Seed Treatment with Trichoderma Species for Control of Damping-off of Cowpea Caused by Macrophomina phaseolina

2001 ◽  
Vol 11 (4) ◽  
pp. 449-457 ◽  
Author(s):  
A. T. Adekunle ◽  
K. F. Cardwell ◽  
D. A. Florini ◽  
T. Ikotun
2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Mohammed Hamza Abass ◽  
Qusai Hattab Madhi ◽  
Abdulnabi Abdul Ameer Matrood

Abstract Background Wheat is the most consumed cereal crops in the world infected by several pathogens and pests causing significant losses. The most threatening pathogens are fungi which cause serious diseases on roots, leaves and heads as one of the most threatening pathogens in specific wheat-growing countries. This study aimed to identify and evaluate the prevalence of damping-off fungal pathogens in different wheat fields at Basra and Maysan provinces. Results Disease incidence determination and fungal isolation were carried out from two sites at Basra province (Al-Qurna and Al-Madinah) and three sites at Maysan province (Al-Amarah, Kumit, Ali Al Sharqi and Ali Al Gharbi). Al-Qurna fields had the highest disease incidence (32%), while Ali-Alsharqi fields had the lowest one (11%). Fourteen fungal genera were identified. Rhizoctonia solani had the highest appearance (21.6) and frequency (20.20%) percentages followed by Fusarium solani (16.11,14.01) percentages and Macrophomina phaseolina (12.2,11.1) percentages. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Conclusions These results revealed the prevalence of wheat damping-off disease in all examined fields at both Basra and Maysan province; the highest disease incidence was seen in Basra wheat fields (Al-Qurna fields); the identification of fungal pathogens showed that the most isolated fungus was R. solani followed by F. solani and M. phaseolina. Laboratory experiments showed the pathogenicity of isolated fungi which varied according to the isolate type.


2021 ◽  
Vol 47 (3) ◽  
pp. 157-161
Author(s):  
Augusto César Pereira Goulart

ABSTRACT The aim of this study was to verify the influence of previous crops and fungicide seed treatment in the incidence and control of damping-off caused by Rhizoctonia solani in cotton seedlings under greenhouse conditions. This experiment was carried out during two years at Embrapa Western Agriculture, in Dourados, Mato Grosso do Sul State, Brazil. In addition to cotton (treated and untreated seeds) and fallow, the following cover crops were tested as previous crops: black oats, millet, corn, forage sorghum, soybean, common beans, crotalaria (Crotalaria juncea), brachiaria (Urochloa ruziziensis) and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea). The fungicide mixture used as treatment to cotton seeds was triadimenol + pencycuron + tolylfluanid (50 + 50 + 30 g a.i./100 kg seeds). Seeds from cotton and previous crops were sown in soil contained in plastic trays and pots; the seeds were placed in individual and equidistant 3cm-deep wells. Inoculation of R. solani was obtained by homogeneously distributing the fungal inoculum onto the substrate surface (2.5g/tray and 0.34g/pot). The fungus was grown for 35 days on autoclaved black oat seeds subsequently ground to powder using a mill (1mm). Damping-off was daily evaluated from the seventh day after sowing. There was a significant effect of the interaction previous crops x fungicide treatment (P<0.05). The fungicide seed treatment was efficient in controlling seedling damping-off caused by R. solani and its effect was potentiated when grasses were the previous crops. Use of grasses such as brachiaria (Urochloa ruziziensis), black oats, millet, corn and forage sorghum as previous crops, besides fallow, significantly contributed to a smaller R. solani population in the soil, which resulted in lower rates of cotton seedling damping-off. On the other hand, using cotton continuously, as well as the legumes soybeans, beans, crotalaria (Crotalaria juncea), and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea) as previous crops to cotton, was consistently associated with higher rates of seedling damping-off, contributing to the increase or at least the maintenance of R. solani inoculum in the soil. The highest damping-off percentages were observed in plots under continuous cotton cultivation without fungicide seed treatment. The present results reinforce the need of improving damping-off control in cotton seedlings by adopting integrated management programs in areas infested with R. solani.


Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1421-1432 ◽  
Author(s):  
Kelsey Scott ◽  
Meredith Eyre ◽  
Dair McDuffee ◽  
Anne E. Dorrance

Phytophthora, Phytopythium, and Pythium species that cause early-season seed decay and pre-emergence and post-emergence damping off of soybean are most commonly managed with seed treatments. The phenylamide fungicides metalaxyl and mefenoxam, and ethaboxam are effective toward some but not all species. The primary objective of this study was to evaluate the efficacy of ethaboxam in fungicide mixtures and compare those with other fungicides as seed treatments to protect soybean against Pythium, Phytopythium, and Phytophthora species in both high-disease field environments and laboratory seed plate assays. The second objective was to evaluate these seed treatment mixtures on cultivars that have varying levels and combinations of resistance to these soilborne pathogens. Five of eight environments received adequate precipitation in the 14 days after planting for high levels of seedling disease development and treatment evaluations. Three environments had significantly greater stands, and three had significantly greater yield when ethaboxam was used in the seed treatment mixture compared with treatments containing metalaxyl or mefenoxam alone. Three fungicide formulations significantly reduced disease severity compared with nontreated in the seed plate assay for 17 species. However, the combination of ethaboxam plus metalaxyl in a mixture was more effective than either fungicide alone against some Pythium and Phytopythium species. Overall, our results indicate that the addition of ethaboxam to a fungicide seed treatment is effective in reducing seed rot caused by these pathogens commonly isolated from soybean in Ohio but that these effects can be masked when cultivars with resistance are planted.


Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 459-464 ◽  
Author(s):  
P. A. Abbasi ◽  
G. Lazarovits

A formulation of phosphonate (AG3) was tested as a seed treatment for the control of Pythium damping-off of cucumber (Cucumis sativus L.) plants under controlled environment and field conditions. Cucumber seed were treated by soaking for 10 min in phosphonate solution. They were then planted into peat-based mix or sandy-loam soil mixed with Pythium aphanidermatum or P. ultimum inoculum or into muck soil naturally infested with P. irregulare, P. ultimum, and other Pythium spp. Under growth-room conditions, phosphonate seed treatment provided more than 80% control of damping-off in all infested substrates tested. Effective disease control was obtained even when treated seed were stored for 5 weeks and up to 18 months prior to planting. In microplots containing naturally infested muck soil, phosphonate seed treatment decreased the percentage of diseased cucumber plants and increased total fresh weights compared with untreated seed and phosphonate post-planting drench. In field-plot tests 6 weeks after planting treated seed in Pythium-infested muck soil, cucumber stands were 63% compared with 18% in the control, which had no phosphonate exposure, and 53% in the post-planting drench. Tests for potential phytotoxicity in the greenhouse showed that radish and bok choy germination was reduced by phosphonate treatment but corn, cucumber, soybean, sugar beet, tomato, and wheat were not affected. Phosphonate seed treatment is a cost-effective way of protecting cucumber plants from Pythium damping-off.


1988 ◽  
Vol 34 (5) ◽  
pp. 631-637 ◽  
Author(s):  
D. Walther ◽  
D. Gindrat

Seed treatment with ascospores of Chaetomium globosum reduced damping-off of sugar-beet caused by seed-borne Phoma betae and soil-borne Pythium ultimum or Rhizoctonia solani in growth chamber experiments. Seed treatment with a fluorescent Pseudomonas sp. controlled Ph. betae and P. ultimum but not R. solani. Coating cotton seeds with ascospores controlled P. ultimum and R. solani damping-off. In some experiments, biological seed treatments were equally or more effective than seed treatment with captan. However, greater variability in disease control occurred with the antagonists than with captan. Fifty percent of freshly harvested ascospores of C. globosum germinated in 8 h on water agar. When ascospores were stored under air-dried conditions for 3 days to 2.5 years, germination increased to > 90%. Under same storage conditions, survival of Pseudomonas sp. was detected after 4 months. Antagonistic activities observed in vitro were hyphal coiling of C. globosum on R. solani, and mycostasis was induced by C. globosum or Pseudomonas sp. on agar and soil. The presumed cause of mycostasis is the diffusible antifungal metabolites which may also be involved in the biological control of damping-off.


Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 62-72 ◽  
Author(s):  
L. Radmer ◽  
G. Anderson ◽  
D. M. Malvick ◽  
J. E. Kurle ◽  
A. Rendahl ◽  
...  

Pythium spp. cause seed decay, damping-off, and root rot in soybean and corn; however, their diversity and importance as pathogens in Minnesota are unknown. Our objectives were to identify the Pythium spp. present in Minnesota soybean fields, determine their aggressiveness on corn and soybean, and investigate their sensitivity to seed treatment fungicides. For identification, sequences obtained using internal transcribed space ITS4 and ITS1 primers were compared with reference sequences in the National Center for Biotechnology Information database. Seedling and soil samples yielded over 30 oomycete species. Aggressiveness was determined using two methods; a seed assay, which also examined temperature effects on aggressiveness, and a seedling assay. Of 21 species evaluated, seven Pythium spp. were pathogenic on both soybean and corn, reducing root growth by 20% or more while two Pythium and one Phytopythium spp. were pathogenic only on soybean. Aggressiveness of many isolates increased as temperature increased from 15°C to 25°C. The sensitivity of 10 pathogenic species to azoxystrobin, ethaboxam, mefenoxam, pyraclostrobin, or trifloxystrobin was tested. EC50 values for mefenoxam and ethaboxam were 10−2 of those to strobilurin fungicides. Pythium spp. in Minnesota are diverse and a significant cause of seedling disease on soybean and corn. Most Pythium spp. isolated in this study were more sensitive to mefenoxam and ethaboxam than to strobilurin fungicides.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1110f-1110
Author(s):  
Nancy W. Callan ◽  
James B. Miller ◽  
Don E. Mathre

Shrunken-2 supersweet (sh2) sweet corn is susceptible to preemergence damping-off caused by Pythium ultimum, especially when planted into cold soil. Bio-priming, a seed treatment which combines the establishment of a bioprotectant on the seed with preplant seed hydration, was developed to protect seeds from damping-off.In a series of field experiments conducted in Montana's Bitterroot and Gallatin Valleys, bio-priming or seed bacterization with Pseudomonas fluorescens AB254 protected sweet corn from P. ultimum damping-off. Bio-priming corn seed with P. fluorescens AB254 was comparable to treatment with the fungicide metalaxyl in increasing seedling emergence. Seedlings from bio-primed seeds emerged from the soil more rapidly than from nontreated seeds and were larger at three weeks postplanting. Seeds of sh 2 and sugary enhancer (se) sweet corn, as well as that of several sh 2 cultivars, were protected from damping-off by bio-priming.


2013 ◽  
Vol 55 (1) ◽  
pp. 255-263 ◽  
Author(s):  
Bogdan Nowicki

Seed treatment ofroot parsley was done to protect <i>Petroselinum santivum</i> seedlings against damping off. Fungicides used as seed dressers were applied in 3 doses: 3, 5 and 10 g/kg. Seeds were treated with 7 dressers (Table l) used separately and in mixture with 3 g/kg of Rovral 50 WP (50% iprodione) and 1 g/kg of Apron 35 SD (35% metalaxyl). Two seed samples of Berlińska cultivar were used: first sample was strongly infected by <i>Alternaria petroselini</i> and <i>A.radicina</i> both 27,6% and also by <i>Fusarium</i> spp. 5,4% (Test I), and second sample revealed lower percentage of infection 4,6% and 1,2%, respectively (Test II). The experiments were conducted under laboratory, glasshouse and field conditions. Complete seedlings protection in all experiments was achieved for treatments when fungicide mixture was used in the highest dose (10 g/kg). Decrease of fungicides concentrations were connected with lower effectiveness of disease control. No phytotoxic effects of the tested fungicide mixtures were observed under the glasshouse or field conditions.


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