White Muscardine Research Articles

Identification and Toxicity Evaluation of <i>Beauveria</i> sp. Associated with White Muscardine Disease in Muga Silkworm <i>Antheraea assamensis</i> Helfer

The present study is an effort to isolate and identify the Beauveria sp. from white muscardine infected Antheraea assamensis Helfer (muga silkworm) larvae collected from rearing fields. The isolate was subjected to morphological identification followed by DNA barcoding analysis by sequencing the ITS1-5.8S-ITS2 region. The isolate was identified morphologically up to genus level. For molecular identification, the DNA was first isolated, amplified by using PCR followed by sequencing the ITS region. A phylogenetic tree was also constructed based on the data obtained from sequencing to trace the evolutionary history of the isolated fungus. The fungal species was identified as Beauveria bassiana with 98.6% sequence similarity with already documented B. bassiana strains. The toxicity of the isolated fungus was also evaluated against A. assamensis larvae. The LC50 value was determined at 96 hr and recorded at 1.1x108 spore/ ml concentration.

The potential of the entomopathogenic fungus Beauveria bassiana to manage insect pests and diseases

The saprophytic white muscardine fungus Beauveria bassiana (Balsamo) Vuillemin is a potential biocontrol agent against varied insect pests, is a commercially available mycopesticide in many countries, and is extensively used for insect pest management. It produces several metabolites, such as antibacterial, antifungal, cytotoxic, and insecticidal compounds that protect against insect pests and plant pathogens, with dual-purpose crop protection, a new concept in plant disease management. This insect pathogen is also beneficial to plant endophytes that are antagonistic to plant diseases and promote rhizosphere colonizers and plant growth, inducing systemic resistance. The induced systemic responses of fungal endophytes enhance genes that are expressed in pathogenesis and increase the production of pathogenesis-related proteins and defense enzymes. The fungus infects the insects by degrading mechanically and chemically their cuticles. It promotes plant growth, provides systemic protection against pests and pathogens in sustainable agricultural crop production, and reduces the usage of chemical pesticides.

Metabolism of plant-derived toxins from its insect host increases the success of the entomopathogenic fungus Beauveria bassiana

Beauveria bassiana is a soil fungus that parasitizes a large number of arthropod species, including numerous crop pests, causing white muscardine disease and is therefore used as a biological insecticide. However, some insects, such as the cabbage aphid (Brevicoryne brassicae), defend themselves chemically by sequestering dietary pro-toxins (glucosinolates) from their Brassicales host plants. Glucosinolates are accumulated by cabbage aphids and activated to form toxic isothiocyanates when under attack. While isothiocyanate formation protects aphids against most attackers, B. bassiana is still able to infect the cabbage aphid under natural conditions. We therefore investigated how this fungus is able to circumvent the chemical defense system of the cabbage aphid. Here, we describe how B. bassiana infection activates the cabbage aphid defense system, but the resulting toxins are metabolized by B. bassiana via the mercapturic acid pathway, of which the first step is catalyzed by glutathione-S-transferases of low substrate specificity. This detoxification pathway enhances B. bassiana growth when isothiocyanates are present in natural concentrations, and so appears to be an important factor in fungal parasitization of these chemically defended aphids.

Impact of imidazolium salts to reduce the infection of Bombyx mori caterpillars by Beauveria bassiana

The silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), is susceptible to several entomopathogens, including the fungus Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales), which causes white muscardine. Aiming at effective alternatives for disease control, the effect of one pyridinium salt (PS) and seven imidazolium salts (IS) on biological parameters of this fungus – conidia germination, colony-forming units (CFU), vegetative growth, and conidia production – were evaluated in vitro. Then, the in vivo action of the IS on silkworm larvae and pupae was verified. Preventive and curative actions of selected IS for disease suppression in B. mori caterpillars were evaluated either via oral or integumentary administration. When administered daily via feeding sheets, the IS 1,3-di-n-decyl-2-methylimidazolium chloride at 100 μg ml−1 was effective in reducing the mortality of caterpillars by the fungal infection. In addition, it did not show any negative effects on developing B. mori larvae. Therefore, 1,3-di-n-decyl-2-methylimidazolium chloride can be an effective tool in the management of white muscardine in silkworm rearing houses.

Molecular characterization of gut bacterias of American cockroach and their interaction with white muscardine fungus

Molecular characterization of gut bacterias of American cockroach and their interaction with white muscardine fungus

Efficacy of botanical extracts on the Economic characters of Silkworm, Bombyx mori L. infected with Beauveria bassiana (Bals) Vuill

White muscardine disease due to Beauveria bassiana causes high mortality with a cocoon yield loss upto 30 percent almost throughout the year. Due to the risks associated with the use of hazardous chemicals in disease management, the significance of research on environmentally friendly solutions with natural and biological sources has been realised in recent years. A different approach to managing silkworm diseases uses botanicals that are non-toxic, biodegradable, non-polluting and have antibacterial properties. Apart from the disease management, the botanical extracts have significant effect on silkworm growth and development. Three locally available botanicals, Datura stramonium (seed), Ficus carica (leaf), and Vitis vinifera (seed), had their extracts tested in this study at three different concentrations. Using percentages of 10, 15, and 20 to investigate their impact on the economic characteristics of the silkworm. The results showed that these botanicals, which were tested for their effectiveness on the economic characteristics of silkworms, had no negative effects on the health of the silkworms or the quality of the cocoons/silk. The silkworm's characteristics, including its larval weight, larval duration, cocoon weight, shell weight, shell ratio%, and average filament length were found to be par to those of a healthy batch of silkworms (Untreated healthy).

Antagonistic potential of Beauveria bassiana (Balsamo) Vuillemin against Pythium myriotylum causing damping off of tomato

Beauveria bassiana (Balsamo) Vuillemin, a white muscardine fungus has widely drawn attention of crop protection practitioners as potential biocontrol agent against insect-pests since decades. In the present study, antagonistic potential of 22 native of B. bassiana isolates were evaluated against damping-off disease of tomato caused by Pythium sp. Results showed that all B. bassiana isolates were able to inhibit mycelial growth of P. myriotylum to the extent of 68–82%. Further studies were conducted to understand the ability of screened B. bassiana isolates to produce cell wall degrading enzymes (CWDEs) viz., amylase, caesinase, chitinase, cellulase, lipase and protease respectively. The potential B. bassiana isolates showed dynamic colonization efficiency in tomato plants with colonization percentage (%) as high as 72–80% through seed inoculation. Eventually, potential isolate BP1.1 has showed wide pH tolerance ability ranging from pH 6–10. Further, potential isolate B. bassiana BP1.1 was evaluated for their efficacy against damping off of tomato under in vitro condition yielding higher germination percentage of 87.34% of and lower disease incidence up to 33.45% under treatment combinations. These findings provide substantial evidences on multifarious potential of B. bassiana as antagonist as well as plant growth promoter in addition to a potential entomopathogen, thus paves the way of a newer domain in the arena of crop protection.

Antifungal ability of Beauveria bassiana (Balsamo) Vuillemin against Curvularia lunata causing leaf spot of rice

Beauveria bassiana (Balsamo) Vuillemin, a white muscardine fungus has widely drawn attention of crop protection practitioners as potential biocontrol agent against insect-pests since decades. In the present study, antagonistic potential of 53 native isolates of B. bassiana were evaluated against Curvularia lunata causing leaf spot as well as seed borne disease of rice. Results showed that all B. bassiana isolates were able to inhibit mycelial growth of C. lunata to the extent of 50-63.33% through varied mechanisms viz., competition and diffusible non-volatile metabolites. However, potential isolates of B. bassiana also exhibited inhibition of mycelial growth of C. lunata to the maximum up to 67.78% through release of volatile inhibitory metabolites. These findings provide substantial evidences on multifarious potential of B. bassiana as plant disease antagonist in addition to a potential entomopathogen, thus paves the way of a newer domain in the arena of crop protection.

Management of white muscardine disease of silkworm (Bombyx mori L.) and improvement of economic characters by using botanicals: A review

Exploitation of naturally occurring plant materials and avoidance of synthetic chemicals (drugs, fungicides etc.) of paramount importance in present day strategy against pest and disease to develop management system to avoid environmental pollution and its hazardous effects on humans, animals and plants. Use of botanicals in an appropriate means for minimizing residual effect and the spread of diseases. Management with botanicals is eco-friendly and can be acceptable to the farmers because of low cost and easily availability at farmer's level. Botanicals can be utilized successfully in the management of white muscardine disease of silkworm depending on their local availability in the area of sericulture.

Comparison Analysis of Species Composition of Entomopathogenic Fungi Isolated from Bark Beetles (Coleoptera: Scolytidae)

The monitoring outbreaks of bark beetles, flight activity of imago and development of larvae were conducted with pheromone traps and trap logs. We found more than 50 dead adults with symptoms white muscardine from several points under the bark. Healthy adults of Ips typographus without any pathogenic symptoms collected from pheromone traps and trap logs under bark in the forest Czech Bohemian Switzerland (?eske Svýcarsko). For adaptation bark beetles Ips typographus in the laboratory conditions and excluded any other abiotic factors as a potential reason for their mortality. They were placed in bark in the Petri plates with filter paper and treated by 1 ml of entomopathogenic fungi conidial suspensions.The isolates Bcz38 and Inc2 showed low level of mortality of Ips typographus . But the isolate Bcz2, Bcz8, Bcz9, Bcz12-Bcz25 of B . bassiana and Bcz31 B . pseudobassiana had high virulence against of Ips typographus 100%.

RNA-Seq Analyses for Two Silkworm Strains Reveals Insight into Their Susceptibility and Resistance to Beauveria bassiana Infection.

The silkworm Bombyx mori is an economically important species. White muscardine caused by Beauveria bassiana is the main fungal disease in sericulture, and understanding the silkworm responses to B. bassiana infection is of particular interest. Herein, we investigated the molecular mechanisms underlying these responses in two silkworm strains Haoyue (HY, sensitive to B. bassiana) and Kang 8 (K8, resistant to B. bassiana) using an RNA-seq approach. For each strain, three biological replicates for immersion treatment, two replicates for injection treatment and three untreated controls were collected to generate 16 libraries for sequencing. Differentially expressed genes (DEGs) between treated samples and untreated controls, and between the two silkworm strains, were identified. DEGs and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the two strains exhibited an obvious difference. Several genes encoding cuticle proteins, serine proteinase inhibitors (SPI) and antimicrobial peptides (AMP) and the drug metabolism pathway involved in toxin detoxification were considered to be related to the resistance of K8 to B. bassiana. These results revealed insight into the resistance and susceptibility of two silkworm strains against B. bassiana infection and provided a roadmap for silkworm molecular breeding to enhance its resistance to B. bassiana.

Alternative phytosanitary products against to white muscardine in Bombyx mori L. (Lepidoptera: Bombycidae)

ABSTRACT: This work aimed to evaluate the effects of the products Biogermex®, Agro-mos®, Soil-Set® and Planta Clean® on the development of white muscardine in Bombyx mori. Products have been tested at two stages for effects on biology of caterpillars and on silk production (1), and then they were evaluated to know their potential in the prevention/control of white muscardine (2). Products were sprayed on mulberry leaves (preventive treatment) and also on the integument of silkworms (curative treatment). At the first stage, the products were applied on four consecutive days, in one of the daily feeds. Planta Clean® - curative treatment - and Soil-Set® - preventive treatment - caused mortality in 63.3% and 30% of silk worms, respectively. The fungus Beauveria bassiana was inoculated at the concentration 5 × 107 conidia/mL on the leaves and insects. The products were applied three hours after application on the fungus, in a single application, and also for four days in the other groups. A group of silkworms sprayed only with the fungus served as control. Biogermex® - curative treatment applied once and for four times - was the most effective, reducing mortality by 25 and 26.7%, respectively, as compared with the control group. None of the evaluated products acts preventively against white muscardine.

Problems faced by sericulture farmers by adoption of improved production technology practices from Koppal district of Karnataka

The case study was conducted to know the adoption of improved sericulture production technologies and problems faced by farmers in Koppal district of Karnataka during the year 2016–17. The findings revealed that majority of the respondents (54.00%) belonged to medium adoption category with respect to sericulture production technologies. Whereas 34% of the respondents belonged to low adoption category and only 12% of the respondents belonged to high adoption category. The variables, namely, age, education, occupation, land holding, family annual income, farming experience in sericulture, mass media participation, extension participation, extension contact, scientific orientation and risk orientation were found important in influencing the adoption of mulberry sericulture production technologies by farmers. With regard to problems, the major problems faced by the farmers are lack of knowledge regarding control of pests and diseases like uzifly, ants, pebrine, white muscardine and yellow muscardine (100.00%), lack of marketing facility and fluctuation in price of cocoon (100.00%), lack of information about crossbred races of silkworm (94.00%), lack of information about concentration of the disinfectant (87.00%), lack of knowledge regarding controlling of pest and diseases (84.00%), lack of supply of disease free laying (DLFs) from govt. sources (84.00%), high cost of establishment at initial stage (80.00%), high incidence pest and disease like stem borer (78.00%), lack of knowledge about training and pruning of mulberry plant (70.00%) and inadequate training facilities (70.00%).

CELLULAR ABNORMALITIES INDUCED BY TRICHODERMA SPP. DURING IN VITRO INTERACTION AND CONTROL OF WHITE MUSCARDINE (BEAUVERIA BASSIANA) AND GREEN MUSCARDINE (METARHIZIUM ANISOPLIAE) DISEASE OF SILKWORM BOMBYX MORI

The silkworm is the larva of the domesticated silk moth, Bombyx mori. It is an economically important insect, being a primary producer of silk in sericulture industry. Among the silkworm diseases, white muscardine and green muscardine caused by Beauveria bassiana and Metarhizium anisopliae respectively possess a major threat to silk cocoon production. White muscardine is more common during rainy and winter seasons whereas green muscardine has its profound effect during hot and humid spells. Both these fungi Beauveria bassiana and Metarhizium anisopliae can be used as biopesticides to control a number of pests such as termites, whiteflies, and many other insects from larvae to adult stages. In this paper in vitro biological control of B. bassiana and M. anisopliae and cellular abnormalities induced by the application of two strains (T12 and T13) of Trichoderma viride, Trichoderma harzianum and Trichoderma spp. were studied, where T. viride T 12 (80.52%) provides maximum in vitro control of B. bassiana followed by T. harzianum (71.88%), Trichoderma spp. (68.16%) and T. viride T13 (62.89%). Against M. anisopliae, T. harzianum provides maximum in vitro control (68.02%), followed by T. viride T13 (64.68%), T. viride T12 (59.47%) and Trichoderma sp. (57.98%). During the interaction of pathogens and biocontrol agents hyphal coiling, granulation, distortion, vacuolation and bulging were recorded.

Molecular tracing of white muscardine of the silkworm, Bombyx mori I: genetic structure analysis of Beauveria bassiana populations as the causal agents in China

ABSTRACTBeauveria bassiana is a ubiquitous entomopathogenic fungus, which causes white muscardine in the silkworm, Bombyx mori, and is an important limiting factor in global silk production. Knowledge of the genetic structure of B. bassiana populations as the causal agents in China will aid in tracing the origins of muscardine and in developing effective control strategies. In the present study, a total of 489 B. bassiana isolates were obtained from silkworm cadavers in 12 different provinces of China. An analysis of the genetic structure of the causal agent populations using the internal simple sequence repeat technique to trace their origins revealed a high level (100%) of DNA polymorphism. An unweighted pair group method with arithmetic mean dendrogram revealed that the 489 B. bassiana isolates were heterogenic and polyphyletic and displayed typical regional distribution, although the genetic differentiations were not associated with geographic distance. The genetic differentiation (Gst) among populations reached 0.406, with the maximum Gst between populations reaching 0.647. The general gene flow (Nm) was low at 0.366, with the lowest at only 0.137, suggesting that the low gene flow maintained a high degree of differentiation. These data indicated that the white muscardine in each local silkworm population was predominantly caused by a native group of B. bassiana, rather than by any exotic strain as in the case of biological control based on B. bassiana insecticides.

Molecular tracing of white muscardine in Asian corn borer using inter-simple sequence repeat (ISSR) analysis

Beauveria bassiana is a soil fungus that parasitizes arthropod species, and is used to control the Asian corn borer in Northeast China. In this study, B. bassiana was investigated in Xiaoxian County and Baicheng City, and the results were compared with those of Gongzhuling City, where the fungus was not applied. Using the inter-simple sequence repeat (ISSR) molecular marker technique, 198 isolates were extracted from Asian corn borer and other insect cadavers, and soil and air, and two released strains were analyzed to trace the infection source. In Xiaoxian and Baicheng populations, artificially released B. bassiana subpopulations were more abundant than indigenous fungi, and the released strains were the main cause of disease in those areas. Artificial B. bassiana displayed positive effect on overwintering of Asian corn borers in corn straw stacks in Xiaoxian County. Indigenous populations in Gongzhuling City showed higher genetic variation. In summary, we identified a significant correlation between genetic distance and geographic distance (P < 0.01).

Molecular tracing of white muscardine in the silkworm, Bombyx mori (Linn.) II. Silkworm white muscardine is not caused by artificial release or natural epizootic of Beauveria bassiana in China

The fungal pathogen Beauveria bassiana causes serious economic losses in sericulture. Its origin is usually attributed to the release of B. bassiana insecticides against pine caterpillars (Dendrolimus punctuatus). In the present study, 488 B. bassiana isolates obtained from silkworm (Bombyx mori) collected from 13 Chinese provinces, and 327 B. bassiana isolates obtained from D. punctatus collected from 9 provinces, were analyzed for population genetic structure using the ISSR technique based on genetic distance. A UPGMA dendrogram clustered them into three independent clades: two B. mori clades and one D. punctatus clade. A 3-D principal component analysis further divided them into two completely independent host groups, revealing high host-specificity. This suggested that white muscardine occurring in B. mori populations throughout southern China was not caused by any B. bassiana strain either naturally prevailing in D. punctatus populations or by any strain artificially released as a fungal insecticide against D. punctatus. We further investigated the genetic differentiation coefficient Gst and gene flow between B. mori-pathogenic and D. punctatus-pathogenic B. bassiana isolates from across China and from five provinces inhabited by both B. mori and D. punctatus. The Gst value across China was computed as 0.410, while the values of the five provinces ranged from 0.508 to 0.689; all above 0.25, which is the threshold for significant genetic differentiation. This suggests that B. bassiana strains isolated from the two different hosts maintained their respective heredity without a convergent homogenization trend, and reduces the possibility that the host range of the caterpillar isolates could expand and enhance their virulence in B. mori. These findings indicate that the use of B. bassiana does not threaten the safety of sericulture.

Mathematical Modelling of Beauveria Bassiana

The isolate of white muscardine, Beauveria bassiana was isolated from soil using SDAY media. The experiment was studied under submerged culture in selective broth at varied interval of days, in view of dry weight of hyphal biomass. In this presentation we want to introduce a mathematical growth model of Beauveria bassiana and the perspective of stochastic analysis of this fungus and compare with experimental data.

Biopesticidal Formulation Of Beauveria Bassiana Effective Against Larvae Of Helicoverpa Armigera

The present study was to emphasize entomopathogens in pest management of cash crops over chemical pesticides, optimization of media for growth of Beauveria bassiana and bioassay of different formulations for their efficacy as marketable and easily applicable biopesticide. Beauveria bassiana (Order: Hypocreales, Family: Cordycipitaceae) popularly known as white muscardine entomogenous fungi was isolated from soyabean fields of Misrod, Bhopal. Media for optimal growth of fungus were standardized. Its different formulations viz. carrier based powder formulation, oil based formulation and bentonite oil based formulation using homogenizers were prepared. These formulations were bioassayed against Helicoverpa armigera (Order: Lepidoptera, Family: Noctuidae), the most destructive pest in soyabean. Bentonite based liquid formulation was observed to be most effective as determined by measuring larval mortality as well as viability of fungal spores and ease of applicability.

Efficacy of Systemic Fungicides for Control of White Muscardine in Tasar Silkworm, Antheraea mylitta D.

Efficacy of Systemic Fungicides for Control of White Muscardine in Tasar Silkworm, Antheraea mylitta D.