Interactions between Cercospora arachidicola and Phoma arachidicola, and their effects on defoliation and kernel yield of groundnut

Cercospora arachidicola and Phoma arachidicola spread independently on groundnuts when leaf area was not limiting, but where C. arachidicola colonized leaves early, it usually spread at the expense of P. arachidicola. Juice extracted from leaflets infected with C. arachidicola and separated by thin-layer chromatography contained unidentified compounds which were not present in juice from uninfected leaflets, and prevented the growth of P. arachidicola. Cercospora leaf spot reduced photosynthesis and was the major contributor to premature leaf drop, which had an adverse effect on yield. Well blotch ( P. arachidicola ) only caused defoliation and depressed yield where there was very little Cercospora leaf spot present.     

Influence of glyphosate on selected plant processes

Biochemical effects of glyphosate have been examined with a variety of plant materials using mostly merislematic or actively growing tissues. The accumulation of chlorophyll was severely retarded and photosynthetic CO₂ uptake was inhibited to a lesser extent. These inhibitory effects could not be alleviated by the simultaneous admixture of divalent cations. Glyphosate enhanced the initial substrate-induction of nitrate reductase, but repressed induction of nitrite reductase, in Ihe latter case correlating with both inhibition of chlorophyll accumulation and CO₂ uptake. Inhibition of macromolecule synthesis in single node buds of Agropyron repens(L.) Beauv. was due partly to inhibition of ¹⁴C-precursor uptake. The specific activity of soluble acid phosphatase was enhanced as was the evolution of ethane. Ethylene production was not greatly affected. A marked decrease in microsomal protein was observed but the specific activities of several microsomal enzymes did not decline. Glyphosate had little inhibitory effect on the activity of microsomal ATPases in vitro.     

DISSOCIATION OF HOMOGRAFT RESPONSE TO ALLOGENEIC VERSUS XENOGENEIC SKIN GRAFTS IN IRRADIATED MICE

Lethally x-irradiated (C3H x DBA/2)F(1) mice were protected with syngeneic (isogenic) bone marrow and/ or prior treatment with urethan and skin grafted at various times after irradiation. The ability to reject a first-set xenogeneic (heterologous) skin graft with normal vigor returned within 92 days; the first-set response to allogeneic (homologous) grafts was still impaired 350 days after irradiation.     

The laboratory culture of Dichelobacter nodosus in a footrot eradication program

SUMMARY As part of a program to eradicate virulent footrot from Western Australia, 2745 isolates of Dichelobacter nodosus were isolated from 5263 specimens from 1883 submissions. The virulence of each isolate was assessed using protease thermostability and isoenzyme zymogram. We describe changes to the materials and methods required to handle these specimens and to reduce the interval between submission and report to 8 days.     

Detection of Aphanomyces invadans and epizootic ulcerative syndrome in the Murray‐Darling drainage

Epizootic ulcerative syndrome was diagnosed, and the presence of Aphanomyces invadans confirmed, from an outbreak of clinical disease in wild‐caught bony bream (Nematalosa erebi) from the Darling River near Bourke, in New South Wales, Australia, during 2008. This confirms a significant extension of the agent beyond its historical range.