Pénétration, translocation et métabolisme de dinitrophénols

Penetration, transloealion and metabolism of dinitrophenols We had at our disposal DNTBP and DNOC uniformly labelled with ¹⁴C on the benzene ring. Leaf penetration and root uptake were slow with DNTBP as was translocation. After 3 days it was already possible to show degradation compounds far removed from the original herbicides. A catabolite fifty times less active than DNTBP, methyl-2-(hydroxy-2′dinitro-3′5′phenyl)-2-propanol-1, was identified. On the biological plane, DNTBP and DNOC have a disruptive effect on the lipid membranes. Aufnahme, Translokation und Stoffwechsel von Dinitrophenolen     

A New Species of Ectoparasite,<Emphasis Type="Italic">Erythraeus ankaraicus</Emphasis> Saboori,Cobanoglu and Bayram,on<Emphasis Type="Italic">Asymmetrasca (=Empoasca) decedens</Emphasis> in Cotton

The infestation intensity of the ectoparasiteErythraeus ankaraicus Saboori, Cobanoglu and Bayram (Acari: Erythraeidae) onAsymmetrasca (=Empoasca) decedens (Paoli) (Homoptera: cicadellidae),Aphis gossypii Glov. (Homoptera: Aphididae) andThrips tabaci Lind. (Thysanoptera: Thripidae) in cotton was investigated during the 2004 and 2005 growing seasons in Aydin Province, TurkeyE. ankaraicus was recorded for the first time onA. decedens leafhopper nymphs during the early growth stage of cotton. Parasitism ofE. ankaraicus on leafhopper nymphs during the first week of July 2004 was 68.9%, whereas in the middle of July 2005 — when mite populations peaked — it reached only 15.1%. Parasitism of the leafhopper was not observed from the middle of the season onward (August to October).     

ACTION D'UNE URÉE SUBSTITUÉE, LE MÉTHBENZ-THIAZURON, SUR LA CROISSANCE DE PLANTULES DE BLÉ ET RÔLE DES ADDITIFS

Résumé. Une nouvelle urée substitutée le méthbenzthiazuron (N-benzothiazol-2-yl-NN'-diméthylurée), a été utilisée en culture hydroponique de Triticum sativum cv. Vilmorin 27. La substance active selon qu'elle est pure ou sous sa forme commerciale provoque des inhibitions de croissance différentes. On a mis en évidence le röle joué par les ingrédients théoriquement inactifs ajoutés à la substance active. L'utilisation de diquat marqué permet de conclure à la présence de l urée dans i'ensemble des tissus. La cinétique de la réponse suggére un phénoméne de détoxification. C'est la concentration extérieurc aux racines qui provoque T inhibition de croissance.     

Persistent,symptomless, systemic,and seed-borne infection of lettuce by <Emphasis Type="Italic">Botrytis cinerea</Emphasis>

Experiments are presented which show that Botrytis cinerea, the cause of grey mould disease, is often present in symptomless lettuce plants as a systemic, endophytic, infection which may arise from seed. The fungus was isolated on selective media from surface-sterilised sections of roots, stem pieces and leaf discs from symptomless plants grown in a conventional glasshouse and in a spore-free air-flow provided by an isolation propagator. The presence of B. cinerea was confirmed by immuno-labelling the tissues with the Botrytis-specific monoclonal antibody BC-12.CA4. As plants grew, infection spread from the roots to stems and leaves. Surface-sterilisation of seeds reduced the number of infected symptomless plants. Artificial infection of seedlings with dry conidia increased the rate of infection in some experiments. Selected isolates were genetically finger-printed using microsatellite loci. This confirmed systemic spread of the inoculating isolates but showed that other isolates were also present and that single plants hosted multiple isolates. This shows that B. cinerea commonly grows in lettuce plants as an endophyte, as has already been shown for Primula. If true for other hosts, the endophytic phase may be as important a component of the species population as the aggressive necrotrophic phase.     

Epigallocatechin gallate,a major tea catechin,induces biofilm formation of <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">theae</Emphasis>

Plants constitutively produce a variety of secondary metabolites that have antimicrobial activities against phytopathogens; however, interactions between these performed antimicrobial compounds and phytopathogens were poorly understood. In this study, interactions between epigallocatechin gallate (EGCg), which was a major tea catechin that had antimicrobial activities against varieties of bacteria, and Pseudomonas syringae pv. theae (P.s. theae), the causal of bacterial shoot blight of tea, were investigated. EGCg had less antimicrobial activity against P.s. theae; however, subinhibitory concentrations of EGCg induced biofilm formation. Because biofilms are induced in the presence of sucrose in the culture medium but not by P.s. theae strains deficient in exopolysaccharide levan production, biofilm induction by EGCg and levan production are closely related. EGCg increased survival of P.s. theae under dry conditions on nonwounded leaf surfaces in the presence of sucrose. These data indicate the possibility that tea catechins affect the survival of P.s. theae on the phyllosphere. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Note: First record of the eucalyptus gall wasp<Emphasis Type="Italic">Ophelimus maskelli</Emphasis> and its parasitoid,<Emphasis Type="Italic">Closterocerus chamaeleon</Emphasis>, in Turkey

The Eucalyptus gall waspOphelimus maskelli (Ashmead) (Hymenoptera: Chalcidoidea: Eulophidae: Ophelimini) and its introduced parasitoidClosterocerus chamaeleon (Hymenoptera: Chalcidoidea: Eulophidae: Entedoninae) are recorded for the first time in the Mediterranean and Aegean Regions of Turkey. Some morphological characters of adult and larva ofO. maskelli and larva ofC. chamaeleon are described and illustrated. Distributions of the two wasps collected in Turkey are given. Results indicate that the biological control agent,C. chamaeleon, has spread over 1,300 km in the 16 months since its initial release.     

Molecular characterization of <Emphasis Type="Italic">Phoma tracheiphila</Emphasis>, causal agent of Mal secco disease of citrus,in Israel

Mal secco disease of citrus caused by Phoma tracheiphila is a devastating disease in the Mediterranean basin. Susceptible citrus species include lemon, citron, lime and others. Trees attacked by the fungus show characteristic symptoms; the smallest twigs die first, followed by the larger branches. Eventually, the whole tree is killed. The symptoms are clear in the orchards but by the time they are visible the disease is already well established. The need for a sensitive, reliable and rapid diagnostic method for the early identification of the fungus in trees and fruit exists. We have developed a PCR-based method for the identification of P. tracheiphila from plant tissues including fruit. Any such method must take into account the genetic variability in the pathogen population. Molecular methods were used to compare different isolates of P. tracheiphila. This study found no significant differences between different isolates from different citrus species from different parts of Israel.