19 research outputs found
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Not AvailableNWith the ever-increasing awareness of the harmful effects of the chemical on man and his environment, the immediate need for sustainable, eco-friendly pest management has been felt very strongly providing an impetus to research and development of microbial pesticides. The approach to pest management has seen a significant change over the years from chemical control to integrated pest management with emphasis currently on Bio-intensive integrated pest management. The shift in this paradigm is the outcome of the search for eco-friendly pest management strategies driven by the impact of the ill effects of injudicious use of chemical pesticides on human health and environment. Among the different microbial agents developed and tested, bacteria, viruses and fungi are considered promising for the control of insect pests. Mass production of the promising entomopathogens holds the key for promoting their large scale field use for insect pest management. Mass production of the insecticidal bacterium Bacillus thuringiensis and the entomopathogenic fungus Nomuraea rileyi are discussed .ICA
Exploitation of Nomuraea rileyi and Beauveria bassiana for the management of lepidopteran pests.
Not AvailablePest management in agriculture started leaning towards biocontrol options for increasing agricultural production, sustaining the health of farmers and environment. Entomopathogenic fungi are potential biocontrol agents due to their infectivity by contact unlike bacteria or viruses which infect after ingestion. Nomuraea rileyi (Farlow) Samson and Beauveria bassiana (Balsamo) Vuilemin are potentially versatile fungi because of their wide spread occurrence, broad host ranges, ability to infect at different stages of their hosts and cause natural epizootics on major lepidopteran pests. Recent advances in large-scale in vitro production, formulation and application technology have resulted in commercial availability of several mycoinsecticide products based on B. bassiana and N. rileyi. These formulations provide good control of pests and are being used as biocontrol agents in various crop ecosystems with minimal effects on non-targets. Combination formulation of B. bassiana and Bacillus thuringiensis lowered the dose requirement and improved the speed of kill. Improving our understanding on the mode of action of the fungi at cellular and molecular level, exploiting secondary metabolites of the fungi to develop natural insecticides, refinement of formulation and application technology, and use of nanotechnology for improved delivery and persistence will enable us to utilize these fungi more effectively as well as economically under varied agro-climatic conditions. This chapter brings together the information generated on various aspects of N. rileyi and B. bassiana, their biocontrol potential in insect pest management as mycoinsecticides, registration requirements and regulatory approaches for commercial exploitation of these entomopathogenic fungi.Not Availabl
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Not AvailableA local strain DOR Bt-1 belonging to Bacillus thuringiensis var. kurstaki (Bt.k)
was multiplied through solid state fermentation and the resulting technical powder
was milled and sieved to obtain particles of various sizes. Efficacy of Bt.k. against
larvae of Helicoverpa armigera was found to increase with the decrease in
particle size. Boric acid was found to be synergistic to DOR Bt-1 technical powder.
LC50 of the Bt and boric acid mixture (75:25) was lower at 89.63 mg/100 mL
in comparison to Bt alone at 116.75 mg/100 mL. A suspension concentrate
formulation with DOR Bt-1 technical was developed using boric acid as an
adjuvant. The formulation was found to be highly effective against H. armigera in
laboratory bioassays with an LC50 of 185 μL (containing 53.36 mg Bt). The
formulation gave effective control of H. armigera on sunflower within 3 days after
spray even at the lowest dose of 1.0 mL/L under field conditions.ICA
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Not AvailableScreening 50 isolates of Bacillus thuringiensis (Bt) kurstaki from soil samples of Rajasthan and Telangana states, India led to identification of 10 isolates promising against the polyphagous pests
Spodoptera litura (Fabricius) and Helicoverpa armigera (Hübner). Rep-PCR revealed distinctness of one isolate DOR Bt-127 with cry1Ac, 1Ae, 1C, 1E, 2Aa, 2Ab genes coding for toxins effective against a wide range of insect pests. Spore-crystal mixture of Bt-127 had a high spore count of 9 × 1022/g and delta endotoxin content 18.28%, possessed bipyramidal crystals (0.64–2.12 µm) and ellipsoidal spores (1.92–2.2 µm). SDS-PAGE resulted in a 62 kDa band corresponding to the Cry1 toxin. Potencies against the less susceptible pests S. litura and S. exigua (Hübner) were 71309 and 46205 SU/mg, respectively while potencies against the susceptible pests H. armigera, Plutella xylostella (Linnaeus) and Achaea janata (Linnaeus) were 35844, 26571 and 51667 IU/mg, respectively. DOR Bt-127 holds great promise for management of these important pests overcoming the need for using different Bt varieties.AMAA
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Not AvailableField persistence of SC formulations of Bacillus thringiensis singly and in combination with entomopathogenic fungi against lepidopteran pests in oilseeds ecosystem.Not Availabl
Insect Pests of Castor (Ricinus communis L) and their Management Strategies
Not AvailableCastor is an industrially important non-edible oilseed crop belonging to the family Euphorbiaceae. Development of location-specific varieties and hybrids with appropriate crop production technologies led to increased production and productivity of the crop. However, cultivation of the crop under input-intensive conditions resulted in increased vulnerability of the high yielding cultivars to a multitude of insect pests attacking the crop at all phenological stages and includes seedling pests, foliage feeders and inflorescence pests. The red hairy caterpillar in endemic areas, the defoliators, viz., castor semilooper, Spodoptera and other hairy caterpillars, and sucking pests, such as jassid, whitefly, thrips and mites, cause huge damage to castor crop. Yield loss estimates indicate a reduction of seed yield up to 35-50% depending on the crop growth stage and the pest outbreak. Several insect pest management tactics are being developed for control of the major pests and includes cultural, biological, insecticidal and combinations of two or more methods, which are employed at three stages of prevention, observation, and intervention. In the recent past, attempts are directed towards formulation of potent microbial pesticides besides development of genetically modified castor. This chapter deals with the biology of major insects attacking castor along with the control methods being adopted, and gaps in the knowledge of pest management strategies that need to be addressed are discussed.Not Availabl
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Not AvailableStudies were conducted to evaluate the efficacy of microbial [combination formulation of Beauveria bassiana + Bacillus thuringiensis var. kurstaki (Btk), indigenous and commercial formulations of Btk], botanical (karanj oil and neem seed kernel extract) and chemical (profenofos) insecticides against semilooper (Achaea janata) and capsule borer (Conogethes punctiferalis) in castor. In laboratory bioassay, Btk (Delfin®) @ 1g/L, combination formulation of B. bassiana + Btk @1.25 ml/L and 2 ml/L effected 100% mortality in third instar larvae of semilooper 48h after treatment as compared to 100% mortality by profenofos @ 1ml/L at 24h after treatment. Btk @1g/L and combination formulation of B. bassiana + Btk @ 2ml/L were found effective in reducing semilooper population (97.5% and 91.0% larval reduction over untreated control) and at par with profenofos (100% reduction over control) in field trial. However, their efficacy in reducing capsule borer damage (39.2 and 27.8% reduction over control, respectively) and seed yield obtained (1897 and 1836 kg/ ha, respectively) was significantly lower than profenofos (53.6% reduction in capsule damage and seed yield of 2036 kg/ha) but superior over botanicals. Cocoons of larval parasitoid of semilooper, Snellenius (Microplitis) maculipennis were more in numbers in microbial and botanical treatments compared to profenofos. The microbial formulations viz., combination formulation of B. bassiana + Btk and Btk can be opted for inclusion as a component in the Integrated Pest Management in castor.Not Availabl
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Not AvailableMicroencapsulation of Beauveria bassiana (Bb) conidia with
sodium humate (SH) was undertaken successfully through spray
drying at a high inlet air temperature of 175 C with corresponding
outlet air temperature of 86.5 1.3 C using 0.2% SH. The obtained
product was a free-flowing, dark-brown powder containing microcapsules
of Bb conidia coated with sodium humate (Bb-SH). These
microcapsules measured 2.47–3.57 lm and possessed an uneven,
fluffy surface. The colony-forming units (CFU) of Bb-SH microcapsules
spray-dried at 175 C were 21.54 LCFUg 1, on par with 21.59
LCFUg 1 for Bb conidial powder not subjected to spray drying.
Bb-SH microcapsules resulted in a high mortality of 93.0% against
six-day-old Helicoverpa armigera larvae within five days after treatment.
Bb-SH microcapsules readily dispersed in water, releasing
sodium humate from the conidial surface. Germination of conidia
was not affected by sodium humate as visualized by scanning electron
microscopy of the cuticular surface of treated larvae. Bb-SH microcapsules
showed good viability (21.11 LCFUg 1) at the end of six
months of storage at room temperature ( 30 ). Thus, sodium
humate is a promising biopolymer for encapsulation of Bb conidia
for extended shelf-life at room temperature.Not Availabl