朱砂叶螨种群动态的模拟预报模型

以河南省虞城县、获加县和灵宝县棉田朱砂叶螨种群动态数据和气象资料为建模材料，通过逐步回归分析分别组建了雌成螨、幼若螨和卵的预报模型。利用该模型对太康县和郑州市棉田朱砂叶螨种群动态进行了模拟，结果表明，该模型具有较高的准确度     

羊螨病及其防控

羊螨病是由痒螨或疥螨等螨类在羊皮肤寄生而引起的一种慢性寄生虫病,主要在秋冬季节发病,其特征是皮肤发炎、剧痒、患部脱毛、消瘦。主要对该病的病原、临床症状及防治措施等作一介绍,以期为有效防治该病提供参考。     

山羊痒螨病对机体抗氧化系统的影响

为了研究山羊痒螨病对机体氧自由基及抗氧化系统的影响,分别对感染山羊和健康山羊GSH-Px、T-SOD、CAT的活力和MDA、LPO的含量进行了测定。试验结果显示,感染组山羊血清中GSH-Px活力极显著低于对照组(P<0.01),T-SOD活力极显著低于对照组(P<0.01),MDA含量显著高于对照组(P<0.05),LPO含量极显著高于对照组(P<0.01);感染组与对照组CAT活力差异不显著。试验结果表明,山羊患痒螨病后,体内氧自由基含量升高,抗氧化酶活力降低,脂质过氧化物含量上升。     

食用菌螨种类研究进展

螨害是食用菌生产的突出问题之一,本文综述了我国食用菌螨种类研究进展现状,目前我国食用菌螨类主要有29科,重点阐述了福建食用菌螨类隶属23科,52种,阐述了国内外食用菌捕食性螨类应用研究情况,对目前存在的问题及应用前景进行了展望,以期为食用菌生产和害螨防治提供理论依据,并为捕食螨的生物学和应用技术研究提供理论参考。     

影响小枕异绒螨发生量和对棉蚜控制作用因素的研究

在江苏射阳7块棉田观察调查的结果表明,小枕异绒螨的幼螨是棉蚜的重要天敌。幼螨发生量随田块和调查时期而不同,一般5月中下旬为发生高峰。5、6月间4次调查,平均每100头蚜虫有幼螨8.8头,最多61.6头,棉蚜平均被寄生率为6.5％,最高34.8％。影响幼螨发生量和棉蚜被寄生率的主要因素有:(1)旱改后连续旱作的年份,(2)茬口,(3)棉田用药治虫。旱作年份长、纯作棉和棉田用药少均对幼螨发生有利,棉蚜的被寄生率也较高。     

An index for selective toxicity of miticides to phytophagous mites and their predators based on orchard trials

Data from nine trials conducted from 1990 to 1998 in apple orchards in Nova Scotia and Quebec, Canada, were used to estimate the predator-prey selectivity of miticides and their potential compatibility with biological control of mites. The European red mite Panonychus ulmi (Koch) was the dominant and more harmful phytophagous species, followed by the apple rust mite, Aculus schlechtendali (Nalepa). Two predacious mites, the phytoseiid, Typhlodromus pyri Sheuten, and the stigmaeid, Zetzellia mali (Ewing), were often found in the orchards. We used one minus the ratio of mite-days in treated plots to those in the control plots as an index of population suppression and toxicity of the miticides. Miticides were then categorized into classes similar to those employed by the International Organization for Biological Control to rate pesticide toxicity to natural enemies of insect and mite pests. Selectivity of miticides was mostly based on toxicity to P ulmi, the major pest, versus toxicity to T pyri, the major predator, with some consideration of the two lesser species, A schlechtendali and Z mali. In most cases, our findings were in accord with other studies. Abamectin and clofentezine had favourable selectivity (more toxic to the two phytophagous mites than to T pyri). The higher recommended rate of pyridaben (450 g ha(-1)) and two rates of spirodiclofen (180 and 240 g ha(-1)) were neutral (equally toxic to pests and predators). The lower rate of pyridaben (216 g ha(-1)), dicofol, formetanate hydrochloride and propargite were unfavourably selective (more toxic to T pyri). A higher than recommended rate of pyridaben (2160 g ha(-1)) applied before bloom was disruptive--P ulmi-days after treatment were actually greater than with the untreated control. P ulmi resistance to dicofol and propargite were probable complicating factors in some of the orchard trials.     

Pneumonyssoides caninum infection – a risk factor for gastric dilatation-volvulus in dogs

The pathophysiology, clinical course and therapeutic management of gastric dilatation-volvulus (GDV) in dogs are well known. However, the aetiology remains elusive. Aerophagia has often been put forward as a contributing cause of GDV. The most common clinical sign in dogs with nasal mite (Pneumonyssoides caninum) infection is reversed sneezing, which may result in aerophagia. A prospective one-year necropsy study was conducted. Of 250 dogs, 17 were GDV cases and, of these, 35% had concurrent nasal mite infection compared to 5% in the control population. Multivariate logistic regression analyses performed using the 187 dogs with complete records included nasal mite infection status, age, weight and gender. Nasal mite infection was found to be the most important risk factor for GDV in this study, with an odds ratio and confidence interval of 27.6 (4.8–157.5). Other risk factors that were marginally significant included weight and age with odds ratios of 1.08 (1.02–1.13) and 1.37 (1.04–1.79), respectively. Gender was not found to be a significant risk factor for GDV. This study suggests that nasal mite infection may contribute to the development of GDV in otherwise predisposed dogs.     

茶树品种对侧多食跗线螨种群的影响

研究结果表明:侧多食跗线螨种群在各品种上的田间密度有明显差异,平均螨量早白尖上最多,906最少。室内该螨在各品种上的发育历期、产仔动态、增长速度、生命参数均有明显差异。雌成螨历期蜀永3号最长,蜀永1号最短;产卵数以早白尖最多,906最少,内禀增长率蜀永3号最大,蜀永1号和906最小。因此,蜀永1号和906抗螨性强,蜀永3号抗螨性弱。     

截形叶螨抗药性主导机制的研究

研究室内汰选培育的截形叶螨(Tetranychus truncatus Ehara)抗性种群表明,截形叶螨抗久效磷的主导机制可能是乙酰胆碱酯酶(AchE)敏感性降低,谷胱甘肽—S—转移酶(GST)和多功能氧化酶(MFO)活性升高。抗三氟氯氰菊酯截形叶螨的主导机制是MFO和羧酸酯酶活性增强,以及羧酸酯酶发生变构,对底物(α—NA)的亲和力(R/S=5)和比活力(R/S=2)上升。生物测定结果TPP、SV_1和PBo对三氟氯氰菊酯都有增效作用,增效比值分别为2、3和6倍。截形叶螨抗三氯杀螨醇的主导机制是GST代谢毒物的能力增强,GST比活力上升(R/S=2),CH_3I对三氯杀螨醇有一定增效作用(2倍)。     

棉花蚜螨繁殖率及棉蚜再猖獗

氰戊菊酯曾对棉蚜有极好的防治效果,而对棉叶螨防治效果极差。棉蚜抗药性的发展使药效发生了变化,近来的试验表明,该药对蚜虫药效很差,对伏蚜根本无效,１００和２００ｐｐｍ对棉蚜已属低浓度,可使其繁殖率增加４－８倍,在田间使用氰戊菊酯可形成大的棉蚜群体。在相同浓度下一般可抑制棉叶蚜群体,使药后存活很少的棉叶螨在种间竞争中处于劣势而使群体越来越小。氰戊菊酯的复配剂－丰收菊酯弥补了氰戊菊酯的不足,可同时控制蚜