益害比及花粉存在对江原钝绥螨和柑橘全爪螨种群动态的影响

研究了在以不同益害比释放江原钝绥螨的情况下,益害比及花粉存在对江原钝绥螨捕食效果的影响.结果表明,当柑橘全爪螨平均每片叶低于5头时,按益害比1:10和1:20的比例释放江原钝绥螨,当平均每片叶柑橘全爪螨多于5头时,按益害比1:5释放江原钝绥螨,可将柑橘全爪螨数量控制在经济阈值以下.花粉的存在能减缓猎物密度下降对江原钝绥...     

西葫芦病毒病和螨虫危害症状识别的关键及防治

为了有效、正确地防治西葫芦病毒病及螨虫,需要对其进行正确识别,在介绍病毒病和螨虫危害症状及田间识别的基础上,从田间再侵染速度、危害症状、结瓜数量、受害植株生长可逆性等方面介绍了病毒病和螨虫区别的关键点,并总结了防治对策,其中病毒病防治采取"防虫致病,加强栽培管理,提高植株本身抗病性"的防治对策,螨虫防治采取化学药剂喷雾...     

A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91)

Abstract The medical records of 81 dogs (47 juvenile, 34 adult) with generalized demodicosis were reviewed. There was a significant difference in the distribution of breeds (juvenile P < 0.002, adult P < 0.001; chi squared) presented for demodicosis compared with the distribution of the same breeds presented to our practice during the same time period. Cocker Spaniels and mixed-breed dogs were likely to be under-represented in both the adult- and juvenile-onset groups. Significantly more miticidal treatments were required to achieve clinical remission in adult dogs with pustular demodicosis compared with juvenile dogs with pustular disease (P < 0.05; Kruskall-Wallis). Concurrent disease and associated drug administration were assessed for adult dogs with demodicosis. Of dogs with concurrent conditions (n=15), administration of corticosteroids and endogenous hyperadrenocorticism were recognized most often (10/15). Concurrent neoplastic, infectious, parasitic or metabolic disease was uncommon in dogs with adult-onset demodicosis. Résumé— Les dossiers médicaux de 81 chiens présentant des démodécies généralisées (47 formes juvéniles, 34 formes adultes) ont été analysés. Il existait une différence significative (forme juvénile P < 0.002, forme adulte P < 0.001) dans la distribution des races présentées pour démodécie par rapport aux mêmes races présentées à notre consultation à la même époque. Les cockers spaniels et les chiens métissés sont sous - représentés dans les deux groupes. Le nombre de traitements acaricides nécessaires pour obtenir une rémission clinique était significativement plus élevé chez les chiens adultes présentant une démodécie pustulcuse que chez les jeunes (P < 0.05; Kruskall-Wallis). La présence de pathologies intercurrentes ou iatrogènes a été recherchée chez les chiens adultes. Chez les chiens présentant une pathologie intercurrente (n=15), les diagnostics les plus fréquents (10/15), étaient l'administration de corticoïdes ou un hypercorticisme endogène. Une pathologie intercurrente de type néoplasique, infectieuse, parasitaire ou métabolique est rarement associée à la forme adulte de démodécie canine. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Analyse retrospective de formes juveniles et de formes adultes de demodecie generalisee chez le chien (1986–91). Veterinary Dermatology 1996; 7 : 3–10.] Resumen Se revisó la historia médica de 81 perros (47 jóvenes, 34 adultos) con demodicosis generalizada. Habia diferencias significativas en la distribución de razas (jóvenes P < 0.002, adulto P < 0.001; chi cuadrado) con una presentación de demodicosis comparado con la distribución de las mismas razas que se presentaron en nuestra consulta durante el mismo período. Los Cocker Spaniel y los cruzados tenían menos posibilidades de presentarse tanto en el grupo de perros jóvenes como en el de adultos. Se necesitaron tratamientos significativamente más miticidas para consequir curación clínica en los perros adultos con demodicosis pustular comparado con los perros jóvenes con presentación pustular (P < 0.05; Kruskall-Wallis). Se detectaron con mayor frecuencia enfermedades concomitantes (n = 15), administración de corticosteroides e hiperadrenocorticismo endógeno (10/15). Fueron poco frecuentes las enfermedades neoplásicas, infecciosas, parasíticas o metabólicas en los casos de demodicosis del adulto. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Estudio retrospectivo de la demodicosis canina en el adulto y en el perro joven (1986–91). Veterinary Dermatology 1996; 7 : 3–10.] Zusammenfassung— Die Krankenblätter von 81 Hunden (47 juvenil, 34 adult) mit generalisierter Demodikose kamen zur Auswertung. Es bestand einer signifikanter Unterschied in der Verteilung der Rassen (juvenil P < 0,002, adult P < 0,001; Chi-quadrat), die wegen Demodikose vorgestellt wurden, im Vergleich zur der Verteilung der selben Rassen, die während des gleichen Zeitabschnitts in unserer Praxis kamen. Cockerspaniel und Mischlinge schienen unterrepräsentiert sowohl in der Adult- wie in der Juvenil-Demodikosegruppe. Es wurden signifikant mehr akarizide Behandlungen für das Erreichen einer klinischen Remission bei adulten. Hunden mit pustulärer Demodikose benötigt im Vergleich zu juvenilen Hunden mit pustulärer Erkrankung (P < 0,05; Kruskall-Wallis). Bestehende Krankheit und die damit verbundene Arzneimittelanwendung wurden bei adulten Hunden mit Demodikose ausgewertet. Bei Hunden mit bestehenden Krankheitsbildern (n = 15) wurde am häufigsten die Verabreichung von Kortikosteroiden und endogener Hyperadrenokortizismus festgestellt (10/15). Gleichzeitige neoplastische, infektiöse, parasitäre oder stoffwechselbedingte Erkrankung war bei Hunden mit adult-beginnender Demodikose selten. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Retrospektive Studie über juvenil- und adult-beginnende Demodikose beim Hund (1986–91). Veterinary Dermatology 1996; 7 : 3–10.]     

杀虫剂对朱砂叶螨扩散行为及繁殖力的影响

４种扩散试验法证明氧化乐果,杀虫脒,溴氰菊酯和氰戊菊酯对朱砂叶螨有较强的刺激扩散作用,扩散率基本随药剂浓度增加而升高,扩散高峰在施药后２４ｈ,叶螨对药剂处理叶（株）有很强的忌避性。３种激发生殖力试验证明,１１种农药中,增殖最大又持久的４种,且逐日上升;抑制力高又持久的２种,并逐步下降;５种居中,即先抑制后增殖,而且增殖作用还包括直接和间接两种。这些可能是引起叶螨再猖獗的重要原因。     

Spiromesifen resistance in Tetranychus urticae (Acari: Tetranychidae): Selection,stability, and monitoring

The two-spotted spider mite, Tetranychus urticae Koch, is an important pest of many agricultural crops. Studies on artificial selections, stability of resistance and monitoring of spiromesifen resistance were carried out to provide basic information for a spiromesifen resistance management program in T. urticae. Artificial laboratory selections for resistance to spiromesifen were performed in a population originating from a mixture of four field populations collected in commercial chrysanthemum fields in the State of São Paulo, Brazil. After 20 cycles of selection for spiromesifen resistance, the resistance ratio (RR₅₀) reached 121. Spiromesifen resistance was shown to be unstable in the absence of selection pressure under laboratory conditions. The frequency of spiromesifen resistance decreased from 75 to 0.15% in six months. The evaluation of 23 T. urticae populations from several crops in the States of Goiás, Mato Grosso and São Paulo in Brazil indicated that the susceptibility of the spider mites to spiromesifen was variable, with percentages of resistant mites ranging from 0.0 to 81.5%. The highest resistance frequencies were observed in ornamental plants (roses and chrysanthemum) in the State of São Paulo. Populations of T. urticae with up to 29.8% resistant mites were also detected in strawberry fields, in the same State. This is the first report on spiromesifen resistance in T. urticae on several crops in Brazil. Strategies for the management of acaricide resistance are discussed.     

胡瓜钝绥螨控制大棚甜椒烟粉虱的研究

在我国山东省寿光市的蔬菜基地开展利用胡瓜钝绥螨控制日光大棚甜椒烟粉虱的研究.结果表明:(1)胡瓜钝绥螨能够捕食烟粉虱卵、成虫、若虫和伪蛹.在(25±1)℃、(30±1)℃、(35±1)℃下胡瓜钝绥螨以烟粉虱为猎物的发育历期与其取食柑橘全爪螨Panonychus citri(Mc Gregor)和二斑叶螨Tetranyc...     

基于光谱反射率的果树病虫害级别定量化测评

【目的】 分析红富士苹果树分别在各级红蜘蛛虫害、黄叶病害胁迫下的反射光谱特征,并利用光谱数据对果树受害程度进行定量化测评。【方法】 于2007年6~7月,在陕西省礼泉县测定了患有各级红蜘蛛虫害、黄叶病害果树的光谱反射率,将正常、轻度、中度、重度受害果树的光谱反射率分别记为R_正常、R_轻度、R_中度、R_重度。首先,在对光谱数据进行预处理和一阶微分变换的基础上,对各级红蜘蛛虫害、黄叶病害胁迫下果树的光谱特征分别进行分析;随后,基于各级红蜘蛛虫害、黄叶病害对应的光谱特征,分别构造了6种光谱指数,并从中择优建立对红蜘蛛虫害、黄叶病害级别进行测评的数学模型;最后,利用检验样本果树的反射光谱分别对所建立的红蜘蛛虫害、黄叶病害级别测评模型的精度进行检验。【结果】 各级红蜘蛛虫害对应的反射光谱在630～695 nm,R_重度＞R_中度＞R_轻度＞R_正常,且在684 nm处变异系数最大;在730～950 nm,R_重度＜R_中度＜R_轻度＜R_正常,且在762 nm处变异系数最大。各级黄叶病害对应的反射光谱在515～716 nm,R_重度＞R_中度＞R_轻度＞R_正常,且在603 nm处变异系数最大;在740～950 nm,R_重度＜R_中度＜R_轻度＜R_正常,且在764 nm处变异系数最大。果树反射光谱的“红边”位置随虫害、病害程度的加重而依次发生“蓝移”。建立的红蜘蛛虫害、黄叶病害级别测评模型对相应虫害、病害级别的测评准确率分别为96%,98%。【结论】 各级红蜘蛛虫害、黄叶病害胁迫下的红富士苹果树的反射光谱差异较大,利用光谱数据可精确地对各级红蜘蛛虫害、黄叶病害级别进行定量化测评。     

The Measurement of Brown Leaf Spot on Rice

Abstract

To obtain the potential range in disease development, a progressive increase in spore concentration of the imperfect state of Cochliobolus miyabeanus was used on twelve rice varieties differing in their resistance to brown leaf spot. An analysis of the relative contributory effect of increase in lesion size and numbers on the percentage leaf area diseased was used as a basis to develop a quantitative scoring method in chart form for brown spot disease. The chart was aided by the provision of diagrams of the different categories in disease intensity. The usefulness of this disease scoring chart and its limitations are discussed. Other methods of assessment are proposed to overcome the limitations especially in respect of varietal resistance and seedling blights.     

Synthetic Pyrethroid Insecticides: Some Studies with Locusts

Abstract

Laboratory studies were carried out to determine the course of poisoning and toxicity of some synthetic pyrethroid insecticides (bioresmethrin, cismethrin, cypermethrin, deltamethrin, fenpropathrin, fenvalerate and permethrin) against the desert locust. From doses in excess of the LD₉₉ all the insecticides were quick acting; from doses of about the LD₉₉ or less the insects are rapidly knocked down or show symptoms of poisoning, but may recover. The symptoms which follow treatment by the various insecticides are described. Although these insecticides are all highly toxic to locusts there are many other insecticides which are similarly toxic, can be sprayed at high concentrations and are much cheaper.