Biological control of potato Verticillium wilt under controlled and field conditions using selected bacterial antagonists and plant extracts

2008 ◽  
Vol 44 (1) ◽  
pp. 90-100 ◽  
Author(s):  
A.K. Uppal ◽  
A. El Hadrami ◽  
L.R. Adam ◽  
M. Tenuta ◽  
F. Daayf
2013 ◽  
Vol 53 (2) ◽  
pp. 154-157 ◽  
Author(s):  
Mahdiyeh Mansoori ◽  
Asghar Heydari ◽  
Nader Hassanzadeh ◽  
Saeed Rezaee ◽  
Laleh Naraghi

Abstract Verticillium wilt is considered the most important disease of cotton in the world, including Iran. Cultural practices and the use of resistant varieties are the most common strategies used to control Verticillium wilt of cotton. These strategies are not always available or effective. In recent years, biological control using fungal and bacterial antagonists, has been applied to control some cotton diseases including damping-off. In this study, we investigated the possibility of biological control of Verticillium wilt of cotton using bacterial antagonists. Suspension of eight bacterial strains of Pseudomonas fluorescens and Bacillus spp. isolated from different rhizospheric soils and plant roots in the Iranian cotton fields, were prepared with a concentration of 108 cfu/ml. Ten cotton seeds (cv Varamin) were then coated with each bacterial suspension and were planted in soil pre-inoculated with Verticillium dahliae microsclerotia. The efficacy of bacterial antagonists in reducing wilt disease was evaluated by determination of the disease index in different treatments. The results indicated that most isolates were effective in reducing disease (compared to the untreated control) 90 days after sowing. Isolates B5, B6, B2, B7, and B3 were the most effective, respectively, in reducing wilt index. In contrast, isolates B1, B4, and B8 did not significantly reduce the disease. In general, P. fluorescens isolates were more effective than Bacillus isolates. This study suggests that bacterial antagonists might be potential biological control agents of cotton.


2016 ◽  
Vol 68 (1) ◽  
pp. 41-66 ◽  
Author(s):  
Shazia Parveen ◽  
Abdul Hamid Wani ◽  
Mohd Yaqub Bhat ◽  
Jahangir Abdullah Koka

2021 ◽  
Vol 735 (1) ◽  
pp. 012079
Author(s):  
Muneer Saeed M. Al-Baldawy ◽  
Ahed A A H Matloob ◽  
Mohammed K. N. Almammory

2020 ◽  
Vol 12 (18) ◽  
pp. 7816
Author(s):  
Vivek Kumar ◽  
Lucky Mehra ◽  
Cindy L. McKenzie ◽  
Lance S. Osborne

The early establishment of a biocontrol agent in the production system, whether in the greenhouse, nursery, or field, is essential for the success of the biological control program, ensuring growers’ profitability. In an effort to develop a sustainable pest management solution for vegetable growers in Florida, we explored the application of a preemptive biological control strategy, “Predator-In-First” (PIF), in regulating multiple pepper pests, Bemisia tabaci Gennadius, Frankliniella occidentalis Pergande, and Polyphagotarsonemus latus Banks under greenhouse and field conditions during different growing seasons. In these studies, two bell pepper cultivars (7039 and 7141) and the phytoseiid mite Amblyseius swirskii Athias–Henriot were used as a model system. Pepper seedlings (~8 week) of each cultivar were infested with varying rates of A. swirskii (20 or 40 mites/plant or one sachet/10 plant) and allowed to settle on plant hosts for a week before planting in pots or field beds. Results showed a comparative consistent performance of the treatment with the high rate of phytoseiids (40 mites/plant) in regulating B. tabaci and F. occidentalis populations in greenhouse studies, and B. tabaci and P. latus pests under field conditions. During two fall field seasons, higher marketable yields of 12.8% and 20.1% in cultivar 7039, and 24.3% and 39.5% in cultivar 7141 were observed in the treatment with the high rate of phytoseiids compared to the untreated control, indicating yield benefits of the approach. The outcome of the study is encouraging and demonstrates that PIF can be an important tool for organic vegetable growers and a potential alternative to chemical-based conventional pest management strategies. The advantages and limitations of the PIF approach in Florida pepper production are discussed.


Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 386-394 ◽  
Author(s):  
George W. Sundin ◽  
Nicole A. Werner ◽  
Keith S. Yoder ◽  
Herb S. Aldwinckle

The bacterial antagonists Pseudomonas fluorescens A506, Pantoea agglomerans C9-1, and Pantoea agglomerans E325 and preparations of Bacillus subtilis QST 713 containing bacterial endospores and lipopeptide metabolites were evaluated for efficacy in controlling fire blight in Michigan, New York, and Virginia. When examined individually, the biological control materials were not consistently effective in reducing blossom infection. The average reduction in blossom infection observed in experiments conducted between 2001 and 2007 was variable and ranged from 9.1 to 36.1%, while control with streptomycin was consistent and ranged from 59.0 to 67.3%. Incidence of blossom colonization by the bacterial antagonists was inconsistent, and <60% of stigmata had the antagonists present in 12 of 25 experiments. Consistent control of blossom infection was observed when the biological control materials were integrated into programs with streptomycin, resulting in a reduction of the number of streptomycin applications needed to yield similar levels of control. Our results indicate that the prospects for biological control of fire blight in the eastern United States are currently not high due to the variability in efficacy of existing biological control options.


2012 ◽  
Vol 48 (No. 2) ◽  
pp. 74-79 ◽  
Author(s):  
S.M.A. Nashwa ◽  
K.A.M. Abo-Elyousr

The antimicrobial activity of six plant extracts from Ocimum basilicum (Sweat Basil), Azadirachta indica (Neem), Eucalyptus chamadulonsis (Eucalyptus), Datura stramonium (Jimsonweed), Nerium oleander (Oleander), and Allium sativum (Garlic) was tested for controlling Alternaria solani in vitro and in vivo. In in vitro study the leaf extracts of D. stramonium, A. indica, and A. sativum at 5% concentration caused the highest reduction of mycelial growth of A. solani (44.4, 43.3 and 42.2%, respectively), while O. basilicum at 1% and 5% concentration and N. oleander at 5% concentration caused the lowest inhibition of mycelial growth of the pathogen. In greenhouse experiments the highest reduction of disease severity was achieved by the extracts of A. sativum at 5% concentration and D. stramonium at 1% and 5% concentration. The greatest reduction of disease severity was achieved by A. sativum at 5% concentration and the smallest reduction was obtained when tomato plants were treated with O. basilicum at 1% and 5% concentration (46.1 and 45.2 %, respectively). D. stramonium and A. sativum at 5% concentration increased the fruit yield by 76.2% and 66.7% compared to the infected control. All treatments with plant extracts significantly reduced the early blight disease as well as increased the yield of tomato compared to the infected control under field conditions.


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