二斑叶螨与朱砂叶螨在四季豆上种间竞争力研究

对二斑叶螨与朱砂叶螨在以四季豆为寄主时的种间竞争进行了研究。结果表明：无论单种种群还是混合种群。二斑叶螨的活动虫态和成虫的内禀增长力均高于朱砂叶螨,这表明在以四季豆为寄主植物时,二斑叶螨比朱砂叶螨具有更强的种问竞争力。     

茄子对红蜘蛛的抗螨性鉴定及方法研究

通过在开花结果初期进行人工接虫,采用叶片危害指数法和田间种群密度法对20份材料进行了对红蜘蛛的抗螨性鉴定,结果表明,供试材料的叶片为害指数和田间种群密度均存在极显著差异.两种方法的鉴定结果总体趋势一致,茄子材料E3099的叶片为害指数和红蜘蛛种群密度最小,表现出对红蜘蛛抗性最强;材料E3022、E3023的叶片危害指数和红蜘蛛种群密度最大,表现出对红蜘蛛的抗性最差.叶片危害指数法可作为评价茄子对红蜘蛛抗性的方法.     

二斑叶螨抗性种群对6种杀螨剂的敏感性测定

以昌乐县（R1）和寿光市（R2）蔬菜大棚内的二斑叶螨为试虫,采用玻片浸渍法测定了其对6种杀螨剂的敏感性。结果表明：对两个种群毒力最高的均为唑螨酯,其LC50分别为2.384 mg/L（R1）和1.939 mg/L（R2）;其次为阿维菌素,LC50分别为2.426 mg/L（R1）和9.921 mg/L（R2）。R1种群中甲维盐、除尽、噻螨酮的LC50在34.383～1237.592 mg/L之间,相对毒力分别为哒螨灵的82.499、9.808、2.292倍。R2种群中噻螨酮的毒力最低,LC50为1 225.602 mg/L;除尽、哒螨灵、甲维盐的LC50分别为791.649、308.580 mg/L和13.892mg/L,相对毒力倍数在1.548～88.223倍之间。     

智利小植绥螨对朱砂叶螨的捕食效能

在实验室条件下研究了智利小植绥螨雌成螨对朱砂叶螨卵、幼螨和成螨的捕食效能。结果表明：朱砂叶螨各螨态不同密度分布情况对智利小植绥螨的捕食效能有一定的影响,在一定范围内,当害螨各螨态分布密度增加,智利小植绥螨的捕食量随之增加,但当增加到一定程度后,智利小植绥螨的捕食量又随密度的增加而减少。试验以朱砂叶螨卵密度为80粒／叶碟、若螨密度30头／叶碟、成螨密度10头／叶碟时,智利小植绥螨的捕食量最多。     

Efficacy of five selected acaricides against Tetranychus urticae (Acari: Tetranychidae) and their side effects on relevant natural enemies occurring in citrus orchards

BACKGROUND: Three groups of natural enemies are fundamental in citrus IPM in Spain: coccinellid and phytoseiid predators and hymenopteran parasitoids. Tetranychus urticae Koch is an important pest affecting citrus, for which biological control has not yet been achieved; therefore, acaricides are commonly used to control it. The goal of this study was to measure the efficacy of different acaricides on this mite and their side effects on three natural enemies relevant for citrus (Cryptolaemus montrouzieri Mulsant, Neoseiulus californicus McGregor and Aphidius colemani Viereck).RESULTS: Some products proved highly effective against T. urticae and harmless to A. colemani (mineral oil, tebufenpyrad, clofentezine and fenazaquin). However, almost all products tested were slightly harmful for both the predators considered. Fenazaquin was even moderately harmful for N. californicus. CONCLUSION: Further studies, like that presented here, are necessary to gain a better understanding of integrating biological and chemical controls. When considering both efficacy and side effects on beneficial arthropods, the best options would seem to be mineral oil, tebufenpyrad and clofentezine. However, it is urgent to complete testing of the side effects of the acaricides used in citrus. This question is crucial if the fact that two recently introduced Tetranychidae are being controlled in citrus by chemical means exclusively is considered.     

Induction of cytochrome P450 monooxygenase activity in the two-spotted spider mite Tetranychus urticae and its influence on acaricide toxicity

Detoxification by cytochrome P450 monooxygenases is an important mechanism involved in pesticide resistance in insects and mites. The activity of these enzymes can be induced by a variety of chemicals. The aim of this study was to evaluate the effect of six P450 inducers (phenobarbital, barbital, 3-methylcholanthrene, geraniol, isosafrole, pentamethylbenzene), known to have an inducing activity in insects and mammals, on the O-deethylation activity in the two-spotted spider mite Tetranychus urticae. Treatment with barbital, phenobarbital and geraniol resulted in a dose-dependent increase in activity. Neither 3-methylcholanthrene, isosafrole nor pentamethylbenzene were effective inducers. Time course studies showed that induction by geraniol and barbital started rapidly within a period of 1-4 h after initiation of the treatment, while maximal activity was reached within 4 and 48 h, respectively. In addition, it was shown that induction with xenobiotic compounds can alter the monooxygenase-mediated acaricide tolerance in a susceptible strain of T. urticae. Although barbital induced higher levels of P450 activity, geraniol proved to be a better compound to decrease toxicity of the tested acaricides.     

山楂叶螨对胡瓜钝绥螨的吸引作用研究

采用两侧吸引作用试验测定天敌胡瓜钝绥螨Amblyseius cucumeris Oudemans在田间对山楂叶螨的搜索和控制能力。结果表明:山楂叶螨不同螨态对胡瓜钝绥螨均有显著的吸引作用,排泄物对胡瓜钝绥螨没有明显的吸引作用。山楂叶螨对胡瓜钝绥螨的这种吸引作用说明胡瓜钝绥螨在田间具有自动搜索山楂叶螨的能力,可用于山楂叶螨的生物防治。     

Evaluation of corn plant as potential banker plant for supporting predatory gall midge, Feltiella acarisuga (Diptera: Cecidomyiidae) against Tetranychus urticae (Acari: Tetranychidae) in greenhouse vegetable production

The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important and highly polyphagous pests of vegetables and other crops worldwide. Experiments were conducted in the laboratory and greenhouse to evaluate corn (Zea mays L.) as a banker plant for the predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae) to potentially control T. urticae. Choice and no-choice experiments were carried out to determine the host plant preference of an alternative prey, Oligonychus pratensis (Banks)(Acari: Tetranychidae) to corn and green bean (Phaseolus vulgaris L.). Results showed that O. pratensis adults strongly preferred corn as a host plant and posed no risk to green bean. F. acarisuga was found to fly at least 7.0 m to search for new preys on green bean plants, and over 176 F. acarisuga larvae per leaf were recorded at 14 d after dispersal. F. acarisuga proved to be an excellent predator of both T. urticae and O. pratensis. The predation by F. acarisuga to T. urticae and O. pratensis ranged from 43.7 to 67.9% and 59.2 to 90.3%, respectively, under laboratory conditions. In a non-cage study, 81.2% of T. urticae population was suppressed by F. acarisuga in reference to the control (cage treatment). The results showed that this banker plant system has potential for controlling T. urticae in greenhouse vegetable production.     

沼液对韭菜迟眼蕈蚊的防治效果

通过室内选择性测定和田间试验,评价了沼液对韭菜迟眼蕈蚊的防治效果。结果表明,沼液对韭菜迟眼蕈蚊表现出一定的驱避活性,对幼虫的驱避率、拒食率分别达55.30%、53.81%,雌雄成虫选择反应率分别为33.2%、30.5%,对雌虫产卵驱避率为36.82%。田间试验结果表明,以沼液∶水(1∶1)处理幼虫、成虫,随着时间的延长防效逐渐提高,处理后45d防效达到最大,分别为43.16%、56.50%。     

朱砂叶螨对阿维菌素及高温的交互耐性

以朱砂叶螨敏感种群(SS)、抗阿维菌素种群(RA)和耐高温种群(RH)为材料,应用生物测定方法以及荧光实时定量PCR技术,研究朱砂叶螨抗药性和耐高温间存在的交互耐性及机制.结果显示:46℃高温下RH和RA种群的半致死时间(LT50)显著长于SS种群,其顺序依次是:RHRASS,阿维菌素对朱砂叶螨的半致死浓度(LC50)各种群间的顺序依次是:RARHSS,其中,RH和RA种群显著高于SS种群.这表明长期的高温胁迫能诱导其对阿维菌素药剂的抗性,同样对阿维菌素的抗药性也能诱导其对高温的耐性.SS、RA和RH经阿维菌素处理后体内O2?(超氧自由基)含量分别是对照的2.08、1.85和2.00倍,SOD(超氧化物歧化酶)活性分别是对照的3.81、4.84和4.26倍,CAT(过氧化氢酶)和POD(过氧化物酶)活性也都高于对照;经高温(40℃)和低温(4℃)处理后,O2?及SOD、CAT和POD活性也表现出相同的趋势.说明朱砂叶螨虫体内的O2?、SOD、CAT和POD与阿维菌素药物和热(冷)刺激有关,RA和RH在长期阿维菌素或高温胁迫作用下对保护酶活性的诱导能力加强.朱砂叶螨Tc HSP90 mRNA在正常情况下的表达是RA和RH高于SS,分别是SS的1.64倍和1.29倍,经阿维菌素、高温(40℃)和低温(4℃)处理后,RA和RH的表达量显著高于SS,表明朱砂叶螨HSP90在抗药性和耐热性方面发挥了作用.