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.     

刺激稻飞虱再增猖獗的试验研究

在湖南宁乡经２ａ早、晚稻大田试验表明，三唑磷在水稻分蘖期施用可引起穗期稻飞虱数量的明显增加，建议慎用。     

川滇无患子提取物用于农药的生物活性研究

本文研究了川滇无患子果实不同部位提取物对小菜蛾、甘蓝蚜的生物活性,以及川滇无患子果皮提取物与吡虫啉、阿维菌素复配后的混合物对甘蓝蚜、小菜蛾的生物活性。研究结果表明:川滇无患子果皮提取物对小菜蛾幼虫有较好的致死率,而且对其化蛹和羽化也有较好的抑制作用;在对蚜虫致死作用上,川滇无患子果皮、果仁提取物对甘蓝蚜都有较好的生物活性。川滇无患子果皮提取物与吡虫啉复配后能明显提高吡虫啉对甘蓝蚜的生物活性,但对提高阿维菌素对小菜蛾的生物活性不明显。     

Methacrifos as a grain protectant: A comparison of the vapour effects of some organophosphorus insecticides used in grain protection

A simple Sradiochemical method was devised for the estimation at ambient temperatures of vapour uptake and toxicity of relatively non-volatile organophosphorus insecticides to the red flour beetle Tribolium castaneum. Over a three-day period the insecticides pirimiphos-methyl and chlorpyrifos-methyl exhibited no vapour activity and only small amounts of vapour were accumulated by test insects. Methacrifos appeared to be much more active as a vapour and much of its toxic action in an ideal situation could be attributed to this phenomenon.     

Studies on the possible formation of polychloroazobenzenes in quintozene treated soil

Treatment of different soils with quintozene at a level of 1000 parts/10⁶ and incubation for 24 days at 30 °C did not result in the formation of polychloroazobenzenes, although pentachloroaniline was formed. This negative finding is in line with previous work, where it was shown that azobenzenes can only be formed from substituted anilines with at least one free ortho position. Soil activity was demonstrated by incubation of 3,4-dichloroaniline under similar conditions yielding the expected 3,3′,4,4′-tetrachloroazobenzene. Mass fragmentography with a quadrupole mass spectrometer was used for the detection of polychloroazobenzenes. Mass spectra for the synthesised reference compounds are presented.     

Botrytis cinerea in stored cabbage: the use of germ-tube growth on leaf discs as an indicator of potential head rot

The growth of germ-tubes of Botrytis cinerea at 24°C on leaf discs of six cabbage cultivars taken from heads prior to storage, was directly related to the proportion of whole heads developing rots caused by Botrytis during storage for 6 months at 1–2°C. Dipping heads in iprodione before cold storage substantially reduced losses, particularly in the most susceptible cultivar (Decema Extra). Both leaf disc assays of germ-tube growth and studies of whole heads in store indicated significant and similarly ranked differences in cultivar susceptibility.     

A three‐year field study on the short‐term effects of insecticides used to control cereal aphids on plant‐dwelling aphid predators in winter wheat

Short‐term effects of six insecticides used to control aphids were assessed in wheat on plant‐dwelling aphid predators. Products were applied to small plots of winter wheat in June or at the beginning of July and the densities of predators were estimated three days after treatment using a beating method. Insecticides were tested in 1994, 1995 and 1997 at a single dose, corresponding to their maximum recommended field rate in Belgium. Fluvalinate and esfenvalerate did not significantly reduce catches of syrphid larvae compared to the control but ladybirds were affected by these compounds. Pirimicarb was the only product tested that had no effect on ladybirds. However, syrphid larvae appeared sensitive to this product. Cyfluthrin, deltamethrin and phosalone reduced catches of both syrphids and ladybirds. Populations of lacewing larvae were unaffected by any of the insecticide treatments. Syrphid larvae were the most abundant aphid predator and Episyrphus balteatus the most common species. Ladybirds (Coccinella septempunctata and Propylea quatuordecimpunctata) were less numerous and only a few Chrysoperla carnea larvae were recorded. These results indicate that products that are less toxic to syrphid larvae, like esfenvalerate and fluvalinate, may be preferable to other compounds to control cereal aphids in wheat in spring and early summer. However, other criteria, such as the effectiveness of the different aphid‐specific predators, cost, efficacy of the treatment and side effects on other aphid antagonists (including parasitic hymenoptera and polyphagous predators) must also be taken into consideration. © 2000 Society of Chemical Industry     

Studies on the action mechanism of benzoylurea insecticides to inhibit the process of chitin synthesis in insects: A review on the status of research activities in the past, the present and the future prospects

In this review an effort was made to summarize the up to date information on the knowledge on the action mechanism of diflubenzuron (DFB), a prototype chemical for the benzoylurea type insecticides, with respect to its molecular mechanism to inhibit insect chitin synthesis. The key problem in pinpointing the action site of this insecticide has been the lack of in vitro demonstration of its action to inhibit insect chitin synthesis under cell free conditions. This problem was solved when an approach using a intracellular vesicle preparation from the cuticle of newly molted Periplaneta americana was developed. Using this approach it has become possible to identify that DFB indeed inhibits the process of incorporation of N-acetylglucosamine into insect chitin. Recently there has been a breakthrough in this field, when a sulfonylurea receptor (SUR) was identified in Drosophila melanogaster. This information was instrumental in establishing that insect SUR in the above intracellular vesicular preparation from P. americana as well as Blattella germanica is likely the actual target site of DFB to cause inhibition of chitin synthesis. The role of SUR in this case has been determined, by using glibenclamide, a typical SUR specific inhibitor as an aid, to be helping the exocytotic movement of these vesicles as is the case of other members of the group of ABC-transporters to which insect SUR belongs. In this case both DFB and glibenclamide have been shown to cause the depolarization of the vesicle membrane through inhibition of the K⁺ channel, which leads to their inhibition of chitin synthesis.     

大麦黄矮病毒-GAV在燕麦植株体内运动规律的初步研究

 利用RT-PCR方法研究了大麦黄矮病毒-GAV在燕麦植株内的移动规律。先将介体麦二叉蚜(Schizaphis graminum)在BYDV-GAV新鲜病叶上饲毒,再将获毒蚜虫放置到二叶期的健康燕麦植株接种48h,随后分期提取接种植株的第1~6片叶和根组织的总RNA,利用特异引物扩增BYDV-GAV的外壳蛋白(CP)基因以检测病毒在燕麦植株内的复制和移动。结果表明,在接种5d后,接种叶片(第2片叶)呈现阳性,接种7d后,植株新生的第4片叶被侵染,接种9d后,部分的第3片叶呈现阳性,至接种16d,几乎所有的叶片均呈现阳性。仅在接种的第5、7和9d收集的根组织呈现阳性,而所有的第1片叶均为阴性,可能是由于这些组织内病毒含量太低所致。本研究初步揭示了BYDV-GAV长距离运动的规律并且发现该病毒在燕麦根部从接种到系统发病都没有进行大量增殖,为今后进一步研究病毒运动机制选取适当的植物材料提供了基本信息。     

Studies on the control of zucchini yellow mosaic virus in courgettes by mild strain protection

Mild-strain cross protection was used in field trials at Wellesbourne and in Jersey in attempts to protect courgette plants against severe strains of zucchini yellow mosaic virus. Test plants were sap inoculated with the mild strain and then challenged by an aphid-transmitted severe strain after different periods. Approximately 14 days of incubation were required following mild-strain inoculation to provide protection against subsequent infection by severe strains. No protection occurred if severe strains were introduced 2 days (48 h) after mild-strain inoculation and protection was intermediate if the severe-strain challenge occurred after 7–8 days. Some breakdown in protection occurred in the later stages of the trial at Wellesbourne, but not in Jersey. This loss of protection may be associated with high inoculum pressures.     

枣疯病过氧化物酶及苯丙氨酸解氨酶的研究

采用分光光度计和不连续聚丙烯酰胺凝胶电泳,比较分析了不同枣树品种及株系接入病原植原体后,其过氧化物酶及同工酶和苯丙氨酸解氨酶的变化。结果表明:同一枣树品种,不同发病程度的株系间过氧化物酶活性和同工酶有一定差异,抗病品种苯丙氨酸解氨酶活性高于感病品种。这两项可作为研究枣树抗枣疯病机理的重要生理指标。     

噻虫嗪种子处理可分散粉剂防治春油菜田害虫的应用研究

对比试验表明,70%噻虫嗪种子处理可分散粉剂用油菜种子重量的0.3%～0.7%拌种,防治油菜田黄宽条菜跳甲等菜跳甲和茎龟象的效果达78.7%～93.0%,比5%甲拌磷GR高10～20个百分点.多年在不同地区进行大面积防治示范,其防效与上述趋势基本一致.试验还显示,油菜播种前3 d至3个月拌种,对害虫防效无明显差异,且对油菜前期生长有一定促进作用.说明噻虫嗪拌种防治油菜害虫效果高、安全性好,是取代甲拌磷的较好药剂.     

Studies on the sterile-male technique as a means of control of Adoxophyes orana F.R. (Lepidoptera,Tortricidae). 2. Dose-response curves after irradiation of the moths with X-rays or fast neutrons

Every degree of sterility can be induced in young months (up to 24 h old) ofAdoxophyes orana F.R. with ionizing radiation. Measurements under experimental conditions did not reveal any effect of the dosages used on life-span, mating frequency and fecundity. The same doses of radiation induced a higher degree of sterility in female moths than in male ones.The relative biological effectiveness of fast neutrons to X-rays is 2.5–5.0, as indicated by the parameter induction of dominant lethal factors in 90% of the reproductive cells.Samenvatting Uit bestralingsexprimenten met motten (hooguit 24 uur oud) vanAdoxophyes orana F.R. is gebleken dat zowel met X-stralen als met snelle neutronen iedere gewenste graad van steriliteit geïnduceerd kan worden, zonder een, onder de proefomstandigheden te meten effect op levensduur, paringsfrequentie en aantal gelegde eieren (Fig. 1, 2, 3 en 4). Vrouwelijke motten blijken gevoeliger voor inductie van steriliteit door beide soorten ioniserende straling dan mannelijke motten (Fig. 1 en 2).Proeven ter bepaling van het effect van de doseringssnelheid en van gefractioneerde bestraling (Tabel 1 en 2) geven aanwijzingen dat enzymatische herstelprocessen geen grote rol spelen. Wel zijn aanwijzingen gevonden dat na verloop van enkele dagen, misschien ten gevolge van afsterven van beschadigd sperma, het percentage steriliteit afneemt (Tabel 3). De RBE van snelle neutronen ten opzichte van X-stralen met dominant lethale factoren in 90% van de vootplantingscellen als parameter, blijkt 2,5 voor vrouwelijke motten en 5 voor mannelijke motten te bedagen.De verzamelde gegevens vormen een basis voor verder onderzoek naar praktische mogelijkheden van een steriele-mannetjestechniek en semisteriliteit en voor meer fundamenteel onderzoek naar bijv. de wijze van overerving van semisteriliteit en naar stralingsbiologische aspecten in het algemeen.     

Environmental risk assessment of carbosulfan on target and non-target beetles when used as white grub larvicide in the cork oak forest of Mamora (Morocco)

The protection of new cork oak plantations against the larvae of the beetle Sphodroxia maroccana (Melolonthidae), which destroy the roots of newly planted trees, was provided for many years in the forest of Mamora in Morocco by the use of carbosulfan, usually formulated as dry granules for direct incorporation into the soil at planting. Ecotoxicological tests were conducted in the laboratory on S. maroccana and on two non-target beetle species, namely Pachychila obtusecostata and Pimelia platynota (Tenebrionidae), to measure the acute effects of carbosulfan and evaluate the potential risk associated with inappropriate practices. The mortality was measured at both 4 d and 7 d after ingestion of a known quantity of carbosulfan. The recommended dose by the manufacturer was exceeded by at least four-fold in the Mamora Forest, with obvious environmental risks. Risks were identified for wildlife when the pesticide is misused and spread on the soil around the plants.     

黄瓜绿斑驳花叶病毒对西瓜产量、品质及种子带毒的影响

研究了西瓜不同时期接种黄瓜绿斑驳花叶病毒(Cucumber green mottle mosaic virus,CGMMV)后对其生长、产量、品质和种子带毒的影响。西瓜植株接种CGMMV越早其生长受到抑制越明显,砧木期、嫁接后定植前、定植期、压蔓期、授粉期各处理的株高、叶片数、叶片长与对照相比差异极显著(p0.01),而结瓜以后接种CGMMV对西瓜生长状况无显著影响。压蔓期前3个生育期接种该病毒,西瓜产量损失分别为56.49%、55.48%和51.14%。而压蔓期以后接种该病毒,西瓜产量损失与对照相比仍分别降低17%、13.1%和14.35%。关于倒瓤情况,压蔓期前接种该病毒可导致西瓜果实100%倒瓤,压蔓期、授粉期接种处理西瓜倒瓤率分别为48%和34%,即使结瓜后再接种病毒西瓜倒瓤率仍高达18%。血清学检测表明,压蔓期前接种的西瓜其果肉和种子均携带CGM-MV,带毒率达100%;结瓜后再接种CGMMV西瓜种胚和果肉的带毒率仍然高达64%。检测种胚和果肉病毒含量表明,接种时期越早病毒含量越高,但结瓜后接种仍有较高的病毒含量,种胚和果肉的病毒含量分别达5.98 mg/mL和5.64 mg/mL。     

Studies on pathogenesis of Rhizoctonia solani in beans: an evaluation of the possible roles of phenylacetic acid and its hydroxy derivatives as phytotoxins

All isolates of Rhizoctonia solani used in this study, when grown in Weinhold medium supplemented with phenylalanine, accumulated phenylacetic acid (PAA) and its ortho-, meta- and para-hydroxy derivatives in culture. Major metabolites which accumulated were PAA and m-hydroxyphenylacetic acid (m-OH-PAA). However, the accumulation in vitro of total phenylacetic acid derivatives by isolates of R. solani was not related to their pathogenicity and/or virulence. On the contrary, the non-pathogenic and weakly virulent isolates of R. solani produced the highest quantities of PAA-derivatives per unit weight of mycelium in comparison to the highly virulent isolates.The phenylacetic acid derivatives used in this investigation, when bioassayed at high concentrations, caused inhibition of growth of tomato and bean seedlings. The most active compounds were PAA and -α-methoxy-phenylacetic acid (MeO-PAA). However, when m-OH-PAA was assayed at low concentrations there was a stimulation of seedling growth. In addition, when m-OH-PAA solutions were injected into bean hypocotyls or into tobacco leaves they never caused necrotic lesions or symptoms resembling those caused by R. solani on beans.These results indicate that PAA-derivatives are not directly involved in pathogenesis of R. solani in beans.     

Evaluating side effects of newer insecticides on the vine mealybug parasitoid <Emphasis Type="Italic">Anagyrus</Emphasis> sp. near <Emphasis Type="Italic">pseudococci</Emphasis>, with implications for integrated pest management in vineyards

Control of the invasive vine mealybug Planococcus ficus (Signoret) can be achieved through integration of different management strategies such as the application of chemical treatments and biological control. However, compatibility between these control methods is considered crucial when adopting integrated pest management (IPM) programs against this insect pest. The recently used insecticides Prev-Am®, a contact biopesticide, and spirotetramat, a systemic tetramic acid insecticide, were assessed in laboratory conditions for their side effects on the vine mealybug parasitoid Anagyrus sp. near pseudococci with reference to chlorpyriphos-methyl, an organophosphate insecticide conventionally used for mealybug control in vineyards. Regarding contact toxicity, chlorpyriphos-methyl caused 100% parasitoid mortality 24 h after treatment, but parasitoid mortality from Prev-Am® or spirotetramat was almost absent. Neither the total parasitoid offspring/female nor the sex ratio of the progeny was negatively affected by Prev-Am® or spirotetramat relative to the untreated control. According to the IOBC classification for laboratory trials, both Prev-Am® and spirotetramat were rated harmless (IOBC category 1), whereas chlorpyriphos-methyl was categorized as harmful (IOBC category 4) to A. sp. near pseudococci. None of the insecticides adversely affected the development of the parasitoid pupal stage inside mealybug mummies or the survival of the emerged parasitoids. The practical implications of the results for implementing mealybug IPM programs in vineyards are emphasized and discussed.     

家蝇（Musca domestica Vicina L.）头部乙酰胆碱酯酶检测农药残留最佳条件研究

系统研究了敏感家蝇Musca domestica Vicina L.羽化后不同天数其头部乙酰胆碱酯酶(AChE)的比活力、敏感度以及酶源蛋白质含量的变化;缓冲液pH值对家蝇头部AChE比活力的影响。结果表明:家蝇初羽化至羽化后第15 d,其头部AChE的比活力逐渐升高 ,而酶源蛋白质的含量逐渐下降(187.022 2±9.021 3~83.022 2±7.111 1 μg/头)。羽化后2~4 d,其头部AChE的敏感度最高;初羽化和羽化后第15 d,敌敌畏的I50分别是羽化后第3 d的1.4倍和2.1倍。在一定的pH值范围内(6.6~8.0),家蝇头部AChE的比活力随缓冲液pH值的升高而增大。本研究为利用家蝇头部AChE检测有机磷残留量探索了最佳条件。