Dispersal of Formulations of Fusarium oxysporum f. sp. erythroxyli and F. oxysporum f. sp. melonis by Ants

ABSTRACT A natural epidemic of Fusarium wilt on coca (Erythroxylum coca) in Peru prompted the suggestion of possibly using the pathogen Fusarium oxysporum f. sp. erythroxyli as a mycoherbicide against this narcotic plant. During field trials conducted in Kauai, HI, to test the pathogenicity of the coca wilt pathogen, ants were observed removing formulations from test plots. While removal of formulations by ants was considered detrimental with respect to conducting field tests, ant removal was considered potentially beneficial in disseminating the mycoherbicide. Thus, research was initiated to assess the ability of formulation additives to alter the preference of ants for the formulated mycoherbicide. In Hawaii, preference of indigenous ants for removing formulations was tested using three different food bases (rice, rice plus canola oil, and wheat flour [gluten]). Similar tests were conducted at Beltsville, MD, using F. oxysporum f. sp. melonis, in which the formulation based on wheat flour was replaced by a formulation based on canola meal. Formulations based on wheat were preferred by ants in both locations; up to 90% of the wheat plus rice flour granules (C-6) and the wheat gluten plus kaolin granules (pesta) were removed within 24 h, while only 20% of those containing rice without oils were taken. However, when either canola, sunflower (Maryland only), or olive oil was added to the rice formulation, up to 90% of the granules were taken. The formulation based on canola meal was less attractive to ants, as only 65% of the granules were removed within a period of 24 h. Ants showed no preference with respect to presence or absence of fungal biomass. To alter the attractiveness of the C-6 formulation to ants, C-6 was amended with three natural products. Canna and tansy leaves were added to C-6 at a ratio of 1:5 (wt/wt), while chili powder was added at 1:25 or 1:2.5 (wt/wt). Canna, tansy, and the higher rate of chili powder significantly reduced the number of C-6 granules removed by ants. Canna and tansy leaves affected neither germination nor sporulation of the mycoherbicide, while the high concentration of chili powder reduced viability of propagules in the formulation. More F. oxysporum f. sp. erythroxyli-type colonies were recovered from inside ant nests (9 cm depth) than from nest surfaces, indicating that ants may distribute the mycoherbicide in the soil profile. Ants passively carried propagules of F. oxysporum f. sp. erythroxyli outside their bodies, as well as either very closely adhering to the outside or within their bodies.     

Zaadbehandeling met D.D.T. tegen de Uienvlieg

Summary Several field-trials in the Netherlands during the season of 1946 proved the effectiveness of a seed-treatment with D.D.T. to control the onion maggotChortophila antiqua Meig. in onions and leeks.The results obtained with D.D.T. were as good as or perhaps even a little better than those with calomel.After coating the seed with glue, the seed has to be stirred with the insecticide.The dose was 20 g D.D.T. on 100g onionseed, applied as 40 g of a D.D.T.-talc powder containing 50% D.D.T. on 100 g onionseed.     

Application of reverse-phase h.p.l.c. for the determination of partition coefficients

Reverse-phase high performance liquid chromatography (h.p.l.c.), using a C₁₈ analytical column, has been applied to the determination of partition coefficients for a range of agrochemicals and industrial chemicals. Using a correlation plot of the logarithm of the capacity factor (k) with the logarithm of the n-octanol/water partition coefficient (P_ow), partition coefficients were predicted with a 95% tolerance interval of ± log 0.80 of the literature ‘shake flask’ value for compounds of random structure over the log P_ow range 0–6. Individual regression lines were fitted for compounds of comparable size and functional grouping, which reduced any bias and thereby enabled more accurate predictions to be made. The reverse-phase h.p.l.c. method has a number of advantages over the traditional ‘shake-flask’ method. Quantitative methods are not required or do not have to be developed and only the determination of the retention time is necessary. Quick and precise determinations of retention times are facilitated by h.p.l.c. and further improvement can be obtained by automation of solvent mixing, solute injection and data processing. H.p.l.c. was used to generate partition coefficient data for highly hydrophobic materials and, because of its resolving power, data for mixtures and solvent fractions. Dual detection, using u.v. and r.i. in series, was necessary for some compounds, particularly unknown mixtures and impure compounds. Calculations of log P_ow based on the fragment-addition method using the structural data file, MACCS, was of considerable value in confirming experimentally derived values. In certain cases, calculated log P_ow values were considered more trustworthy than experimental values.     

Attempted somatic hybridization of Puccinia striiformis f. sp. tritici and P. striiformis f. sp. hordei

Attempts were made to produce somatic hybrids between isolates of Puccinia striiformis f. sp. tritici and f. sp. hordei. A mixed infection was produced on a common susceptible barley host, Fong Tien, using white-spored isolates of P. striiformis f. sp. tritici and yellow-spored isolates off. sp. hordei. Selection was made for non-parental spore colour on selective wheat and barley hosts, and variants thus isolated were analysed for virulence markers, and for isozyme and double-stranded RNA (dsRNA) markers, all of which clearly differentiated the parental isolates. Two white-spored (non-parental) isolates were found on the selective barley host which otherwise resembled the parental f. sp. hordei isolate in virulence, isozyme and dsRNA markers. The most likely explanation of the origin of these isolates is mutation to white spore colour in the f. sp. hordei isolate.     

Interactions between Fusarium oxysporum f. sp. tracheiphilum and Meloidogyne spp. in Vigna unguiculata. 3. Pathogenesis by F. o. tracheiphilum as affected by M. javanica and host cultivar

Experiments were conducted to determine the temporal and spatial effects of Meloidogyne jav anica and host cultivar on pathogenesis by Fusarium oxysporum f. sp tracheiphilum in cowpea. In the wilt-susceptible cowpea cultivar California Blackeye No. 5 (CB5). F. o. tracheiphilum proliferated rapidly in both the hypocotyl and first internode 6 weeks after inoculation. The fungus spread quickly upward as plants grew, colonized most tissues within 6 weeks, and caused severe wilt. In wilt-resistant cultivar CB3. there was little proliferation of F. oxysporum in any tissue, whether or not plants were infected by St. javanica. The fungus was found above the primary internode in 15"., of all CB3 plants, but did not continue to spread upward after 4 weeks Vascular discoloration was greatest when St. javanica was added 4 weeks before F. o. tracheiphilum, but simultaneous inoculation also increased wilt symptoms Root wounding did not increase wilt. Split-root experiments provided no evidence that infection by, M. javanica results in a translocatable factor that reduces wilt resistance. When hypocoivls were inoculated with F. o. tracheiphilum at different intervals after roots infected by St. jav anica were removed, there was no evidence that the effect of the nematode on wilt susceptibility was translocated or persistent.     

A Comparison of DDT w.p. and Dieldrin e.c. for Tesetse Fly Control in Botswana

Abstract

During the present century increasing world demand for forest products has brought about a rapid expansion of even-aged forest plantation estates, requiring the forester to adopt the outlook and techniques of the farmer to an increasing extent, both to maintain yield and protect crops from damage.

Aircraft have already proved their worth in the protection of natural and artificial forests from fire and are frequently used for seeding, fertiliser application, survey and the control of insect pests. They are also potentially useful for the control of forest diseases, although their role in this respect has so far been limited. The development of aerial spraying to control dothistroma blight of Pinus radiata is reviewed in this paper.     

Genetic diversity in Fusarium oxysporum f.sp. dianthi and Fusarium redolens f.sp. dianthi

Pathogenic isolates were selected representing all known vegetative compatibility groups (VCGs) and races of Fusarium oxysporum sensu lato from Dianthus spp. On basis of differences in the internal transcribed spacer region of the ribosomal DNA, six VCGs were classified as F. oxysporum f.sp. dianthi and four as F. redolens f.sp. dianthi. All VCGs of F. oxysporum f.sp. dianthi were characterized by unique restriction fragment length polymorphisms (RFLPs), unique overall esterase profiles, and unique virulence spectra, supporting a clonal lineage concept. Two VCGs of F. oxysporum f.sp. dianthi nevertheless comprised more than one race, but races within the same VCG shared the same distinct overall virulence spectrum. VCGs belonging to F. redolens f.sp. dianthi also had unique RFLPs and unique virulence spectra, but had grossly identical esterase profiles. Three new races (9, 10 and 11) are described for F. oxysporum f.sp. dianthi, and four for F. redolens f.sp. dianthi. Two races previously considered lost were recovered; race 7 was identified as a member of VCG 0021 of F. oxysporum f.sp. dianthi while race 3 was identified as a distinct VCG and race of F. redolens f.sp. dianthi. A summary of races and VCGs in F. oxysporum f.sp. dianthi and F. redolens f.sp. dianthi is presented.     

Pewenomyces kutranfy gen. nov. et sp. nov. causal agent of an important canker disease on Araucaria araucana in Chile

Araucaria araucana, (commonly referred to as araucaria, pewen, or monkey puzzle tree) is an ancient conifer endemic to the Chilean and Argentinian mountain ranges where it has a sacred relevance to indigenous communities. During 2015, a serious disease was noticed on trees of all ages in most of the natural distribution of this iconic tree. Four areas were surveyed, and the most important symptoms of the disease were cankers on branches and stems resulting in copious resin exudation. Trees were monitored for a period of two years and isolations were made from the cankers. Field observations showed that the disease typically begins on the leaves or at the leaf bases and progresses downwards to initiate cankers that can girdle branches or stems within a two-year period. Black ascomata, resembling those of Caliciopsis species previously described from A. araucana, were consistently found developing in the cankers from which isolations were made. Phylogenetic analyses of the ITS, nucSSU, and nucLSU gene regions showed that the fungus resides in the Coryneliaceae but is distinct from other genera in that family. The morphological characteristics and phylogenetic position of the fungus show that it represents a new genus and species, described here as Pewenomyces kutranfy gen. nov. et sp. nov. Pathogenicity trials on trees under field conditions confirmed that this newly described fungus is able to cause cankers on A. araucana similar to those found under natural conditions.     

小麦白粉菌的联合致病性分析

 根据传统应用的生理小种研究方法存在着因鉴别品数的不同及其数目的改变而引起小种命名的混乱;同小种不同菌株致病性不同及有限的鉴别寄主不能及时区分出危险性小种等问题,本文改用病菌群体对品种的毒力频率和联合致病性方法,用河南各地的90个小麦白粉菌株分别接种9个已知抗性基因的品系和8个推广或区试品种所得到的侵染型资料,分别计算菌株群体对各对品种的联合致病性系数和联合毒性系数.结果表明本省小麦白粉菌群体中的V₁和V₃c、V₁和V₅及V₃b和V₃C等毒性基因是联合的;花培28和周80—48及周80—48和郑州831等品种组合搭配种植可有效地控制小麦白粉病.因此这套方法对生产和抗病育种的作用是直接的.文中提出应根据研究对象和研究目的不同,选择适当的研究方法,以提高病原物致病性研究结果的有用性.     

Pythium uncinulatum sp. nov. and P. tracheiphilum pathogenic to lettuce

From mature lettuce heads with bottom rot symptoms severalPythium species were isolated, two of which were studied further. Pathogenicity tests with both fungi have been carried out only with seedlings. P. uncinulatum sp. nov. was isolated frequently. Its relation to otherPythium spp. with spiny oogonia is discussed. It proved to be very pathogenic to seedlings of lettuce and somewhat less to those of cucumber and tomato. P. tracheiphilum, which was isolated far less frequently, proved to be highly pathogenic to seedlings of lettuce, cucumber and cauliflower, and somewhat less to tomato and pea.Samenvatting Van slaplanten met smetsymptomen werden behalveBotrytis cinerea, Rhizoctonia sp. enSclerotinia spp. dikwijlsPythium-soorten geïsoleerd. Twee hiervan zijn nader onderzocht. P. uncinulatum (Fig. 1, 3a, 3b), die dikwijls werd geïsoleerd, wordt beschreven als nieuwe soort en de relatie met anderePythium-soorten met gestekelde oögoniën wordt besproken. In proeven bleekP. uncinulatum zeer pathogeen te zijn voor zaailingen van sla en iets minder voor zaailingen van komkommer en tomaat (Fig. 4a, Tabel 2). Het planten van slazaailingen in metP. uncinulatum geïnoculeerde grond had meer effect dan het dopen van de wortels in een myceliumsuspensie van de desbetreffende schimmel vóór het planten. Het effect uitte zich in groeivertraging van de plant en beschadiging (necrose) van het gehele wortelstelsel. P. tracheiphilum (Fig. 2, 3c), die slechts een paar maal werd geïsoleerd, was zeer pathogeen voor zaailingen van sla, komkommer en bloemkool (Fig. 4a) en iets minder voor zaailingen van tomaat en erwt (Tabel 2). Groeiremming van de planten was sterker wanneer de wortels van de zaailingen vóór het planten in een myceliumsuspensie vanP. tracheiphilum gedoopt werden (Fig. 4b), dan wanneer de zaailingen in geïnoculeerde grond geplant werden. De hoofdwortels van de zaailingen werden ernstig beschadigd, maar zich later vormende zijwortels werden weinig door de schimmel beïnvloed.Tot nu toe zijn de pathogeniteitsproeven slechts met zaailingen uitgevoerd. Proeven met volwassen planten moeten volgen om te onderzoeken of er een verband kan bestaan tussen de aanwezigheid van de betreffendePythium-soorten in de grond en het optreden van smet in sla.     

Control of Glomerella cingulata f.sp. camelliae with fungicides

A critical test of fungicidal activity against the wound pathogen Glomerella cingulata f.sp. camelliae on camellias involved the application of a conidial suspension to scratches on detached leaves, treated with fungicide 24 h previously. In this test, prochloraz at 250–500 μg/ml a.i. in both EC and manganese WP formulations was highly effective, inhibiting leaf rotting by 90–100% compared with 55% or less in some tests with benomyl, chlorothalonil and captafol at 500–1000 μg/ml and captan at 1200 μg/ml. Prochloraz gave similar protection to leaves when applied to whole plants. Protection was less, especially on older leaves, when wounding and inoculating were delayed by 7 or more days after treatment. Prochloraz did not prevent all infection through comparatively large wounds, e.g. leaf scars, made on stems 24 h after treatment.
Poor control of the disease in a nursery was not due to resistance of the pathogen to benomyl; in vitro tests failed to detect full resistance at this time. Under nursery conditions a statutory policy of destroying infected plants and spraying the remainder with prochloraz or prochloraz manganese (both at 500 μg/ml), alternating with benomyl (500 μg/ml) on a weekly basis apparently prevented spread of the disease to healthy plants.     

Dormancy and sprouting of bulbs in Oxalis ladfolia H.B.K. and O. pes-caprae L.

A series of laboratory experiments was made to find a reliable and quick method of terminating the dormancy of bulbs of Oxalis lalifolia H.B.K. and Oxalis pes-caprae L. It was found that the dormant period of the bulbs of O. latifoliti could be terminated by chilling al 5°C for 3 weeks followed by dry heating at 45°C for 4 h and then moist storage at 23°C. The dormancy of bulbs of O. pes-caprae was overcome by chilling them for 6 weeks in polyethylene bags at temperatures between 2and 10°C and then storing without added moisture in polyethylene bags at 20°C. Some physiological and ecological aspects of the work arc discussed. Dormance et germination des bulbes d'Oxalis latifolia H.B.K. et d'O. pes-caprae L. Une série d'expériences de laboratoire a été réealisée pour rechercher une méthode süre et rapide pour rompre la dormance des bulbes d'OxaHs latifolia K.B.K. et d'Oxalis pes-caprae L. II a été constaté que Ton pouvait mellre fin à la période de dormance des bulbes d'O. latifolia par un refroid-issement à 5° C pendant 3 semaines, suivi d'un chauffage à sec à 45°C pendant 4 heures. puis d'une conservation en atmosphere humide à 23°C. La dormance des bulbes d'O. pes-caprae a été rompue par exposition au froid pendant 6 semaines dans des sacs de polyethylene à des températures comprises entre 2° et 10°C et en les conservant sans les humidifier en sacs de polyéthylene à 20°. Certains aspects physiologiques et écotogiques de cc travail sont discutés. Dormanz und Austrieb der Zwiebeln von Oxalis latifolia H.B.K. undo, pes-caprae L. Es wurde eine Reihe von Laboruntersuchungen durchgeführt, um ein zuverlässiges und schnelles Verfahren zur Brechung der Dormanz der Zwiebeln von Oxalis latifolia H.B.K. und Oxalis pes-caprae L. zu linden. Dabei wurde herausgefunden. dass die Dormanz der Zwiebein von O. latifolia durch dreiwöchige Lagerung bei 5°C, gefolgt von einem vierstündigen Trocknen bei 45°C und anschliessender feuchter Lagerung bei 23°C, gebrochen werden kann. Bei O.pes-caprae wurde die Dormanz der Zwiebein wie folgt gebrochen: Sechs Wochen Lagerung in Polyäthylenbeuteln bei 2 10°C und Aufbewahrung ohne Zusatz von Feuchtlgkeit bei 20°C in Polyäthylenbeuteln. Einige physiologische und ökologische Gesichtspunkte der Arbeit werden besprochen.     

The biology of Bassia birchii (F. Muell.) F. Muell.

The native perennial shrub, Bassia birchii. occurs as a weed over large areas of semi-arid eastern Australia. Its germination requirements and seedling growth were investigated and related to field observations and to possible means of control. Seeds cannot germinate until the woody fruit has broken down. Laboratory experiments showed that seeds would germinate throughout the year with most germinating at autumn and spring temperatures. Seedling deaths in the field are attributed to poor root growth, before the effects of water stress occurs. The spasmodic appearance of Bassia birchii infestations, particularly after droughts, is related to the dependence on the death of mature plants to provide propagules and fruit breakdown for germination. The unpredictable infestation pattern and the early development of spined fruits and basal buds on seedlings hinder control. Short period rotational or strategic grazing are suggested as possible means of control of seedlings in areas where perennial pastures can be established.     

杆垫刃属新属和一个新种的描述(垫刃目:垫刃科)

杆垫刃属新属(Rhabdotylenchus n. gen.)以其尾粗短,尾后部透明部分呈杆状,尾端平截有一凹痕,以及第一体环明显宽于其他体环并且该环角质层显著加厚与唇和其后的体部形成缢缩而显著区别于垫刃亚科(Tylenchinae rley, 1880)的其它属,该新属与近似属Tylenchus Bastian,1865的区别,除了独特的尾形和第一体环外,还以唇区显著缢缩,阴门位置较后(V>70vsV=60～70),明显区别于该近似属。广东杆垫刃线虫新属新种(Rhabdotylenchus guangdongensis n. gen., n. sp.)发现于广东省深圳市郊区的苦瓜根际土中。     

High resolution g.l.c. specifications for plant spray oils

High resolution g.l.c. chromatograms of a series of reference plant-spraying oils were used for the development of proposed g.l.c standards for spraying oils in Australia. The mean size and size-range of molecules in the oils have been specified in relation to carbon number positions for reference n-paraffins. Problems with reproducibility and precision with reduced pressure distillation (10 mm Hg) of plant-spraying oils have been demonstrated and discussed.     

Two new nematodes,Paraseuratoides ophisterni gen. et sp. n. (Quimperiidae) and Philometra ophisterni sp. n. (Philometridae), from the swamp-eel Ophisternon aenigmaticum in Mexico

Two new nematodes, Paraseuratoides ophisterni gen. et sp. n. (Seuratoidea: Quimperiidae) and Philometra ophisterni sp. n. (Dracunculoidea: Philometridae) are described based on specimens recovered from the intestine and mesentery, respectively, of the swamp-eel Ophisternon aenigmaticum Rosen et Greenwood (Synbranchiformes: Synbranchidae) from a canal of the Papaloapan River in Tlacotalpan, State of Veracruz, Mexico. The genus Paraseuratoides is mot similar to Paraseuratum Johnston et Mawson, 1940, differing from it mainly in the absence of a bulbous inflation on the anterior end of the oesophagus and in the structure of the mouth (presence of 6 spines in addition to 6 oesophageal teeth). Neoquimperia Wang, Zhao, Wang et Zhang, 1979 and Wuinema Yu et Wang, 1992 are synonymised with Ezonema Boyce, 1971 and Paragendria Baylis, 1939, respectively, and Haplonema hamulatum Moulton, 1931 is considered a junior synonym of Ichthyobronema conoura Gnedina et Savina, 1930. Philometra ophisterni (only females) is mainly characterised by minute cephalic papillae, a greatly developed anterior oesophageal bulb separated from the cylindrical part of the oesophagus, anterior extension of the oesophageal gland anterior to the nerve ring, and by the character of large caudal projections. This is the first Philometra species recorded from inland fishes in Mexico.     

肉桂后半啮的生物学特性及其防治

肉桂后半啮是桂皮产品的主要仓储害虫,在广东１ａ发生３～４代,世代重叠。以成虫在土壤缝隙中越冬,翌年３月下旬开始产卵,完成一代约４５～５５ｄ。每年６～７月是肉桂后半啮发生危害的高峰期,采用常规清洁措施结合药物防治效果较好。     

Some studies on the competition between Avenu fatua L. and spring barley.II. Variation of A. fatua emergence and development and its influence on crop yield.

The emergence and development of A fatua were studied in 23 spring barly fields in 1972 and nine in 1973 nautarally infested with yhe weed. Emergence occurred up to the four-leaf stages of the crop. The mean number of days from drilling to 50% emergence of A fatua plants was 22 in 1972 and 36 in 1973.The majority of seeds were shed by early emerging plants in 1972, 79% and in 1973. 59% of A fatua plants had emerged by the two-leaf stage of the crop and these plants produced 97 and 89% respectively of all the seed shed. In both years, A fatua plants emerging before the crop produced five times as many seeds per plant as those emerging between the crop two and three-leaf stages. The earliest emerging plants were also the heaviest and had most stems per plant.In both years there was a significant relationship between the density of A fatua plants in the crop in spring and their mortality.A large variation occured between the sites in the number of A fatua plants that emerged by a given crop leaf stage. In 1973.insufficient numbers of sites were investigatesd to derive a relationship between time to A fatua emergence and crop yield loss, but in 1972, a given density of A fatua plants emerging at an early stage caused agreater crop yields loss than the same density emerging later. This was also evident to aleser extent in data derived from a similar series of 15 experiments in 1971.     

高效液相色谱检测苏云金杆菌生物农药中氰戊菊酯的方法研究

市场上已发现有些B.t.生物农药中掺入了化学农药,因此分析检测生物农药中的化学农药就显得十分必要。本文建立了一种高效液相色谱测定B.t.可温性粉剂中氰戊菊酯的分析方法．并对市场上5个品牌的B.t.产品进行了检测。