首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Insecticides can have consequences for beneficial arthropods. Insect parasitoids can contact insecticides through direct exposure spray droplets or residues on crop foliage. Here, we focus on better understand the response of Meteorus pulchricornis (Wesmael), a parasitoid wasp of lepidopteran pests, and its detoxification mechanisms on stress caused by phoxim and cypermethrin. Hence, we determined the dose–mortality curves and estimating the sublethal concentrations (LC30 and LC50). Then, we applied the sublethal concentrations against adult parasitoids to assess its survival, parasitism efficacy, and also developmental and morphometric parameters of their offspring. Simultaneously, we check the activities of glutathione S-transferase (GST), acetylcholinesterase (AChE), and peroxidase (POD) after sublethal exposure of both insecticides, which has measured until 48 h after treatment. Overall, phoxim and cypermethrin exhibited acute lethal activity toward the parasitoid with LC50 values 4.608 and 8.570 mg/liter, respectively. Also, we detect that LC30 was able to trigger the enzymatic activity of GST, AChE, and POD, suggesting a potential detoxification mechanism. However, even when subjected to sublethal exposure, our results indicate strong negatives effects, in particular for phoxim, which has affected the parasitism efficacy and also the developmental and morphometric parameters of M. pulchricornis offspring. Therefore, it can be concluded that both phoxim and cypermethrin have negative impacts on M. pulchricornis and we suggest cautioning their use and the need for semifield and field assessments to confirm such an impact.  相似文献   

2.
《Crop Protection》1986,5(5):355-357
The toxicity of six synthetic pyrethroids, permethrin, cypermethrin, flucythrinate, fenvalerate, cyfluthrin and deltamethrin, were evaluated on two populations of potato tuber moth (PTM) Phthorimea operculella (Zeller) in Peru. Deltamethrin was most toxic with an LC50 of 120 μg/ml for male PTM from La Molina and 137 μg/ml for female PTM from San Ramon. Fenvalerate was least toxic and the other four insecticides were intermediate in toxicity. At field recommended concentrations (0·05-0·04%) none of the six synthetic pyrethroids were effective on the two populations tested.  相似文献   

3.
Cyantraniliprole 200 mg ai l−1 (Cyazypyr™ 200 SC) is a new xylem systemic insecticide in the anthranilic diamide chemistry class. A systemic laboratory bioassay using cut stems of cotton seedlings was developed to quantify the baseline susceptibility of nymphs and adults of the sweet potato whitefly, Bemisia tabaci (Genn.) biotype B, to cyantraniliprole. Bioassays were conducted on a susceptible laboratory colony and nine field populations collected in 2008, 2009 and 2010 in southern Florida. Bioassays with cyantraniliprole on the susceptible colony (targeting nymphs with exposure initiated at the egg stage) revealed pooled LC50 and slope values of 0.017 mg ai l−1 and 1.766 (SE = 0.125) in 2008, respectively, and 0.013 mg ai l−1 and 1.355 (SE = 0.156) in 2009, correspondingly. Adult bioassays generated pooled LC50 and slope values of 0.049 mg ai l−1 and 3.201 (SE = 0.367) in 2010, respectively. LC50 and slope values targeting nymphs (as above) of field populations ranged from 0.013 to 0.023 mg ai l−1 and 1.425 (SE = 0.167) to 1.923 (SE = 0.187), respectively, in 2008, and 0.023 to 0.034 mg ai l−1 and 1.682 (SE = 0.140) to 2.318 (SE = 0.226), respectively, in 2009. Resistance ratio values at 50% mortality (RR50) on nymphs of field colonies ranged from 0.784 to 1.346 in 2008 and from 1.760 to 2.589 in 2009. Bioassays with adult field populations yielded LC50 and slope values ranging from 0.037 to 0.059 mg ai l−1 and 2.639 (SE = 0.561) to 6.948 (SE = 1.294), respectively, in 2010. The RR50 values for adults from field colonies ranged from 0.752 to 1.207. The overlapping fiducial limits of the LC50 values, the low RR50 values, and the lack of significant differences in the slopes of probit lines between laboratory and field colonies, indicate that the B. tabaci populations present in southern Florida fields were highly sensitive to cyantraniliprole. These data will be helpful in monitoring for any changes in susceptibility as a result of use of the insecticide. The baseline information developed in the present study confirmed the susceptibility of field populations in Florida to cyantraniliprole and will be an essential component of a resistance management program to help ensure the continued viability of cyantraniliprole for B. tabaci management.  相似文献   

4.
The earthworm Eukerria saltensis can cause severe crop establishment problems in aerially sown rice grown on heavy clay soils in southern Australia. Damage occurs indirectly through destabilization of the topsoil, increased water turbidity, and mobilization of soil nutrients into the water column which leads to increased algal growth. We investigated the possibilities for chemical control of E. saltensis using laboratory bioassays and a series of field trials involving either the use of enclosures in flooded crops or soil incorporation of pesticides into rice fields during fallow periods or shortly before flooding. The four most toxic compounds in 7 day soil/water laboratory bioassays were carbofuran, acetamiprid, bendiocarb and lambda-cyhalothrin which provided corrected mortalities of 86–100% at 2 mg a.i. L−1. Other compounds that showed some level of efficacy (corrected mortality >20% at one or more rates) were imidacloprid, esfenvalerate, thiacloprid, niclosamide and alpha-cypermethrin. Twenty-six of the 38 pesticides evaluated failed to produce mean corrected mortalities >6% at application rates of up to 2 mg a.i. L−1. Eight trials were conducted in flooded rice crops using small stainless steel enclosures and carbofuran, thiodicarb, niclosamide and bendiocarb at rates of 1 and 2 kg a.i. ha−1. Trials were assessed 8–14 days after chemical application. None of these treatments produced a statistically significant decrease in Eukerria biomass, although consistent downward trends in response to higher treatment rates were evident in 2 trials (one with carbofuran and one with bendiocarb). Three trials with liquid pesticides watered into fallow rice fields were conducted with carbofuran (0.5, 1.0 and 5.0 kg a.i. ha−1) and thiodicarb (0.94 and 1.87 kg a.i. ha−1) however only the 5.0 kg a.i. ha−1 carbofuran treatment provided significant (P < 0.05) levels of control. Preflood soil applications of liquid carbofuran, thiodicarb and niclosamide (2 kg a.i. ha−1), granular carbofuran and granular ethoprophos (0.5–2 kg a.i. ha−1) also did not provide statistically significant levels of control, although the 2 kg a.i. ha−1 liquid and granular carbofuran treatments did provide moderate levels of suppression (49–84%). Although further field trials with compounds such as acetamiprid and lambda-cyhalothrin may prove valuable, our results suggest chemical control of E. saltensis may be difficult to achieve with environmentally acceptable pesticides applied at economically viable rates. Cultural approaches such as appropriate crop rotations and landforming to ensure uniformly shallow water should continue to form the basis of Eukerria management programs.  相似文献   

5.
Toxicities of the eight quinones were evaluated through leaf dip bioassays conducted against Tetranychus urticae, Myzus persicae, Myzocallis walshii, and Illinoia liriodendri. Based on LC50 values, plumbagin (LC50 = 0.001%) was the most active compound against T. urticae and ubiquinone Q0 (LC50 = 0.005%), plumbagin (LC50 = 0.010%), and dibromothymoquinone (LC50 = 0.012%) were the most active compounds against M. persicae. The most active compounds against M. walshii were juglone (LC50 = 0.011%) and ubiquinone Q0 (LC50 = 0.019%), whereas dibromothymoquinone (LC50 = 0.030%), plumbagin (LC50 = 0.033%) and ubiquinone Q0 (LC50 = 0.058%) were the most toxic to I. liriodendri. Ecotrol (positive control) was the least toxic compound (LC50 = 0.39%) against T. urticae and M. persicae (LC50 = 0.447%). Although the majority of the compounds tested were toxic to all four test species in residual bioassays, there was little overlap among the test species in terms of susceptibility to the compounds and interspecific differences were observed. Regarding structure-activity relationships for quinones, the addition of a hydroxyl group resulted in a significant increase in the toxicity of the 1,4-naphthoquinones, and those possessing a methyl group exhibited the highest levels of activity in T. urticae. The bromine atom at the 2- and 5-positions of the benzoquinone ring is crucial to the toxicity of the compounds against I. liriodendri. Toxicity was greatly affected not only by the number of hydroxyl groups, but also by their positions in the ring in the case of M. walshii. Juglone and plumbagin as residual toxins in the laboratory also reduced the population of two-spotted spider mites compared to EcoTrol™ (positive control) and the negative control in the greenhouse experiment. Some quinones tested may have potential as commercial insecticides and miticides, or alternatively, could serve as lead compounds for the development of more potent crop protection agents.  相似文献   

6.
The cotton bollworm Helicoverpa armigera (Hubner) is one of the most destructive pest insects in Iran and many other countries. In this study, lethal and sublethal effects of methoxyfenozide, and thiodicarb were evaluated against H. armigera larvae that fed on insecticide-treated artificial diet. The effects of methoxyfenozide and thiodicarb were assessed in 3rd instars. Methoxyfenozide and thiodicarb showed LC50 values of 4 and 639 mg a.i./ml, respectively, in H. armigera larvae. Sublethal effects on development, adult longevity, and reproduction were observed in H. armigera larvae that survived exposure to an LC30 of the insecticides. Larvae that were exposed to an LC30 concentration of methoxyfenozide exhibited lower pupal weight and increased larval and pupal developmental times compared with thiodicarb treated larvae or control larvae. Adults that were exposed as larvae to an LC30 concentration of methoxyfenozide or thiodicarb showed reduced fecundity (35% and 30%, respectively) compared to control adults. The tested insecticides significantly reduced adult longevity. The longevity of adult females that as larvae were treated with an LC30 concentration of methoxyfenozide or thiodicarb was reduced by 28% and 23%, respectively, in comparison to control females. We predict that the combination of lethal and sublethal effects of the insecticides, especially methoxyfenozide, will induce significant effects on field population dynamics of H. armigera.  相似文献   

7.
A sandy loam soil was treated with 2·5 kg carbofuran/ha on each of five occasions between May and October 1984. In 1985, the field performance of benfuracarb, carbofuran, carbosulfan, chlorfenvinphos and furathiocarb against cabbage root fly (Delia radicum) and carrot fly (Psila rosae) was studied in this soil and in identical but previously untreated soil by applying exponentially increasing doses of granular formulations to radish and carrots at drilling. Chlorfenvinphos reduced numbers of larvae of both pests by >90% in both soils but the performance of all the carbamates was significantly worse in the previously treated soil than in the previously untreated soil. Dazomet, a partial soil sterilant, was applied to part of the experimental area in October 1985 and the performance of aldicarb, carbofuran, carbosulfan, chlorfenvinphos and thiofanox against cabbage root fly was assessed in 1986. The efficiency of aldicarb and chlorfenvinphos was not affected by any of the pre-treatments but that of carbofuran and carbosulfan was reduced in all the pre-treated soils, including the soil treated with dazomet. Carbofuran residues in radish were detectable only in plants grown in previously untreated soil. In laboratory incubations, a dustless base formulation of carbofuran was degraded more quickly in pre-treated than in untreated soils but a granular formulation was degraded more slowly and at a similar rate in both soils.  相似文献   

8.
The tobacco whitefly, Bemisia tabaci (Gennadius), is an important pest because of its potential to threaten agricultural crops worldwide. Currently, this pest is controlled by the application of chemical insecticides. In our pursuit to identify better insecticides for an effective control of this insect pest, we investigated the lethal effects of five neonicotinoid insecticides including four commercial neonicotinoids and a novel neonicotinoid (cycloxaprid) on B. tabaci MED and MEAM1 cryptic species. In addition, we assessed the sublethal effects of cycloxaprid on B. tabaci MED. Lethal effects of the insecticides were determined using the leaf-dip bioassay, and the results showed that among the tested insecticides cycloxaprid was more toxic to B. tabaci MED and MEAM1 than others, with LC50 values of 0.70 mg/L and 0.59 mg/L, respectively. Cycloxaprid at LC25 (0.16 mg/L) induced sublethal effects in adult MED by prolonging the developmental periods and decreasing the survival rates of all larval instars, pseudopupal and adult stages. Moreover, it significantly shortened the oviposition period of females and decreased their fecundity. Hatching rate of eggs laid by females exposed to LC25 was also markedly reduced. These results indicate that cycloxaprid is a novel alternate insecticide that may effectively control B. tabaci populations.  相似文献   

9.
Aeroz™ (9,10-anthraquinone (AQ)), a chemical rice seed treatment that effectively deters birds from depredating newly planted fields, could be an important management tool that enables rice producers to plant earlier in the season and increase yields. This bird repellent, while non-lethal to birds, has unknown toxicity to crayfish that often are closely integrated with rice production in southern regions of the USA. This study was conducted to assess if AQ, the active ingredient in Aeroz™, could be acutely toxic to the red swamp crayfish Procambarus clarkii (Girard), the crayfish species most often associated with rice cultivation, via seed ingestion and/or through their contact with chemical in pond water. Mortality data from a 96 h feeding study indicate that AQ-treated (1.76% by wt) rice seed was not acutely toxic to juvenile (∼3 mo.) crayfish through the ingestion exposure route. In addition, a 96 h aquatic acute toxicity test showed that the LC50 of AQ in juvenile crayfish is >85 μg L−1 and above the water solubility limit of AQ. These results indicate that very minimal, if any, acute toxicity would be observed in juvenile crayfish if exposed to AQ via ingestion or dissolved or suspended in the water column.  相似文献   

10.
In Taiwan, Camellia seed meal is often sprayed on rice paddies during rice transplantation season to stop the growth of Pomacea canaliculata. However, the application of camellia seed meal endangers muciferous mollusks and fishes in paddy fields. Though researchers have examined the effects of the saponin in the camellia seed meal on Pomacea canaliculata, previous studies ignore the effects of saponin on fish. Loaches often inhabit the rivers, lakes, ponds, paddy fields, and canals of low elevation where there have muddy layer with plant chips. This study uses vanillin-sulfuric acid method and field tests on loaches in paddy fields to determine the duration of camellia seed meal’s effect on loaches (Misgurnue Angullicaudatus). Results indicated that the best application to stop the growth of Pomacea canaliculata is to seal the rice field immediately after transplantation, apply the camellia seed meal, and then irrigate the field 2?days after camellia seed meal application for the summer transplantation, and 3?days for the spring transplantation. Water should not be drained from the paddy field after the application of camellia seed meal to reduce the chance of endangering loaches in irrigation canals. Field Tests show that high water temperature during summer also has a negative effect on loaches in paddy fields and irrigation canals.  相似文献   

11.
The sweetpotato whitefly, Bemisia tabaci (Gennadius), has become a major threat to agriculture worldwide. The development of insecticide resistance in B. tabaci has necessitated the exploration of new management tactics. The toxicity of imidacloprid and buprofezin to various life stages of B. tabaci was determined in the laboratory. Also, the sublethal effects of both insecticides were studied on demographic and biological parameters of B. tabaci. Both insecticides were very toxic against first stage larvae of the pest with LC50 values of 1.0 and 19.3 ppm for buprofezin and imidacloprid, respectively. Toxicities decreased between successive stages (LC50 values ranging from 1.0 to 2854.0 ppm). The LC50 values of imidacloprid for adult males, females and eggs were 11.8, 71.6 and 151.0 ppm, respectively. Buprofezin had no significant effect on adults and eggs. The sublethal concentration of imidacloprid had no significant effect on demographic and biological parameters of B. tabaci but the maximal value for the mean generation time (T) (18.8 day) was observed in imidacloprid treatment. Buprofezin significantly decreased stable population and biological parameters of B. tabaci except it did not decrease the rate of population increase or the sex ratio of offspring.  相似文献   

12.
《Crop Protection》1988,7(4):267-272
A comparison of the toxicity to two aphids, Elatobium abietinum and Adelges cooleyi, and a coccinellid predator, A. obliterata, of dimethoate, fenitrothion and malathion with Safer's insecticidal soap (SIS) and saponified corn oil and sunflower oil confirmed that the organophosphates were more toxic. This did not detract from the effectiveness of the soaps under field conditions provided that appropriately higher concentrations were applied. SIS was not more toxic to the insects than the saponified oils with corn oil soap, which is rich in oleic and linoleic acid, frequently producing higher insect mortality levels. In E. abietinum a linear relationship was demonstrated between insecticide susceptibility and aphid instar, with late instars apparently becoming progressively more susceptible. This relationship disappeared when LC50 values were corrected for size differences. Larval Aphidecta obliterata were more susceptible than adults and field applications of these chemicals should be timed to avoid the larval feeding period. Phytotoxic symptoms appeared on Sitka spruce needles after application of sunflower oil soap, current year needles being particularly susceptible to damage. Corn oil soap or SIS could be substituted during this susceptible period.  相似文献   

13.
Both sheath blight and blast are important rice diseases worldwide. The exploration of environmentally sound practices to control these diseases will help to reduce fungicide application. Effects of rice (Oryza sativa) intercropping with water chestnut (Eleocharis dulcis) on rice sheath blight and rice blast disease as well as the extracts of different plant parts and root exudates from water chestnut on pathogens of rice sheath blight (Rhizoctonia solani) and rice blast disease (Magnaporthe oryzae) were investigated using pot experiments and bioassay tests. The results from pot tests showed that rice-water chestnut intercropping system suppressed sheath blight and blast and improved land equivalent ratio (LER). The results from bioassay tests indicated that extracts and root exudates from water chestnut had significant effects to inhibit the expansion of these pathogens. The scales of these inhibitions were time and concentration dependent. The antifungal activities of the extracts from aboveground parts and pulp of water chestnut were significantly higher than the extracts from other parts and root exudates. The water extracts of aboveground parts showed the highest antifungal activity on both pathogens according to EC50 values. The antifungal activities of the same extracts from water chestnut on R. solani were significantly higher than on M. oryzae. The result suggests that water chestnut possesses bioactive substances to suppress rice sheath blight disease and rice blast disease. The rice-water chestnut intercropping system can be used as an environment-friendly method for diseases control in rice field.  相似文献   

14.
Field populations of beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae), from Pakistan were assessed for their resistance to the chlorinated hydrocarbon endosulfan, the organophosphates chlorpyrifos and quinalphos, and the pyrethroids cypermethrin, deltamethrin, bifenthrin and fenpropathrin. Using a leaf-dip bioassay, resistance to endosulfan was high during 1998–2000 but declined to very low, to low levels during 2001–2007, following a reduced use of the insecticide. Organophosphates and pyrethroids were consistently used over the past three decades, and the resistance had been increasing to these insecticide classes. Generally, the resistance to chlorpyrifos and pyrethroids remained low from 1998 to 2002–2003, but resistance increased to moderate to high levels from 2003–2004 to 2006–2007. For deltamethrin, resistance was very high during 2004–2007. Quinalphos resistance remained low during 1998–2006. Correlation analysis of LC50 and LC90 values showed a positive correlation between organophosphates and pyrethroids, but no correlation between endosulfan and organophosphates or pyrethroids tested herein. These results suggest that the conventional chemistries should be replaced with new chemistries for the successful management of S. exigua.  相似文献   

15.
The full whole culture (FWC), containing parasporal protein toxins of Bacillus thuringiensis israelinsis (Bti) and Bacillus sphaericus 2362 (Bs), either singly or in combination with plant oils and commercial insecticides, was tested against larval and adult stages of Culex pipiens mosquitoes under controlled laboratory conditions. In terms of LC50 values recorded after 24, 48, 72 and 96 h, the bacterial toxins showed high potency towards both larvae and adults of mosquitoes in a dose-dependent manner. Generally, the Bti toxin seemed to be more potent than the Bs toxin. For example, the Bti toxin showed a 24 h LC50 of 8.2 ppm against mosquito larvae compared to 13.6 ppm for the Bs toxin. In the adult bioassay, the obtained 24 h LC50 values were 0.064 and 0.085 mg/cm2, respectively for the two bacterial toxins. The bacterial toxins mixed with plant oils or insecticides at equitoxic doses (e.g., LC25 values) mostly showed potentiation effects, either against larvae or adults of the tested insect. Among a total of 14 paired mixtures, only the joint action estimated for the mixture of malathion + Bti or Bs was accounted as additively. Combining Bti or Bs endotoxins at LC0 with different plant oils and insecticides at LC50 concentration levels each, has resulted in considerable synergism against either larvae or adults. In the case of larval bioassays, the maximum synergistic factor (SF) obtained (ca. 2.0) was entitled to the mixture of Bti + spinosad. In the adult bioassays, the mixtures containing Curcuma longa or Melia azedarach oil extracts with Bti or Bs toxins achieved a SF accounted to 2.0. The results of the present study may be considered as an additional contribution to the area of joint toxicity of biocidal agents combining bacterial toxins, plant oils and traditional insecticides. The reached findings may encourage future research to elucidate its performance under practical field conditions.  相似文献   

16.
Antifeedant, growth inhibitory and toxic effects of crude seed extracts of Annona squamosa and Annona atemoya from Fazenda Viveiro Bona, Parasisópolis – Minas Gerais, Brazil, were evaluated against the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) using different bioassays. Crude methanolic seed extracts deterred feeding of third instar T. ni larvae in a leaf disc choice bioassay. A. squamosa was ∼10 times more active as a feeding deterrent than A. atemoya (DC50 = 2.3 mg/ml vs. 20.1 mg/ml). A. squamosa was ∼three times more active as a growth inhibitor than A. atemoya (EC50 = 38.0 ppm vs. 117.0 ppm). Methanolic seed extracts of A. squamosa and A. atemoya were toxic to third instar T. ni larvae both through topical and oral application. A. squamosa was more toxic through feeding (LC50 = 167.5 ppm vs. 382.4 ppm) whereas, A. atemoya exerted greater toxicity via topical application (LC50 = 301.3 μg/larva vs. 197.7 μg/larva). Both A. squamosa and A. atemoya extracts reduced leaf area consumption and larval growth in a greenhouse experiment. Our results indicate that both A. squamosa and A. atemoya have potential for development as botanical insecticides, especially for local use in Brazil.  相似文献   

17.
The diamondback moth, Plutella xylostella (L.), is an important international pest of cruciferous vegetables. The effects of the new diamide insecticide chlorantraniliprole, at a lethal concentration inducing only 25% mortality (LC25), were assessed on the development and reproductive parameters of P. xylostella under laboratory conditions. In addition, effects on development time, pupation rate, larval and pupae weight, fertility, and survival in the parent and F1 generations were assessed. When 4th instar P. xylostella larvae were exposed to LC25 of chlorantraniliprole on a cabbage (Brassica oleracea var. capitata L.) leaf for 96 h, we observed increased developmental time for 4th instar larval to pupa period (4.27 days vs. 3.34 days in the control), lower pupal weight (3.58 mg vs. 4.17 mg in the control) and decreased adult fecundity (by 42%). F1 generation underwent transgenerational effects, i.e. higher developmental time from egg to pre-pupae and lower egg hatching rate occurred. Demographic growth parameters, such as the net reproductive rate (R0), the intrinsic rate of increase (rm), and finite rate of increase (λ) were significantly lower for the LC25 chlorantraniliprole treated group than for the untreated control. Our results suggest that exposure to LC25 of chlorantraniliprole may have negative effects both on exposed individuals and on subsequent generations in P. xylostella.  相似文献   

18.
Arsenic contamination of shallow groundwater and related health problems are threats for the millions in endemic regions of West Bengal. Contamination of rice grain creates the food chain pathway of mineral arsenic besides drinking water contamination. Present study concentrated on association of arsenic concentration in irrigated water, paddy field soil and rice with the cropping seasons. Irrigated ground water arsenic concentration decreased significantly (p = 0.007) from summer (median 0.42 mg l?1) to winter (median 0.35 mg l?1). Carried over effect created significant decrease (p = 0.03) of paddy field soil arsenic concentration from summer (median 8.35 mg kg?1) to winter (median 6.17 mg kg?1). Seasonal variation was observed in rice straw (p = 0.03) but not in husk (p = 0.91). Arsenic concentration decreased significantly (p = 0.05) in the rice grains collected in winter season (median 0.23 mg kg?1) than the samples collected in the summer season (median 0.30 mg kg?1). In conclusion, seasonal effects need to be considered in case of human health risk assessment from arsenic consumption.  相似文献   

19.
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%.  相似文献   

20.
The tea green leafhopper Empoasca onukii Matsuda (Hemiptera: Cicadellidae), the orange spiny whitefly, Aleurocanthus spiniferus (Quaintanca) (Hemiptera: Aleyrodidae), and the green plant bugs Apolygus lucorum Meyer-Dür (Hemiptera: Miridae) are the important piercing–sucking herbivores in tea trees Camellia sinensis (L.) O. Kuntze (Theaceae). The goal of this study was to evaluate the laboratory toxicities and field control efficacies of botanical insecticides including matrine, azadirachtin, veratrine, and pyrethrin to three tea pests. Via leaf-dip bioassay, toxicity tests with botanical insecticides indicated that there were significant differences between the LC50 values for botanical insecticides within the same insect species. Matrine had the highest toxicity to E. onukii, A. spiniferus, and A. lucorum with the LC50 values of 2.35, 13.10, and 44.88 mg/liter, respectively. Field tests showed that, among four botanical insecticides, matrine at dose of 9 g a.i. ha−1 can significantly reduce the numbers of E. onukii and A. spiniferus and the infestation of A. lucorum on the tea plants. Furthermore, botanical insecticides matrine and azadirachtin had no obvious influence on the coccinellids, spiders, and parasitoids densities in tea plantations. The results of this study indicated that use of botanical insecticides, such as matrine, has the potential to manipulate the population of E. onukii, A. spiniferus, and A. lucorum and will be an effective and environmentally compatible strategy for the control of tea pests.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号