: In-vitro and in-vivo results show no decrease in Phytophthora infestans sensitivity to cymoxanil after more than 16 years of intensive use, and that a single, sensitive population exists within the countries sampled.1998 SCI ( Pestic. Sci., 53, 101È103 (1998)

Pathogenic strains of Phytophthora infestans insensitive to phenylamide have been reported from around the world and are responsible for a lack of late blight control in both potatoes and tomatoes. In vivo laboratory assay methods used to determine the sensitivity of P. infestans to fungicides include floating of leaflet disks on fungicide suspension and the use of potato tuber disks. In our study, these two methods were compared with a new detached-leaf assay. The fungicides chlorothalonil (protective), oxadixyl and metalaxyl (systemic), and cymoxanil (locally systemic) were utilized. Phenylamide-insensitive and -sensitive genotypes of P. infestans were used as inoculum. Significant differences between preventive and systemic fungicides were found, and all assay methods differentiated between phenylamide-sensitive and -insensitive genotypes of P. infestans. Differences among assays were significant when comparing mean inhibitory values. There was no significant difference between the detached leaf and the tuber disk assay, but both methods were significantly different from the floating-leaflet disk assay.

In‐vitro and in‐vivo results show no decrease in Phytophthora infestans sensitivity to cymoxanil after more than 16 years of intensive use, and that a single, sensitive population exists within the countries sampled. © 1998 SCI

A manual kit for determining serum 5'nucleotidase (5'NT, EC 3.1.3.5) activity was adapted for use with rat samples on a large discrete clinical chemistry analyzer. The precision of the method was good (within-run C.V. = 2.14%; between-run C.V. = 5.5%). A comparison of the new automated method with a manual and semi-automated method gave regression statistics of y = 1.18X -3.66 (Sy. x = 4.54), and y = 0.733X + 1.97 (Sy. x = 1.69), respectively. Temperature conversion factors provided by the kit manufacturer for human samples were determined to be inaccurate for converting results from rat samples. Analysis of components contributing to normal variation in rat serum 5'NT activity showed age and sex to be major factors. Increased serum 5'NT activity was observed in female rats when compared to male rats beginning at about 5 to 6 weeks of age. An analysis of variance of serum 5'NT, alkaline phosphatase, and GGT activities observed over a 9-week period in normal rats suggests several advantages for 5'NT as a predictor of biliary lesions in rats.

Sensitivities of Septoria tritici populations to flusilazole were stable across Europe during the three seasons, 1993–1995 inclusive. © 1998 Society of Chemical Industry