抗梅岭霉素和阿维菌素二斑叶螨种群生命力和繁殖力的研究

采用营养液培养的棉苗饲养二斑叶螨Tetranychus urticae Koch,用梅岭霉素、阿维菌素对其逐代进行抗性选育,至第9代,测定了两个抗性种群的抗性水平、生命力和繁殖力。结果表明:梅岭霉素抗性种群的抗性达7.9倍,其雌成螨寿命、产卵量、卵的孵化率和后代若螨成活率分别比对照增加54.08%、39.93%、6.57%和-15.44%。阿维菌素抗性种群的抗性达5.8倍,其雌成螨寿命、产卵量、卵的孵化率和后代若螨成活率分别比对照增加15.88%、10.87%、5.86%和-9.32%。由此发现梅岭霉素和阿维菌素对二斑叶螨的生长发育和繁殖有一定有利作用,抗性风险性较大,应引起重视。     

10%甲氰·阿维乳油配方的筛选及其对朱砂叶螨的联合作用

通过对助剂和配方的筛选,确定10%甲氰·阿维乳油的溶剂为20∶1(质量比,下同)的二甲苯与乙酸乙酯混合溶液,乳化剂为30∶1的QR-9与QR-11混合物,其添加量为60 mg/g。采用玻片浸渍法测定9种不同配比复配剂对朱砂叶螨Tetranychus cinnabarinus (Boisduval)的联合毒力作用。结果表明:9种复配剂对朱砂叶螨的共毒系数均在200以上,表明两种单剂复配具有显著的增效作用,其中以甲氰菊酯与阿维菌素按有效成分97∶3的比例复配,其增效作用最为显著,共毒系数高达357.7,为最佳配比。     

土耳其斯坦叶螨的生殖潜能

为了研究新疆农作物重要害螨土耳其斯坦叶螨TetranychusturkestaniUgarovetNikolski的暴发原因,在实验室条件下研究了土耳其斯坦叶螨在不同温度条件下的生活史、生殖力、实验种群生命表。结果表明:温度是影响土耳其斯坦叶螨发育、产卵的重要因素。从生命表参数分析,19~31℃范围内世代存活率达79.8%~100%,产雌率达83.3%~85.3%。20±1、25±1、30±1、34±1℃时净增殖率R0分别为44.5793、57.0307、52.6785、57.6588。20±1、25±1、30±1、34±1℃时种群增长指数分别为27.03、44.50、43.13、26.59。种群倍增时间随着温度的上升而缩短,20±1℃为4.8799天,34±1℃时仅为2.3610天。研究结果表明土耳其斯坦叶螨世代短、生殖潜能大,在新疆棉田特殊的气候、生态和管理模式下易暴发成灾。     

几种药剂对朱砂叶螨的田间防效试验

进行了5种杀螨剂对朱砂叶螨的田间药效试验.试验结果表明,灭扫利在药后1,3 d具有较高的防效,但持效性差;齐螨素、霸螨灵的速效性较差,但持效期长,药后30 d校正防效分别为98.1%和93.6%.     

扫螨净对国槐叶螨的防治研究

使用扫螨净乳油对国槐叶螨的防治效果表明，在喷施２０００倍和３０００倍扫螨净乳油１２小时后，叶螨校正杀虫率分别为９６．７％和９５．６％，有效防治时间长达３０～５０天，是目前防治国槐叶螨的理想药物。     

First record of the invasive mite<Emphasis Type="Italic">Tetranychus evansi</Emphasis> in Greece

The red spider miteTetranychus evansi (Acari: Tetranychidae) Baker and Pritchard was recorded for the first time in Greece, in the area of Tympaki (south-central Crete) onSolanum nigrum. T. evansi is a pest of crops of the family Solanaceae, which are grown extensively in Crete. The species identification was based on both morphological and molecular data. The second internal transcribed spacer was PCR amplified and sequenced in samples from Crete. Sequences were compared with the sequence ofT. evansi from Brazil and with the ITS2 sequences (retrieved from GenBank) of the two closely related tetranychid species most commonly found in Greece,Tetranychus turkestan andTetranychus urticae.     

Tetranychus urticae Koch induced accumulation of salicylic acid in frijole leaves

The contents of free salicylic acid and conjugated salicylic acid were determined by using TLC and HPLC at different time after attack by Tetranychus urticae Koch in the first true leaf of frijole (Phaseolus vulgaris. L) plant. A maximal nine fold increase in the free salicylic acid content in the attacked leaves was observed. The increase of conjugated salicylic acid was also significant. The content of free salicylic acid in the systemic leaves increased about 500%, while the content of conjugated salicylic acid in the systemic leaves increased by two to three times.     

核桃叶提取物对朱砂叶螨体内几种酶活性的影响

 测定了核桃叶石油醚提取物对朱砂叶螨体内谷胱甘肽-S-转移酶、单胺氧化酶、Ca²⁺Mg²⁺-ATP酶、乙酰胆碱酯酶活性的影响。结果表明，核桃叶石油醚提取物处理朱砂叶螨后，螨体内谷胱甘肽-S-转移酶活性被激活；而乙酰胆碱酯酶、单胺氧化酶、Ca²⁺Mg²⁺-ATP酶的活力受到一定程度的抑制，这可能会引起神经传递的阻断，导致螨体的死亡。结果表明核桃叶作为新型植物源农药具有良好的开发前景。     

3种植物对二点叶螨的生物活性

采用玻片浸渍法,对狼毒,苦参和百部根丙酮提取物对二点叶螨的生物活性进行了测定。3种植物提取物对二点叶螨都有较高的生物活性,狼毒,苦参和百部根提取物48 h的LC50分别为8.47mg/mL,0.62 mg/mL和1.51 mg/mL,对于二点叶螨,苦参提取物的活性最强,百部提取物的次之,狼毒提取物的最弱。     

Comparative acaricide susceptibility and detoxifying enzyme activities in field-collected resistant and susceptible strains of Tetranychus urticae

A field-collected strain (MR-VL) of the two-spotted spider mite, Tetranychus urticae Koch, exhibited strong resistance to bifenthrin, dicofol and fenbutatin oxide in comparison with a susceptible laboratory strain (LS-VL). The MR-VL strain was screened for cross-resistance with several currently used acaricides. Cross-resistance was detected with clofentezine (RR = 2631), dimethoate (RR = 250), chlorfenapyr (RR = 154), bromopropylate (RR = 25), amitraz (RR = 17), flucycloxuron (RR = 15) and azocyclotin (RR = 7). Abamectin, acequinocyl, bifenazate, tebufenpyrad and spirodiclofen did not show any signs of cross-resistance. Enhanced detoxification by increased activity of mono-oxygenases (MO) and esterases is at least partially responsible for the observed resistance and cross-resistance. MO assays with 7-ethoxycoumarin (7-EC) were optimised and 7-ethoxy-4-trifluoromethylcoumarin (7-EFC), a new MO-substrate, was evaluated for the first time in T urticae and proved to be a good alternative to 7-EC. Approximately 3- and 4-fold higher MO activity was detected with 7-EFC and 7-EC respectively in the MR-VL strain. Kinetic parameters of general esterase assays with 4-nitrophenyl acetate and 1-naphthyl acetate as substrate indicated that more esterases were present in the MR-VL strain. A first attempt was made to classify the esterases present in T urticae. Acetyl-, aryl- and carboxyl-esterases were detected with the use of inhibitors after separation by native PAGE. Glutathione-S-transferases did not seem to play any role in the observed resistance and no differences were detected when the general oxidative capacities of the two strains were compared.