Distribution of fenvalerate and permethrin residues on cattle hair following variable application rates of impregnated ear tags

Fenvalerate and permethrin residues on hair of groups of cattle that received either two tags per adult animal or one tag for every other adult animal were determined using gas chromatography over a three-month period in 1987 and 1988. Cattle with two tags had consistently higher residues than cattle with one tag. This difference was statistically significant (P < 0.05) in the first month for residues on the head and in the first two weeks for residues from the body in 1987. Residues on cattle with one tag and without a tag in the same herd were similar (P > 0.05) on each sampling day on all regions. Residues on the hair from the head of cattle with two tags were greater than on the body and rump (P < 0.05) during the first 28 days. Residues found on hair on days 14 and 84 following tag application declined by 80–86% on the head, 73–78% on the body, and 36–86% on the rump. Isomeric compositions of fenvalerate (range 51–61% SR, RS: 39–49% SS, RR) and permethrin (range 61–67% trans: 33–39% cis) were consistent during the study. Rainfall reduced residues on hair.     

A comparison of cypermethrin distribution on cattle hair after application of impregnated ear and tail tags

Ten dairy cows were separated into two groups of five. One group was ear tagged with a PVC ear tag containing 8-5 g kg^?1 cypermethrin in each ear. A PVC strip impregnated with the same quantity of cypermethrin was attached to the tail of each cow in the other group. The concentration of cypermethrin in hair samples from the neck, flanks and the anterior, sides and the posterior of the udder was measured for a period of 10 weeks after application. Concentrations were found to be high in those body areas nearest to the points of application, moderate on the flanks but low on the front and sides of the udder.     

Pesticide residues in fat of cattle treated with backrubbers impregnated with coumaphos,methoxychlor or DDT

Cattle were treated thrice weekly for 12 weeks with simulated backrubbers impregnated with 1% solutions of pesticides in mineral oils. Both coumaphos and methoxychlor applied in S.A.E. 50 oil induced maximum residues of 0–21 ppm in omental fat after 12 weeks treatment. Application of DDT in S.A.E. 50 oil or in used crankcase oil induced residues of 0·5–7 ppm DDT in omental fat after 12 weeks treatment. Where diesel fuel oil was the vehicle, DDT residues in omental fat were in the range 17–26ppm.     

Transfer of insecticide residues to food stored on or near plywood impregnated with organochlorine insecticides

Formulations of aldrin and dieldrin have been used for a number of years to treat exposed timber components used in the construction of freight containers. The extent to which these insecticides migrate to foodstuffs stored on or near treated plywood has been examined under laboratory conditions and is reported here. A limited survey of organochlorine insecticide residues in samples of foodstuffs, taken from commercial loads carried in freight containers, indicated that residue levels are unlikely to present a health hazard.     

尾菜再生水灌溉对土壤酶活性与重金属含量的影响

为探究尾菜再生水灌溉对土壤酶活性和重金属含量的影响，采用室内土柱模拟试验，分别以尾菜再生水(VW)和自来水(TW)为灌溉水，设置充分灌溉(90%田间持水量，09FC)和非充分灌溉(70%田间持水量，07FC)2个灌水水平，以18 d为1个灌水周期，累计灌溉16期，分别在第72、144、216、288 d进行分层取样，测定土壤过氧化氢酶(CAT)、脲酶(UE)、蔗糖酶(IA)、碱性磷酸酶(ALP)活性及重金属(Pb、Zn、Cr、Cd、Cu)含量的时空变化特征，并对各处理进行相关性分析和潜在生态风险评价。结果显示，与TW-07FC处理相比，长期再生水非充分灌溉0～20 cm土层土壤UE、IA活性分别显著提高了31.36%和6.55%;与TW-09FC处理相比，再生水充分灌溉ALP活性显著提高了15.63%,CAT活性无显著性变化；随着灌溉次数的增加，再生水2个灌水水平均会增加土壤Pb、Cr、Zn含量，但增加效果不显著，土壤Cd含量与自来水灌溉相比无显著变化(P>0.05),土壤Cu含量有降低的趋势；由相关性分析可知，CAT活性与Cu、Zn含量呈极显著正相关关系(P<0.01);...     

玉米雌穗挥发物对亚洲玉米螟幼虫取食选择的影响

为了探明玉米雌穗挥发物组成及其对亚洲玉米螟(Ostrinia furnacalis)幼虫取食行为的影响,本研究利用顶空吸附法及气相色谱/质谱联用技术(GC/MS)测定了离体玉米雌穗的挥发物组分,并通过幼虫取食选择试验测定了11种玉米雌穗挥发物在4个不同浓度下(5×10-6、5×10-5、5×10-4、5×10-3g/mL,正己烷为溶剂)对亚洲玉米螟取食行为的影响。结果表明:从离体玉米雌穗中共计收集并鉴定出32种挥发物组分,主要包括绿叶气味物质、萜类化合物和脂肪族化合物。其中,萜类化合物的含量最高,占玉米雌穗挥发物总释放量的84.40%。在所有测定的浓度范围内,β-石竹烯、十四烷表现为引诱活性,壬醛表现为驱避作用。除浓度为5×10-3 g/mL外,癸烷、反-罗勒烯、6-甲基-5-庚烯-2-酮对幼虫取食表现为引诱作用。     

玉米穗、茎腐病镰刀菌相互关系的同工酶分析

对沈阳、河北、北京、吉林等地区玉米穗、茎腐病禾谷镰刀菌和串珠镰刀菌进行了可溶性蛋白和同工酶的聚丙烯酰胺凝胶电泳。以研究玉米穗、茎腐病镰刀菌在病原学上的相互关系。结果表明：各地区玉米穗、茎腐病串珠镰刀菌均具有高度的同源性,相似系数在0．89～0．98之间,菌株间差异表现为个体间多样性。两种病害禾谷镰刀菌病原学的相互关系因地域不同而不同。河北、吉林两地区穗、茎腐病禾谷镰刀菌间均未发现生理分化现象,相似系数均在0．93以上。沈阳地区玉米穗、茎腐病存在明显的生理分化现象,相似系数仅为0．65～0．67。     

玉米穗腐病和茎腐病镰孢菌病原学相互关系及遗传多态性研究

 本文从体内传播和体外传播2条途径,研究了玉米穗、茎腐病串珠镰孢菌(Fusarium moniliforme)和禾谷镰孢菌(Fusarium graminearum)在侵染循环上的相互联系,并运用营养亲和性、血清学、同工酶电泳和RAPD分析4种方法,从营养体、蛋白质、核酸3个不同层次,对北方地区玉米穗腐病镰孢菌和茎腐病镰孢菌在病原学上的相互关系进行了全面的研究,同时对北方地区玉米穗、茎腐病镰孢菌的遗传多态性进行了研究。     

Observations on the morphology of the hair follicle mites (Acari: Demodicidae) from Cervus elaphus L., 1758 including description of Demodex acutipes sp. n

Morphology of Demodex acutipes sp. n. and Demodex sp. parasitizing the red deer, Cervus elaphus L., 1758 is described and diagnostic characters of three Demodex species from this host are compared.