Percent Disease Incidence Research Articles

Assessing Pathogenicity and Cultural Characteristics of Fusarium oxysporum f. sp. ricini Isolates from Major Castor Growing Regions of India

The present study was undertaken to investigate the pathogenicity and cultural characteristics of 20 isolates of Fusarium oxysporum f. sp. ricini, the causal fungus of wilt disease of castor (Ricinus communis L). Pathogenicity tests on the susceptible cultivar JI-35 revealed that all isolates were pathogenic, with symptoms progressing from yellowing and drooping of leaves to marginal necrosis, wilting and root discoloration. The incubation period varied significantly among the isolates, ranging from 10.0 to 22.5 days, while the per cent disease incidence (PDI) ranged from 51.7% to 100%. Cultural characterization that includes mycelial colour, colony morphology, pigmentation, growth habit and sporulation highlighted significant variability among the isolates of F. oxysporum f. sp. ricini. The colour of mycelium among the isolates ranged from white to various shades of pink and yellow, with growth habits observed as fast, moderate, or slow. Sporulation rates varied from very high to sparse among the isolates. The observed diversity in pathogenicity and cultural traits emphasized the presence of genetic variability in F. oxysporum f. sp. ricini isolates. These results are vital for understanding the pathogen virulence and for developing effective management strategies for wilt disease in castor crop.

Comparative Studies on The Efficacy of Some Fungicides Activities on Fungal Seed Borne Pathogens of Commercial Maize Seeds

This study investigated the efficacy of some fungicides activities on fungal seed borne pathogens of two commercial maize seeds (Sammaz 15 and Sammaz 52). A total of 2500 seeds were randomly picked for each variety to represent a working sample from the seed reference collections. Out of the 2500 seeds, 400 seeds were surface–sterilized with 10% sodium hypochlorite solution, cultured and examined microscopically for the presence of fungal pathogens. Molecular analysis confirmed that all isolated pathogens matched with the reference accession from NCBI molecular database. Seeds were treated with different dosages of fungicides viz Thiram and Metalaxy + Tebuconazole and incubated for 5 days. The effect of the various fungicides on the incidence of seed- borne fungi, effect on seed germination and interaction of the fungicide were evaluated and analyzed. Percentage occurrence of the fungal pathogens revealed that Sammaz 15 have F. solani (29.0%), A. flavus (20.3%), A. niger (19.0%) and Rhizpus stolanifera (15.0%). In Sammaz 52, A.niger (40.0%), A. flavus (19.7%) and F. solani (27.0%). It was observed that F. solani was predominant in sammaz 15 while A. niger was predominant in Sammaz 52. Thiram (45.88 mm) at all doses showed greater inhibitory effects on mycelia growth than Metalaxyl + Tebucanozole (24.25 mm). The correlation analysis performed on the data set reveals that there is a negative significant correlation between zone of inhibition and percent disease incidence (r = -0.99***), but the relationship was positive with number of non-infected seeds (r = 0.99***). This shows that increasing the zone of inhibition will increase the number of non-infected seeds and the normal seedling (germination percentage). Thiram fungicides observed to be more effective in reducing the disease incidence than Metalaxyl fungicides.

Improving Pepper Inbreds for Resistance to Pepper Yellow Leaf Curl Thailand Virus (PepYLCTHV) through Challenged Inoculations

Chili peppers (Capsicum annuum L.) are an economically important crop worldwide. Pepper yellow leaf curl Thailand virus (PepYLCTHV), a Begomovirus causing yellow leaf mosaic disease of chili pepper, has been reported to incur 95% economic loss under epiphytotic conditions. Thirty-one chili genotypes were screened for resistance to PepYLCTHV disease through inoculation using 10–15 viruliferous whiteflies per plant. We purified two resistant lines (PEP6 and PEP12) through four generations of selfing and selection. At 28 days after inoculations, two chili genotypes (PEP6 and PEP12) had low disease severity and percentage of disease incidence (DI) compared to four susceptible checks, viz., Yodsonkeam80, Homsupan, Huareau12, and Pong Charian, which had a disease severity score of 5 with 100% DI. Thirty initial plants of PEP6 showed an average disease severity of 3.64 with 69.33% DI, and PEP12 showed an average disease severity of 3.83 with 77.67% DI. From these populations, we selected nine highly resistant plant of PEP6 and seven plants of PEP12 having a disease severity of 0 through pure-line selection for four selfing generations. The ratio of resistance (R) to susceptibility (S) consequently decreased. In PEP6, the ratio decreased from 1R:2S to 1R:1S, while in PEP12 the ratio decreased from 1R:3S to 1R:1S. These lines have potential for release as resistant lines for improving chili pepper resistance to PepYLCTHV and for developing makers associated with the resistant trait.

Integrated Management of Foliar Diseases of Mungbean (Vigna radiata L.) Under Natural Field Conditions

Aims: To determine the efficacy of chemicals/bioagents against foliar diseases of mungbean. Study Design: Randomized Block Design (Field experiments) Place and Duration of the Study: Field experiments were conducted at Agricultural Research Station, Mandor, Jodhpur during the Kharif 2022 & Kharif 2023 Methodology: Different novel fungicides/bioagents were applied against foliar diseases of mungbean. Ten treatments viz; soil application with Trichoderma harzianum @ 5kg/ha enriched in 100 kg of FYM., seed treatment with Trichoderma harzianum @ 10g/kg seed, foliar spray of Trichoderma harzianum @ 2g/l, foliar spray of carbendazim 50% WP @ 0.1%, foliar spray of difenoconazole 25 EC @ 0.1 %, foliar spray of tebuconazole 250 EC @ 0.1%, foliar spray of tebuconazole 50% + trifloxystrobin 25% WG @ 0.1%, foliar spray of pyraclostrobin 133g/l+ epoxiconazole 50 g/l w/w SE @ 0.15%, foliar spray of azoxystrobin 18.2 % + difenoconazole 11.4 % SC @ 0.1%, and control (untreated) were taken in study. The diseases assessment was done after 10 days of spraying and percent disease incidence was calculated. Results: Foliar spray of tebuconazole 50% + trifloxystrobin 25% WG @ 0.1% was most effective in reducing the anthracnose PDI (19.41%) and cercospora leaf spot (18.26%) followed by foliar spray of azoxystrobin 18.2 % + difenoconazole 11.4 % SC @ 0.1% (24.36 and 21.05 %). Conclusion: Among all the tested treatments, foliar spray of tebuconazole 50% + trifloxystrobin 25% WG @ 0.1% was most effective followed by foliar spray of azoxystrobin 18.2 % + difenoconazole 11.4 % SC @ 0.1% in managing both the diseases.

Effectiveness of some novel fungicides against the sheath blight pathogen Rhizoctonia solani in rice under in vitro and in vivo conditions

Sheath blight of rice, caused by Rhizoctonia solani, is one of the most aggressive and damaging diseases in rice cultivation, leading to significant crop losses. Consequently, chemical fungicides are the most effective method to inhibit R. solani infection and control this disease. In the present study, R. solani isolate was obtained from infected rice plants, and its pathogenicity was confirmed using Koch’s postulates on 20-day-old rice seedlings at three different inoculum levels. The lowest percent disease index and disease incidence were recorded with the 1 ml pathogen inoculum suspension, while the 2 ml and 3 ml suspensions resulted in 100% disease incidence, significantly affecting plant parameters. Furthermore, five different fungicides, Duphetar Plus, Evito, Nativo, Ridomil Gold, and Shincar, were evaluated at three concentrations (10, 100, and 1000 ppm) against R. solani using poisoned food method. The results revealed that two fungicides, Shincar and Nativo, resulted in maximum mycelial growth inhibition of R. solani, whereas the other fungicides failed to inhibit the mycelial growth of the pathogen at all concentrations. Shincar and Nativo were further tested in a greenhouse setting to control pathogen infection in rice plants. These fungicides showed excellent results, reducing R. solani infection and minimizing disease incidence in treated rice plants compared to the control. The highest root length, shoot length, and plant weight were observed with Shincar, followed by Nativo. It is suggested that the use of these fungicides may reduce sheath blight disease incidence, effectively control pathogen infection, and improve plant growth parameters in field conditions.

Integrated Management of Collar Rot of Chickpea (Cicer arietinum) Caused by Sclerotium rolfsii under Greenhouse Conditions

Collar rot, one of the major soil borne diseases of chickpea incited by Sclerotium rolfsii causes significant economic losses in chickpea crop. The present study was undertaken to identify the eco-friendly management of this soil borne disease in chickpea. In this study, the efficacy of chemical, biocontrol and biofumigation to manage the chickpea collar rot disease was tested under Greenhouse conditions. Our results revealed that the treatments involving the sole application of chemical fungicide Tebuconazole 60 FS (as seed treatment or soil application) or in combination with other treatments resulted in 100% germination of chickpea seeds. Two treatments namely T5 (SA of Tebuconazole 60 FS) and T12 (ST with Tebuconazole and SA of mustard seed cake) recorded 0.00% total mortality and hence found to be highly effective in protecting chickpea seeds from both pre emergence seed rot and post emergence seedling mortality.The results on the percent disease incidence revealed that, T10 (ST with Trichoderma spp and SA of mustard seed cake) provided maximum disease reduction of 81.93 per cent (PDI 12.04%) and 75.93 (PDI 24.07% ) per cent over the control at 30 and 45 DAS respectively. This was followed by Treatment T7 which exhibited 72.22 % (PDI 18.52%) and 69.45 % (PDI 30.55%) disease reduction over the control at 30 and 45 DAS respectively. Overall, the results of our study (considering both germination and percent disease incidence percentages), revealed that T7 (ST and SA of Trichoderma spp.) was the most effective treatment in managing the collar rot disease of chickpeas.

Some Chemical and Biological Methods to Control Pepper Root Rot Disease in Iraq

Background: Pepper growing fields in the Babil and Wasit governorates in Iraq, are suffering from a decline in production due to the spread of root rot diseases. The use of biological control techniques, such as the use of beneficial bacteria in the rhizosphere and natural plant extracts, along with chemical fungicides, has recently contributed to reducing the damage of plant pathogens globally. Methods: In this research, the main cause of root rot disease in pepper plants was isolated and diagnosed using polymerase chain reaction technology using (TEF-1α) gene, antagonistic activities of 75 rhizobacterial isolates, natural extracts of garlic and nerium and the fungicides of Promess and Tecto 500 SC were tested in vitro against the pathogen, then the superior bacterial isolates were identified. The ability of biological and chemical agents to control the disease was tested under greenhouse conditions according to the completely randomized design (CRD). Result: The results of isolation showed that the fungus Fusarium solani was dominance and the isolate Fsw45 was the most virulent. 3 of 75 rhizobacterial isolates outperformed the pathogen in an antagonistic tests and identified as Pseudomonas mendocina, P. fluorescens and Staphylococcus kloosii also the fungicides and botanical extracts showed significant antagonistic activities as well in vitro. Under greenhouse conditions, the fungicide treatments excelled in disease control by 100%. As for the 3 bacterial isolates, they achieved a significant reduction in the percentage of disease incidence and disease severity index, their abilities were higher than the nerium and garlic extracts.

Ability of Beauveria bassiana to suppress Colletotrichum truncatum and increase the growth of chili plants (Capsicum annuum)

Anthracnose is a disease caused by Colletotrichum sp., which can reduce the quality and yield of red chili by 45-60%. This study aimed to determine the ability of different Beauveria bassiana isolates to control anthracnose in chili. The research employed a Randomized Block Design (RBD) consisting of 6 treatments and 5 replications. The treatments included a control and 5 different B. bassiana isolates (PD114, TD312, WS, BbKo, KT2B21). The observed variables included incubation period, disease incidence and severity, plant height, number of leaves, flowering time, and chili fruit weight. The results showed that the application of different B. bassiana isolates have effectively inhibited the development of Colletotrichum truncatum, which caused anthracnose in chili. B. bassiana has demonstrated the ability to prolong the incubation period of C. truncatum (5.40 days) and reduce the percentage of disease incidence (16%). Furthermore, the application of B. bassiana increased the height of chili plants (40.40 cm) and the number of leaves (32 leaves), accelerated the flowering time (42.80 days), and boosted chili production (178.25 g). The WS and TD312 isolates revealed the most significant results. Although the severity of the disease was not impacted, the 2 isolates provided notable agronomic benefits to the chili plants.

Isolation and characterization of native antagonistic rhizobacteria against Fusarium wilt of chilli to promote plant growth.

In the eastern coastal regions of Odisha, wilt caused by Fusarium oxysporum f. sp.capsici is an extremely damaging disease in chilli. This disease is very difficult to manage with chemical fungicides since it is soil-borne in nature. The natural rhizosphere soil of the chilli plant was used to isolate and test bacterial antagonists for their effectiveness and ability to promote plant growth. Out of the fifty-five isolates isolated from the rhizosphere of healthy chilli plants, five isolates, namely Iso 01, Iso 17, Iso 23, Iso 24, and Iso 32, showed their highly antagonistic activity against F. oxysporum f. sp. capsici under in vitro. In a dual culture, Iso 32 (73.3%) and Iso 24 (71.5%) caused the highest level of pathogen inhibition. In greenhouse trials, artificially inoculated chilli plants treated with Iso 32 (8.8%) and Iso 24 (10.2%) had decreased percent disease incidence (PDI), with percent disease reduction over control of 85.6% and 83.3%, respectively. Iso 32 and Iso 24 treated chilli seeds have shown higher seed vigor index of 973.7 and 948.8, respectively, as compared to untreated control 636.5. Furthermore, both the isolates significantly increased plant height as well as the fresh and dry weight of chilli plants under the rolled paper towel method. Morphological, biochemical, and molecular characterization identified Bacillus amyloliquefaciens (MH491049) as the key antagonist. This study demonstrates that rhizobacteria, specifically Iso 32 and Iso 24, can effectively protect chilli plants against Fusarium wilt while promoting overall plant development. These findings hold promise for sustainable and eco-friendly management of Fusarium wilt in chilli cultivation.

Plant Growth Promotion and Biological Control against Rhizoctonia solani in Thai Local Rice Variety "Chor Khing" Using Trichoderma breve Z2-03.

Several strains of Trichoderma are applied in the field to control plant diseases due to their capacity to suppress fungal pathogens and control plant diseases. Some Trichoderma strains also are able to promote plant growth through the production of indole-3-acetic acid (IAA). In southern Thailand, the local rice variety "Chor Khing" is mainly cultivated in the Songkhla province; it is characterized by slow growth and is susceptible to sheath blight caused by Rhizoctonia solani. Therefore, this research aimed to screen Trichoderma species with the ability to promote plant growth in this rice variety and enact biological control against R. solani. A total of 21 Trichoderma isolates were screened for indole compound production using the Salkowski reagent. The Z2-03 isolate reacted positively to the Salkowski reagent, indicating the production of the indole compound. High-performance liquid chromatography (HPCL) confirmed that Z2-03 produced IAA at 35.58 ± 7.60 μg/mL. The cell-free culture filtrate of the potato dextrose broth (CF) of Z2-03 induced rice germination in rice seeds, yielding root and shoot lengths in cell-free CF-treated rice that were significantly higher than those of the control (distilled water and culture broth alone). Furthermore, inoculation with Trichoderma conidia promoted rice growth and induced a defense response against R. solani during the seedling stage. Trichoderma Z2-03 displayed an antifungal capacity against R. solani, achieving 74.17% inhibition (as measured through dual culture assay) and the production of siderophores on the CAS medium. The pot experiment revealed that inoculation with the Trichoderma sp. Z2-03 conidial suspension increased the number of tillers and the plant height in the "Chor Khing" rice variety, and suppressed the percentage of disease incidence (PDI). The Trichoderma isolate Z2-03 was identified, based on the morphology and molecular properties of ITS, translation elongation factor 1-alpha (tef1-α), and RNA polymerase 2 (rpb2), as Trichoderma breve Z2-03. Our results reveal the ability of T. breve Z2-03 to act as a plant growth promoter, enhancing growth and development in the "Chor Khing" rice variety, as well as a biological control agent through its competition and defense induction mechanism in this rice variety.

Synergistic Action of New Combination of Fungicides in the Management of Tikka Leaf Spot and Rust Diseases in Groundnut

Tikka leaf spot and rust diseases are major constraints in groundnut at Nellore district of Andhra Pradesh. We conducted front line demonstration on effect of new combination of fungicides for management of foliar diseases in groundnut and the experiment was carried out at different farmer’s field. The farmers practicing variety TAG24 is highly susceptible to tikka leaf spot and soil borne diseases. The trial was conducted during rabi season for two years. During rabi, 2022-2023, the percent disease incidence of tikka leaf spot recorded 38.46% in demo plot where as in farmer practice 74.62% recorded. During rabi 2023-2024, recorded 38.8% and 65.4% tikka leaf spot disease in demo plot and farmer practice respectively. The average pod yield was increased 5% more in demo plot over farmer practicing plot. The average of 2 years, rust diseases recorded 5% in demo plot and 16% in farmer practice. In both treatments the incidence of tikka leaf spot was high due to farmers cultivating variety is highly susceptible to foliar diseases and farmers are used higher seed rate i.e. 200kg/acre. Based on results we concluded that the combination fungicides i.e. tebuconozole 50% +trifloxystrobin 25% WG and pyraclostrobin 5% +metiram 55% WG are best chemicals than single mode of action fungicides and time of application of fungicide is also important.

Deciphering the antiviral nature of endophytic Bacillus spp. against groundnut bud necrosis virus in cowpea and tomato.

Tomato, the important vegetable crop, is severely affected by Orthotospovirus arachinecrosis which impacts heavy economic losses. The application of insecticide to manage viral diseases is not an environmentally safe approach. In view of these issues, we investigated the antiviral efficacy of 21 bacterial endophytes against GBNV in local lesion host (Cowpea-VBN3). Based on the reduction in lesion number and virus titer as estimated through both DAC ELISA and qPCR in cowpea, the bacterial endophytes viz., Bacillus licheniformis Soya1, Bacillus tequilensis NBL6, and Bacillus velezensis VB7 were selected and further tested in tomato. The study revealed the well-defined antiviral efficacy of these endophytes against GBNV. The percentage of disease incidence ranged from 16 to 24% in endophyte-treated tomato plants compared with untreated plants (88%). In addition, symptom severity was reduced, and the application of endophytes also in promotion of the growth compared with untreated control. DAC ELISA revealed that the tomato plants treated with bacterial endophytes challenged with GBNV showed reduction in the virus titer (0.26-0.39 @ OD 405 nm) at different days of interval after inoculation (0, 5, and 10 days) compared with untreated control (3.475 @ OD 405 nm). Additionally, reduction in the viral copy number in bacterial endophyte-treated plants was evident by real-time PCR. Furthermore, tomato plants bacterized with endophytes depicted significant correlation and reduction in viral load and disease incidence as revealed by the principal-component biplot analysis. Thus, the application of bacterial endophytes has a potential role in reducing the disease incidence, severity, and titer value of GBNV, which will be the promising management approach in future to mitigate the virus infection in tomato plants.

Germplasm Screening for Identification of BCMV Resistance Sources from Diverse Cowpea [Vigna unguiculata (L.) Walp.] Germplasm using Serological and Molecular Diagnostics

Background: Bean common mosaic disease (BCMD) caused by Bean common mosaic virus (BCMV) has been regarded as one of the most important seed-borne and aphid vector transmitted destructive disease of cowpea not only affecting its yield but also reducing its grain quality globally. Since the dawn of crop improvement, germplasm served as the source of resistance for various biotic stresses. Currently, host plant resistance is the best, reliable, economic and environmental friendly practice of virus disease management. The objective of this study was to assess the response of diverse cowpea germplasm against BCMV under natural and controlled conditions followed by serological and molecular detection. Methods: In this study, 85 cowpea germplasm accessions and one known BCMV susceptible (C152) and one resistant (CP55) varieties are evaluated for their response to the BCMD in augmented block design (ABD). The reaction of cowpea accessions were assessed using percent disease incidence (PDI). Transmission Electron microscopy (TEM), Direct Antigen Coating-Enzyme-linked Immunosorbent Assay (DAC-ELISA) and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) were used for confirming the BCMV. Result: Natural and controlled condition screening data analysis revealed a significant difference among diverse cowpea germplasm for BCMV diseases incidence. Based on field screening at Ranchi and New Delhi (2019 and 2020) and artificial confirmation. 24 out of 85 accessions were found to be immune and confirmed through DAC-ELISA and RT-PCR. As a consequence these accessions could be a potential new source of disease resistance for BCMV in breeding programs.Further, DAC ELISA of seed coat and Embryo revealed the presence of virus in 5% and 15% of samples tested. Accession IC418505 recorded highest disease incidence (40.0%).

A Comprehensive Survey and Assessment of Rice Blast Disease Incidence from Major Rice Growing Districts of Telangana State, India

Aim: The aim of this study was to assess the incidence and severity of rice blast disease caused by Pyricularia grisea in various rice cultivars grown in Telangana State during the kharif season of 2019. Methodology: A purposive disease survey was conducted in major rice-growing areas of Telangana State. Disease incidence and severity were recorded from the tillering to grain hardening stage. Percentage disease incidence and severity were calculated at each sampling location. Additionally, pathogenicity tests were conducted on susceptible rice cultivar TN-1 using different isolates of P. grisea. Results: The study revealed significant variations in rice blast disease incidence and severity across the surveyed areas. Disease incidence ranged from 18.5% in Mancherial to 79.41% in Peddapalli, while severity ranged from 22.2% to 85.1%. All sampled cultivars exhibited varying degrees of susceptibility, with severity scores ranging from moderately resistant (2.0) to highly susceptible (9.0). TN-1 showed the highest blast severity, while WGL 1368 exhibited the least severity. Pathogenicity tests showed significant differences among P. grisea isolates, with reactions on TN-1 ranging from moderately susceptible (4.0 to 5.0) to highly susceptible (8.0 to 9.0). Conclusion: The study highlights the widespread occurrence of rice blast disease in Telangana State and underscores the varying susceptibility levels among rice cultivars. These findings emphasize the importance of continued monitoring and management strategies to mitigate the impact of rice blast disease on rice production in the region.

Screening of some commonly cultivated tomato varieties against Fusarium wilt in Jama’are, Bauchi State, Nigeria

Fusarium wilt disease of tomato is caused by Fusarium oxysporum f.sp. lycopersici and is a limiting factor to tomato production in Nigeria. This research was conducted to assess the effect of Fusarium oxysporum on some tomato varieties cultivated in Jama’are, Bauchi state. The objectives of this research work were to isolate and identify pathogen (Fusarium oxysporum) from the soil, to determine the incidence and severity of Fusarium wilt on different varieties of Tomato grown in Jama’are, and to determine the most resistance variety among four different varieties. The experiment was laid in a Completely Randomized design (CRD) with four replications. The four tomato varieties (Roma Savanna, Rio Grande, UC82B and Tropimech) were inoculated at the root region by making shallow groove around the base of the plant in the root region and placing 3 g mycelia plug of 7 days old pure culture of F. oxysporum face-down close to the root of the seedling and covered with soil. At two weeks intervals after treatments the seedlings were then observed for symptoms of wilt infection. Data on disease incidence (%), were collected based on observation after which they were analyzed using Analysis of Variance (ANOVA) test. The Disease Incidence Percentage for Roma Savanna, Rio Grande, UC28B and Tropimech were evaluated to be 51.6%, 18.2 %,38.4 % and 43.3 % respectively while the Disease Severity Percentage were 72.1%, 24.8%, 40.9% and 62.3% respectively. The findings of this research reveals that; there is a significant effect of F. oxysporum on the tomato varieties, all the varieties were severely infected to some degree, and that of all species, Roma savanna was moderately resistant to F. oxysporum to some degree. This agrees with other findings in the literature, as Fusarium oxysporum affects different varieties of tomato at different growth stages. Also, it was observed that screening excises involving selecting of non-infected seedlings with Fusarium species and other fungi should be done prior to transplanting.

Studies on inheritance of yellow vein mosaic virus (YVMV) resistance in okra (Abelmoschus esculentus L.) cv. Pusa Bhindi-5 and effect of YVMV disease on fruit nutritional quality

The present investigation was carried out by involving six generations of okra, i.e., P1, P2, F1, F2, B1 (F1 × Pusa Bhindi-5) and B2 (F1 × Pusa Sawani) developed from two contrasting parents, one susceptible cultivar Pusa Sawani (P1) and another newly developed Bhendi yellow vein mosaic virus (YVMV) resistant variety Pusa Bhindi-5 (P2). The experimental data showed the maximum PDI (percent disease incidence) in susceptible parent Pusa Sawani (95.56%) followed by B2 (47.5%) and F2 (29%) after 90 days of sowing, whereas Pusa Bhindi-5, B1 and F1 were recorded highly resistant to YVMV disease even after 90 days of sowing. Backcross population B2 and F2 fell into the moderately susceptible (MS) category, whereas parent Pusa Sawani was recorded as highly susceptible (HS). Based on F2 and backcross data, the nature of inheritance of YVMV resistance in Pusa Bhindi-5 was found to be monogenic dominant. Analysis of t-test for the significance of the difference between the mean values of infected and healthy fruits was found to be highly significant with higher probability (p-value <0.05), indicating that the viral infection caused changes in the biochemical/nutrient contents such as protein, carbohydrate, dietary fiber, total ash and minerals. Most of the nutrients were negatively affected by the YVMV. Thus, this study ascertained the qualitative damage caused by this virus.

Exploring Yellow Leaf Disease Patterns in Areca Plantations in Chikkamagaluru District of Karnataka

Yellow Leaf Disease (YLD) poses a significant threat to arecanut cultivation, particularly in the South Indian states of Karnataka and Kerala. This study aimed to assess the incidence and intensity of YLD in the Malnad regions of Karnataka during 2021-22. Intensive roving surveys were conducted in major arecanut-growing areas, namely Sringeri, Koppa, and Narasimharajapura taluks of Chikkamagaluru district. The assessment was made through selecting five fields per location and calculating the percent disease incidence and intensity based on observed symptoms following established scoring systems. Results revealed varying levels of disease incidence and intensity across surveyed taluks and villages. In Chikkamagaluru district, Koppa, Narasimharajapura, Sringeri, and Kalasa taluks exhibited incidence ranging from 0 per cent to 100 per cent and intensity from 80 per cent to 100 per cent, while Narasimharajapura and Mudigere taluks showed incidence from 0 per cent to 60 per cent and intensity from 0 per cent to 30 per cent. The study underscores the endemic nature of YLD in these regions, likely influenced by soil and environmental factors, particularly in hilly areas with high rainfall.

Grafting Bell Pepper onto Local Genotypes of Capsicum spp. as Rootstocks to Alleviate Bacterial Wilt and Root-Knot Nematodes under Protected Cultivation

In soil-based protected cultivation, the prevalence of certain diseases like bacterial wilt and nematodes in the bell pepper plant due to its successive cropping pose a threat for maximizing productivity. Considering the potential of grafting to alleviate various biotic and abiotic stresses, often relying on rootstock’s capability, we explored the potential of diverse local genotypes of Capsicum spp. to utilize as rootstocks. In this research, we assessed the performance of a commercial bell pepper cv. Massilia F1, grafted onto twenty-five rootstocks along with non-grafted and self-grafted Massilia plants under artificial inoculation conditions of bacterial wilt (Ralstonia solanacearum) and nematodes (Meloidogyne incognita) in a plastic greenhouse. The response of rootstock grafting was determined by assessing disease incidences and their effect on plants growth, yield, and physiology, as well as their efficiency in nutrient accumulation. The grafted plants exhibited varied responses to diseases depending on rootstock genotypes. Notably, Massilia grafted onto the CRS-8 and CRS-1 rootstocks exhibited high bacterial wilt resistance by showing lower percent disease incidence (PDI) (22.22 and 27.78 percent, respectively). Others, like CRS-11, CRS-12, CRS-13, CRS-21, and CRS-24, showed moderate resistance (PDI ranging from 33.33 to 38.89 percent, respectively). The self-grafted and non-grafted plants were highly susceptible and recorded complete mortality by the end of the experiment. All of the grafted plants exhibited promising resistance against nematode infestation compared to non-grafted and self-grafted plants with 26.17 and 8.67 percent root galls, respectively. The susceptible plants had lower shoot and root dry weights, while the resistant graft combinations had comparatively higher biomass. Importantly, grafting induced earliness in flowering and provided higher yields, especially in graft combinations involving the CRS-15, CRS-11, and CRS-8 rootstocks. These graft combinations exhibited significantly higher yields over the non-grafted and self-grafted plants. The plant yield was positively associated with plant height, number of leaves, fresh and dry weight of roots, number of fruits per plant, and average fruit weight, but negatively related to bacterial wilt and root-knot nematode incidences. The increased level of antioxidant enzymes such as polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD) and the higher total chlorophyll content in the resistant grafted plants indicates their better ability to cope with diseases at the cellular level. This study highlights the robust performance of certain rootstocks from Capsicum annuum (CRS-1, CRS-2, CRS-11, CRS-15) and Capsicum frutescens (CRS-8, CRS-13, CRS-22) species across multiple measured parameters. Grafting emerges as a sustainable solution for bell pepper production in bacterial wilt- and nematode-infested soil under plastic greenhouses.

Evaluasi Ketahanan Varietas Cabai Rawit Terhadap Penyakit Antraknosa (Colletotrichum Gloesporioides) Asal Isolat Dari Cabe Hiyung

The category of resistance level of several cayenne pepper varieties planted in swamps to anthracnose disease (Colletotrichum gloesporioides) originating from isolates from hiyung chilies is important to know as basic information for determining control strategies. This research aims to determine the level of resistance of several varieties of cayenne pepper planted in swamp land to anthracnose isolates from Hiyung chilies. This research used RAL (Completely Randomized Design) with 10 treatments and 3 replications and 2 plants were used in each replication so that the total number of plants was 60 plants. The varieties used are the Bara, Hiyung, Dewata 43 F1, Tiung Tanjung, Tiung Ulin, Genie, Sekar, Alip, Sret and CR-9 varieties. Inoculation of the fungus Colletotrichum gloesporioides was carried out at the time of fruiting, with variables observed, namely the incubation period and disease incidence. The results of the research show the resistance of chili plants to anthracnose disease in the susceptible category, namely the Hiyung variety with a disease incidence percentage of 42.08%. The moderate category is the Bara, Dewata 43 F1, Tiung Tanjung, Genie, Sekar, and CR-9 varieties with disease incidence percentages of 30.11%, 28.94%, 35.93%, 20.87%, 21, respectively. 52% and 28.20%. The resistant category is the Tiung Ulin, Alip and Sret varieties with disease incidence percentages of 18.37%, 19.36% and 17.11% respectively. The incubation period for several cayenne pepper varieties that have been tested varies with an average of between 3.5-5.3 days.

EFFICACY ANTIMICROBIAL ENDOPHYTICS METABOLITES TO CONTROL SIGATOKA DISEASE (MYCOSPHAERELLA MUSICOLA) ON BANANAS IN NORTHERN SUMATERA

The secondary metabolites show diverse biological activities, including phytotoxic, antibacterial, antifungal, and antitumor. This study aimed to obtain secondary metabolites that are more effective in suppressing the development of Sigatoka disease in bananas. A field trial was performed to screen the antifungal metabolitesactivity of three isolates against Mycosphaerella musicola. This research used a randomised block design with four treatments and six replications. The results showed that the fastest incubation period was obtained at 14 days in the control treatment, and with Bacillus sp occurred after 30 days, 25 days in the treatment of Pseudomonas aeruginosa, and 40 days in the treatment of Trichoderma asperellum. The percentage of disease incidence and spot area on the leaves was most significant in the control treatment, 62,5% and 66,45%, then followed by Pseudomonas aeruginosa respectively, 41,67% and 34,48%, and the lowest disease incidence and spot area in the treatment, Trichodermasp were 25% and 21,78%, respectively. Further, the lowest disease severity was found in the secondary metabolite of Trichoderma asperellum at 23.36%, followed by Pseudomonas aeruginosa secondary metabolite at 32.57%. Meanwhile, the highest disease severity was found in the control treatment, with an average of 60.27%. Secondary metabolites of Bacillus sp, Trichoderma asperellum and Pseudomonas aeruginosa effectively suppress Sigatoka disease. The highest banana production was found in the secondary metabolite of Trichoderma asperellum, with a harvestweight of 13.98 kg, and the lowest harvest weight found in the control treatment was 11.90 kg