The article about pencycuron (part 4)

Infection of strawberries was effectively reduced by dipping seedlings in 250 ppm benomyl suspension before transplanting. Treatment with pencycuron, copper oxyquinolate + carboxin or tolclofos-methyl were also effective, while dichlofluanid gave poor control. Yields increased correspondingly. Growth inhibition of R solani f.sp fragariae by benomyl was reduced when ammonium sulfate was also present in PDA, and a similar effect was observed for tolclofos-methyl. Ammonium sulfate alone had no effect on fungal growth. The nematicide oxamyl also had no effect on the pathogen in vitro but reduced the action of tolclofos-methyl. Carboxin, furmecyclox, thiabendazole, fenpropimorph and vinclozolin also inhibited all AGs but with wide variations in toxicity levels. Pencycuron showed strong activity towards 4 AGs but was ineffective towards the other 6 AGs. The AGs were generally insensitive to fenarimol and imazalil. Further tests with 5 fungicides showed that tolclos-methyl strongly inhibited 23 AG2-1 and 20 AG4 R solani isolates from rape collected in different locations in western Canada. The same isolates were also sensitive to iprodione, cyproconazole and carboxin. All the AG4 isolates were insensitive to pencycuron, while the AG2-1 isolates showed highly variable levels of sensitivity. The following results were obtained: larvae, pupae and young adults were parasitized by Heterorhabditis. At soil temperatures above 12 degrees C decreases in host densities of 81-100% were found as well in containerized ornamentals as in field production of strawberries. Dosage levels could be reduced to 10 000 nematodes per 2 litre-container or 600 000 nematodes per msuperscript 2 without significant loss of efficiency. It is recommended that Heterorhabditis should be applied as soon as they are delivered, as cool storage for several weeks drastically reduced their efficiency. Soil treatments with the fungicides benomyl, fosetyl, iprodion, metalaxyl, prochloraz, propamocarb or pencycuron did not show negative effects on the efficiency of Heterorhabditis against larvae of O sulcatus. Vine growth in untreated soil with or without dilution using clean sand was compared with growth in soil subjected to a range of treatments including: disinfestation either by aerated steaming or by fumigation with methyl bromide, amendment with 1% corn-meal, or treatment with fungicides and/or fenamiphos. Vines grown in infested soil suffered root rot caused by R solani and galling caused by M incognita. Both disinfestation treatments effectively prevented root rotting and galling, and increased the growth of Colombard but not Ramsey. Fenamiphos increased the growth of the nematode-susceptible Colombard but not Ramsey at a low initial population density of three juveniles per 200 g of soil. Nematode reproduction on Ramsey in the shadehouse and in the field nursery on other rootstocks regarded as being highly resistant to root-knot nematode was higher than previously reported with other South Australian Meloidogyne spp populations. Soil dilution increased Colombard growth and amendment with corn-meal reduced nematode reproduction on both cultivars Rhizoctonia solani caused root rot in both cultivars but quintozene and tolclofos-methyl increased root growth only of Ramsey. These fungicides and pencycuron reduced the severity of root rot; tolclofos-methyl was particularly effective in reducing the frequency of isolation of R solani from roots. Potassium phosphite did not reduce root rot or increase root growth. Quintozene, tolclofos-methyl and pencycuron also inhibited nematode reproduction but these effects were not consistently observed in both cultivars Most isolates of R solani from grapevine roots belonged to anastomosis group 4 

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