scholarly journals Efficacy of a Nonpathogenic Acidovorax citrulli Strain as a Biocontrol Seed Treatment for Bacterial Fruit Blotch of Cucurbits

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 697-704 ◽  
Author(s):  
K. L. Johnson ◽  
G. V. Minsavage ◽  
T. Le ◽  
J. B. Jones ◽  
R. R. Walcott
Keyword(s):  
Biological Control ◽  
Seed Treatment ◽  
Management Strategies ◽  
Fruit Production ◽  
Management Program ◽  
Control Seed ◽  
Bacterial Fruit Blotch ◽  
Watermelon Seed ◽  
Acidovorax Citrulli ◽  
Phosphate Buffered Saline

Bacterial fruit blotch (BFB), caused by the seedborne, gram-negative bacterium Acidovorax citrulli, is a serious threat to cucurbit seed and fruit production worldwide. Because of the lack of effective management strategies, we investigated the efficacy of a nonpathogenic A. citrulli strain as a biological control seed treatment for BFB. For this study, we generated a type III secretion system mutant of A. citrulli, AAC00-1ΔhrcC, that was nonpathogenic on watermelon but retained its ability to colonize germinating watermelon seed. With watermelon seed naturally infested with A. citrulli, AAC00-1ΔhrcC reduced BFB seedling transmission by 81.8% relative to control seed. In comparison, another A. citrulli antagonist, A. avenae strain AAA 99-2, reduced BFB seedling transmission by 74.6% for seed samples from the same lot. Additionally, when female watermelon blossoms were protected with AAC00-ΔhrcC and subsequently challenged with AAC00-1, the resulting seedlots displayed 8% BFB seedling transmission. This was not significantly different than seed from blossoms protected with AAA 99-2 (4%) but significantly less than those from blossoms protected with 0.1 M phosphate-buffered saline (36%). These results suggest that nonpathogenic A. citrulli has potential as a biological control seed treatment component in a comprehensive BFB management program.

scholarly journals Biological Control to Protect Watermelon Blossoms and Seed from Infection by Acidovorax avenae subsp. citrulli

2005 ◽  
Vol 95 (4) ◽  
pp. 413-419 ◽  
Author(s):  
A. Fessehaie ◽  
R. R. Walcott
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Disease Suppression ◽  
Biological Control Agents ◽  
Positive Bacterium ◽  
Control Seed ◽  
Bacterial Fruit Blotch ◽  
Feasible Option ◽  
Phosphate Buffered Saline ◽  
Seed Infestation

The efficacy of biological control seed treatments with Pseudomonas fluorescens (A506), Acidovorax avenae subsp. avenae (AAA 99-2), and an unidentified gram-positive bacterium recovered from watermelon seed (WS-1) was evaluated for the management of bacterial fruit blotch (BFB) of watermelon. In growth chamber and greenhouse experiments, seed treated with AAA 99-2 displayed superior disease suppression, reducing BFB transmission by 96.5%. AAA 99-2, P. fluorescens A506, and Kocide also suppressed the epiphytic growth of A. avenae subsp. citrulli when applied to attached watermelon blossoms 5 h prior to inoculation. Watermelon blossom protection reduced seed infestation by A. avenae subsp. citrulli. From blossoms treated with 0.1 M phosphate buffered saline (PBS), 63% of the resulting seed lots were infested with A. avenae subsp. citrulli. In contrast, for blossoms protected with WS-1, Kocide, P. fluorescens A506, and AAA 99-2, the proportion of infested seed lots were 48.3, 21.1, 24.1, and 13.8%, respectively. The effect of blossom treatments on seed lot infestation was statistically significant (P = 0.001) but WS-1 was not significantly different from PBS. These findings suggest that blossom protection with biological control agents could be a feasible option for managing BFB.

scholarly journals Prevalence of Acidovorax citrulli in Commercial Cucurbit Seedlots During 2010–2018 in China

Plant Disease ◽  
2020 ◽  
Vol 104 (1) ◽  
pp. 255-259 ◽  
Author(s):  
Yanli Tian ◽  
Yuqiang Zhao ◽  
Jiaju Zhou ◽  
Ting Sun ◽  
Xue Luo ◽  
...  
Keyword(s):  
Seed Production ◽  
Inner Mongolia ◽  
Fruit Production ◽  
Colony Pcr ◽  
Primary Inoculum ◽  
Bacterial Fruit Blotch ◽  
Growing Seasons ◽  
Acidovorax Citrulli ◽  
High Prevalence ◽  
Production Areas

Acidovorax citrulli is the causal agent of bacterial fruit blotch (BFB), a serious threat to cucurbit fruit and seed production worldwide. In recent years, the BFB has spread to many areas of China, mainly via the inadvertent distribution of contaminated commercial seeds. To assess the prevalence of seedborne A. citrulli in commercial watermelon and other cucurbitaceous seedlots in China, a 9-year survey was conducted between 2010 and 2018. A total of 4,839 seedlots of watermelon and other cucurbitaceous species were collected from 13 major seed production areas of China and tested by a semiselective media-based colony PCR technique for A. citrulli. Overall, A. citrulli was detected in 18.00% (871/4,839) of all cucurbitaceous seedlots. The bacterium was detected in 21.59% (38/176), 19.19% (33/172), 23.44% (214/913), 40.76% (247/606), 13.28% (85/640), 15.40% (95/617), 13.25% (73/551), 8.03% (48/598), and 6.71% (38/566) of all commercial seedlots tested from the 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, and 2018 growing seasons, respectively. Additionally, the prevalence of A. citrulli in cucurbit seedlots was determined for different seed production areas. The prevalence of A. citrulli in cucurbitaceous seedlots produced in Xinjiang, Gansu, Ningxia, Inner Mongolia, and 9 other provinces was 18.76% (582/3103), 26.34% (103/391), 21.47% (82/382), 11.11% (14/126), and 10.75% (90/837), respectively. This is the first survey for A. citrulli in commercial cucurbit seeds in China, and the relatively high prevalence suggests that commercial seeds represent a substantial source of primary inoculum that can threaten cucurbit seed and fruit production in China.

scholarly journals Etiology, diagnostic approaches and management strategies of Acidovorax citrulli, a bacterial fruit blotch pathogen of cucurbits

2021 ◽  
Vol 57 (No. 2) ◽  
pp. 75-94
Author(s):  
Ainur Ainiah Azman Husni ◽  
Siti Izera Ismail ◽  
Noraini Jaafar ◽  
Dzarifah Zulperi
Keyword(s):  
Control Strategies ◽  
Management Strategies ◽  
Characterization Methods ◽  
Bacterial Fruit Blotch ◽  
Acidovorax Citrulli ◽  
Group I ◽  
Wide Range ◽  
Research Findings ◽  
Management Approaches ◽  
The Impact

Bacterial fruit blotch (BFB) caused by Acidovorax citrulli, represents one of the most destructing diseases of cucurbits, especially to watermelon- and melon producing-regions. This disease has been spread sporadically to many countries globally, due to the unintentionally dispersal of contaminated commercial seeds. The BFB causes massive yield losses up to 100% under conducive conditions. Once infected, all parts of the host plants are extremely susceptible to this bacterium, especially the seedlings and fruits parts. In recent years, various management approaches and detection tools have been employed to control A. citrulli. Genotypic characterization methods revealed two distinct groups of A. citrulli strains; (i) group I strains primarily isolated from non-watermelon cucurbits and consist of moderate to highly aggressive strains from wide range of cucurbit hosts, and (ii) group II strains isolated from watermelon which are highly aggressive on watermelon, but mildly aggressive on non-watermelon hosts. In this paper, an attempt has been made to review research findings where the impact of diverse methods and management approaches were applied in detection and controlling of A. citrulli infection. A better understanding of this devastating bacterium will serve as guidelines for agricultural practitioners in developing the most efficient and sustainable BFB control strategies.

scholarly journals Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria

2017 ◽  
Vol 33 (2) ◽  
pp. 170-183 ◽  
Author(s):  
Mahesh Adhikari ◽  
Dil Raj Yadav ◽  
Sang Woo Kim ◽  
Young Hyun Um ◽  
Hyun Seung Kim ◽  
...  
Keyword(s):  
Biological Control ◽  
Associated Bacteria ◽  
Bacterial Fruit Blotch ◽  
Acidovorax Citrulli

Electron investigations of rhabdovirus-like particles in mexican bean beetles and crickets

1978 ◽  
Vol 36 (2) ◽  
pp. 378-379
Author(s):  
J. R. Adams ◽  
G. J Tompkins ◽  
A. M. Heimpel ◽  
E. Dougherty
Keyword(s):  
Biological Control ◽  
Integrated Pest Management ◽  
Pest Management ◽  
Developmental Stages ◽  
Management Program ◽  
Acheta Domesticus ◽  
Epilachna Varivestis ◽  
House Cricket ◽  
Similar Morphology ◽  
Bean Beetle

As part of a continual search for potential pathogens of insects for use in biological control or on an integrated pest management program, two bacilliform virus-like particles (VLP) of similar morphology have been found in the Mexican bean beetle Epilachna varivestis Mulsant and the house cricket, Acheta domesticus (L. ).Tissues of diseased larvae and adults of E. varivestis and all developmental stages of A. domesticus were fixed according to procedures previously described. While the bean beetles displayed no external symptoms, the diseased crickets displayed a twitching and shaking of the metathoracic legs and a lowered rate of activity.Examinations of larvae and adult Mexican bean beetles collected in the field in 1976 and 1977 in Maryland and field collected specimens brought into the lab in the fall and reared through several generations revealed that specimens from each collection contained vesicles in the cytoplasm of the midgut filled with hundreds of these VLP's which were enveloped and measured approximately 16-25 nm x 55-110 nm, the shorter VLP's generally having the greater width (Fig. 1).

Can Anastrepha fraterculus larval feeding influence chemotaxis and parasitism of Diachasmimorpha longicaudata and Aganaspis pelleranoi?

2021 ◽  
pp. 1-8
Author(s):  
Patricia Daniela da Silva Pires ◽  
Josué Sant’ Ana ◽  
Luiza Rodrigues Redaelli
Keyword(s):  
Biological Control ◽  
Artificial Diet ◽  
Psidium Guajava ◽  
Fruit Production ◽  
Larval Feeding ◽  
Parasitoid Species ◽  
Major Barrier ◽  
Anastrepha Fraterculus ◽  
Diachasmimorpha Longicaudata ◽  
Control Programmes

Abstract Anastrepha fraterculus (Diptera: Tephritidae) is a major barrier to fruit production and exportation. In Brazil, the native parasitoid Aganaspis pelleranoi (Hymenoptera: Figitidae) and the exotic parasitoid Diachasmimorpha longicaudata (Hymenoptera, Braconidae) stand out as biological control agents. Knowledge of the factors that affect interactions among parasitoids, A. fraterculus, and host fruits may enhance the use of these agents in biological control programmes. This study evaluated the chemotaxis and parasitism of A. pelleranoi and D. longicaudata females reared on A. fraterculus larvae and kept on an artificial diet, red guava (Psidium guajava) or apple (Malus domestica). Females of both parasitoid species that emerged from larvae raised on artificial diet, guava or apple, were tested to Y olfactometer choice tests. In the parasitism tests, both parasitoid species were made to choose between A. fraterculus larvae brushed with water, apple pulp or guava pulp. D. longicaudata females from artificial diet (control) did not distinguish between fruit odours; however, females of D. longicaudata from larvae kept in apple or guava directed to the odours of their original fruit. The greatest parasitism for D. longicaudata occurred in the units that contained the pulp in which the larvae grew. A. pelleranoi from artificial diet preferred guava odours, including the females kept in apple. Similar results were observed in the parasitism bioassays. Our results found that A. fraterculus larval feeding influenced search behaviour and parasitism of D. longicaudata, whereas A. pelleranoi rearing experience did not affect its host choices.

scholarly journals Development of Molecular Markers for Detection of Acidovorax citrulli Strains Causing Bacterial Fruit Blotch Disease in Melon

2019 ◽  
Vol 20 (11) ◽  
pp. 2715 ◽  
Author(s):  
Md. Rafiqul Islam ◽  
Mohammad Rashed Hossain ◽  
Hoy-Taek Kim ◽  
Denison Michael Immanuel Jesse ◽  
Md. Abuyusuf ◽  
...  
Keyword(s):  
Infected Leaf ◽  
Bacterial Fruit Blotch ◽  
Early Disease Detection ◽  
Acidovorax Citrulli ◽  
Seed Health ◽  
Field Samples ◽  
Whole Genomes ◽  
Pathogenesis Related ◽  
Primer Sets ◽  
Inoculation Assay

Acidovorax citrulli (A. citrulli) strains cause bacterial fruit blotch (BFB) in cucurbit crops and affect melon significantly. Numerous strains of the bacterium have been isolated from melon hosts globally. Strains that are aggressively virulent towards melon and diagnostic markers for detecting such strains are yet to be identified. Using a cross-inoculation assay, we demonstrated that two Korean strains of A. citrulli, NIHHS15-280 and KACC18782, are highly virulent towards melon but avirulent/mildly virulent to the other cucurbit crops. The whole genomes of three A. citrulli strains isolated from melon and three from watermelon were aligned, allowing the design of three primer sets (AcM13, AcM380, and AcM797) that are specific to melon host strains, from three pathogenesis-related genes. These primers successfully detected the target strain NIHHS15-280 in polymerase chain reaction (PCR) assays from a very low concentration of bacterial gDNA. They were also effective in detecting the target strains from artificially infected leaf, fruit, and seed washing suspensions, without requiring the extraction of bacterial DNA. This is the first report of PCR-based markers that offer reliable, sensitive, and rapid detection of strains of A. citrulli causing BFB in melon. These markers may also be useful in early disease detection in the field samples, in seed health tests, and for international quarantine purposes.

scholarly journals Biological control agents in the integrated nematode management of potato in Egypt

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Mahfouz M. M. Abd-Elgawad
Keyword(s):  
Biological Control ◽  
Crop Yields ◽  
Integrated Management ◽  
Management Strategies ◽  
Economic Value ◽  
Potato Production ◽  
Parasitic Nematodes ◽  
Main Body ◽  
Biological Control Agents ◽  
Economic Significance

Abstract Background Potato represents Egypt’s largest vegetable export crop. Many plant-parasitic nematodes (PPNs) are globally inflicting damage to potato plants. In Egypt, their economic significance considerably varies according to PPN distribution, population levels, and pathogenicity. Main body This review article highlights the biology, ecology, and economic value of the PPN control viewpoint. The integration of biological control agents (BCAs), as sound and safe potato production practice, with other phytosanitary measures to manage PPNs is presented for sustainable agriculture. A few cases of BCA integration with such other options as synergistic/additive PPN management measures to upgrade crop yields are reviewed. Yet, various attributes of BCAs should better be grasped so that they can fit in at the emerging and/or existing integrated management strategies of potato pests. Conclusion A few inexpensive biocontrol products, for PPNs control on potato, versus their corresponding costly chemical nematicides are gathered and listed for consideration. Hence, raising awareness of farmers for making these biologicals familiar and easy to use will promote their wider application while offering safe and increased potato yield.

scholarly journals “Predator-In-First”: A Preemptive Biological Control Strategy for Sustainable Management of Pepper Pests in Florida

2020 ◽  
Vol 12 (18) ◽  
pp. 7816
Author(s):  
Vivek Kumar ◽  
Lucky Mehra ◽  
Cindy L. McKenzie ◽  
Lance S. Osborne
Keyword(s):  
Biological Control ◽  
Pest Management ◽  
Control Strategy ◽  
Frankliniella Occidentalis ◽  
Management Strategies ◽  
Control Program ◽  
Field Conditions ◽  
High Rate ◽  
Polyphagotarsonemus Latus ◽  
Consistent Performance

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.

Spider mites of agricultural importance in China, with focus on species composition during the last decade (2008–2017) 

2018 ◽  
Vol 23 (11) ◽  
pp. 2087 ◽  
Author(s):  
Peng-Yu Jin ◽  
Lu Tian ◽  
Lei Chen ◽  
Xiao-Yue Hong
Keyword(s):  
Species Composition ◽  
Dominant Species ◽  
Integrated Management ◽  
Management Strategies ◽  
Spider Mites ◽  
Management Program ◽  
Pest Species ◽  
Panonychus Citri ◽  
Important Species ◽  
River Region

Understanding pest species composition and their geographic distribution of important spider mites is fundamental and indispensable to establish an integrated pest management program. From a long-term survey during 2008–2017 in mainland China, we found that Tetranychus truncatus was the most frequently sampled Tetranychus spider mite (48.5%), followed by T. pueraricola (21.2%), T. kanzawai (12.5%), T. urticae (red) (5.7%) and T. urticae (green) (4.5%). Among them, T. truncatus was the major mite pest in the north of China. T. kanzawai was the dominant species in the Middle and Lower Reaches of the Yangtze River Region and T. pueraricola was the most important species in the southwest region. Other common and serious pests include Amphitetranychus viennensis (6.8%) and Panonychus citri (3.8%). This pattern was largely different from that in 2002–2004, when T. urticae (green and red) was believed to be the most serious mite pest. The factors involved in the change of species composition are not clear and need more exploration. We suggested that the increasing corn planting range may be partly responsible for the conversion of dominant species from other spider mites to T. truncatus. Further research on the mechanisms underlying the change of dominant species will help develop integrated management strategies.

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