南美番茄潜叶蛾Tuta absoluta,a.幼虫及为害状,b.蛹,c.成虫,d.卵

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西德著名植病流行学家J.Kranz来华讲学

1985年8月12日—8月31日,西北农学院植保系受农牧渔业部委托,举办了全国“植物病害流行学”讲习班,邀请西德吉森(GIESSEN)大学农学院著名植病流学行学家 J.Kr-anz 主讲。参加讲习班的有数十名来自全国高等农业院校的中青年教师和农科院、所的研究人员。J.Kranz 讲述了十五个专题,内容有:(1)植病流行学概论;(2)植病流行学的基本概念和方法;(3)病害流行的发展过程、要素及与环境因子的相互作用;(4)病害的传播;     

Host–pathogen interaction between Phytophthora infestans and Solanum nigrum, S. villosum, and S. scabrum

Potato and tomato are the two major hosts for Phytophthora infestans causing late blight. The susceptibility of leaves and whole plants of Solanum nigrum, S. villosum, and S. scabrum to infection by P. infestans was tested under laboratory conditions. Out of 39 plants representing 38 different S. nigrum accessions, 16 were highly resistant (seven accessions did not show any symptoms of infection, nine were highly resistant showing necrotic lesions in the place of infection), and 23 plants of S. nigrum were colonized by, at least, 1 of the 2 isolates of P. infestans (17 accessions were infected with two P. infestans isolates, and 6 accessions showed different reactions depending on the isolate used for inoculation). Three accessions of S. villosum, and one accession of S. scabrum were tested and did not show any symptoms of infection. The majority of S. nigrum accessions infected by P. infestans in a detached leaf assay were also infected in the whole plant assay. The reaction of field- and greenhouse-grown plants to inoculation with P. infestans in detached leaf assays was similar, but in some cases leaves from field-grown plants reacted as resistant in comparison with the leaves from greenhouse-grown plants, which were susceptible.     

“Zwartbenigheid” bij tulp en iris,veroorzaakt doorSclerotium wakkerii nov. spec.

Samenvatting Aansluitend op een vorige publikatie over de z.g. zwartbenigheid bij tulpen (Boerema, 1960) zijn in dit artikel nadere gegevens medegedeeld over deze ziekte en de veroorzakende schimmel. Een 23-tal bloembolgewassen zijn door uitplanting op zwaar besmette grond getoetst op hun gevoeligheid voor deze ziekte. Daarbij kon het typische ziektebeeld van de zwartbenigheid alleen worden verkregen bij tulpen en bolirissen. De uit de praktijk afkomstige stelling dat ook krokussen voor deze ziekte gevoelig zijn (Silver & Slootweg, 1959), kon niet worden bewezen.De kenmerkende eigenschappen van de sclerotiën vormende schimmel die deze zwartbenigheid veroorzaakt, zijn uitvoerig besproken. Daar de schimmel onbekend blijkt te zijn, is deze beschreven als een nieuwe soort:Sclerotium wakkerii. Deze schimmel is nauw verwant aanSclerotium denigrans Pape, die een zwarte verkleuring vanConvallaria-kiemen veroorzaakt (Pape, 1943).Summary After reference to an earlier paper on black leg of tulips (Boerema, 1960) the present paper gives further data on the disease and the causal fungus. Besides affecting tulips, the disease is also found in the field on bulbous irises. The disease symptoms are shown in figs. 1, 2, 3 and 4.The susceptibility to black leg of 23 bulb species was tested in heavily contaminated soil. In agreement with experience in practice, only tulips and irises developed the typical black leg symptoms. In other bulb species a black discoloration of the dead membraneous bulb or tuber tunic was sometimes found, but no disease symptoms appeared above ground. This applied also to crocus, for which susceptibility to black leg in the field has been claimed (Silver & Slootweg, 1959).The black leg-fungus is easily isolated on cherry agar at 20 °C (fig. 5a), after treating the attacked tissue with a detergent and rinsing with tap water. Growth of the fungus was studied on malt agar, as this medium favours good and rapid growth. The relation between the growth rate on malt agar in the dark and temperature is shown in fig. 6. In the early stage a white flat mycelium is formed; later this turns brownish-black, secreting a typical dark pigment in the medium (fig. 7a and 7b). The hyphae (fig. 5d) vary in width from 1.8 to 7.5 , the walls being rather thick, 0.4 to 0.8 . The hyphae are often anastomosed and branched. After 2 or 3 weeks in culture the fungus develops brownish-black round or flattened irregular sclerotia 2–5 mm in diameter and 0.5–1.5 mm thick, consisting of a compact mass of hyaline hyphae surrounded by thick-walled dark coloured cells (fig. 5a and 5c). When the fungus is grown at low temperatures sclerotia sometimes develop in the aerial mycelium. These are always somewhat spherical and at first white in colour (fig. 5b). In an old culture of the fungus grown on malt agar microconidia formed in phialides were found in 1960 (Boerema, 1960). This has not been observed again, however, so possibly a contamination was concerned.The black leg fungus differs from all other known sclerotia producing fungi.¹ It is therefore described as a new species,viz. Sclerotium wakkerii Boerema & Posthumus nov. spec. We take pleasure in naming this species after Dr.J. H. Wakker (1859–1927), originator of scientific work on bulb diseases. Living cultures of the fungus have been placed at the disposal of the Centraalbureau voor Schimmelcultures at Baarn (type culture) and at the Commonwealth Mycological Institute at Kew. Dried plate cultures were sent to the Commonwealth Mycological Institute at Kew and the Rijksherbarium at Leyden. Sclerotium wakkerii closely resemblesSclerotium denigrans Pape, the cause of a black discoloration of the shoots of lily of the valley (Pape, 1943). However, the sclerotia ofSclerotium denigrans are considerably smaller than those ofSclerotium wakkerii.     

P.D.A.

P.D.A.是三个英文字的缩写,P.=patato(马铃薯),D.=Dextrose(萄葡糖)A.=Agar(洋菜或称琼脂),是一种微生物培养基的代表符号。 不同种类的微生物,所要求的营养物质有差异,因此培养基的种类很多,P.D.A.是培养基中最常用的一种,适于植物病害中多种真菌、细菌的正常生长,因此又称普通培养基。     

Effectiveness of antagonistic bacteria,commercial fungicides,and fourth generation quaternary ammonium salts,against Fusarium oxysporum f. sp. cubense race “1 or 2”

European Journal of Plant Pathology - There are three races of Fusarium oxysporum f.sp. cubense (Foc) that significantly affect commercial banana plantations. Most banana cultivars are very...     

C.d.a.–Controlled Droplet Application

Abstract

Efficiency of pesticide application can be improved if more consideration is given to where and when the active ingredient is most needed, and the optimum droplet size selected for a given target. Even when minimal volumes of spray are applied concentrate sprays are not justified as a greater proportion of the spray is collected on the target. Sprays with a narrow range of droplet size can be produced from ligaments thrown from centrifugal energy nozzles; droplet size being inversely proportional to the rotational speed.     

Margaritaella gracilis gen. n. et sp. n. (Eucestoda: Proteocephalidea), a parasite of Callichthys callichthys (Pisces: Siluriformes) from the Paraná River basin, Argentina

Margaritaella gracilis gen. n. et sp. n. (Proteocephalidea: Proteocephalinae) found in the intestine of Callichthys callichthys (Linnaeus) from the Paraná River basin is described. The new genus is placed in the Proteocephalinae because of the medullary position of the genital organs. It differs from all known genera included in the Proteocephalinae by the following combination of characters: 1) scolex with a conspicuous cluster of drop-shaped gland cells posterior to suckers; 2) strobila with a low number of proglottides, all much longer than wide; 3) testes arranged in one field, composed of two parallel rows of testes separated by the uterus; 4) ovary delicate, H-shaped, with branches slender and deeply folliculate at the edges, located at 25-35% from the posterior end; 5) uterus largely extended posterior to the ovary but not reaching the end of proglottis; and 6) vitelline follicles in two narrow lateral bands, largely extended posterior to the ovary. Scanning electron microscopy revealed three types of microtriches on the tegument surface: acicular and capiliform filitriches and gladiate spinitriches. The relative size of the ovary, a character recently used in the systematics of the proteocephalidean cestodes, was calculated for the new species and compared with other species of the group. M. gracilis is the first record of a proteocephalidean cestode parasitizing a callichthyid catfish.     

猪殃殃Galium aparine L.var.tenerum(Gren.et Godr.)Rchb.发生规律观察

猪殃殃是我省分布广泛,危害严重的麦田恶性杂草。近年来,发生数量和危害面积还在不断上升,是麦子增产的障碍之一。笔者从1979年秋播开始对其生物学特性和发生规律作了调查观察,现将观察结果简报如下: 一、分布特点猪殃殃的分布和土质有很大关系,据在本地区9个县46个公社调查1561亩麦田(代表面积一万七千余亩)每平方尺发生10株以上的危害面积,沙土地区占调查面积的12.2％,粘土     

Effektive Kontrolle des Braunrostes (Puccinia recondita f. sp. secalis Rob. ex Desm.) in Winterroggen mit Fungiziden unterschiedlicher Wirkstoffgruppen – Auswertung der Ringversuche der L?nder Brandenburg, Sachsen-Anhalt, Sachsen und Thüringen

To investigate different control measures against the diseases in winter rye several trials were done in the German federal states. As a result from these trials the brown rust,Puccinia recondita f. sp.secalis, was the disease with the most negative influence on the yield. The brown rust occurrence at different times on the top three leaves depend on the winter and spring weather. It should be verify whether the protective use of fungicide mixtures with the new carboxamides active ingredient benefits the curative use (disease onset) in terms of achieved efficiency againstP. recondita. It can be stated that the action threshold does not need to be changed when using fungicide mixtures with carboxamides. Regarding the duration of the fungicide efficacy againstP. recondita an order in increasingly levels of efficiency could be determinate. The order is, from lowest to highest, azole fungicides, strobilurin-azole compounds, azole carboxamide compounds, and azole-carboxamide strobilurin mixtures. Due to the variability in the values of the individual test sites in the experimental series the tendency could be confirmed, however, no statistical significant differences between the various mixtures could be determined. The new carboxamides enrich the possibilities of targeted anti-resistance strategy againstP. recondita in winter rye. These trials results are introduced into recommendations for agricultural practice.     

B.t.乳剂防治蔬菜害虫技术

B．t．杀虫剂是由苏云金杆菌发酵生产的一种微生物杀虫剂，能在细胞内形成菱形伴抱晶体的芽抱杆菌。其伴抱晶体是一种强毒性蛋白，在昆虫中肠碱性环境下释放出后，可使昆虫瘫痪致死。芽炮也能在虫体内萌发繁殖，从而加速昆虫死亡。B．t．杀虫剂具有化学农药不可替代的优越性，其治虫效果好，对害虫天敌和作物安全，使害虫不易产生抗药性，对生态系统无不良影响等优点，是生物防治蔬菜害虫的首选杀虫剂。我县自1992年将B．t．应用于蔬菜害虫的防治，取得了良好的防治效果和效益。特别是应用干蔬菜地防治菜青虫、小菜蛾和棉铃虫等害虫，防治…     

克.多.酮种衣剂的分析方法研究

本文用气相色谱２％ＯＶ－１玻璃柱，ＦＩＤ检测器，１６０～２００℃程序升温分析测定了１７％克．多．酮衣种剂中的克百威和三唑酮，用薄层－紫外法测定了多菌灵的含量，克百威，三唑酮和多菌灵的变异系数分别为１．３６％，２．１３％和０．９６％，平均回收率分别为９７．８％，９８．９％和９８．５％。