硫酰氟的杀虫毒性和毒理学研究

介绍高效熏蒸剂 硫酰氟的国内外概况,它的杀虫毒性和药效以及有关的毒理学研究。

辽宁省大型真菌浸提液及发酵液对线虫的毒力作用

利用从辽宁省采集的206株大型野生真菌的浸提液和部分发酵液,测定其对根结线虫Meloidogyne incognita、胞囊线虫Heterodera glycines、小杆线虫Caenorhabditis sp.和水稻干尖线虫Aphelenchoides basseyi的活性。结果表明:有22种真菌对靶标线虫的致死率达70%以上,且同一菌株的浸提液和发酵液对线虫亦有明显的选择毒性作用。有7株菌浸提液对2种以上靶标线虫的致死率超过90%。蛇头菌Mutinus caninus F149浸提液对南方根结线虫毒力最高,致死率达97.74%,对胞囊线虫和水稻干尖线虫的毒力也超过90%,而对小杆线虫毒力仅为24.04%,因其对人毒性大而未获得纯培养。薄蜂窝菌Hexagonia tenuisF128浸提液对大豆胞囊线虫J2毒力最高,致死率达96.55%,但其发酵液毒力下降;浸提液对根结线虫的毒力仅次于F149,对水稻干尖线虫毒力较弱,但发酵液对干尖线虫致死率却提高至91.38%。块鳞青鹅膏Amanita excelsaF155浸提液对根结线虫的致死率达96.67%,但发酵液仅为70.93%。粉迷孔菌Daedalea biennis F139的浸提液对小杆线虫的毒力最强,致死率达90.40%。松生拟层孔菌Fomitopsis pinicola F130的浸提液与裂褶菌Schizophyllum commune F107的浸提液和发酵液及小灰孢Lycoperdon pusillus F102的发酵液对水稻干尖线虫的致死率均超过95%。血红菇Russula sanguinea F204和大红菇R.alutacea F153的浸提液和发酵液对3种植物线虫的致死率均超过85%,而对小杆线虫的毒力较弱。

我国仓贮昆虫病原芽孢杆菌的研究

对９５１个样品分离鉴定，有７４７个样品含芽孢杆菌，有菌率为７８．５５％．共分离得到芽孢杆菌１１３８株，其中苏云金杆菌（Ｂａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ，简称Ｂ．ｔ）１４３株，占１２．５％；球形芽孢杆菌（Ｂａｃｉｌｌｕｓｓｐｈａｅｒｉｃｕｓ，简称Ｂ．ｓ）１１株，占０．９７％；其他芽孢杆菌９８４株，占８６．４０％．从芽孢杆菌中选出产生晶体、苏云金素或磷酸酯酶Ｃ（ＰｈｏｓｐｈａｌｉｐａｓｅＣ，简称ＰＬＣ）的毒素菌株１６８株，其中Ｂ．ｔ占１４３株，Ｂ．ｓ有５株，其他芽孢杆菌１０株．在产毒素菌株中，经测定有１２０株菌对供试昆虫毒性达标．占７７．９２％．不同菌株的杀虫毒素、杀虫范围和毒力各异，认为这种差异取决于毒素和虫种两方面的特异性．

单甲脒及单甲脒盐酸盐的急性毒性

本文用霍氏测定单甲脒对小白鼠经口半数致死剂量为１７８毫克／公斤体重（雄性）和２１５毫克／公斤体重（雌性）；其商品农药是单脒盐酸盐，对小白鼠经口半数致死剂量为２１８毫克／公斤体重（雄性）和１４８毫克／公斤体重（雌性），单甲脒代谢较快，内脏中的残留量只占给予量的１００～５００分之一。

扑螟虱可湿性粉剂

扑螟虱可湿性粉剂重庆市植保站扑螟虱是重庆市中稻穗期配方施药技术研究课题组研制的最新复配杀虫剂，由昆虫激素、沙蚕毒素、助剂等组成，有效成分含量５０％，具有触杀、胃毒和内吸杀虫毒性，适用于稻田兼治稻飞虱、螟虫等多种害虫，对稻飞虱的持效期可达３０天，每袋６...

Isolation and Characterization of a Dichlorvos-Degrading Strain DDV-1 of Ochrobactrum sp.

The objective of this research was to isolate a dichlorvos (2,2-dichlorovinyl dimethyl phosphate)-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium (strain DDV-1) was successfully isolated and identified as an Ochrobactrumsp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L-1 or 500 mg L-1 dichlorvos and inoculated with 0.5% or 1.0% (v/v) strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation.

Evaluation of Cytotoxicity and Genotoxicity of Insecticide Carbaryl to Flounder Gill Cells and Its Teratogenicity to Zebrafish Embryos

In this study, we determined the cytotoxicity and genotoxicity of carbamate insecticide carbaryl to flounder gill （FG） cells and its teratogenicity to zebrafish embryos. The cytotoxicity of carbaryl to FG cells was determined with methods including MTT and neutral red uptaking （NRU）, lactate dehydrogenase （LDH） releasing and Hoechst 33342 and propidiurn idodide （PI） double staining. Moderate cytotoxicity in a concentration-dependent manner was observed. The 24h-IC50 value of 53.48 ± 1.21, 59.13 ± 1.19 and 46.21 ± 1.24 mgL 1 carbaryl was obtained through MTT, NRU and LDH assays, respectively. Double fluorescence staining dem- onstrated that carbaryl induced the death of FG cells mainly through necrosis. There was no significant genotoxicity found in the FG cells exposed to the highest testing concentration of carbaryl （20mgL-1, P〉0.05） as was demonstrated by Comet assay. Zebrafish embryos exposed to carbaryl at concentrations 〉10 mg L-1 displayed moderate toxic effects on the survival, spontaneous movement, hatching, heart rates of the embryos and their development, which were evidenced by yolk and pericardial sac edemas, body length reduction and tail flexure in time- and concentration-dependent manners at specific stages. The 24h-, 48h- and 96h-LC50 values of carbaryl to zebra fish embryos were 41.80 ± 1.10, 17.80 ± 1.04 and 14.46 ± 1.05 mg L-1, respectively. These results suggested that car- baryl is moderately toxic to FG ceils cultured in vitro and zebrafish embryos, and the FG cells were similar to zebrafish embryos in their sensitivity to carbaryl as 24h-IC50 and LC50 indicated.

Effect of Industrial Effluents on Embryos of Lefteye Flounder (Paralichthys olivaceus)

The studies have been carried out in laboratory on the effect of dyeing,electroplating, pesticide effluents and their intermixture on embryos of lefteye flounder (Paralichthys olivaceus ). The main toxic substances in dying effluent are aniline ( 20 mg/L ) andphenol ( 24 mg/L ). The main toxic substances in electroplating effluent are Zn ( 1 970 mg/L ). Cu (9 mg/L ) and Pb ( 7.5 mg/L ). The main toxic substances in pesticide effluent are monocrotophos andphosphite. The test results indicate that the lowest concentrations of dyeing, electroplating,pesticide effluents and their intermixture, having significant effect on the hatch rate anddevelopment of P. olivaceus embryos, are 0.5 %, 0.15 %, 0.25 % and 0.25 %, respectively; and theincipient LC_(50) of dyeing, electroplating, pesticide effluents and their intermixture are 3.38 % (2.29 %～3.87 % ), 0.81 % ( 0.71 % ～0. 92 % ). 1.57 % ( 1.37 %～1.82 % ) and 1.48 % ( 1.24 %～1.76% ). Based on the incipient LG_(50) values, the toxicity sequence of the three industrial effluentsis in the order of electroplating effluent > pesticide effluent > dyeing effluent.

Carbendazim resistance and calculation effective concentration of carbendazim for Trichoderma harzianum

There is a method for investigating the transformation of resistance gene of carbendazim into Trichoderma harzianum. In order to introduce the resistance to benzimidazole fungicide into bio-control microorganism Trichoderma harzianum was transformed with the resistance gene. In this study, we investigate resistance level and calculate EC 50 (effective concentration of carbendazim that can survive 50% of Trichoderma harzianum in that concentration) and stability of the resistance for the transformant isolate of Trichoderma harzianum. Results show the transformants can growth on the medium containing more than 1 000 μg/ml carbendazim and the resistance is stabled after 10 times transfer on non-selective medium and have EC 50 average about, 1 200 μg/ml.

Toxicity of selected insecticides against nymph of whitefly （Bemisia tabaci Gennadius）

Bemisia tabaci is one of serious insect pests attacking vegetables and has been difficult to control using conventional insecticides. In the past 10 years, new insecticides have been introduced that provide a diversity of novel modes of action and routes of activity to effectively control whitefly. Consequently, intensive used of insecticides in vegetable cultivation has resulted in reduced susceptibility and develops resistance in agriculture industry. In controlling B. tabaci population, insecticides are the common method used by farmers. This study aimed to determine the most effective insecticide against B tabaci by using LC5o value. This study was conducted at the Crop Protection Laboratory, Faculty of Applied Science, Universiti Teknologi MARA Malaysia with the controlled room temperature of 24.33 ± 0.14℃ with dark and light ratio of 1：1 （12 hours： 12 hours） is an ideal condition for rearing the insect. The hypothesis of the study is to test if insecticides can control the nymph of whitefly. A total of 50 two-day-old nymphs were treated with insecticides using leaf-dip bioassay procedure. This experiment was replicated three times. The survival rates of the nymphs were analyzed using analysis of variance （ANOVA）. Data on toxicity was analyzed by a special Probit Programme-Single Line Analysis based on Finney （1971）. There was a significant difference （df = 8, F = 85.84, P = 0.000） in survival rate of nymph ofB. tabaci to eight insecticides tested. Among the insecticides tested, dimethoate, chlorpyrifos ＋ cypermethrin and diafenthiuron showed significantly higher survival rate of nymph compared to other treatments. When LC50 values were compared for diafenthiuron which is less potent （LCs0 ---- 2.44）, abamectin was found to be 3.44 times more potent than diafenthiuron, followed by esfenvalerate,acetamiprid, profenofos, chlorpyrifos ＋ cypermethrin and dimethoate, and the least potent was deltamethrin. The toxicity of eight insecticides tested against nymphs was in the following orders： abamectin = esfenvalerate = acetamiprid = profenofos =- chlorpyrifos ＋ cypermethrin ≥ dimethoate ≥ deltamethrin 〉 diafenthiuron respectively. This study implies that a proper application of the insecticide is a key component to a successful control programme of insect oests.

Acute toxicity of organochlorine insecticide endosulfan to the giant freshwater prawn Macrobrochium rosenbergii

Endosulfan, an organochlorine pesticide, is highly toxic and effective at controlling pests in agriculture, horticulture, and public health programs. In this study, static bioassays were used to evaluate the toxicity of endosulfan to freshwater prawns( Macrobrachium rosenbergii) of various lengths(1.5±0.03,4±0.08, and 7±0.06 cm). Additionally, the activities of peroxidase(POD), acid phosphatase(ACP),alkaline phosphatase, acetylcholinesterase(AChE), and Na + /K +-ATPase were analyzed to refl ect the effects of endosulfan exposure. The 96 h LC 50 of endosulfan for prawns 1.5, 4, and 7 cm long were 1.86, 4.53,and 6.09μg/L, respectively, improved tolerance to endosulfan with growth. The POD activities of test organisms exposed to low concentrations of endosulfan were inhibited, indicating the presence of oxygen damaged tissue. Moreover, a notable decrease in AChE activity was observed due to overstimulation of neurotransmission, which might result in abnormal behavior. The effect caused by endosulfan on phosphatase production in the hepatopancreas of prawns 1.5, 4, and 7 cm long was different because the ability of nonspecifi c immune regulation increased with growth. The 96 h LC 50 values obtained in this study could be used in the formulation of water-quality criteria in China. Moreover, the changes in enzymes activities of M. rosenbergii under stress of endosulfan could be applied in the establishment of early warning indicators for bio-safety.

Comparative Toxicity of Selected Insecticides to Phytoplasma Transmitted Leafhopper Cicadulina bipunctata （Melichar）

Leafhopper Cicadulina bipunctata is represented the main insect as a pathogen for phytoplasma disease occurring by insect-transmitted plant viruses in date palm orchards. Therefore, it is important to investigate the potential effect of some insecticides against such insect. The adults of leafhopper C. bipunctata were collected from date palm orchards in Alhasa, Eastern province, Saudi Arabia. Three insecticides from different classes--beta-cyfluthrin （pyrethroids）, imidacloprid （neonicotinoids） and abamectin （natural compounds）--have been evaluated in vivo against adults C. bipunctata. This stage was exposed to residual film of various concentrations of each insecticide on transparent plastic cups using a Potter precision laboratory spray tower. Bioassay test showed that both beta-cyfluthrin and imidacloprid caused 100% mortality by 500 ppm at 24 h after treatment, whereas abamectin gave the same mortality by 50 ppm at the same time. Toxicity values revealed that abameetin was the most potent insecticide compared with beta-cyfluthrin and imidacloprid, where the lethal concentrations LC50 and LC95 were 24.58 ppm and 116.73 ppm at 3 h after treatment, respectively. Therefore, abamectin can be a possible candidate to be applied on date palm or ground grass by the Ministry of Agriculture after successful field experiments.

Toxicity of organophosphorus pesticide sumithion on larval stages of stinging catfish Heteropneustes fossilis

Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.

Influences of insecticides on toxicity and cuticular penetration of abamectin in Helicoverpa armigera

Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin+HMO (1:206)'. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin+HMO' or ‘abamectin+synergist', respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of ^3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of ^3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.