sugarcane and root rot of jute were noticed with 10 to 50% incidence. In fruit crops; sigatoka disease of banana was noticed with >50% incidence, while, anthracnose/ die back and floral malformation of mango, wilt of banana, foot rot of papaya and anthracnose of guava and citrus canker were observed with 10-50% incidence. Diseases viz., late blight, bacterial wilt, black leaf spot/ rot, leaf curl, yellow vein mosaic virus, die back and late blight were recorded with >50% incidence in tomato, brinjal, cauliflower, cucurbits, okra, chilli and potato, respectively. The purple blotch of onion, black leaf rot of cabbage and collar rot of elephant foot yam were noticed with 10-50% incidences.

Effect of integrated management on purple blotch (Alternaria porri (Ellis) Cif.) progression and bulb yield of onion at Arba Minch in Southern Ethiopia

A field experiment was conducted at Arba Minch area, southern Ethiopia during the 2018 and 2019 cropping seasons to determine the integrated effects of varieties and fungicide spray frequencies on onion purple blotch (PB) epidemics, bulb yields, and economic returns. Fifteen treatment combinations consisting of three onion varieties and five fungicide spray frequencies were arranged in a factorial experiment in a randomized complete block design with three replications. Integrating varieties with fungicide spray frequencies significantly reduced onion PB epidemics and increased bulb yields and economic returns. Due to four times spray of ridomil gold (RG) at 14-day interval, PB severities as low as 35.7, 42.2, and 58.9% were recorded on Nasik-Red, Bombay-Red, and Adama-Red varieties, respectively. The lowest area under the disease progress curve of 625.3, 706.7, and 1131.1%-days was also recorded on Nasik-Red, Bombay-Red, and Adama-Red varieties, respectively, due to four sprays of RG at a 14-day interval. Three times spray of RG at 10-day interval gave the highest bulb yields of 33.4, 38.9, and 23.7 t ha-1 on Nasik-Red, Bombay-Red, and Adama-Red varieties, respectively. The results showed the existence of variability in onion genetic resistance that was complemented by fungicide spray frequencies against PB epidemics to increase bulb yields. The use of Bombay-Red variety along with three and four-time spray frequency of RG was found to be the most effective option in reducing PB epidemics and increasing onion bulb yields. However, the use of Bombay-Red variety along with three-time spray frequency of RG could be recommended, because of its highest economic returns, to farmers in the study areas and elsewhere with similar agro-ecologies to manage PB and sustain onion production and productivity in the country.

A comparative study of onion purple blotch (caused by Alternaria porri) and tomato early blight (caused by A. solani) diseases in Southern Ghors of Jordan

A comparative study of onion purple blotch (caused by Alternaria porri) and tomato early blight (caused by A. solani) diseases in Southern Ghors of Jordan

Characterization of Alternaria porri causing onion purple blotch and its antifungal compound magnolol identified from Caryodaphnopsis baviensis.

Alternaria porri (Ellis) Clf. causes purple blotch disease on Allium plants which results in the reduction of crop yields and quality. In this study, to efficiently find natural antifungal compounds against A. porri, we optimized the culture condition for the spore production of A. porri and the disease development condition for an in vivo antifungal assay. From tested plant materials, the methanol extracts derived from ten plant species belonging to the families Cupressaceae, Fabaceae, Dipterocarpaceae, Apocynaceae, Lauraceae, and Melastomataceae were selected as potent antifungal agents against A. porri. In particular, the methanol extract of Caryodaphnopsis baviensis (Lec.) A.-Shaw completely inhibited the growth of A. porri at a concentration of 111 μg/ml. Based on chromatographic and spectroscopic analyses, a neolignan compound magnolol was identified as the antifungal compound of the C. baviensis methanol extract. Magnolol showed a significant inhibitory activity against the spore germination and mycelial growth of A. porri with IC50 values of 4.5 and 5.4 μg/ml, respectively. Furthermore, when magnolol was sprayed onto onion plants at a concentration of 500 μg/ml, it showed more than an 80% disease control efficacy for the purple blotch diseases. In terms of the antifungal mechanism of magnolol, we explored the in vitro inhibitory activity on individual oxidative phosphorylation complexes I–V, and the results showed that magnolol acts as multiple inhibitors of complexes I–V. Taken together, our results provide new insight into the potential of magnolol as an active ingredient with antifungal inhibitory action to control purple blotch on onions.

Relative efficacy of fungicides in managing onion purple blotch incited by Alternaria porri

Relative efficacy of fungicides in managing onion purple blotch incited by Alternaria porri

Nutritional and Physiological Requirement of Alternaria porri (Ellis) Cif Causing Purple Blotch of Onion

An experiment was carried out to study the nutritional requirement and response of different physiological parameters viz., temperature and pH on mycelial growth of different isolates of Alternaria porri (Ellis) Cif causing purple blotch of onion. The five different pH levels, temperature, carbon sources and nitrogen sources were tested for their effect on mycelial growth and sporulation of A. porri. The results showed that the maximum mycelial growth and sporulation of A. porri was observed at pH 7.0 and minimum at pH 9.0. In temperature range the maximum mycelial growth and sporulation was recorded at 30 oC and minimum at 10 o. The mycelial growth of A. porri was different on Czapek’s dox agar basal medium with different carbon sources. Maximum radial growth was observed on maltose followed by sucrose and minimum on dextrose maltose. The mycelial growth of A. porri grown on varied Czapek’s dox agar basal medium with different nitrogen sources. Maximum mycelial growth and sporulation was observed on potassium nitrate followed by sodium nitrate and minimum on urea, respectively.

Efficacy of bio control agents under in vitro against Alternaria porri (Ellis) Cifferi. Causing purple blotch in onion

Purple blotch of onion caused by Alternaria porri (Ellis) Cif. is most devastating disease of onion in India has it causes huge loss under field conditions. In the recent days bio control agents are playing an important role in controlling the incidence of purple leaf blotch disease. Hence the study was undertaken to check the efficacy of nine fungal and eight bacterial antagonists under laboratory conditions by employing dual culture techniques. From the study it was clear that fungal bioagents takes upper hand in inhibiting the pathogen growth when compared to bacterial antagonists. Among nine fungal antagonists under study the highest mycelial inhibition was recorded in the isolate Trichoderma viride-1 with the per cent inhibition of 94.50 per cent. Followed by isolate Trichoderma harzianum-1 showing the inhibition per cent (90.19%). However the least inhibition of the mycelia growth 33.72 was noticed in Bacillus subtilis -3 isolate.

Exploration and Antifungal Assay of Endophytic Fungi as Biocontrol of Onion Purple Blotch Disease Caused by Alternaria porri (Ell) Cif In Vitro

Purple blotch disease caused by Alternaria porri is the main destructive foliar disease of genus Allium, causing significant losses in yield of the crops. Recently, purple blotch disease is controlled by synthetic fungicides. However, fungicides have negative effects on the environment. Endophytic fungi can be used as an alternative control because a close symbiosis with the internal tissue of the host can minimize competition in new and complex ecosystems. This study aimed to explore and identify endophytic fungi that have the highest inhibition ability against A. porri and investigate the antagonistic mechanism. The method used in this study is an exploration of endophytic fungi, isolation of A. porri, in vitro antagonism tests, observation of the antagonistic mechanism, extraction of crude protein, SDS-PAGE, and identification. The antagonistic fungi that had the highest inhibition ability were identified as Penicillium citrinum with an inhibitory of 60.04%. Crude protein extracted from P. citrinum which showed inhibitory activity against A. porri is saturation level of ammonium sulfate 80% with a molecular weight of 40 kDa. This study implies that P. citrinum can inhibit the growth of A. porri through its anti fungi compounds. Further in vivo assays or field trials will need to be conducted in future studies.

EFFECT OF POTASSIUM SALTS ON ONION PURPLE BLOTCH INCIDENCE AND SOME PHYSIOLOGICAL AND YIELD PARAMETERS IN ONION SEED PLANTS

Purple blotch disease is one of the most destructive diseases of onion in Egypt, which could cause 100% loss of onion seed production. The excessive use of chemical fungicide harms the environment and natural balance, leading to find another safe and effective alternative controlling onion purple blotch disease. Field experiments were conducted at Demo in El-Sultan Bahnas village, Fayoum County at El-Fayoum Governorate during the growing seasons 2017/2018 and 2018/2019 on onion for seed production. Plants were sprayed with four potassium salts; potassium silicate (K-silicate), potassium citrate (K-citrate), dipotassium phosphate (K2HPO4) and potassium carbonate (K2CO3). Two control treatments one with distilled water and the other with mancozeb 80%. K2HPO4 gave the best result in decreasing disease incidence or disease severity in leaves and flower stalks in respectively, followed by K2CO3 and K-silicate. While, the treatment of K2CO3 gave the highest inflorescences’ fresh and dry weights followed by K2HPO4, then K-Citrate. The treatment of K2HPO4 generated the highest inflorescence and yield components compared to control treatment. K-silicate application exceeded the all other treatments and led to significant increases in free phenols and reduced sugars contents in onion leaves compared to control treatment. Examined Potassium salts in this study gave promised safe alternative control methods for onion purple blotch in onion seed production with reference to the chemical fungicide.

Survey of Purple Blotch Disease in Onion growing Districts of Bihar

Onion (Allium cepa L.) is one of the most important commercial vegetable crops grown in India. Inviewofthedestructivenature of purple blotch of onion the present investigation was conducted in different district of Biharduring Kharif and Rabi2018-2019.The highest disease incidence (37.17%) and intensity (38.95 %) was noticed in field of Pariaunna village of Nalanda district during Rabi season whereas highest disease incidence (21.24%) was recorded in field of village Kushahar and highest intensity (28.30 %) wasnoticedin field of village Paharpur district Vaishali during kharif season. While,thelowestdiseaseincidence(17.62 % )and (21.25%) intensity was recorded in Azampur village of Vaishali district during rabi season, but in kharif season lowest (8.74%) disease incidence and (10.85%) intensity was observed in village Basaria district Samatipur . Among the districts, severity of disease more in Nalanda (36.64%) and less in Vaishali (26.78%) were recorded duringrabi season, while less disease intensity (14.41%) in Samastipur district recorded in kharif season with highest value 26.21 % in Begusarai district.

Essential Oils as Alternative Control Materials of Onion Purple Blotch Disease Caused by Alternaria porri

Treatments with the fungicides against Alternaria porri mycelia growth were arranged according to their effectiveness in the following descending order, Ridomil gold plus 71.5 % WP, Galben copper 69.8% WP, Ridomil gold MZ-68% WG, Dithane M 45% WP and Kocide 2000 53.8% DF. The mixtures of fungicides were more efficiency than any single fungicide against mycelia growth of A. porri. The candidate essential oils were arranged according to their reduction percentages in mycelial growth at all tested concentrations in the following descending order, clove, cinnamon, thyme, camphor and nigella. Camphor and thyme oils have approximately the same inhibitory activity at all tested concentrations. The current study of greenhouse experiment indicated that the essential oils; camphor and thyme gave low efficiency against onion Purple blotch, while cinnamon and clove oils had approximately the same controlling effect. Generally, efficiency of Ridomil gold plus against onion Purple blotch was more than the essential oils. Mostly, efficiency results of essential oils against Purple blotch in the field through the two agricultural seasons 2017/18 and 2018/19 were compatible with those obtained in the greenhouse experiments. There are no significant differences in disease severity between the treatments of the essential oils, thyme, cinnamon and clove. Data in both seasons confirmed that camphor oil was the least efficient material. All treatments significantly increased the onion yield comparing with the untreated control. The high efficiency of Ridomil gold plus against purple blotch caused a high increase in onion yield. Meanwhile, the tested essential oils were moderately efficient and resulted in significant increase in onion yield.