The physical and chemical properties of the herbicide cinmethylin (SD 95481)     

B. Terence Grayson  Karen S. Williams  Paul A. Freehauf  Rodney R. Pease  William T. Ziesel  Richard L. Sereno  Ronald E. Reinsfelder 《Pest management science》1987,21(2):143-153

Cinmethylin (SD 95481), is a novel herbicide developed for the selective pre-emergence control of many annual grass weeds in a wide range of temperate and tropical crops. Representing new herbicide chemistry, cinmethylin is in the cineole family. Cinmethylin is a mobile colourless liquid with a boiling point of 313°C under an inert atmosphere at atmospheric pressure. It has a density of 1015 kg m^?3 and a viscosity of 70–90 mPa s, both at 20°C. It is miscible in all proportions with most organic solvents but has a low solubility, 63 mg litre^?1, in water. It has a vapour pressure of 10.2 mPa (20°C) and the vapour pressure/temperature relationship is given by log_e P(Pa)=28.9–9816/T (K). The n-octanol/water partition coefficient is 6850 and soil organic matter/water sorption coefficient (K_om) ranges between 165 and 235 over the three types of soil used in these studies. Cinmethylin is stable in water over the pH range 3–11. Solutions of cinmethylin in water or solvents are reasonably stable to sunlight, though thin films on a quartz surface photooxidise mainly to an ester within 24 h. This rate can be reduced by the addition of photostabilisers or by sorption onto soil surfaces. In an inert atmosphere cinmethylin is stable to high temperatures, though, in air, oxidation occurs at temperatures above 100°C to give the same product as by photodecay.  相似文献   

Comparative effects of three isoxazole-urea herbicidal derivatives on the metabolism of enzymatically isolated soybean leaf cells*     

W. T. HENRY  K. K. HATZIOS 《Weed Research》1987,27(1):23-30

The effects of the herbicide isouron and of its plant degradation products designated as metabolite l {N-[5-(1,1-dimethylethyl)-3-isoxazolyl]-N-methylurea} and metabolite 2 {N-[5-(1,1-dimethylethyl)-3-isoxazolyl]-urea} on the metabolism of enzymatically isolated leaf cells of soybean [Glycine max (L.) Merr., cv. Essex] were compared under laboratory conditions. Photosynthesis, protein synthesis, ribonucleic acid synthesis, and lipid synthesis were assayed by the incorporation of NaH¹⁴CO₃, [¹⁴C]-leucine, [¹⁴C]-uracil, and [¹⁴C]-acetate, respectively, into the isolated cells. Time-course and concentration studies included incubation periods of 30, 60, and 120 min and concentrations of 0.1, 1, 10 and 100 μM of the three herbicides. The urea derivative of isouron (metabolite 2) was the least active of the three compounds. The activity of the mono-methylated derivative of isouron (metabolite 1) was comparable to that of isouron and the sensitivity of the four processes to both chemicals decreased in the order: photosynthesis > ribonucleic acid synthesis > lipid synthesis > protein synthesis. The concentration of isouron that caused a 50% inhibition of photosynthesis of the isolated soybean leaf cells was calculated at 0.51 μM. The effects of isouron and metabolite 1 on photosynthesis, lipid and RNA synthesis appeared to be independent of incubation lime as maximal inhibition occurred within 30 min. Inhibition of protein synthesis by both chemicals was time-dependent, increasing in magnitude with concomitant increases in incubation time.  相似文献   

Rhabdovirus-like particles in the sporocyst of the trematode Brachylaimus fuscatus from terrestrial mollusc Ponsadenia duplocincta     

Z Zdárská  T N Soboleva  J Weiser 《Folia parasitologica》1986,33(3):277-279

Rhabdovirus-like particles containing nucleoprotein in a helix with eight turns was demonstrated by transmission electron microscopy in subtegumental cells and syncytial layer of tegument in Brachylaimus fuscatus sporocyst. This is the first case of virus infection in trematodes. The possibility of transfer of the virus to intra-molluscan parasitic generations of the trematode is discussed with respect to the peculiarities of the life cycles of the family Brachylaimidae.  相似文献   

The relative resistance of wheat, rye and triticale to take-all caused by Gaeumannomyces graminis   总被引：5，自引：1，他引：5  

T. W. HOLLINS  P. R. SCOTT  R. S. GREGORY 《Plant pathology》1986,35(1):93-100

In seven field experiments conducted over 6 years with a wide range of disease severities, triticale was intermediate in resistance to Gaeumannomyces graminis between wheat (susceptible) and rye (resistant). Use of triticale is suggested as an immediately available means of introducing take-all resistance into cereal cultivation.
Octoploid triticale was slightly more susceptible than hexaploid triticale. There was little evidence of consistent variation in resistance among wheat or rye cultivars but a few hexaploid triticale cultivars varied in resistance. The resistance of triticale was not reliably expressed in the glasshouse tests used, so selection for resistance to take-all in a breeding programme would need to be conducted in the field. Individual pairs of rye chromosomes added to wheat did not significantly reduce its susceptibility. The feasibility of transferring the resistance of rye to wheat is considered.  相似文献   

Effects of fungicides on powdery mildew, tree growth and cropping of apple     

T. LOCKE  LINDA ANDREWS 《Plant pathology》1986,35(2):241-248

In a 6-year orchard experiment, seven fungicide programmes were assessed for control of powdery mildew (Podosphaera leucotricha) and for long-term effects on growth and cropping of the apple cultivar Cox's Orange Pippin. Programmes based on binapacryl, bupirimate, fenarimol, nitrothal-isopropyl and triadimefon gave better control than dinocap or triforine. The heaviest cumulative yields of marketable fruit were obtained with the non-systemic fungicides binapacryl and nitrothal-isopropyl, the former significantly outyielding triadimefon and triforine over 6 years. Tree vigour, as assessed by extension shoot length and internode length, was found to be better after 4-5 years of programmes based on binapacryl than on triadimefon or fenarimol. A relation was demonstrated between cumulative marketable yield and mean annual mid-season incidence of secondary mildew on extension shoot leaves.  相似文献   

Characteristics distinguishing invasive weeds within Echium (Bugloss)   总被引：1，自引：0，他引：1  

F. FORCELLA  J. T. WOOD  S. P. DILLON 《Weed Research》1986,26(5):351-364

Plant quarantine agencies attempt to regulate the continuing worldwide problem of spread of alien plants, but systems of plant quarantine have not been based entirely on objective criteria. Comparative epidemiological research of known alien weeds may provide such criteria and thereby improve the success of plant quarantine. For this reason biogeographical and ecophysiological data were gathered and analyzed for Echium (Boraginaceae), especially for the three differentially distributed and weedy species in Australia: E. italicum L. (rare), E. vulgare L. (uncommon), and E. plantagineum L. (common). Such data included the following: native distributions in Eurasia and North Africa, historical spread in Australia, seed germination, vegetative growth and propensity to flower. Quantitative plant characteristics which distinguish weedy species of Echium from their innocuous counterparts, and whose values could most easily be determined by plant quarantine officials, are the breadth of native distribution and rapidity of seed germination. Although these results were derived from only a few temperate taxa, they may apply in principle to many species. Caractères distinctifs des mauvaises herbes envahissantes dans le genre Echium Des agences de mise en quarantaine de végétaux s'attachent à contrôler le problème permanent à travers le monde de la propagation des végétaux étrangers; cependant, les systèmes de quarantaine n'ont pas étéétablis exclusivement sur des critères objectifs. Des études d'épidèmiologie comparatives pour des adventices étrangères connues peuvent fournir de tels critères et ainsi accroître le succès de la mise en quarantaine des végétaux. Pour cette raison, des données biogéographiques et écophysiologiques ont été regroupées et analysées pour le genre Echium (Boraginacée), en particulier pour trois espèces de mauvaises herbes différemment réparties en Australie: E. italicum L. (rare), E. vulgare L. (peu répandu), E. plantagineum L. (commun). Parmi ces données, on trouvait les suivantes: répartition originelle en Eurasie et en Afrique du Nord, historique de la propagation en Australie, germination des semences, croissance végétative et propension à fleurir. Les caractéristiques quantifiables qui permettraient de distinguer les espèces nuisibles d'Echium de leurs équivalents inoffensifs et dont les valeurs pourraient très aisément être déterminées par les organismes officiels responsables des quarantaines sont: l'ampleur de la distribution d'origine et la rapidité de la germination des semences. Bien que ces résultats proviennent de seulement quelques taxons, ils peuvent être appliqués, en principe, à de nombreuses espèces. Merkmale zur Definition schädlicher Arten in der Gattung Echium (Natterkopf) Pflanzenquarantäneämter versuchen das weltweite Problem der Ausbreitung von eingeschleppten Pflanzen zu kontrollieren; die Quarantän-evorschriften sind jedoch nicht völlig auf objektiv erfassbare Kriterien abgestützt. Vergleichendc epidemiologische Erforschung von Adventivpflanzen kann derartige Kriterien liefern und damit den Nutzeffekt von Quarantänemassnahmen verbessern. Zu diesem Zweck wurden für die Gattung Echium (Boraginaceen) biogeographische und ökophysiologische Daten gesammelt und analysiert; es wurden dabei speziell die drei in Australien als Unkräter geltenden und verschieden verbreiteten Arten E. italicum L. (selten). E. vulgare L. (gelegentlich vorkommend) und E. plantagineum L. (häufig) untersucht. Der Datenkatalog enthielt Angaben über: die ursprüngliche Verbreitung in Eurasien und N-Afrika, Geschichte der Ausbreitung in Australien, Samenkeimung, vegetatives Wachstum und Blühbereitschaft. Der Ausdehnungsbereich der ursprünglichen Vorkommen und die Geschwindigkeit der Samenkeimung sind quantitativ erfassbare, durch Quarantäncbeamte leicht zu bewertende, Kriterien zur Unterscheidung zwischen unschädlichen und als Unkräuter schädlichen Echium-Arten. Obwohl diese Ergebnisse nur von relativ wenigen, unter temperierten Bedingungen vorkommenden, taxonomischen Einheiten abgeleitet worden sind, mögen sie im Prinzip für viele Arten Gültigkeit haben.  相似文献   

Activity of two novel insecticides against permethrin-resistant Pseudoplusia includens     

James D. Thomas  Jeffrey S. Mink  David J. Boethel  Alan T. Wier  B. Roger Leonard 《Pest management science》1994,40(3):239-243

Two experimental insecticides, AC 303,630 and MK 244, were tested against a laboratory colony and three field strains of Pseudoplusia includens (Walker). Topical application bioassays indicated that permethrin resistance in the field strains ranged from 3.9 to 489.0-fold. In leaf dip bioassays, LC₅₀ and LC₉₀ values for AC 303,630 ranged from 6.7 to 15.1 mg litre ?1 and 8.7 to 28.2 mg litre ?1, respectively, for third-instar larvae. The Louisiana 1991 field strain was significantly more susceptible to AC 303,630 than the laboratory and other field strains. The LC₅₀ (but not LC₉₀) for the Louisiana 1992 field strain was significantly higher than that of the laboratory strain. However, there was no difference in toxicity of AC 303,630 between the field strain with the highest level of permethrin resistance and the laboratory strain. LC₅₀ and LC₉₀ values for MK 244 in leaf dip bioassays ranged from 0.014 to 0.023 mg litre ?1 and 0.079 to 0.174 mg litre ?1, respectively. There were no significant differences in LC 50 or LC 90 among any of the strains for MK 244. Field trials in soybean were also conducted in 1991 and 1992 in an area of Louisiana where permethrin efficacy against P. includens has declined. In both years, AC 303,630 at 0.11–0.22 kg ha ?1, and MK 244 at 0.0042–0.0084 kg ha ?1, provided significantly better control than permethrin at 0.11 kg ha ?1, and control equal to the recommended standard, thiodicarb. These studies indicate no cross-resistance exists between the experimental insecticides and permethrin.  相似文献   

Susceptibility of some North American and Yugoslav plum cultivars to plum pox potyvirus in Poland1     

B. ZAWADZKA  E. ROZPARA  Z. GRZYB  T. MALINOWSKI 《EPPO Bulletin》1994,24(3):767-770

All North American plum cultivars investigated in Poland for their reaction to plum pox potyvirus appeared to be susceptible, showing severe symptoms on the leaves. Fruits of cvs Valor and Empress were also heavily damaged. Of the Yugoslav cultivars evaluated, Cacanska Najbolja was most tolerant whereas Cacanska Rodna appeared to be most sensitive to PPV.  相似文献   

Interactions among maize streak virus disease, leafhopper vector populations and maize cultivars in forest and savanna zones of Nigeria   总被引：1，自引：0，他引：1  

C. M. ASANZI  N. A. BOSQUE-PEREZ  I. W. BUDDENHAGEN  D. T. GORDON  L. R. NAULT 《Plant pathology》1994,43(1):145-157

Monthly plantings of three maize cultivars with differing resistance/susceptibility to maize streak geminivirus (MSV) and samplings of Cicadulina leafhopper vectors were made from December 1988 to April 1990 in the humid forest and from May to November 1989 in the Guinea savanna zones of Nigeria. High MSV disease incidences (43–56%) were recorded on susceptible cultivar TZB-Gusau in late-season (July-October) plantings. Hybrid 8321-21 showed significantly lower MSV disease incidence and severity than the other two cultivars, TZB-Gusau and 8329-15. Cicadulina species population peaks (5.2-13.5 leafhoppers/m²) were observed before the rains ended in savanna locations and after the end of the rains in the forest zone. Cicadulina mbila was the predominant species, whereas C. storeyi (syn. C. triangula ), C. arachidis, C. similis and C. ghaurii were less common. The proportion of viruliferous leafhoppers increased as the season progressed, reaching maxima of 15–25% at the end of the growing season. Interactions between disease incidence, Cicadulina populations, maize cultivars and rainfall are discussed.  相似文献   

Resistance to Peronospora viciae expressed as differential colony growth in two cultivars of Pisum sativum     

J. S. C. CLARK  P. T. N. SPENCER-PHILLIPS 《Plant pathology》1994,43(1):56-64

Peronospora viciae sporulated frequently following localized inoculation of leaflets of Pisum sativum cv. Krupp Pelushka but rarely on cv. Early Onward (60 and < 1% of plants respectively). Similar results were obtained following inoculation of seedling shoot apices. The proportions of sporangia that germinated, formed appressoria, invaded via stomata or cuticle, and established colonies, were similar on leaflets of both cultivars. After 2 days, total hyphal lengths of most colonies were greater than 100 μm (94% in Krupp Pelushka, 64% in Early Onward), but in Krupp Pelushka there were five times as many haustoria per unit length of hypha. Subsequently, only occasional colonies in Early Onward grew to the same extent as in Krupp Pelushka, with 8% and 88% respectively attaining lengths > 800 μm after 4 days. Reduced growth of hyphae in Early Onward was associated with increased frequency of host cells stained by trypan blue.  相似文献