桂北地区柑橘全爪螨对6种药剂的抗药性测定

柑橘全爪螨(Panonychus citri McGregor)是柑橘上的重要害虫,目前主要通过化学药剂对其进行防治,但由于长期以来化学药剂的不合理使用使得其对不同杀螨剂产生了不同程度的抗性。通过对监测数据的分析能够更好的指导田间用药,为实际生产中柑橘全爪螨的防治与其抗药性治理提供理论依据。2021年采用叶碟浸渍法对广西桂林临桂区和灵川县两个柑橘全爪螨田间种群进行了抗药性测定。结果标明：桂林临桂、灵川两地柑橘全爪螨田间种群对乙唑螨腈、联苯肼酯、阿维菌素和乙螨唑均已产生高水平抗性(105.6-572.0倍);且对哒螨灵和螺螨酯也产生了中等水平抗性(44.8-96.2倍)。生产上应减少阿维菌素、联苯肼酯和乙螨唑的使用,应合理的进行复配,并结合其他防治措施进行综合防治,保障我国柑橘产量与品质。     

柑橘全爪螨环境相容性农药筛选

从257个柑橘全爪螨田间药效试验中筛选到17种比较好的药剂。对这些药剂的种类和作用特点、使用浓度、防治效果、速效性、持效期、防治技术要点进行了分析和总结,提出了柑橘全爪螨的防控以矿物油为主,其他药剂为辅的综合防治的观点,为绿色柑橘生产中叶螨的防控提供了理论基础。     

桂林地区柑橘全爪螨对几种杀螨剂抗药性分析

为了解近期桂林地区柑橘全爪螨抗药性发展情况,本文采用浸叶法调查了柑橘全爪螨对几种杀螨剂的抗药性,结果表明,对尼索朗,柑橘全爪螨卵抗性倍数为中抗水平,若螨抗性为低抗水平,雌成螨敏感性降低水平;对四螨嗪,柑橘全爪螨卵、若螨、雌成螨均处于低抗水平;对阿维菌素,柑橘全爪螨卵为低抗水平阶段,若螨和雌成螨处于敏感性降低水平;对克螨特和乙螨唑,柑橘全爪螨卵、若螨、雌成螨均没有产生抗性。由于尼索朗、四螨嗪、乙螨唑同属螨虫生长抑制剂,而尼索朗和四螨嗪已出现抗性,可以考虑乙螨唑-阿维菌素-克螨特轮换使用。     

万州果园柑橘全爪螨对不同浓度杀螨剂敏感度比较2

试验选取最新8种杀螨剂进行柑橘全爪螨敏感度试验,结果表明：施药初期柑橘全爪螨敏感度最低的药剂是联苯菊酯乳油,但在后期对该药剂表现出一定的抗药性。害螨对螺螨酯悬浮剂和联苯肼酯悬浮剂的初始敏感度较高,但随着时间的延长,对该药剂越来越敏感。对于5%阿维菌素微囊悬浮剂、20%哒螨灵悬浮剂、20%乙螨唑悬浮剂、22.4%螺虫乙酯悬浮剂、50%丙溴磷乳油,害螨一直处于较为敏感的阶段,施药后30天的死亡率在98%以上,害螨还未对这几种药剂产生抗药性,是万州果园害螨防控的良好备选药剂。     

柑桔全爪螨抗性分子机理研究取得重要进展

柑桔全爪螨又名柑桔红蜘蛛,是一种世界性害螨,在我国各柑桔产区为害特别严重。目前,化学防治仍是控制柑桔全爪螨最为有效的措施,但由于其个体小、世代多、繁殖力强,对药剂极易产生抗性。尽管柑桔全爪螨抗性极其严重,但确切的抗性分子机理仍不明确。     

柑橘全爪螨不同品系谷胱甘肽S-转移酶基因表达差异分析

为了明确谷胱甘肽S-转移酶（glutathion S-transferases, GSTs）基因与柑橘全爪螨抗性的关系,通过BLAST搜索,对柑橘全爪螨转录组数据库的GST基因进行鉴定,应用MEGA4.0.1软件对GST基因进行同源与进化分析,进一步采用RPKM法对柑橘全爪螨敏感品系和噻螨酮抗性品系GST基因进行表达差异分析。从柑橘全爪螨转录组中获得了30条GST基因,其中11条基因属于Delta家族,10条属于Mu家族,2条属于Omega家族,6条属于Kappa家族,1条属于Zeta家族。基因表达差异分析发现,抗性与敏感品系当中有25条GST基因表达量存在差异,抗性品系中有9条GST基因发生了上调,16条发生了下调,其中上调倍数最高的是GSTd6[log2 Ratio(RS/SS)= 1.0505],由此推断,GST基因的上调可能不是柑橘全爪螨对噻螨酮产生抗性的重要原因。     

诱蝇球对柑橘大实蝇防治的研究进展

柑橘大实蝇是危害我国柑橘产业发展的重大害虫之一。传统物理防控、化学防控和理化诱控方法难以清除虫源,易增强实蝇抗药性,诱杀效果不强,而诱蝇球作为一款新型理化诱控产品,能有效克服常规防控方法的不足。本文综述了诱蝇球的起源,并从诱蝇球的制作材料、球体直径、球体颜色和诱杀策略等方面分析了其诱杀效果的改良。与其它防控方法相比,改良后的诱蝇球成本低,操作简单,绿色环保,效果直观,在柑橘病虫害监测和防治中取得了良好成效,对促进我国柑橘产业健康可持续发展具有重要意义。     

蜂螨抗药性对杀螨剂品种发展的影响

随着有机合成杀螨剂使用量的增加 ,蜂螨对其抗性越来越明显 ,特别是对药效高、选择性强的药剂产生抗性更快 ,已成为蜂螨防治的一大难题。抗药性的形成和发展不仅对养蜂生产造成的损失越来越严重 ,同时将对新杀螨品种的开发研究造成许多影响。蜂螨抗药性对杀螨剂品种发展的影响 ,可以归纳为几个方面 :一、抗药性发展与杀螨剂品种类型的关系蜂螨对不同类型杀螨剂产生抗性快慢和抗性的高低 ,有显著的差异。它决定着这些药剂的使用寿命。一般地讲 ,蜂螨对无机杀螨剂和天然植物杀螨剂不易产生抗性。如硫磺、升华硫 ,自蜂螨 1 96 0年发生前后开始…     

苹果叶螨类猖獗成因及防治技术

1　种群分布为害苹果的叶螨主要有山楂叶螨、苹果全爪螨和苜蓿叶螨等三种。三种叶螨的分布及为害在我国北方果区各有主次不同 ,而且在同一地区 ,不同时期 ,主次的种类也有所变化。山楂叶螨分布最广 ,为害最重 ;苹果全爪螨分布区域在发展 ,为害逐年加重 ;苜蓿叶螨仅局部地区发生较重。2　猖獗成因叶螨的猖獗发生和为害是多种因素综合作用的结果。叶螨繁育力强 ,一年发生代数多 ,对环境适应性强 ,这是造成猖獗的基本条件。但是造成猖獗发生 ,与气候、食料和天敌等因素及药剂防治所引起的副作用有密切关系。2 1　气候条件。夏季高温干旱是促使…     

丁硫克百威20%乳油防治柑橘锈壁虱效果评价

摘要：柑橘锈壁虱(Eriophyes oleivorus),是湖南安化县柑橘主要害螨之一,为了筛选出安全、高效和低毒药剂防治该螨,在2011和2012年,进行了20%丁硫克百威乳油与24%螺螨脂悬浮剂等5种杀螨剂田间药效对比试验,并通过测定药后柑橘的铜果率对其商品性进行了评价。结果表明20%丁硫克百威乳油对柑橘锈壁虱成螨、若螨速效性最好,持效期最长,防治效果最显著。此外,螺螨脂24%悬浮剂也有较好的防效,二者可在生产中交替轮换使用,以避免害螨对单一药剂抗生抗药性。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein