Bacillus subtilis SPB1 biosurfactant: Production optimization and insecticidal activity against the carob moth Ectomyelois ceratoniae

Bacillus subtilis SPB1 was shown to produce a lipopeptide biosurfactant. The insecticidal activity of this biosurfactant was evaluated against Ectomyelois ceratoniae Zeller, a moth pest of stored dates in Tunisia. The LC₅₀ and LC₉₀ values after six days of contact were 152 μg/g and 641 μg/g, respectively. To promote an economical production of this highly effective bioinsecticide, statistical experimental designs and response surface methodology were employed to optimize the concentrations of agro-industrial residues and humidity, for lipopeptide biosurfactant production by B. subtilis SPB1 under solid state fermentation. The optimal medium leading to a production yield near to 28 mg of crude lipopeptide preparation per g of wet solid material was composed of a mixture of 4.34 g of tuna fish flour and 5.66 g of potato waste flour with a moisture content of 76%.     

Comparison of spinetoram,imidacloprid, thiamethoxam and chlorantraniliprole against life stages of Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on concrete

Spinetoram, imidacloprid, thiamethoxam and chlorantraniliprole are new insecticides with novel mode of actions, low mammalian toxicity and low impact to environment. In the present study, the efficacy of these insecticides was tested against Tribolium confusum Jacquelin du Val on concrete. Among the tested insecticides, spinetoram proved to be more effective, providing complete control of T. confusum adults and young larvae after 14 days of exposure. For the young larvae, thiamethoxam at the highest dose and chlorantraniliprole at both doses were equally effective with spinetoram. On the other hand, none of the tested insecticides were able to control T. confusum pupae. Moreover, none of the insecticides had ovicidal effect, with the exception of chlorantraniliprole in some combinations. From the mobile life stages, the most tolerant life stages were old larvae and the most susceptible young larvae. The presence of food (flour) moderated T. confusum mortality. From the results of the present study, we can conclude that spinetoram, thiamethoxam and chlorantraniliprole showed potential and need be further evaluated for surface treatments in stored product facilities. Our work underlined the need for good cleaning and sanitation procedures in warehouses and food processing facilities.     

Induction of a malathion-resistant strain in the common predacious mite Amblyseius cydnodactylon (Acari: Phytoseiidae)

This study demonstrates a laboratory induction of a malathion - resistant strain in Amblyseius cydnodactylon Shehata & Zaher and effect of selection on reproduction. Initially 500 sensitive females obtained from a laboratory mass culture were exposed to malathion at LC70. Subsequent selections were conducted every two generations at progressive LC70 values and number of eggs/female/day was recorded at each selection. Experiments were carried out under laboratory conditions of 24-28°C and 70-80 % R. H. The LC70 in the parent generation was 5.19 ppm and increased to 20 ppm in F4 selection generation. The dosage mortality relationships continued to increase up to a maximum of 282.3 ppm in F16. The rate of developing resistance increased from 1.75 folds in F2 to 1.97 folds in F4 and gradually reached a maximum of 54.39 folds in F16. There was an obvious decrease in reproduction corresponded to increasing resistance. For example, the number of eggs/female/day in F 16 was 8 eggs, contrasting 3 eggs in the parent generation.     

宁夏襀叉科(襀翅目)二新记录种记述(英文)

文章记述了宁夏襀叉科二新纪录：乳突倍叉襀Amphinemura mamillata和刀突原叉襀Protonemura macrodyctala。乳突倍叉襀的主要特征为第九背板后缘中部形成两个乳状突起，其上着生许多小刺，肛侧突外叶近端部膨大，有刺，并与中叶相连，中叶端半部沿外缘有数列黑刺，中部向上强烈弯曲。刀突原叉襀的主要鉴征为肛上突端部向前延伸形成刀状的刺突，背骨片端部外缘有两簇黑刺，且肛侧突外叶端部有1～3根明显的黑刺。观察标本保存在中国农业大学标本馆。     

Optimization of germination conditions to enhance hydroxyl radical inhibition by water-soluble protein from stress millet

This study aimed to further increase the yield of the hydroxyl radical inhibitory water-soluble protein from stress germinated millet. For this, the effects of the sprouting conditions (temperature, time and pH of stress medium) on the hydroxyl radical inhibition were investigated carefully by single-factor experiments and statistical experimental designs, which included a fractional factorial design, steepest ascent experiments, a central composite experimental design and response surface methodology. The optimal conditions were identified as temperature 28 °C, culture time 54 h and stress medium pH 7.5. Under the optimum conditions, the highest inhibition (60.38%) was achieved.     

性信息素诱捕防治棉红铃虫

1980～1981年在浙江海盐和上虞进行了性信息素诱捕防治棉铃虫的大田试验。面积分别为3500、3000亩。试验证明,每亩设置3～4只诱捕盆的大面积诱捕防治能明显降低田间红铃虫雌蛾的交配率(下降68.2～96.7%),棉株受害程度也减轻,与常规农药防治的对照相比,花害率下降42.4～78.9%,铃害率下降30.3～54.4%,同时还减少了用药次数,间接起到保护天敌、减少环境污染的作用。因此认为,性信息素诱捕法有可能作为棉红铃虫综合防治中的一项有效措施。     

Ethylene sensitivity and changes in ethylene production during senescence in long-lived Delphinium flowers without sepal abscission

We investigated changes in ethylene production, sensitivity, effects of ethylene inhibitors and levels of ethylene receptor genes to determine factors responsible for long-lived flowers in a Delphinium line ‘B-10’. Flower longevity of ‘B-10’ was clearly longer than that of the control cultivar ‘Bellamosum’, and sepals of ‘B-10’ did not abscise. ‘B-10’ did not show the climacteric-like ethylene production during flower senescence but constitutively produced ethylene from days 0 to 9. The ethylene inhibitors silver thiosulfate (STS) and aminoethoxyvinylglycine (AVG) extended flower longevity in both cultivars. Exogenous ethylene treatment did not affect flower longevity but did increase ethylene production in ‘B-10’. These results suggest that low sensitivity to ethylene is responsible for long-lived ‘B-10’ flowers, and may suppress climacteric-like ethylene production.     

Prediction of watermelon quality based on vibration spectrum

Judging watermelon quality based on its apparent properties such as size or skin color is difficult. A non-destructive method is employed here, based on vibrational response spectrum, to determine the quality indices of watermelon (Charleston gray). The responses of samples to vibration excitation were recorded by laser Doppler vibrometry (LDV). The phase shift between input and output signals were extracted over a wide frequency range. The total soluble solids (TSS), titratable acidity (TA) and TSS/TA ratio also measured as watermelon quality characters. Stepwise multiple linear regression (SMLR) as well as partial least square regression (PLS) was applied to extracted vibration spectrums to construct prediction models of watermelon quality. The results showed that performance of SMLR models were better than PLS. The determination coefficients (R²) of SMLR validation models were 0.9976, 0.9985 and 0.9542 for TSS, TA and TSS/TA respectively. It is likely that reduction of cell wall materials to soluble solids during ripening process changes viscoelastic properties of watermelon reflected by vibrational response. This study demonstrated the feasibility of mentioned method for predicting the quality of watermelons in an industrial grading system.     

Metabolism of fenitrothion by organophosphorus-resistant and -susceptible house flies, Musca domestica L

The metabolism of fenitrothion was investigated in highly resistant (Akita-f) and susceptible (SRS) strains of the house fly, Musca domestica L. The Akita-f strain was 3500 times more resistant to fenitrothion than the SRS strain. Fenitrothion, topically applied to the flies, was metabolized in vivo far faster in the Akita-f strain than in the SRS strain. In vitro studies revealed that fenitrothion was metabolized by a cytochrome P-450-dependent monooxygenase system and glutathione S-transferases. The former oxidase system metabolized fenitrothion in vitro into fenitrooxon and 3-methyl-4-nitrophenol as major metabolites, and into 3-hydroxymethyl-fenitrothion and 3-hydroxymethyl-fenitrooxon as minor metabolites. Glutathione S-transferases metabolized fenitrothion into desmethylfenitrothion. The cytochrome P-450-dependent monooxygenase system and glutathione S-transferases of the resistant Akita-f strain had 1.4 to 2.2 times and 9.7 times, respectively, as great activities as those of the susceptible SRS strain. These results suggest the importance of glutathione S-transferases in fenitrothion resistance in the Akita-f strain.