模拟仓中甲酸乙酯对4种储粮害虫的熏蒸活性研究

在小麦、玉米和稻谷等3种粮食的模拟仓中测定甲酸乙酯对4种重要储粮害虫成虫米象Sitophilus oryzae L.、谷蠹Rhyzopertha dominica F.、赤拟谷盗Tribolium castaneum H.、嗜卷书虱Liposcelis bostrychophila B.的熏蒸活性,结果表明甲酸乙酯在小麦仓中的熏蒸效果最好,在玉米仓中的熏蒸效果次之,在稻谷仓中的熏蒸效果最差.在30℃条件下,以70 g/m3的药剂浓度熏蒸处理24 h,在小麦仓的上、中、下3层的4种害虫死亡率均达到100%;在玉米仓的上、中层4种害虫的校正死亡率也均为100%,而下层也仅有少量米象个体存活;在稻谷仓内,上、中、下3层的4种害虫均有存活,即使浓度达到90 g/m3,下层4种害虫的校正死亡率也均低于50%.对不同的害虫种类而言,甲酸乙酯对嗜卷书虱和谷蠹的熏蒸效果较好,赤拟谷盗次之,而相同条件下对米象成虫的熏蒸效果最差.     

甜菜夜蛾对虫酰肼的抗药性监测及抗性风险评估

用浸叶法监测了江苏丰县、大丰、射阳、阜宁、南京江宁及河南新野6个地区甜菜夜蛾初孵幼虫对虫酰肼的抗性,结果表明:各种群对虫酰肼的抗性倍数为2.1~4.2,属敏感至敏感性下降阶段。用虫酰肼筛选甜菜夜蛾广东深圳种群34代后,与起始种群相比,抗性为17.0倍。筛选前17代,甜菜夜蛾对虫酰肼的抗性现实遗传力为0.1021,筛选后17代,现实遗传力为0.1519,前半段现实遗传力小于后半段的现实遗传力。整个34代筛选期间,现实遗传力为0.1695。当抗性现实遗传力为0.1021,杀死率为80%~90%时,抗性上升10倍,需要14~18代。试验结果证明甜菜夜蛾对虫酰肼产生抗性的风险较低。并对甜菜夜蛾的抗性治理进行了讨论。     

一种替代FAO方法测定储粮害虫磷化氢高抗性的方法

对3个米象的抗性品系（其中两个是国内的，一个为澳大利亚提供的）进行群体选择，对1个米象的敏感品系进行了单对选择，对3个谷蠹的抗性品系和1个敏感品系也进行同样处理，用FAO方法测出3个米象抗性品系中最高抗性品系的抗性倍数为198倍，但因谷蠹在高浓度磷化氢测定中有保护性昏迷现象，用FAO方法无法测出3个抗性谷蠹的抗性倍数，对抗性虫用低浓度0.5mg/L和对敏感虫用低浓度0.01mg/L进行不同时间的处理。用LCT50的方法可得出抗性虫的抗性倍数，使用这种LCT50方法得到最高抗性谷蠹的抗性倍数为209。同时用这种LCT50得出最高抗性米象的抗性倍数是193.7，非常接近于用FAO方法测出的198的抗性倍数，证明该方法可以用来替代FAO方法。     

棉铃虫对甲氨基阿维菌素苯甲酸盐的抗性遗传力

 为了评估棉铃虫对甲氨基阿维菌素苯甲酸盐的抗性风险,在室内进行了棉铃虫对该药剂的抗性选育和现实遗传力分析。连续用甲维盐对棉铃虫选育25代,与同源对照种群相比,获得抗性倍数为2.974倍的汰选种群。采用阈性状分析方法,获得棉铃虫对甲维盐的抗性现实遗传力 (h²)为0.05218。进一步预测其抗性发展速度,假设以90%致死率继代处理棉铃虫,其抗性达到5倍、10倍分别需要18.67代和26.71代。     

氮气与甲酸乙酯混合熏蒸对锯谷盗的毒力研究

采用广口瓶密闭熏蒸法,在实验室条件下研究了氮气与甲酸乙酯混合熏蒸对锯谷盗成虫的毒力。结果表明,氮气和甲酸乙酯混用具有良好的熏蒸效果。在81%、87%和95%的氮气浓度下,甲酸乙酯为10μL/L熏蒸处理24h,锯谷盗的校正死亡率分别为55%、75%和97%,表明氮气可显著提高甲酸乙酯的熏蒸毒力;温度对氮气和甲酸乙酯混合熏蒸效果具有显著影响作用,相同条件下,在30℃时校正死亡率为41%,在15℃时则提高至90%,表明低温条件下熏蒸效果比高温条件下更好。     

苏云金杆菌降低储粮害虫对磷化氢的抗药性

主要研究经过苏云金杆菌处理的米象对磷化氢、马拉硫磷、溴氰菊酯的敏感性。试验结果表明,抗磷化氢的米象品系经过苏云金杆菌处理7代后,对磷化氢的抗性有所降低;但经过苏云金杆菌处理的米象对马拉硫磷、溴氰菊酯却未表现负交互抗性。     

华南地区主要害虫防治新技术应用研究

通过不同食物引诱剂与害虫诱捕器结合对不同虫种储粮害虫进行诱捕,试验表明水平距离5m、粮食深度2m左右诱捕检测害虫效果明显,对主要储粮害虫有良好的诱捕效果;摆放位置对于诱捕器的诱捕效果影响大;采用控氧储存技术进行生态储粮,经分析,米象、米象抗性品系、谷蠹、谷蠹抗性品系及赤拟谷盗对除氧剂毒力LD99.9分别为8.60g/kg、11.01g/kg、9.14g/kg、8.16g/kg、4.18g/kg,其中赤拟谷盗最敏感,米象抗性品系需要脱氧剂最多;试验粮堆投放除氧剂量为0.50g/kg、1.0g/kg、1.5g/kg、2.0g/kg、2.5g/kg、3.0g/kg,脱氧剂在用量为2.5g/kg、3.0g/kg对谷蠹、谷蠹抗性品系、米象、米象抗性品系、赤拟谷盗及用量1.5g/kg、2.0g/kg对赤拟谷盗杀灭效果在90%以上;脱氧剂在用量为2.0g/kg时对谷蠹抗性品系、米象、米象抗性品系杀灭效果在85%以上;经实仓应用除氧剂用量为2.5g/kg、3.3g/kg、2.5g/kg并抽真空、3.3g/kg并抽真空能保证稻谷储存1年基本无活虫,可保证稻谷储存安全;经应用除氧宝0.5g/kg、1.0g/kg、1.5g/kg、2.0g/kg、2.5g/kg、3.0g/kg、3.3g/kg对稻谷发芽无显著影响。     

甲酸乙酯对锯谷盗的熏蒸活性研究

采用密闭熏蒸法,在实验室条件下研究甲酸乙酯(EtF)对储藏物害虫锯谷盗Oryzaephilus surinamensis成虫的熏蒸活性。结果表明,熏蒸时间和温度显著影响甲酸乙酯对锯谷盗的熏蒸致死效果。甲酸乙酯在24 h内就能发挥很好的熏蒸活性,在低温条件下处理比在高温下熏蒸效果更好。在20℃、25℃和30℃条件下,熏蒸处理锯谷盗成虫24 h,其LC50分别为14.78、16.77和17.65μL/L。     

甲酸对谷蠹乙酰胆碱酯酶及酯酶活性的影响

研究离体条件下甲酸对谷蠹酯酶和乙酰胆碱酯酶的抑制作用,结果表明较高浓度的甲酸对谷蠹酯酶和乙酰胆碱酯酶有抑制作用,但其抑制中浓度远远高于甲酸乙酯对谷蠹的致死中浓度,这说明甲酸对害虫酯酶和乙酰胆碱酯酶的抑制作用不是甲酸乙酯杀虫的主要机理。     

我国主要储粮害虫抗性调查研究

通过对全国范围内23个省、市和自治区的55个地区粮库中的主要储粮害虫进行取样，用FAO抗性测定方法对92个虫样进行磷化氢抗性测定，得出无抗性虫样占调查虫样总数的54．3％、低抗性虫样占9．8％、中等抗性虫样占7．6％、高抗性虫样占13．0％、极高抗性虫样占15．2％。在调查的几种主要储粮害虫中，高抗性虫样主要为锈赤扁谷盗、谷蠹和米象，其中锈赤扁谷盗的抗性普遍比较严重，谷蠹和米象通过与1995年抗性调查所取的样品进行比较，在最近的8年内米象的抗性倍数增加了10．7％、谷蠹增加了71．2％。磷化氢抗性较高的区域主要是我国西南、华中和华南地区。     

Durability of resistance against fungal, bacterial and viral pathogens; present situation

In evolutionary sense no resistance lasts forever. The durability of a resistance can be seen as a quantitative trait; resistances may range from not durable at all (ephemeral, or transient) to highly durable. Ephemeral resistance occurs against fungi and bacteria with a narrow host range, specialists. It is characterised by a hypersensitive reaction (HR), major gene inheritance and many resistance genes, which often occur in multiple allelic series and/or complex loci. These resistance genes (alleles) interact in a gene-for-gene way with a virulence genes (alleles) in the pathogen to give an incompatible reaction. The pathogen neutralises the effect of the resistance gene by a loss mutation in the corresponding avirulence allele. The incompatible reaction is not elicited any more and the pathogenicity is restored. The pathogens can afford the loss of many avirulences without loss of fitness. Durable resistance against specialised fungi and bacteria is often quantitative and based upon the additive effects of some to several genes, the resulting resistance being of another nature than the hypersensitive reaction. This quantitative resistance is present to nearly all pathogens at low to fair levels in most commercial cultivars. Durable resistance of a monogenic nature occurs too and is usually of a non-HR type. Resistance against fungi and bacteria with a wide host range, generalists, is usually quantitative and durable. Resistances against viruses are often fairly durable, even if these are based on monogenic, race-specific, HR resistances. The level of specialisation does not seem to be associated with the durability of resistance. This revised version was published online in August 2006 with corrections to the Cover Date.     

The integrated concept of disease resistance: A new view including horizontal and vertical resistance in plants

Summary Horizontal, uniform, race-non-specific or stable resistance can be discerned according to Van der Plank, from vertical, differential, race-specific or unstable resistance by a test in which a number of host genotypes (cultivars or clones) are tested against a number of pathogen genetypes traces of isolatest. If the total non-environmental variance in levels of resistance is due to main effects only differences between cultivars and differences between isolates) the resistance and the pathogen many (in the broad sense) are horizontal in nature. Vertical resistance and pathogenicity are characterized by the interaction between host and pathogen showing up as a variance compenent in this test due to interaction between cultivars and isolates.A host and pathogen model was made in which resistance and pathogenicity are governed by live polygenic loci. Within the host the resistance genes show additivity. Two models were investigated in model I resistance and pathogenicity genes operate in an additive way as envisaged by Van der Plank in his horizontal resistance. Model II is characterized by a gene-for-gene action between the polygenes of the host and those of the pathogen.The cultivar isolate test in model I showed only main effect variance. Surprisingly, the variance in model II was also largely due to main effects. The contribution of the interaction to the variance uppeared so small, that it would be difficult to discern it from a normal error variance.So-called horizontal resistance can therefore be explained by a polygenic resistance, where the individual genes are vertical and operating on a gene-for-gene basis with virulence genes in the pathogen. The data reported so far support the idea that model II rather than model I is the realistic one.The two models also revealed that populations with a polygenic resistance based on the gene-for-gene action have an increased level of resistance compared with the addition model, while its stability as far as mutability of the pathogen is concerned, is higher compared to those with an additive gene action. Mathematical studies of Mode too support the gene-for-gene concept.The operation of all resistance and virulence genes in a natural population is therefore seen as one integrated system. All genes for true resistance in the host population, whether they are major or minor genes are considered to interact in a gene-for-gene way with virulence genes either major or minor, in the pathogen population.The models revealed other important aspects. Populations with a polygenic resistance based on a gene-for-gene action have an increased level of resistance compared to populations following the addition model. The stability, as far as mutability of the pathogen is concerned, is higher in the interaction model than in the addition model.The effect of a resistance gene on the level of resistance of the population consists of its effect on a single plant times its gene frequency in the population. Due to the adaptive forces in both the host and the pathogen population and the gene-for-gene nature of the gene action an equilibrium develops that allows all resistance genes to remain effective although their corresponding virulence genes are present. The frequencies of the resistance and virulence genes are such that the effective frequencies of resistance genes tend to be negatively related to the magnitude of the gene effect. This explains why major genes often occur at low frequencies, while minor genes appear to be frequent. It is in this way that the host and the pathogen, both as extremely variable and vigorous populations, can co-exist.Horizontal and vertical resistance as meant by Van der Plank therefore do not represent different kinds of resistances, they represent merely polygenic and oligogenic resistances resp. In both situations the individual host genes interact specifically with virulence genes in the pathogen. Van der Plank's test for horizontal resistance appears to be a simple and sound way to test for polygenic inheritance of resistance.The practical considerations have been discussed. The agro-ecosystems should be made as diverse as possible. Multilines, polygenic resistance, tolerance, gene deployment and other measures should be employed, if possible in combination.     

Plant pathosystems: An attempt to elucidate horizontal resistance

Summary Resistance to parasites can be distinguished into true resistance and pseudo or escape resistance. In the former resistance mechanisms operate after intimate contact between the host tissue and the parasite has been established. The resistance is expressed by a reduced growth of the parasite in or on the host tissue. Escape resistances operate before the parasite has made contact with the host tissue and is expressed by a reduced chance of such contacts. True resistance genes are assumed to act in a gene-for-gene way with virulence genes in the parasite. Genes governing escape resistances are supposed to function independently from genes in the parasite (no gene-for-gene action). It is deduced, that escape resistances and polygenic true resistances both are of a horizontal nature. Vertical resistance is to be found in the category of monogenic true resistances.     

Quantitative resistance to downy mildew (Plasmopara halstedii) in sunflower (Helianthus annuus)

Downy mildew of sunflower, caused by the Oomycete, Plasmopara halstedii is at present controlled by major resistance genes. However, the pathogen has shown a considerable capacity for changes in virulence and these resistance genes are overcome only a few years after they have been introduced into new sunflower varieties. This paper presents research for quantitative, non-race-specific resistance independent of major genes. The reaction of cultivated sunflower genotypes to field attack by downy mildew was studied over 4 years in several environments and in the presence of the two most common races in France: 703 and 710. An experimental protocol with pre-emergence irrigation was developed, making it possible to observe downy mildew reaction whatever the weather conditions. Significant levels of partial resistance were observed in about 50 inbred sunflower lines among the 800 observed. These results suggest that it should be possible to select for non-race-specific downy mildew resistance and to include it in modern varieties. However, since this non-specific resistance is partial, it may be necessary to combine it with major gene resistance. Possible strategies are discussed to obtain durable resistance to downy mildew.     

解磷细菌对7种常见抗生素的抗性研究

摘要：测定8株供试菌株对氨苄青霉素,四环素,链霉素,卡那霉素,利福平,头孢霉素,氯霉素的不同浓度的抗性反应。结果发现抗氨苄青霉素的菌株有PSB3,PSB4,PSB13,PSB26,PSB58,PSB67,PSB77;抗链霉素的菌株PSB4,PSB13,PSB26,抗卡那霉素的菌株PSB4,PSB26,PSB67,PSB77;PSB4,PSB26,PSB77菌株对四环素具有较强的抗性;PSB4,PSB13,PSB15,PSB26,PSB67,PSB77菌株对氯霉素具有较强的抗性;PSB3,PSB4,PSB26,PSB58,PSB77菌株对利福平有抗性,PSB77菌株对头孢霉素有较强抗性。解磷细菌对抗生素的抗性实验结果,可用于研究今后8株解磷细菌在土壤中的定殖状态。     

洛阳市番茄灰霉病菌对嘧霉胺的抗药性检测

为了明确洛阳市番茄灰霉病菌对苯胺基嘧啶类杀菌剂嘧霉胺的抗药性状况,2012—2013年从洛阳市不同保护地中采集番茄灰霉病病果或病叶,经单孢分离共获得番茄灰霉病菌54株。采用菌丝生长速率法测定了其对嘧霉胺的敏感性。结果显示,高抗菌株9株（16.67%）,中抗菌株19株（35.19%）,低抗菌株10株（18.52%）,敏感菌株16株（29.63%）。比较抗性水平不同菌株间的菌丝生长情况,发现菌丝生长速度和抗性水平无相关性。研究表明,洛阳市番茄灰霉病菌已对嘧霉胺产生不同水平的抗药性,且以中抗菌株为主,生产上应合理更换或轮换使用与嘧霉胺无交互抗性的药剂防治番茄灰霉病。     

Resistance of barley genotypes to brown leaf spot

Resistance of 59 barley cultivars to three distinct isolates of Bipolaris sorokiniana, causing brown leaf spot was tested on seedlings and adult plants in a screen house and in a growth room, by determination of disease incidence, disease severity, and rate of lesion expansion. The disease reaction and severity at the seedling stage differed among cultivars. The cultivars MNS Brite, NDB 112, Kindred, Parkland, and Oderbrucke were moderately resistant to brown leaf spot, but the resistance was partial to all three isolates. None genotype with complete resistance was found. The cultivars CI 9539, Svanhals, and Chevron, considered as sources of resistance, were classified as moderately susceptible, and susceptible, respectively. Disease severity, disease reaction, and incidence of B. sorokiniana in grains also differed among the cultivars at the adult plant stage. Nevertheless, none of the genotypes was resistant to B. sorokiniana. The rate of lesion expansion differed among cultivars BR 2, MN 698, Kitchin, Svanhals, and NDB 112, with NDB 112 having the slowest expansion rate (0.194–0.205 mm²/day).