The effect of polymers on the stability of microencapsulated formulations ofBacillus thuringiensissubsp.kurstaki(Bt-KD2) after exposure to Ultra Violet Radiation

Khorramvatan, Soodeh; Marzban, Rasoul; Ardjmand, Mehdi; Safekordi, Ali Akbar; Askary, Hassan

doi:10.1080/09583157.2013.871503

Cited by 22 publications

(14 citation statements)

References 22 publications

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“…Cohen et al (1991) tested the effect of ultraviolet irradiation at 300-350 nm of Bt where its activity decreased to 70 and 95%, after 6 and 12 h from irradiation, respectively. Khorramvatan et al (2014) found that the activity of Bt decreased to 50 and 40%, respectively after 1 h from exposing to ultraviolet irradiation at 245 and 385 nm. Moreover, the same authors found that the addition of UV protectants could reduce photo degradation and reported that addition of sodium alginate to Bt formulations decreased of UV effect, as also the degradation rate is changed by changing the concentration of solutions that exposed to UV light.…”

Section: Photo Degradation Under Uv Lightmentioning

confidence: 99%

“…The suspensions from the two Bt formulation samples were prepared in a clear bottle. These samples were exposed directly to UV light inside the box for 1, 2, and 4 h according to Talkhan et al (2013) and Khorramvatan et al (2014). At the end of time, samples were collected and analyzed.…”

Section: Photo Degradation By Uv Lightmentioning

confidence: 99%

“…In addition, these products are not stable under natural environmental stresses such as temperature, ultra violet (UV) radiation, and sunlight. Radiation from sunlight or UV light is the main limitation that obviously reduced the potency of Bt crystals against different insect pests ( Dunkle and Shasha 1988;Ignoffo 1992;Khorramvatan et al 2014). …”

Section: Introductionmentioning

confidence: 99%

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Influence of some environmental conditions on stability and activity of Bacillus thuringiensis formulations against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Moustafa

Saleh

Ateya

et al. 2018

Egypt J Biol Pest Control

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The entomopathogenic bacterium Bacillus thuringiensis (Bt) has been used in crop protection for the last 70 years; however, many environmental conditions affect its activity. The present study was directed to evaluate the influence of certain environmental conditions on stability and activity of Bt samples of the two commercial formulations (Dipel 2 × 6. 4% WP and Protecto 9.4% WP), when stored under accelerated hot storage, shelf, and outdoor storage. Photo degradation of the two formulations was studied in aqueous solution. The results revealed that the loss percentage of Protecto formulation was above the permissible limits of WHO specifications after 2 years of storage at ambient conditions and the thermal stability of the Bt was affected negatively depending on the storage periods. In accordance with this trend, the bioassay tests versus neonate and second instar larvae of the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), showed a decrease in toxicity of the formulations to (60%) after storage at 35 ± 2°C for 12 weeks and about (70%) after storage under sunlight for 2 days. Photolysis of aqueous solutions reduced the half-life of formulations by about 1-2 days. The stability of Bt should be evaluated prior to submission for registration as these products have showed less stability under storage at ambient conditions. The stakeholders and decision-makers can utilize these results and examine such products case by case.

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Section: Photo Degradation Under Uv Lightmentioning

confidence: 99%

Section: Photo Degradation By Uv Lightmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of some environmental conditions on stability and activity of Bacillus thuringiensis formulations against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Moustafa

Saleh

Ateya

et al. 2018

Egypt J Biol Pest Control

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“…Además del uso de fagoestimulantes un formulado requiere un soporte inerte para el ingrediente activo, el cual generalmente es un polímero (Rosas-García, 2008). Los polímeros como la gelatina, almidón, celulosa, alginatos, entre otros han sido de los más extensamente estudiados para la miscroencapsulación debido a sus excelentes propiedades como su biocompatibilidad y baja toxicidad (Khorramvatan et al, 2014).…”

Section: Media Del Número De Larvas ± Eeunclassified

“…kurstaki se ha reportado como un agente eficaz para el control de H. cunea (Saruhan et al, 2014). Sin embargo, la mayoría de los entomopatógenos no son estables en condiciones ambientales y están sujetos a daños por la radiación UV, lluvias, temperaturas desfavorables, entre otros (Khorramvatan et al, 2014); entonces es necesario recurrir a procesos de formulación altamente eficaces para asegurar la persistencia del ingrediente activo. El método de secado por aspersión utilizado para encapsular compuestos es económico, flexible, y se obtienen partículas uniformes de buena calidad, donde el material activo queda atrapado dentro de una matriz protectora.…”

Section: Introductionunclassified

ROENCAPSULACIÓN DE Bacillus thuringiensis (BERLINER) EN MATRICES BIOPOLIMÉRICAS CON SECADO POR ASPERSIÓN PARA EL CONTROL DE Hyphantria cunea (DRURY)

Palacios-Cortez

Gandarilla-Pacheco

Morales-Ramos

et al. 2022

Trop Subtrop Agroecosyst

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Background. The formulation of agents of biological origin with insecticidal activity is one of the most effective methods for the control of lepidopteran pests due to their feeding forms. The insecticidal activity of B. thuringensis is widely known, which is why it is believed that native strains of this bacillus could have toxic activity on larvae of the cobweb worm, H. cunea. Objective. To prepare by means of the spray drying technique microencapsulated formulations of a native strain of B. thuringensis with toxic activity on H. cunea. Methodology. The experimental design was completely randomized and the means were compared with the Tukey test (p ≤ 0.05). The strain selected for the formulation is a key Mexican strain GM-10 belonging to the aizawai variety and presented an LC50 of 0.007 ng cm-2 in artificial diet, and a LT50 of 80.83 h. To prepare the formulations, a phago-stimulant was first selected by means of food preference tests with powdered leaves of walnut, blackberry, ash, loquat and walnut shell powder and a commercial phage-stimulant (Coax®), and ash was selected with 61.4% of the larvae attracted. Once the phagostimulant was selected, encapsulated formulations were developed with a mixture of polymers (Capsul®-bovine gelatin), as a base. Several formulations were then made to select an adhesion additive, and the ingredients tested were guar gum, core® gum and xanthan gum. Results. Food preference bioassays to establish the affinity of H. cunea for some of the formulations showed that the larvae had a similar affinity for feeding on all formulations (p ≥ 0.05), while in the trials to select an adherent for the formulation xanthan gum presented the best adherence (p ≤ 0.05). Implications. The evaluated formulations preserved their toxic activity after microencapsulation with an LC50 of less than 0.05 ng cm-2 of B. thuringensis. Conclusion. These results show the feasibility of using the spray drying method to obtain an effective formulation for the treatment of the immature stages of H. cunea.

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Microbial Biopecticides: Opportunities and Challenges

Moosavi

Minassian

2021

Progress in Biological Control

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The effect of polymers on the stability of microencapsulated formulations ofBacillus thuringiensissubsp.kurstaki(Bt-KD2) after exposure to Ultra Violet Radiation

Cited by 22 publications

References 22 publications

Influence of some environmental conditions on stability and activity of Bacillus thuringiensis formulations against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Influence of some environmental conditions on stability and activity of Bacillus thuringiensis formulations against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

ROENCAPSULACIÓN DE Bacillus thuringiensis (BERLINER) EN MATRICES BIOPOLIMÉRICAS CON SECADO POR ASPERSIÓN PARA EL CONTROL DE Hyphantria cunea (DRURY)

Microbial Biopecticides: Opportunities and Challenges

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