جستجوی مقالات مرتبط با کلیدواژه "wettable powder" در نشریات گروه "گیاهپزشکی"

The purpose of this study was to determine the effect of some additives on stability and suspensibility of wettable powder (WP) formulation of Bacillus thuringiensis (Bt) in laboratory products (optimized formulation) and commercial formulations. For preparation of optimized formulation; sucrose, lactose, sodium alginate, coconut fiber and aluminum silicate were added to the dried powder of bacterial product in two different treatments; which were different in aluminum silicate (optimized formulation 1) and coconut fiber (optimized formulation 2). The efficacy and toxicity of wettable powders were tested on diamondback moth, Plutella xylostella (L.) (Lep.: Plutellidae) larvae. The results of various tests for stability showed that the additives had positive effects on the storage life of the optimized formulation. The suspensibility of the optimized formulations (70%) was significantly higher than those of the commercial formulations. Our results showed that adding sucrose in both commercial products caused an increase in toxicity (lower LC50s), whereas, the suspensibility parameter varied depending on the type and feature of the products. In conclusion, selecting low-cost and available additives would improve the physical and biological characteristics of Bt formulations, which has a significant effect on the development and application of biopesticides.

The objective of the present study was to optimize awettable powder formulation for twoiranianBtstrains (YD5 and KH4) in order to enhance efficiency and durability as biological agent against lepidopteran and coleopteran pests.Mass production of the mentioned strains was done in a batch fermentor based on the peviouselyoptimized economical medium and fermentation conditions, and the final concentration was achieved 6 ×109(CFU/mg). To optimize formulation for the strains, 25% spore crystal mixture of the strain and 75% adjuvants including different fillers, surfactants, materials enhancing durability, anti UV materials, suspensors, wetters, palatability materialsand antimicrobial materials in the framework of 5 statistical treatments were used.Based on the results, the treatment containing milk powder (4%), perlite (6%), irosile (2%), sodium loril sulfate (8%), Alkaline naphthalene (20%), starch (10%), gelatin (9%), sugar (10%), potassium surbate (1%), Casein and gluten (2%), potassium dioxide (3%) and monosodium glutamate (0/2 %) showed maximum suspensibility (73 and 71 %) and wetability (25 and 24%) for YD5 and KH4 strains, respectively, and selected for the next experiments. The selected formulation for both strains had a white to grey color, 6-7 % moisture content, and pH6.1 and 6.2. Crystals in both formulations were stable whithout any changes during one year. The LC50 of the selected formulation for YD5 and KH4 strains againstlarvae cotton bollworm and elm leaf beetle was 550 and 510 ng/cm2 leaf, respectively.

German cockroach، Blattella germanica (L.) is a major worldwide household insect pest. Cockroaches play an important role as mechanical vector agents of pathogens. Also، their secretions act as main allergens of allergic diseases like asthma. The use of various formulations of conventional insecticides remains an integral part of pest management programs for the German cockroach. Contact toxicity of three commercial formulations of lambda-cyhalothrin including wettable powder (ICON® 10 WP)، microcapsule (DEMAND® 10 CS) and emulsifiable concentrate (ICON® 5 EC) were examined against first instar nymphs of B. germanica. Experiments were conducted at 27±2 ºC، 60±10% R. H and a photoperiod of 12:12h (L: D). Six concentrations of each formulation were assayed by ten replications. The mortality of nymphs was increased as consequence of rising the concentrations. The WP formulation had the most effectiveness and its LC50 value was 4. 99 mg ai. m-2. The CS and EC formulations attained LC50 values of 5. 81 and 6. 98 mg ai. m-2، respectively. The results demonstrated that the WP formulation had highest potential for control of the German cockroach.

Formulation of blastospores of entomopathogenic fungi may help to overcome unfavorable climatic conditions and may increase their effectiveness. In the present study, different products of wettable powder of blastospores were prepared for two isolates of Beauveria bassiana and were stored at two different temperature regimes, refrigerator (4±1°C) and laboratory (24±3°C) conditions. After storage durations (24 hours and 30 days), their effects were investigated against second instar larvae of the onion thrips. Results indicated that mortality percent of thrips larvae in blastospore's treatments maintained in laboratory (BML), blastospore's treatments maintained in refrigerator (BMR), new formulated blastospore (NFB) and new blastospore )NB) in 108 spore/ml concentration were 66, 89.4, 92.7 & 91% in B. bassiana EUT105 and 70, 93, 89.8 & 91 % in B. bassiana EUT116, respectively. These results indicated positive effects of storing at low temperature on preserving high viability in treatments maintained in refrigerator than those maintained in the laboratory. The results of this study can be valuable base for research on increasing stability and efficacy of fungal spores, changing or replacement of carrier ingredients in our country.