我国柑橘全爪螨发生及防控研究概况

柑橘全爪螨Panonychus citri McGregor是柑橘上的重要害螨,严重影响柑橘产量和品质。我国作为柑橘生产第一大国,做好柑橘全爪螨的防控意义重大。研究其发生规律、防治技术、抗药性等是做好防控的重要环节。现阶段我国采取以化学防治为主,多种防治手段并存的综合防治策略,化学药剂防治由于其见效快、成本低、防治效果好,能及时的挽回经济损失,是当前我国防治柑橘全爪螨的最有力措施。但近年来柑橘全爪螨对各药剂的抗性发展迅速,因此为解决“3R”问题生物防治也成为我国研究的热点。除此之外,在柑橘全爪螨对各药剂均产生不同程度抗性的情况下,更应该致力于研究发展生物防治等其他绿色防控措施,并密切关注田间柑橘全爪螨抗性发展变化。本文综述了我国柑橘全爪螨发生因子、防治技术、抗药性等研究进展,并提出进一步的研究策略,为防治柑橘全爪螨提供一定的理论依据。     

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。     

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。     

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。     

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。     

乙螨唑对柑橘全爪螨的室内毒力测定

测定了乙螨唑等五种杀螨剂对柑橘全爪螨雌成螨、幼螨和卵的室内毒杀活性,结果表明,乙螨唑对柑橘全爪螨雌成螨、幼螨具有很高的触杀毒力, LC50值分别为41.3 ug/ml和22.5 ug/ml,不及阿维菌素毒力 （LC50值分别为9.4ug/ml和11.3ug/ml）;;乙螨唑对卵的毒杀活性是23.5ug/ml,是常用杀螨剂阿维菌素、尼索朗的1.6倍。此研究为乙螨唑在柑橘生产中的广泛使用提供了参考。     

最新杀螨剂乙唑螨腈对柑桔全爪螨的室内毒力及田间防效

采用玻片浸渍法测定了30%乙唑螨腈悬浮剂对柑桔全爪螨的毒力,并通过田间药效试验检验30%乙唑螨腈悬浮剂对柑桔全爪螨的防治效果。室内毒力结果表明,30%乙唑螨腈悬浮剂对柑桔全爪螨雌成螨24h的LC50为0.3998mg/L, 48h的LC50为0.1714 mg/L。田间药效试验结果表明,30%乙唑螨腈悬浮剂对柑桔全爪螨具有较高的防治效果,其速效性好,持效期亦长,药后1d,高浓度（3000倍）的防效达92.77%,低浓度（6000倍）的防效亦达83.42%,药后3d,各处理浓度的防效均达94%以上,28d后防效仍保持在91%以上,是目前桔园防治柑桔全爪螨较理想的药剂。该药剂试验剂量范围内未发现对柑桔产生药害, 对天敌较安全,可以在生产上大面积推广应用。     

一种柑橘防日灼喷白方法

发明了一种柑橘喷白防治技术,主要是利用喷白涂料+水为试材,在连续日最高温30℃以上时,采用柑橘树体全株喷白的方式,能够有效预防柑橘日灼病,且通过调节配方可以有效降低柑橘全爪螨、柑橘锈瘿螨和柑橘溃疡病的发生率,适宜在易发生柑橘日灼病的高温地区推广使用。以茂谷柑为试材,采用此防日灼喷白处理,结果表明果实生长发育速度和果实内在品质与不喷白的对照无显著差异,且能提高果实的外观品质。     

双甲脒等药剂防治榆（苹）全爪螨的试验简报

双甲脒等药剂防治榆（苹）全爪螨的试验简报云南省楚雄州植保植检站王新生，王贵斌榆（苹）全爪螨，ＰａｎｏｎｙｃｈｕｓｕｌｍｉＫｏｃｈ。俗称红蜘蛛，属蛛形纲婢螨目，叶螨科。在云南省楚雄，陆良等广大蚕桑区普遍发生。近几年来，为害日趋严重。为此，我们用双甲眯等...     

乙螨唑及其复配剂对柑橘全爪螨田间药效试验

田间药效试验结果表明,20%乙螨唑悬浮剂6000～8000倍液和25%阿维菌素o乙螨唑悬浮剂10000～6000倍液对柑橘全爪螨速效性好,持效期长达30天,20%乙螨唑悬浮剂6000～8000倍液药后1-30天,6000、8000倍液防效保持在90.84-100%之间;25%阿维菌素·乙螨唑悬浮剂10000～6000倍液药后1-30天,防效保持在90.92-100%。试验剂量范围内未发现药剂对柑橘产生药害,对天敌比较安全。     

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.     

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.     

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.     

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