温室白粉虱抗药性的成虫快速监测方法初探

根据 FAO 推荐的方法测定温室白粉虱的抗药性结果表明,溴氰菊酯对北京马连洼种群成虫羽化后第1,3,6,10,15,20天不同日龄成虫的毒力,随日龄增加而逐渐降低。LC_(50)为123.51～282.50μg/g,但差异不显著(P<0.05),平均186.63 μg/g.对田间自然混合日龄与饲养的不同日龄成虫的 LC_(50)之间亦无显著差异。成虫对药剂的敏感性明显低于若虫,但在不同和相同年份二种虫态的抗药性趋势是一致的。认为温室白粉虱抗药性监测,可采用田间混合日龄成虫代替饲养的不同日龄成虫或1日龄若虫进行监测则更为简便、快速.     

树干喷药环防治松毛虫的研究

本试验选用溴氰菊酯和杀灭菊酯,以柴油和水作稀释剂,用家用手动喷雾器在树干胸高处喷药环防治越冬上下树松毛虫取得了较好的防治效果。持效期可维持40天以上。这是一种局部、微量施药方法,施药时间在秋末或春初,多数有益生物已经停止或尚未开始活动,所以,对森林中许多有益昆虫的影响很小。     

溴氰菊酯对微小牛蜱的毒力测定和杀灭试验

溴氰菊酯对微小牛蜱未吸血幼蜱的半致死浓度（ＬＣ５０）为０．３６×１０－６，对未吸血成蜱的半致死量（ＬＤ５０）为４．６８７μｇ／虫，对饱血雌蜱的ＬＤ５０为６．８６８μｇ／虫；而敌百虫对未吸血幼蜱的ＬＣ５０为１７５×１０－４，对未吸血成蜱和饱血雌蜱的ＬＤ５０分别为１１１６和５２６６μｇ／虫．可见，溴氰菊酯对微小牛蜱未吸血幼蜱、未吸血成蜱及饱血雌蜱的杀蜱效果分别为敌百虫的４８６、２３８和７６７倍．现场杀蜱试验，采用５％溴氰菊酯水和剂１２．５×１０－４时．杀蜱率达９２％，３０×１０－６时达１００％杀蜱效果，对牛无副作用。     

巴氏新小绥螨溴氰菊酯抗药性品系对常见药剂的交互抗性及其种群参数分析

为了明确巴氏新小绥螨Neoseiulus barkeri溴氰菊酯抗性品系对常用杀虫(螨)剂的交互抗性水平及生物适合度,为巴氏新小绥螨抗药性品系田间应用提供科学依据。本文应用玻片浸渍法测定了巴氏新小绥螨溴氰菊酯抗性品系对12种杀虫(螨)剂的交互抗性,采用种群生命表评价了其生长发育及繁殖情况。结果显示,相对于巴氏新小绥螨敏感品系,溴氰菊酯抗性品系(226.38倍)对供试的其他6种拟除虫菊酯类药剂均存在交互抗性,尤其对氯氟氰菊酯的交互抗性倍数最高,达到2 210.91倍。对噻虫嗪、毒死蜱和乙螨唑的交互抗性分别是116.46、110.71倍和20.43倍,对丁硫克百威、阿维菌素和哒螨灵无交互抗性。对其生物适合度研究发现,溴氰菊酯抗性品系相较于敏感品系,前若螨期和产卵前期显著缩短,产卵期和单雌总产卵量显著增加。上述结果表明,巴氏新小绥螨溴氰菊酯抗性品系对10种常用杀虫(螨)药剂产生了不同水平的交互抗性,且其繁殖率显著增加,推荐在田间推广应用。     

Genetics and mechanism of resistance to deltamethrin in a field population of Spodoptera litura (Lepidoptera: Noctuidae)

BACKGROUND: Spodoptera litura (F.) causes enormous losses in many economically important crops. The genetics of insecticide resistance has been extensively studied in several insect pests, but there is a lack of information on S. litura. Therefore, the genetics and mechanisms of the resistance of S. litura to deltamethrin were investigated. RESULTS: Bioassays at generation G1 gave resistance ratios of 9, 5, 41, 52 and 49 for deltamethrin, cypermethrin, profenofos, chlorpyrifos and triazofos respectively, when compared with the susceptible Lab-PK strain. Bioassays at G4 with a deltamethrin-selected population (Delta-SEL) showed that selection gave resistance ratios of 63 and 7 for deltamethrin when compared with the Lab-PK and UNSEL strains respectively. Cross-resistance to other insecticides tested was observed in the selected population. A notable feature of the Delta-SEL strain was that resistance to deltamethrin, cypermethrin, profenofos and chlorpyrifos did not decline over the course of five generations. Synergism tests with microsomal oxidase (MO) and esterase-specific inhibitors indicated that the deltamethrin resistance was associated with MO and, possibly, esterase activity. Reciprocal crosses between the Delta-SEL and Lab-PK strains indicated that resistance was autosomal and incompletely dominant. A direct test of monogenic inheritance suggested that resistance to deltamethrin was controlled by more than one locus. CONCLUSION: Stability and dominance of resistance and cross-resistance suggest that insecticides with different modes of action should be recommended to reduce pyrethroid selection pressure.     

Delayed cuticular penetration and enhanced metabolism of deltamethrin in pyrethroid-resistant strains of Helicoverpa armigera from China and Pakistan

The penetration and metabolism of [14C]deltamethrin was studied in susceptible and resistant Chinese and Pakistani strains of Helicoverpa armigera (Hübner), which were resistant to deltamethrin by 330- and 670-fold, respectively. The penetration of deltamethrin into resistant individuals was significantly slower than into susceptible individuals over a 24-h period. The time taken for 50% penetration of the applied deltamethrin was 1 h for the susceptible strain and 6 h for both of the resistant strains. The internal radioactivity was reduced by the larvae of resistant strains much faster than by the susceptible larvae. After 48 h, 40% of the penetrated deltamethrin was still inside the larvae of the susceptible strain, in comparison with 1.5-5% in the Pakistani strain and 8-14% in the Chinese strain. Both of the resistant strains produced methanol-soluble and water-soluble metabolites, but the susceptible strain produced methanol-soluble metabolites only. By 12, 24 and 48 h after dosing, the amount of methanol-soluble metabolites excreted by the resistant strains was almost double that of the susceptible strain. Both of the resistant strains also excreted 5-7% of the penetrated dose as a water-soluble metabolite after 48 h. In comparison with the Chinese strain, the Pakistani strain exhibited slower penetration, lower internal content and faster excretion of deltamethrin, which correlated with the higher resistance of the Pakistani strain. These findings show that the resistant Pakistani and Chinese strains of H. armigera possess mechanisms of reduced cuticular penetration and enhanced metabolism of deltamethrin and perhaps other pyrethroids.     

The Effect of Short-interval Deltamethrin Applications to Control Tsetse on the Seroprevalence of Babesiosis in Cattle

For the past decade, treatment of cattle with 0.00375% deltamethrin (Decatix, Coopers) at two-weekly intervals has been part of an integrated approach to counteract continuous invasion of Zimbabwe by tsetse from the Mozambique fly-belt. To determine the effect of these regular deltamethrin treatments on the epidemiology of babesiosis, a survey was conducted to estimate the prevalence of antibodies against Babesia bigemina in adult communal cattle. The seroprevalence of antibodies against B. bigemina in adjacent areas, where cattle are treated with short-residual acaricides, was also determined for comparison. The prevalence of antibodies to B. bigemina was much higher in areas where dipping with a non-pyrethroid acaricide was conducted. This was attributed to the successful control of Boophilus spp. and hence a very low level of B. bigemina transmission in the 'deltamethrin treatment zone'. This low level of disease transmission was confirmed by the low prevalence of antibodies against B. bigemina in sentinel cattle that were introduced to the 'deltamethrin treatment zone'. The potential adverse effects of severely reducing the tick population should be taken into consideration at the onset of tsetse control operations in which cattle are to be treated with deltamethrin at short treatment intervals.     

Control of air-borne field spread of tulip breaking virus,lily symptomless virus and lily virus X in lilies by mineral oils,synthetic pyrethroids,and a nematicide in the Netherlands

The inhibitory effect on the spread of viruses in lilies viz., tulip breaking virus (TBV; nonpersistently aphid-borne, potyvirus,) lily symptomless virus (LSV; non-persistently alphidborne, carlavirus), and lily virus X (LVX; potexvirus of unknown etiology), was studied of brands of mineral oil (Luxan oil H and Duphar-7E oil) and synthetic pyrethroid insecticides (l-cyhalothrin and deltamethrin), and a nematicide (aldicarb) in crops in which virus-infected plants were present as virus sources. The spread of TBV and LSV were controlled by sprays of mineral oil and insecticide, while that of LSV was also limited by the soil-applied nematicide. The spread of LVX was reduced by the insecticides and, not effectively by the mineral-oil spraying, by which data the mode of transmission may be presumed to be by an insect in the persistent or semi-persistent manner.Mixtures of mineral oil and pyrethroid were more effective in the reduction of spread of TBV and LSV than either components tested alone. The mineral oil was the most effective component in the mixtures in which pyrethroid added a slight extra effect. The addition of pyrethroid did not mask either the lower efficacy of the oil brand Duphar-7E oil, or the diminished inhibitory effect of low dosages of oil. The normal rate of mineral oil gave similar control to that of a mixture of mineral oil at half rate plus the pyrethroid at full dosage. Low rates of oil, or even synthetic pyrethroids alone may be used on cultivars which suffer of the loss of bulb weight by the use of normal or decreased rates of oil. Weekly sprays were more effective than fortnightly sprays. The rate of control by the weekly sprays ranged between 90 and 95% for Luxan oil H at half dosage plus the full rate of pyrethroid. Weekly sprayed synthetic pyrethroids alone onto the virus sources and the plants to be infected gave 60–70% control. The weight ratios tended to be slightly reduced if the half dosage of the efficient Luxan oil H was used. Factors which affect the control of the air-borne field spread of viruses by mineral oils and synthetic pyrethroid insecticides in lilies are discussed.     

溴氰菊酯降解菌的分离筛选与应用潜力评价

为解决杀虫剂溴氰菊酯的残留污染问题及丰富其降解菌资源库,采用富集培养法,从长期被溴氰菊酯污染的土壤中分离筛选到1株高效降解菌株XQ08,经形态学特征、生理生化及16S rDNA鉴定其为嗜麦芽寡养单胞菌Stenotrophomonas maltophilia,并对菌株发酵条件、菌剂制备方法及应用潜力进行了初步研究。结果表明:在纯培养条件下,XQ08菌株5 d内对50 mg/L溴氰菊酯的降解率可达66.76%;在35 ℃、pH=8及以麦芽糖为碳源、氯化铵为氮源的条件下可获得理想的发酵效果,同时明确了XQ08液体菌剂的制备方法。分别在室内盆栽与田间种植的香菜上喷施高剂量 (推荐剂量10倍,有效成分6.25 g/hm2) 的25 g/L溴氰菊酯乳油,于施药后2、24和48 h施用XQ08菌剂,3、5、7和9 d后,香菜上溴氰菊酯的降解率分别超过20%、50%、60%及70%;7 d后施用菌剂处理组溴氰菊酯残留量均低于0.5 mg/kg,9 d后残留量均低于0.2 mg/kg。本研究首次报道了嗜麦芽寡养单胞菌对溴氰菊酯的降解,发现其XQ08菌剂可有效促进溴氰菊酯的降解,且其降解符合一级动力学特征。嗜麦芽寡养单胞菌XQ08菌株能有效降低或清除蔬菜上的溴氰菊酯残留,具有较好的应用潜力和开发价值。