Management Of Soil-borne Pathogens Research Articles

Biocontrol Potential of Trichoderma Ghanense and Trichoderma Citrinoviride toward Pythium aphanidermatum.

Pythium-induced damping-off of cucumber is a major constraint to cucumber production in different parts of the world. Although chemical fungicides are used for managing this disease, they have many drawbacks to the environment. The ability of the antagonistic fungi isolated from the rhizosphere and endosphere of Dactyloctenium robecchii and Moraea sisyrinchium in the control of soilborne pathogen Pythium aphanidermatum was inspected. Native Trichoderma isolates, Trichoderma ghanense and Trichoderma citrinoviride, were isolated from plant stem and soil samples collected from Al-Seeb, Oman. Using a dual culture technique, the antagonistic activity of the fungal isolates against P. aphanidermatum was examined in vitro. Among Trichoderma isolates, T. ghanense was more efficient in restraining the mycelial growth of P. aphanidermatum, causing an inhibition percentage of 44.6%. Further, T. citrinoviride induced significantly lower cessation of P. aphanidermatum mycelial growth (31.3%). Microscopic and electrolyte leakage inspection of the pathogen mycelia depicted extreme morphological malformations in their mycelium, which can be attributed to the antifungal metabolites of antagonists. Greenhouse studies demonstrated the effectivity of T. ghanense in controlling Pythium damping-off of cucumber plants, where the number of surviving plants was over 90% when the biocontrol agents were used compared to 0 in the control plants. Furthermore, treatment of the plants with the antagonists promoted growth characteristics of plants compared to uninoculated plants. This included improvements in shoot and root lengths, leaf length and width, and dry weight. These findings suggest that T. ghanense and T. citrinoviride can be developed as alternatives to synthetic chemical fungicides to manage soilborne pathogens of cucumber. This research is also the first to clarify the biocontrol ability of T. citrinoviride and T. ghanense against cucumber damping-off caused by P. aphanidermatum.

Mass multiplication of native rhizospheric bacteria on cheaply available organic substrates and their plant growth promotion potentiality on cowpea

The intensive agricultural system results into considerable environmental damage and its inevitable effects on various environmental and ecological factors. Known for their role in the natural disease-suppressiveness of particular soil, Fluorescent pseudomonads are a genus of root-associated bacteria that may colonise the roots of agricultural plants and create antifungal metabolites, making them a viable alternative to the use of chemical fungicides. The successful application of Fluorescent pseudomonads as bioinoculants depends to a great extent on their capability to establish roots and to contend with indigenous microbiome in the rhizosphere. Because of various limitations, variations in the bio control agents are bound to occur in different agro-climatic regions, so it is advisable to choose native bio control agents. In the present investigation, a comprehensive effort was undertaken to check the growth of Pseudomonas aeruginosa (GP-8), which was found to be much lesser in aqueous extracts of cow dung, vermicompost and groundnut cake as compared to the growth of GP-8 (Pseudomonas aeruginosa) in nutrient broth media. The enrichment of Nitrogen and other supplementary nutrients may be required for the development of low cost indigenous media from cheaply available substrates for commercial mass production of Pseudomonas aeruginosa (GP-8) and also a field level screening trial was undertaken with efficient native Fluorescent pseudomonads solely or in consortia for improvement of plant health and management of soil borne pathogens as well as to develop a culture media with cheap and readily available substrate sources for mass production of Fluorescent pseudomonads strains. In the present study, it was found that shoot length and root length of native Fluorescent pseudomonads inoculated cowpea plants were significantly increased as compared with those of the control plants both at 30 and 60 days after sowing.

Detection and management of soil-borne pathogens in citrus using non-inorganic control practices under greenhouse conditions

Citrus fruits are among the priority crops for Uganda. Government has invested significant resources to boost citrus production due to their potential to increase household income, nutritional security and national exports. However, soil-borne pathogens are among several biotic-factors significantly constraining production. Whereas inorganic chemicals have been applied in the past, they have potential detrimental effects. Therefore, an experiment was conducted in the greenhouse of National Forestry Resources Research Institute (NaFORRI) at Kifu - Mukono in 2020-2021 to determine dominant soil and Citrus pathogens and test efficacy of different non-inorganic citrus pathogen control practices. A randomized complete block design with five treatments replicated thrice was used. The treatments included; hot water, heated wet-soil, fumigated soil, solarized wet-soil, and untreated control. A total of 30 Citrus seeds per variety were treated with sodium-hypochlorite-solution (1:7) before being sown. Soils from above treatments were cultured on Potato and Sabouraud-Dextrose Agar (PDA and SDA) and de Man, Rogosa and Sharp (MRS) agar. Results indicated that Aspergillus niger was the dominant soil-borne pathogen identified in pure cultures. Others included A. flavus, A. fumigatus, A. viridinutans, Penicillium chrysogenum and Fusarium oxysporum. Ranking based on scores in: cost-effectiveness, leaf-health, chlorophyll-intensity and general-health of seedlings revealed solarization (35) as most effective technique for managing soil-borne pathogens, followed by boiling (33), heating (31), untreated control (27) and lastly fumigation (26). Identified pathogens induce aflatoxins in Citrus and lead to great losses during post-harvest handling; they also cause root and fruit-rots. Solarization creates solar-radiation in a miniature greenhouse that kills pathogens. There is a need to study non-inorganic control practices of citrus pathogens under field conditions for improved yields in Uganda.

A Lignin-Rich Extract of Giant Reed (Arundo donax L.) as a Possible Tool to Manage Soilborne Pathogens in Horticulture: A Preliminary Study on a Model Pathosystem

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120 °C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture.

Study on compatibility of Trichoderma viride with different fungicides

Aggressive colonization of T. viride can occurs in diverse environmental condition as a biological control and prevents many soil borne diseases. In this context, laboratory experiment was conducted during 2018-19 at Department of Plant Pathology, Bihar Agricultural University, Sabour, Bhagalpur, Bihar to test the sensitivity of T. viride isolated with selected fungicides to devise the best management practice. In course of investigation, nine fungicides of systemic, non-systemic and their combination were evaluated at lower concentrations compared to recommended dose on sensitivity and sporulation of T. viride with food poisoned techniques. Growth and sporulation of T. viride was totally inhibited by carbendazim, hexoconazole, carbendazim+ mancozeb and iprodione + carbendazim at all the concentrations. Sporulation affected by all the fungicides, but in copper-oxychloride, inhibition of sporulation had minimum, i.e. 19.7, 37.1 and 53.9 at 200, 500 and 1000 μg/ml, respectively. Since, the minimum inhibitory effect on growth and spore production was recorded in copper oxychloride. Thus, the present finding suggest that compatible fungicides copper oxychloride can be used with T. viride in an integrated disease management practices for managing soil borne pathogens.

Management of Chrysanthemum Verticillium Wilt through VIF Soil Mulching Combined with Fumigation at Label and Reduced Rates

Pre-plant soil fumigation for managing soilborne pathogens is practiced worldwide in several intensive ornamental and vegetable production areas. However, global regulations are currently implemented to minimize use of these chemicals. According to these policies, the efficacies of dazomet (DZ, Basamid Granulat®) applied alone to soil and under virtually impermeable film (VIF) at reduced (247.5 kg ha−1 a.i.) and label (495 kg ha−1 a.i.) rates were assessed in managing natural infections of Verticillium wilt and in reducing yield losses on greenhouse chrysanthemum plantations in two trials carried out in the 2012 and 2013 seasons. The performances of this fumigant at a lower rate combined with VIF application were also compared with standardized metam-sodium (MS, Divapan®) fumigation applied at 510 L ha−1 a.i. under VIF and application of dazomet at label rate alone to bare soil. Temperatures were monitored at 20-cm depth in plots covered (VIF) throughout the entire fumigation period. Although all fumigation treatments significantly reduced the infection level by V. dahliae on chrysanthemum, the performances differed among them. DZ and MS applied at label rates under VIF showed the most effectiveness in controlling Verticillium wilt of chrysanthemum. However, DZ applied to soil at a low rate under VIF mulching showed good performances, which were always better than application of DZ alone at label rate to bare soil. Moreover, when combining a reduced rate of DZ with VIF mulching, chrysanthemum yield losses were reduced in a similar manner to the label rate application under VIF. Based on these findings, DZ application at a reduced rate could be suggested on a large scale to prevent Verticillium attacks on chrysanthemum cultivated on a protected crop. Future studies should be performed to verify the ability of VIF application in inducing high temperatures in soil and above all in enhancing performances of soil fumigation at low rates performed with other natural and chemical sterilants.

Effects of Interspecific Grafting Between Capsicum Species on Scion Fruit Quality Characteristics

Production of Capsicum annuum peppers is often limited, especially in tropical environments, by susceptibility to soil pathogens including Ralstonia solanacearum. Grafting desirable cultivars onto selected rootstocks can increase adaptation to abiotic stress and is an alternative to pesticides for managing soilborne pathogens. Cultivars of two other pepper species, Capsicum baccatum and Capsicum chinense, are tolerant or resistant to an array of soilborne pathogens and have potential as rootstocks; however, knowledge of how interspecific grafting may affect scion fruit quality is lacking. Flowering time, yield, and fruit quality characteristics were evaluated in 2017 and 2020 for C. annuum cultivars Dulcitico, Nathalie (2017), Gypsy (2020), and California Wonder used as scions grafted onto Aji Rico (C. baccatum) and Primero Red (C. chinense) rootstocks, including self-grafted and nongrafted scion checks. In 2020, the rootstocks per se were evaluated. The two rootstocks (‘Aji Rico’ and ‘Primero Red’), three scions, and self- and nongrafted scions were evaluated using a factorial, replicated, completely randomized design in fields at the West Madison and Eagle Heights Agricultural Research Stations located in Madison, WI, in 2017 and 2020, respectively. Differences among the main effects for scion fruit quality characteristics were consistent with cultivar descriptions. No scion × rootstock interactions were observed. Rootstocks did not result in changes in total fruit number, yield, fruit shape (length-to-width ratio), or soluble solids of scion fruit compared with self- and nongrafted checks. The rootstock ‘Primero Red’ increased fruit weight and decreased time to flowering regardless of scion compared with self- and nongrafted checks. All scions were sweet (nonpungent) cultivars and both rootstocks were pungent cultivars. No capsaicinoids were detected in the fruit of sweet pepper scions grafted onto pungent pepper rootstocks. The results indicate that interspecific grafts involving ‘Aji Rico’ and ‘Primero Red’ will not have deleterious effects on fruit quality characteristics of sweet pepper scions.

Volatile compounds as potential bio-fumigants against plant-parasitic nematodes - a mini review.

Soil fumigation remains the standard practice to manage soilborne pathogens such as plant-parasitic nematodes, bacteria, and fungi, especially in high-value crops. However, increasing regulatory pressure due to the inherent and broad-spectrum toxicity and negative environmental impact of chemical soil fumigants, its negative effect on overall soil health, and increasing demand for organic produce, has created a growing interest in biological fumigants. Many plants and microorganisms emit volatile compounds, which can potentially be used as bio-fumigants. In this mini-review, we summarize the current status of nematology studies focused on the development of volatile compounds emitted from plants and microorganisms as fumigants to control plant-parasitic nematodes. The gap of knowledge and challenges of studying volatile compounds are also addressed.

The Role of Grafting in the Resistance of Tomato to Viruses.

Grafting is routinely implemented in modern agriculture to manage soilborne pathogens such as fungi, oomycetes, bacteria, and viruses of solanaceous crops in a sustainable and environmentally friendly approach. Some rootstock/scion combinations use specific genetic resistance mechanisms to impact also some foliar and airborne pathogens, including arthropod or contact-transmitted viruses. These approaches resulted in poor efficiency in the management of plant viruses with superior virulence such as the strains of tomato spotted wilt virus breaking the Sw5 resistance, strains of cucumber mosaic virus carrying necrogenic satellite RNAs, and necrogenic strains of potato virus Y. Three different studies from our lab documented that suitable levels of resistance/tolerance can be obtained by grafting commercial tomato varieties onto the tomato ecotype Manduria (Ma) rescued in the framework of an Apulian (southern Italy) regional program on biodiversity. Here we review the main approaches, methods, and results of the three case studies and propose some mechanisms leading to the tolerance/resistance observed in susceptible tomato varieties grafted onto Ma as well as in self-grafted plants. The proposed mechanisms include virus movement in plants, RNA interference, genes involved in graft wound response, resilience, and tolerance to virus infection.

Directed energy system technology for the control of soilborne fungal pathogens and plant-parasitic nematodes.

It is challenging to manage soilborne pathogens and plant-parasitic nematodes using sustainable practices. Here, we evaluated a novel energy application system, Directed Energy System (DES). This system generates pulses of energy capable of impacting selected biological organisms. The oomycete Phytophthora cinnamomi, the fungus Verticillium dahliae, and the plant-parasitic nematodes Meloidogyne hapla and Globodera ellingtonae were added to soil. Then DES-generated energy was applied to soil and impacts on target organisms were determined. DES applied at 20, 40 and 70 J cm-3 to P. cinnamomi and V. dahliae resulted in ≥50% and 92% reductions (respectively) of propagules per gram of soil in comparison to the untreated control. There was a significant reduction of M. hapla eggs per gram of host tomato root between the untreated control, and 2.2, 13 and 25 J cm-3 DES dosages applied pre- or post-planting. Additionally, an 84% reduction in hatch from G. ellingtonae encysted eggs after treatment with 70 J cm-3 DES was observed. The dosages ranged from 40 or 80V mm-1 for nematodes to 200 V mm-1 for fungi. DES-generated energy reduced survival of the soilborne pathogens P. cinnamomi and V. dahlia, and the plant-parasitic nematodes M. hapla and G. ellingtonae. The application of this technology to a field setting remains to be considered. Published 2020. This article is a U.S. Government work and is in the public domain in the USA. Pest Management Science published by Wiley Periodicals, Inc. on behalf of © 2020 Society of Chemical Industry.

Plant growth promoting cyanobacteria Westiellopsis sp. for the eco-friendly management of soil borne pathogens

Cyanobacteria produce unique antibacterial and antifungal bioactive metabolites which can be used for ecofriendly control of phytopathogens. The present study was carried out to explore the biological control and growth promoting activity of Westiellopsis sp. (Cyanobacteria) for the ecofriendly management of fungal pathogens. The work was conducted under in vitro conditions in Anbil Dharmalingam Agricultural College and Research Institute, Trichy, during the year 2016 - 2017. The methanol extracts (100%) of cyanobacteria (Westiellopsis sp.) were tested against pathogens Rhizoctonia solani, Saraclodium oryzae, Macrophomina phaseolina and Fusarium oxysporum in PDA medium using sterile disc and agar bore well method. The maximum inhibition (32.88%) was recorded in Fusarium oxysporum followed by Saraclodium oryzae (32.7%) which were significantly higher among other fungal pathogens. However, Macrophomina phaseolina and Rhizoctonia solani showed considerable low inhibition zone percentage of 23.35 and 15.54, respectively. The rice and cowpea seeds treated with cyanobacterial extract (100%) showed cent percent higher germination rate and higher vigour index of 771.5 and 3440 respectively, than compared to the control.

Improving Soil Health in Pacific Northwest Potato Production: a Review

Many factors are driving interest in improving soil health in potato production systems in the U.S. Pacific Northwest and beyond, including the need for enhanced sustainability and economic viability, and consumer preferences. Potato production poses a particular challenge in terms of soil health due to intensive tillage, minimal residue left on fields, short rotations, and the importance of managing soilborne pathogens. This review discusses existing soil health assessment methods and their relevance for the region and summarizes results of studies conducted in the Pacific Northwest and beyond, examining practices aimed at improving soil health and their effects on soil health, soilborne pathogens, yield and quality of potatoes, and net returns in potato production systems. These practices include reducing tillage; adjusting crop rotation length and species composition; reducing fumigation; and using cover crops, green manures, and organic amendments.

Raspberry Growers’ Perceptions and Practices Regarding Soil Quality, Cover Crops, and Fumigation

A survey was conducted in Washington State in 2015 and 2016 to gauge grower perceptions, understanding, and current practices regarding soil quality. Soil quality has been defined as the ability of the soil to sustain plants, animals, and humans over time. Many current practices of modern agriculture can be detrimental to soil quality, including soil tillage and soil fumigation, both of which are commonly used for the Washington red raspberry (Rubus idaeus) production system. The area between red raspberry beds, known as the alleyway, is frequently tilled and kept bare, without groundcover, to manage weeds. Growers commonly fumigate the soil before planting red raspberry to manage soilborne pathogens and plant-parasitic nematodes. The majority of red raspberry growers surveyed consider soil quality quite often in relation to the management of their fields. The majority of growers during both years considered cover crops to have a positive impact on soil quality. However, growers also perceived soil fumigation to have a positive impact on soil quality. The majority of growers responded that they were willing to adopt alleyway cover crops for a variety of reasons, including improving red raspberry production, physical soil quality, and beneficial soil microorganism populations. This survey demonstrated that there is interest in soil quality among growers; however, there is a difference in perceptions between growers and researchers regarding how management practices impact soil quality.

Multi-study analysis of the added benefits of combining soil solarization with fumigants or non-chemical measures

Soil solarization (SH) is a non-chemical method in which solar heating is used to manage a wide range of soilborne pests. We analyzed several independent studies to assess the efficacy of SH in suppressing a wide range of soilborne pathogens in different agrosystems and under various climatic conditions, and to quantify the added value of combining SH with chemical or non-chemical measures. We analyzed 69 documented experiments and calculated the level of pest management efficacy by SH alone or in combination with either fumigants, organic amendments or biological agents. The analyses were clustered into three groups of soilborne pathogens: (i) various species and formae speciales of Fusarium; (ii) root-knot nematodes; (iii) a group consisting of the pathogens Sclerotium cepivorum, Verticillium, Pyrenochaeta, Rhizoctonia and Pythium. Combining SH with additional measures improved management efficacy, reduced the variance between experimental results, increased the percentage of cases with high management efficacy and reduced the percentage of cases with low management efficacy, compared to SH alone. The efficacy of SH combined with additional measures was not significantly affected by the initial disease pressure. Yield increase in the Fusarium group was positively correlated with disease control efficacy, and the combined measures produced the upper values. These results demonstrate the benefit of combining SH with other control measures in managing soilborne pathogens.

Sustainable management of soil borne pathogens of tomato

Tomato is the second most cultivated crop in world, which not only used in culinary but also has industrial and medicinal value. Tomato plants are susceptible to various soil borne diseases that severely affect its growth and fruit quality either grown in fields or cultivated in greenhouse under controlled conditions. The use of rhizospheric microorganisms as a biocontrol agent (BCA) against phytopathogens is considered as one of the most promising eco-friendly approach for sustainable management for tomato cultivation. The rhizopsheric microorganisms caters several mechanisms to control or suppress soil borne phytopathogenic fungi, bacteria and nematodes, via direct mechanism of mycoparasitism and/or indirect mechanisms such as antibiosis through production of secondary metabolites or antibiotics; and competition for nutrients and ecological niche. The present work outlines role of rhizospheric microbial isolates in management of phytopathogens affecting quantitative and qualitative production of tomato.

Effectiveness of Nontarped Broadcast Fumigation and Root Removal on Root Lesion Nematode and Fusarium and Pythium Species in a Red Raspberry System

Improved methods for the management of soil-borne pathogens are needed in the raspberry production system in the Pacific Northwest. A multiyear experiment was conducted in a commercial raspberry field in northwest Washington with the following objectives: (i) to determine if the standard industry fumigation treatment of nontarped broadcast application of 1,3-dichloropropene/chloropicrin (Telone C-35) is effective against Pratylenchus penetrans and Pythium and Fusarium species; (ii) to determine if root removal prior to nontarped broadcast fumigation with Telone C-35 improves management of P. penetrans and Fusarium and Pythium species; and (iii) to identify microbes that have the potential to be soil-borne pathogens through microbial community analysis. Fumigation alone briefly reduced population densities of P. penetrans but was ineffective at reducing existing, pretreatment populations of Fusarium and Pythium. However, populations of these two genera were lower in fumigated than in nonfumigated plots for at least 6 months after fumigation. Root removal did not enhance fumigant efficacy under the conditions of the experiment. Ilyonectria (Cylindrocarpon) was found to be more dominant in the fungal community of nonfumigated roots and rhizosphere soil compared with fumigated. These results demonstrate that P. penetrans, Fusarium, and Pythium rapidly rebound after nontarped broadcast fumigation in raspberry with the industry standard Telone C-35.

Using Tannery Sludge to Manage Soybean Cyst Nematodes in Soybean Crops

Soybean crop (Glicyne max) is host to a range of pathogens, among them phytonematoids, with emphasis on the soybean cyst nematode (Heterodera glycines), which has recently caused great damages to the crop and compromised its productivity. Alternatives to the management of diseases, caused by phytonematoids, that are effective and less harmful to the environment, are increasingly being sought. Thus, the incorporation of organic compounds into the soil, such as tannery sludge (bovine chain by-product), presents great potential in the management of soil-borne pathogens, as well as reducing environmental impacts caused by the release into the environment. Thus, the aim of present study had as objective to evaluate the effect of different tannery sludge doses on the management of H. glycines in greenhouse. The study used a nematode-susceptible cultivar (BRS Valiosa RR) and followed a completely randomized experimental design, with 5 repetitions. The nematode penetration in the roots was assessed 10 days after inoculation (DAI), whereas the fresh root mass, the number of females per root gram, and the number of eggs per female were assessed 30 DAI. The tannery sludge is efficient in the management of H. glycines in nematode-susceptible soybean cultivars, reducing the number of females per gram of root, the number of juveniles of the second stage (J2) of the nematoid per root system and promoting increases in fresh mass of the roots. However, more studies are needed to understand the dynamics of the nematode reduction in the presence of the organic compound, since nematode reproduction was not affected by the presence of tannery sludge.

Amplicon-based metabarcoding reveals temporal response of soil microbial community to fumigation-derived products

The use of soil fumigation products to manage soilborne pathogens raises the question of whether it has undesirable effects on the soil ecosystem. Therefore, the aim of this study was to investigate the impacts of alternative fumigation products on soil microbial population structure. We characterised soil bacterial and fungal communities in response to the soil treatment with microencapsulated terpene, Brassica seedmeal (BioFence™) and chloropicrin in a field trial. The effect of soil treatments on the overall microbial population structure and relative abundance of individual microbial OTUs (operational taxonomic units) was assessed using an amplicon-based metabarcoding approach at three time points. Classifying representative OTU sequences into taxonomic groups was more uncertain for bacteria than for fungi. Chloropicrin dramatically altered both bacterial and fungal populations within four weeks of application. The effect on bacterial population structure is short-lived and became non-significant 16 weeks after treatment; however, fungal population structure was more persistently affected by chloropicrin. Neither terpene nor BioFence™ significantly affected soil microbiota. This study highlights the need for reliable algorithms in classifying sequences into taxonomic units and also the importance of identifying microbes into finer taxonomic groups for understanding soil microbiota and their effects on crop production.

Science Frontiers in Agronomy, Crops, and Soils

Science Frontiers in Agronomy, Crops, and Soils

Greenhouse Evaluation of Melon Rootstock Resistance to Monosporascus Root Rot and Vine Decline as Well as of Yield and Fruit Quality in Grafted ‘Inodorus’ Melons

Melons (Cucumis melo L.) are generally grafted onto Cucurbita rootstocks to manage soilborne pathogens such as Monosporascus root rot and v ine decline (MRR/VD) and Fusarium wilt. However, g rafting onto Cucurbita rootstocks reportedly results in the reduction of fruit quality. In this study, the resistance to MRR/VD, yield, and fruit quality of melons grafted onto melon rootstocks were evaluated under greenhouse conditions. Eight melon rootstocks (R1 to R8) were used and the inodorus melon 'Homerunstar' was used as scion. Melon rootstocks R1 to R6 were selected based on resistance to MRR/VD under greenhouse conditions. Non-grafted 'Homerunstar' and plants grafted onto squash interspecific hybrid 'Shintozwa' rootstock (Cucurbita maxima D. <TEX>${\times}$</TEX> C. moschata D.) served as controls. Grafted melons were cultivated in the greenhouse infested with Monosporascus cannonballus during two growing seasons (summer and autumn). The responses to MRR/VD, yield, and fruit quality differed depending on the rootstocks and growing season. The melons grafted onto 'Shintozwa' exhibited less severe disease symptoms and higher survival rates than non-grafted melons in both seasons. While the melon rootstocks in the summer cultivation did not increase the survival rate compared to non-grafted melons, the melon rootstocks R1 and R2 in the autumn cultivation led to higher survival rates. The melon rootstocks resistant to MRR/VD increased the percentage of marketable fruits and marketable yields. Grafting onto the melon rootstocks caused little or no reduction of fruit quality such as low calcium content, fruit softening, and vitrescence, especially in lower-temperature autumn season. Accordingly, these results suggest that grafting onto the melon rootstocks may increase the tolerance to MRR/VD and the marketable yield without a reduction of fruit quality.