Stem Rot Research Articles

Phenotypic evaluation of USDA peanut (Arachis hypogaea L.) mini-core collection for resistance against stem rot caused by Sclerotium rolfsii Sacc.

Sclerotium rolfsii is a necrotrophic fungus that causes devastating stem rot disease on peanuts under high temperature and humidity conditions. Developing more resistant stem rot varieties is a better disease management strategy from an economic and environmental point of view. In this study, 105 peanut accessions from the USDA mini-core collection were screened for resistance against stem rot under growth chamber and greenhouse conditions at the New Mexico State University Agricultural Science Center in Clovis, NM, USA. The accessions were inoculated with a virulent isolate of S. rolfsii, and disease development was monitored and scored at 5, 7, 9, 11, and 17-days post-inoculation (DPI). Mean disease score, lesion length and broad sense heritability were calculated, and cluster analysis was performed. Though the accessions were not significantly different for the mean disease parameters, numerical differences were observed in disease score and lesion length among the accessions at 17-DPI. Eleven accessions showed moderate resistance and performed better than stem rot resistant commercial cultivar, ‘G03L’, and ninety-four accessions were susceptible based on mean disease scores under both growing conditions. Low broad-sense heritability for disease score (0.05 to 0.06) and lesion length (0.03 to 0.06) under different environments indicates that most of the variance for these traits is due to environmental effects, and that stem rot resistance can be a complex trait. The identified resistant accessions can be used for genotyping and finding major QTLs through genome-wide association mapping to dissect genetic basis of stem rot resistance in peanuts. This information would be helpful to the peanut breeding program to develop more resistant varieties.

Bio-intensive Management of root and Stem rot (Macrophomina phaseolina (Tasi) Goid) of Sesame

Field experiments were conducted on sesame during Kharif 2014 to 2016 at JNKVV farm, with seven treatments and three replications using susceptible variety of Sesame (Sesamum indicum L.),VRI-1, to find out the effect of Trichoderma viride and Pseudomonas florescence (either alone or in combination ) on incidence of charcoal rot disease caused by Macrophomina phaseolina (Tasi) Goid. Seed treatment with Trichoderma viride (5g/kg seed) + Pseudomonas florescence (10g/kg seed) and soil application of T. viride or pseudomonas florescence@2.5 kg/ha before sowing was found effective for the management of this disease.

Status of Stem Rot Incidence of Groundnut Caused by Sclerotium rolfsii inNorthern Eastern Karnataka

Groundnut is regarded as “King of oilseed crops” on account of its diversified uses. It’s productivity is challenged by several biotic and abiotic stresses. Sclerotium rolfsii Sacc. is one of the major constraints to groundnut production which causes a yield loss of about 25 – 80 %. Hence, the roving survey was conducted during Kharif 2021 in North-Eastern Karnataka region. The mean stem rot incidence among the different districts surveyed ranged between 18.89-36.28 per cent. The maximum stem rot incidence was recorded in Vijayanagar (36.28 %) followed by Ballari district (32.83 %). Whereas, minimum stem rot was recorded in Koppal district (18.89 %).

Unravelling the potential of effective seed bacterial endophyte in groundnut forstem rot disease (Sclerotium rolfsii) management

Groundnut (Arachis hypogaea L.) is known as “King of oilseeds” which is grown extensively in both Kharif and Rabi/Summer seasons.Several among the several pathogens, Stem rot caused by Sclerotium rolfsii Sacc. causes the yield loss up to 80 per cent during favourable conditions. Hence, an attempt has been made to isolate bacterial endophytes for biocontrol management from peanut seeds as an alternative approach. Sixteen isolates (EGN1- EGN16) isolated from peanut were tested against Sclerotium rolfsii under in vitro. Further, the effective isolates were further analyzed for the presence of thermo stable compounds, profiling of secondary metabolites through GC-MS analysis, growth promotion test (rhizo scanner) and pot culture experiment. The results showed that talc formulation of effective isolate EGN 1 (Pseudomonas sp.) significantly increased the vigour index (4902.81), germination rate (91.3per cent), root length (28.1 cm) and shoot length (25.6 cm) along with the simultaneous reduction in disease incidence of 5.54 %.

Identification of resistance germplasm in sesame against root and stem rot (Macrophomina phaseolina) of Sesame

3700 accessions of sesame germplasm were sown during kharif 2021 with susceptible and resistant checks in augmented plot design in 3 meter length row in sick plot (artificial inoculum) condition. Out of these accessions, only 53 accessions were resistant against root and stem rot of sesame and disease incidence was less than 10%.

GG-35: A high yielding Spanish bunch groundnut, Arachis hypogaea L.variety for Gujarat State

A Spanish bunch groundnut genotype GG 35 was developed on the basis of mean pod yield from the state level trials. It has recorded the highest pod yield of 3177 kg/ha as compared to the checks viz., GG 7 (2452 kg/ha), GJG 9 (2471 kg/ha) and TG 37A (2758 kg/ha). GG 35 had recorded average 100 kernel weight of 42.79 g, average 100 pod weight of 101.93 g and average shelling out-turn of 71.36%. The reaction against tikka, rust, stem rot and collar rot, the variety was comparable to the check varieties under field conditions whereas, the damages due to thrips was not observed in the released variety as well as check varieties. Based on the superior performance, GG 35 has been released for general cultivation in the kharif bunch groundnut growing areas of Gujarat state.

Efficacy of seed soaking in different phytoextracts for the management of charcoal rot (Macrophomina phaseolina (tasi) Goid) of sesame

The effect of sixteen plant extracts were evaluated for the management of root & stem rot of sesame by seed soaking method under in-vivo (sick plot condition) at 20 percent of concentrations in two sesame varieties. In variety RT-346 garlic extract was found most effective as a seed treatment among all the tested plant extract against M. phaseolina by 78.44 percent of healthy plant followed by the onion 77.28 percent. In VRI-1 variety, garlic extract was found most effective as a seed treatment among all the tested plant extract against M. phaseolina by 79.66 per cent of healthy plant followed by the onion 75.81 per cent.

Advances in rapeseed mustard disease management

India is the largest producer of oilseeds in the world and oilseed sector occupies an important position in the agricultural economy of the country. Oilseeds are among the major crops that are grown in the country apart from cereals. Among the nine annual oilseeds cultivated in India, the share of Rapeseed-mustard is about 25% of total area and 27% of total production. With the share of 39% in total vegetable oil production which stands at first position. During last 5 years, compound annual growth rate (CAGR) of Rapeseed-mustard production and productivity at National level increased by 10.42 and 8.46%, respectively. Among different biotic stresses, insectpests, diseases (Sclerotinia stem rot, white rust, downy mildew, Alternaria blight, powdery mildew) and weeds, cause yield loss upto 30-40% in different regions of the country. Plant diseases are considered as risks because they constantly contribute to significant yield, economic, and environment losses worldwide. Therefore, the early andaccurate detection, monitoring, and assessment of plant diseases is important and necessary for farmers, managers, and decision makers.

Effect of seed coating in a combination of biopolymer, fungicide and biocontrolagents on the vigour and stem rot incidence of groundnut under in-vitro condition

The experiment was conducted with a combination of effective fungicide, potential biocontrol agents and seed coat biopolymer (chitosan) with different concentrations and their combinations along with untreated seeds as control, were used for coating groundnut seeds. The pathogen was inoculated on each treated and untreated seeds and the maximum germination of 94.0 % was recorded in T5 treatment having double layer seed coat which showed higher vigour index I and II (3190 and 87.4) and minimum seedling mortality of 10.7 %. Whereas untreated seeds (T1 ) showed low germination of 64.0 %, vigour index I and II (1709 and 44.6) with maximum seedling mortality of 75.2 %.

GG HPS-2: A high yielding and large seeded Virginia bunch groundnut (Arachishypogaea L.) variety for Gujarat state

A Virginia bunch large seeded groundnut variety GG HPS 2 was developed from the cross JVB HPS 2 and GG 20. It recorded a higher mean pod yield (2835 kg/ha) and kernel yield (1945 kg/ha) as compared to the checks.GG HPS 2 recorded an average 100 kernel weight of 66.71 g, shelling out-turn of 68.61% and oil content of 48.82%. GG HPS 2 showed restistance reaction to tikka (leaf spot) and rust reaction, whereas it showed comparableresistance to stem rot, collar rot, damages due to leaf defoliators and thrips under field conditions with check varieties. Based on the superior performance, it has been released for kharif groundnut growing areas of the Gujarat State.

Evaluation of fungicides against stem rot of groundnut caused by Sclerotium rolfsii Sacc under in vitro condition

The efficacy of five test fungicides viz., carboxin 37.5 % + thiram 37.5 %, tebuconazole 25 % EC, mancozeb 75 %WP, penflufen 13.28 % w/w + trifloxystrobin 13.28 % w/w FS and chlorothalonil 75 % WP were tested under in vitro by poisoned food technique against S. rolfsii in groundnut. Among five fungicides, penflufen + trifloxystrobin fungicide were found highly effective at all the concentrations (250, 500, 750 and 1000 ppm) tested and inhibited 100.0 % mycelial growth of S. rolfsii in groundnut as compared to control.

Efficacies of new age fungicides against charcoal rot of sesame

Six systemic fungicides were evaluated under in vitro condition by using poison food techniques at three different concentrations 500 ppm, 1000 ppm and 1500 ppm against root and stem rot pathogen of sesame (Macrophomina phaseolina) Tassi Goid. all the treatments were found to be superior over control in which T1 (Tebuconazole 50% + Trifloxystrobin 25%), gave 100% inhibition against test fungus (M. phaseolina) at all the concentrations (500, 1000 and 1500 ppm) followed by T6 (Carbendazim + Mencozeb), which gave 94.43% of average inhibition, followed by T5 (Captan + Hexaconazole), that gave 92.59% of average inhibition, followed by T4 (Cymoxanil + mencozeb) gave 83.15% average inhibition, followed by T5 (Pyraclostrobin + Metiram) with 57.28% of average inhibition. Least mycelial inhibition was given by T2 (Azoxystrobin) with only 41.66%.

Phytophthora palmivora causes root and basal stem rot disease on macaw palm (Acrocomia aculeata) in Brazil

Macaw palm (Acrocomia aculeata Jacq.) is an oleaginous palm native to the American continent. It produces oil and has other important characteristics for the industry. In 2022, a severe disease causing basal stem rot, root rot, and plant mortality in a nursery and the field was detected on macaw palm plants in a farm, in João Pinheiro, Minas Gerais state, Brazil. From the rot symptomatic tissue of affected palms, two Phytophthora isolates were obtained by indirect isolation and were grown on PDA. Based on the morphological characteristics, particularly the coenocytic hyphae and papillate sporangia, the isolates were identified as Phytophthora palmivora. For phylogenetic analyses, the internal transcribed spacer (ITS) regions, β-tubulin gene (TUB), translation elongation factor 1-alpha gene (EF1-α), and two mitochondrial genes: cytochrome c oxidase subunit I (COXI) and cytochrome c oxidase subunit II (COXII), were amplified. Phylogenetic analyses confirmed that it is the species P. palmivora. Fulfillment of the Koch's postulates through pathogenicity test confirmed that P. palmivora was the causal agent of root rot and basal stem rot disease in macaw palm. This is the first report of this pathogen causing disease in macaw palms in Brazil.

Characterization and In Vitro Fungicide Sensitivity of Two Fusarium spp. Associated with Stem Rot of Dragon Fruit in Guizhou, China.

Dragon fruit (Hylocereus polyrhizus) constitutes an important economic industry in Guizhou Province, China, and the occurrence of stem rot has become increasingly severe. In this study, we aimed to determine the causative pathogens of stem rot in this region and analyze their sensitivity to fungicides. Twenty-four fungal isolates were obtained from diseased tissues, from which H-4 and H-5 were confirmed as pathogens based on Koch's postulates. Based on the morphological characteristics of macroconidia, microconidia, and colony morphology, the polygenic phylogenetic tree constructed using internal transcribed spacer, elongation factor 1-alpha, and retinol-binding protein-2 gene fragments, and carbon source metabolism analysis using FF microplates, the two pathogens were identified as F. oxysporum and a newly discovered pathogen, F. concentricum. In addition, the in vitro toxicity of eight fungicides against both pathogens was measured based on the mycelial growth rate. The results showed that trifloxystrobin 25%·tebuconazole 50% (75 WG) exhibited the strongest inhibitory effect against both isolates, with EC50 values of 0.13 µg/mL and 0.14 µg/mL, respectively. These findings hold significant potential for guiding the effective treatment of stem rot in dragon fruit in Guizhou, China.

Testing of Selection Criteria for Screening of Oil Palm Genotypes Partially Resistant to Ganoderma Boninense in Main-Nursery

Resistance to basal stem rot (BSR) caused by Ganoderma boninense is now one of the main breeding objectives by many oil palm breeders. Many studies reported that resistance to G. boninense is partial or incomplete resistance.Screening at a longer period in main-nursery is also needed to see genetic variation in rate of infection (‘r) among genotypes. The objective of this study was to test several criteria suitable for identifying genotypes to have low infection rate. Two hundreds of DxP crosses between 16 dura lines and three Pisifera palms were made for testing of their resistance to G. boninense in main-nursery. Since G. boninense is a root disease, its effect on root would be direct and selection based on FRW must be very reliable and accurate. Genotypes which had values better than average value were selected as moderately resistant genotypes to G. boninense. The results showed that: (1) there were differences in fastness of infection and severity of the disease; (2) variation in DS among tested crosses increase with time and reach maximum at the 12th MAI; (3) only four selection criteria had significant correlation FRW, namely, FBW (0.74), AUDPC (-0.261), DS (-0.233), ‘r (-0.205); and (4) four selection criteria which gave the closest results to FRW criterion consecutively were FBW (73%), AUDPC (65%), ‘r (64%), DS (63%). It could be concluded that main-nursery screening could identify genotypes with lower ‘r value. AUDPC and ‘r values are suitable to be used as selection criteria for selecting oil palm genotypes partially resistant to G. boninense in main- nursery screening.

Current progress on the computational methods for prediction of host-pathogen protein-protein interaction in the Ganoderma boninense-oil palm pathosystem

Ganoderma boninense is a major pathogen for basal stem rot disease that can depolymerize lignocellulosic materials of the oil palm plant by secreting the cell wall-degrading enzymes. The management of this disease is complicated by the asymptomatic phase mediated by the protein-protein interaction (PPI) between the pathogen's effector and plant proteins. There is a lack of network-wide studies on the PPI to elucidate the action of effectors on plant pathways from a systemic perspective as the computational prediction of host-pathogen PPI (HP PPI) is focused on human interaction. Hence, this minireview explores the current computational methods for predicting HP PPI and proposes an approach to predict PPI between G. boninense and oil palm.

De Novo RNA Sequencing and Transcriptome Analysis of Sclerotium rolfsii Gene Expression during Sclerotium Development.

Sclerotium rolfsii is a destructive soil-borne fungal pathogen that causes stem rot in cultivated plants. However, little is known about the genetic basis of sclerotium development. In this study, we conducted de novo sequencing of genes from three different stages of S. rolfsii (mycelia, early sclerotium formation, and late sclerotium formation) using Illumina HiSeqTM 4000. We then determined differentially expressed genes (DEGs) across the three stages and annotated gene functions. STEM and weighted gene-co-expression network analysis were used to cluster DEGs with similar expression patterns. Our analysis yielded an average of 25,957,621 clean reads per sample (22,913,500-28,988,848). We identified 8929, 8453, and 3744 DEGs between sclerotium developmental stages 1 versus 2, 1 versus 3, and 2 versus 3, respectively. Additionally, four significantly altered gene expression profiles involved 220 genes related to sclerotium formation, and two modules were positively correlated with early and late sclerotium formation. These results were supported by the outcomes of qPCR and RNA-sequencing conducted on six genes. This is the first study to provide a gene expression map during sclerotial development in S. rolfsii, which can be used to reduce the re-infection ability of this pathogen and provide new insights into the scientific prevention and control of the disease. This study also provides a useful resource for further research on the genomics of S. rolfsii.

Identification of Pests, Diseases, and Nutrient Deficiencies in Rice (Oriza Sativa L.) Variety Sunggal

This study aims to identify pests, diseases and nutrient deficiencies in the Sunggal variety of rice (Oriza sativa L.). This research was conducted in June 2023. The research location was carried out in rice fields belonging to farmers in Sidorejo Hamlet, Polokarto District, Sukoharjo Regency. This research is descriptive qualitative by making direct observations or observations on rice fields, interviews and literature. The results showed that there were 7 pests that attacked this single variety rice plant, consisting of 5 pests from the insect class (insects), 1 from the mollusk class, and 1 from the aves class. Pests caused by insects (insects), namely: rice bug (Leptocorisa oryzae), ground bed bug (Scotinophara coarctata), white rice stem borer (Scirpophaga innotata Walker), armyworm (Spodoptera litura), grasshopper (Oxya servile). Caused by molluscs, namely the golden snail (Pomacea canaliculate) and caused by birds, namely sparrows (Lonchura sp). While there are 6 caused by diseases, namely caused by fungi/fungi there are 5 and caused by bacteria there is 1. Among those caused by fungi/fungus namely: brown leaf spot on rice (Helminthosporium oryzae), narrow brown leaf spot on rice (Cercospora oryzae), stem rot in rice (Sclerottium oryzae), rice leaf blight (Rhizotonia solani) and leaf blast (Pyricularia grisea). Caused by bacteria, namely bacterial leaf blight of rice (bacteria: Xanthomonas oryzae pv oryzae). Then lastly there is one that is caused by a lack of nutrients, namely: potassium deficiency.

INTEGRATION OF BIOAGENTS AND CHEMICAL FUNGICIDES AGAINST SCLEROTINIA SCLEROTIORUM CAUSING STEM ROT IN CHICKPEA

One of the most harmful infections to chickpea plants, Sclerotinia sclerotiorum, causes stem rot and causes financial losses all over the world. Beneath the soil's surface, as sclerotia, the pathogen can live for a very long time alongside the detritus. As a result, the condition is extremely difficult to manage, has nearly no known treatments, and only a few types have been shown to be somewhat successful against the infection. Thus, the primary goal of the research is to investigate the effects of a variety of treatments, including Rhizobium leguminosarum + Pseudomonas fluorescens combination, Trichoderma viride, Saaf (Carbendazim 12%+ Mancozeb 63% WP), Vitavax Power (Carboxin 37.5%+ Thiram 37.5%), Hexaconazole, and Rhizobium leguminosarum + Pseudomonas fluorescens, to investigate their impact on S. sclerotiorum suppression. While maintaining sustainability, bioagents improve the soil's properties and productivity. Fungicides have been found to be effective when bio-agents are not able to control a disease. Therefore, in this investigation, both methods of treatment were used. The results of an experiment conducted in both in vitro and in vivo conditions showed that chemical treatment with Saaf fungicide and seed treatment with T. viride were highly efficient against S. sclerotiorum.

Morphological and molecular identification of the root and stem base rot pathogen on broad bean crop and control it using some Trichoderma biological agents

This study looked at the effects of biological control strategies for root and stem rot disease caused by Rhizoctonia solani using soil organisms as biocontrol agents. The results of the field survey showed the spread of root and stem rot disease on broad bean plants in some areas of Najaf Governorate, where the infection rate ranged from 32- to 89.5%. The Isolation process showed that five fungal isolates of Rhizoctonia solani were associated with the disease, which differed in some phenotypic characteristics in terms of growth speed and color difference. The results of the molecular diagnosis using the ITS marker sequencing for the three most pathogenic isolates showed that they were belonging to Rhizoctonia solani, thus were named Ahmed 1, 3, 4 and registered in the GenBank under accession numbers; ON 394595.1, ON 394597.1, and ON 394599.1, respectively. In the pathogenicity test, R. solani isolates displayed a difference in their virulence on broad bean plants, where R. solani 1 (Al-Mashkhab isolate) was the most virulent among the isolates and was selected for subsequent studies. Isolate T. longibrachiatum (T3) showed high antagonistic efficiency against isolate of the pathogenic fungus R. solani on P.D.A culture media, gave the highest inhibitory percentage 75.06% compared to isolates T1 and T2 of Trichoderma harzianum, which led to inhibition of the pathogen to 68.71% and 68.94%, respectively. In the culture filtrate test of isolates of the living fungi, isolate T3 had the highest inhibition in the growth of pathogenic R. solani, which was 5.20 cm compared to the two live fungi T1 and T2, which led to 6.20 and 5.95 cm, respectively. As for the pots experiment, the results revealed that the isolate of T. longibrachiatum (T3) protected the broad beans plants from root and stem rot pathogen, where the disease was not seen compared to the treatment of the pathogenic fungus R. solani, only in which the infection severity was 80%.