scholarly journals Compatibility of biocontrol agent formulas and synthetic fungicides in controlling maydis leaf blight on corn caused by Bipolaris maydis

2021 ◽  
Vol 911 (1) ◽  
pp. 012062
Author(s):  
Nurasiah Djaenuddin ◽  
Amelia Sebayang ◽  
Nurnina Nonci ◽  
Amran Muis

Abstract Maydis leaf blight caused by Bipolaris maydis is one of the limiting factors in increasing maize production. The application of biological control agents (BCAs) as a biopesticide to control pests and plant diseases expected to decrease synthetic fungicide usage and its impacts. Several researches showed that the formula of Bacillus subtilis biopesticide suppress the development of several plant diseases including maydis leaf blight in maize. Nevertheless, biological control agents cannot completely replace the need for chemical fungicides in the agro-ecosystem. Therefore, this study was carried out to evaluate the effect and compatibility of several synthetic fungicides with antagonistic bacterial formulas in controlling B. maydis on maize. Five types of synthetic active ingredients used were difenoconazole, propinep, fluopicolide, metalaxyl, and dimethomorph. From the results of laboratory tests, 3 types of active ingredients with the highest inhibitory effectiveness be selected for the field test. Field treatments were arranged using a Randomized Block Design with 2 factors, factor I was biological control agents with 2 levels (T0 = without biological control agents, T1 = with biological control agents) and factor II was synthetic fungicide with different active ingredients with 4 levels (S0 = no synthetic fungicide, S1=diphenoconazole, S2=propinep, S3 = fluopicolide). Each treatment combination was repeated 4 times. The result showed that all the synthetic fungicides tested were compatible with the biological control agent. Fungicide with active ingredient of diphenoconazole was the most compatible with the BCAs showing the lowest disease severity value of 27%, while control treatment conditions without BCAs was 72%.

2020 ◽  
Author(s):  
Andrew C. Wylie ◽  
Zamir K. Punja

Biological control of plant diseases is important in organic greenhouse vegetable production where fungicide use is limited. Organic producers employ microbially-diverse substrates, including composts, as media for plant growth. Previous research into the impact of vermicompost on the efficacy of applied biocontrol agents is limited. An in vitro assay was developed to test the efficacy of two biological control agents in a competitive microbial background. Suppression of the pathogen Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) by Clonostachys rosea f. catenulata (Gliocladium catenulatum strain J1446 (Prestop®) and Bacillus subtilis strain QST 713 (Rhapsody®), was assessed on agar media amended with aerated vermicompost tea (ACT). Pathogen growth was reduced more by C. rosea than ACT alone and C. rosea was equally effective when combined with ACT. In contrast, B. subtilis reduced pathogen growth less than ACT, and when combined, reduced pathogen growth not more than ACT alone. Both biocontrol agents were similarly tested with ACT against Forc and Rhizoctonia solani on cucumber and radish. Additive, neutral, and antagonistic responses, depending on host, pathogen, and biocontrol agent, were observed. ACT alone provided more consistent disease suppression on cucumber compared with B. subtilis or C. rosea. In combination, disease suppression was most often better than each biocontrol alone but not better than ACT alone. ACT had antagonistic or additive interactions with C. rosea in the radish/R. solani pathosystem, depending on the experiment. The specific and general suppression of plant diseases by biological control agents in microbially-rich environments is variable and requires further study.


2021 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Fina Dwimartina ◽  
Tri Joko ◽  
Triwidodo Arwiyanto

One of the determining factors in disease control is the use of superior seeds which have good quality and quantity. The use of biological control agents that form a symbiotic mutualism in their host plants can be used as an effort to obtain quality clove seeds. Endophytic bacteria and rhizobacteria have been reported as potential biological control agents for many plant diseases because of their safety in humans and non-target organisms. The purpose of this study was to identify the physiological and morphological characteristics of endophytic and rhizobacterial isolates obtained from clove plants. A total of 46 endophytic bacterial isolates were isolated from healthy clove roots, stems, leaves and flowers. Also, 66 isolates were isolated from the soil around the rhizosphere area. Based on the results of the identification of physiological and morphological characteristics, it is evident that the endophytic and rhizobacterial bacteria tested have the same character as Bacillus spp.


2004 ◽  
Vol 94 (11) ◽  
pp. 1272-1275 ◽  
Author(s):  
B. J. Jacobsen ◽  
N. K. Zidack ◽  
B. J. Larson

Bacillus-based biological control agents (BCAs) have great potential in integrated pest management (IPM) systems; however, relatively little work has been published on integration with other IPM management tools. Unfortunately, most research has focused on BCAs as alternatives to synthetic chemical fungicides or bactericides and not as part of an integrated management system. IPM has had many definitions and this review will use the national coalition for IPM definition: “A sustainable approach to managing pests by combining biological, cultural, physical and chemical tools in a way that minimizes economic, health and environmental risks.” This review will examine the integrated use of Bacillus-based BCAs with disease management tools, including resistant cultivars, fungicides or bactericides, or other BCAs. This integration is important because the consistency and degree of disease control by Bacillus-based BCAs is rarely equal to the control afforded by the best fungicides or bactericides. In theory, integration of several tools brings stability to disease management programs. Integration of BCAs with other disease management tools often provides broader crop adaptation and both more efficacious and consistent levels of disease control. This review will also discuss the use of Bacillus-based BCAs in fungicide resistance management. Work with Bacillus thuringiensis and insect pest management is the exception to the relative paucity of reports but will not be the focus of this review.


2022 ◽  
Vol 951 (1) ◽  
pp. 012106
Author(s):  
R Sriwati ◽  
T Chamzurni ◽  
F Razi ◽  
Syaifullah ◽  
Yunita ◽  
...  

Abstract To increase plant resistance from an early age, it is necessary to introduce biological control agents from groups of fungi and bacteria. This study aims to determine the effect of Trichoderma harziaunum and Bacillus thuringiensis Aceh isolates in increasing the superiority of Aceh patchouli plants that are resistant to pests and plant diseases. The study used non-factorial RAL method with cover and uncovered seedling methods. Both series were treated with the same biological control agent, the control without any treatment, the treatment of T. harzianum and B. thuringiensis while the observations were made when the seedling covered was opened. Observations included plant morphological characters, plant growth development and peroxidase enzymes. The results showed that morphologically the original patchouli growing in Lhoong district had similar morphological characters to the Lhokseumawe variety. The application of biological control agents of the T. harzianum and B. thuringiensis groups was more effective in increasing plant growth in the closed seedling treatment compared to the uncovered seedling. T. harzianum gave the best effect at a dose range of 1-1.5 while B. thuringensis showed a better effect at a concentration of 10-15 ml. Both treatments increased the growth of patchouli seedlings as indicated by the better plant height and number of shoots. Furthermore, higher peroxidation enzymes were found in the closed seedling treatment with 1.5 g T harzianum and 15 ml B. thuringiensis. The high peroxidase enzyme as an indicator of the more resistant plants have been induced to pests and diseases. From the screen house experiment, T. harzianum and B. thuringiensis were more efficient in inducing plant growth and disease resistance of local varieties of patchouli using the closed seedling method.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Lucas Alexander Shuttleworth

AbstractApple is a globally important tree fruit. In the United Kingdom (UK) and mainland Europe, there is ongoing consumer and environmental concern regarding over-reliance on conventional chemicals for disease control. This has resulted in an increase in withdrawal of active ingredients and legal use restrictions over recent years. The loss of active ingredients can be problematic for growers, who have relied on the generally more predictable and efficacious management that results from using conventional chemicals. Organic disease management methods are generally more sustainable over the long term as organic methods have fewer negative impacts on the environment and on human health. Key diseases of organic UK apple production include scab, European canker, powdery mildew, apple replant disease, and brown rot/blossom wilt. The recommended organic control measures depend on the disease. Measures range from the use of host resistance, rootstock and scion cultivar selection, planting location of trees, application of biological control agents, soil amendments, cultural management, postharvest treatments, disease modelling and forecasting. The challenge when using organic methods is results are often more variable and less predictable than when using conventional chemicals. Biological control agents, for example, often require more applications than chemicals, need correct timing to work effectively, and can be sensitive to weather and orchard management. Additionally, a thorough understanding of disease ecology by growers is helpful for more effective implementation of organic control methods. Invasive pathogens not currently present in the UK that may affect apple production including Xylella fastidiosa and Valsa mali, and the potential effects of climate change on pathogens already present such as Erwinia amylovora (fireblight) are discussed. The consequences of climate change are difficult to predict due to the changeable nature of the weather and the variation in factors contributing to climate change. However, a warming planet and more unpredictable weather patterns may favour range expansion of pathogens, while increasing plant stress and susceptibility. This review presents various methods that can be applied as alternatives to conventional chemicals for disease control in organic apple production to provide economic efficiency, environmental sustainability, and the supply of safe nutritious food.


Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 631-639 ◽  
Author(s):  
David H. Gent ◽  
Howard F. Schwartz

Xanthomonas leaf blight (Xanthomonas axonopodis pv. allii) is a yield-limiting disease of onion (Allium cepa) in the western United States. Frequent applications of copper-based bactericides amended with an ethylenebisdithiocarbamate fungicide (e.g., maneb or mancozeb, class B2 carcinogens) provide some disease suppression, but strategies to reduce conventional bactericide use are needed to minimize grower costs, environmental impact, and public exposure to class B2 pesticides. Applications of acibenzolar-S-methyl reduced in planta and epiphytic populations of X. axonopodis pv. allii as effectively as applications of copper hydroxide-mancozeb in growth chamber studies. Under field conditions, four weekly applications of acibenzolar-S-methyl reduced severity of Xanthomonas leaf blight as or more effectively than 9 to 12 weekly applications of copper hydroxide or copper hydroxide-mancozeb. Acibenzolar-S-methyl applications did not increase bulb yield or grade compared with copper bactericide treatments. However, bulb yield was reduced 22 to 27% when 10 weekly applications of acibenzolar-S-methyl were made in the absence of disease. Application of a commercial formulation of both Pantoea agglomerans strain C9-1 and Pseudomonas fluorescens strain A506 reduced severity of Xanthomonas leaf blight in field experiments. Weekly copper hydroxide applications starting 1 to 2 weeks before bulb initiation were as effective as weekly applications started 3 to 4 weeks before bulb initiation, irrespective of the maneb rate used. Integration of acibenzolar-S-methyl and biological control agents with copper hydroxide in a carefully timed spray program may eliminate the use of the class B2 carcinogens maneb and mancozeb on onion without compromising efficacy for management of Xanthomonas leaf blight.


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