Metalaxyl plus PCNB or metalaxyl plus tolclofos-methyl were field tested in 19851987 in Oklahoma for their effect on pod rot of Florunner and Spanco peanut caused by Pythium spp. and Rhizoctonia solani. Total a.i. (kg/ha) of metalaxyl and PCNB applied in 1985, 1986 and 1987 were 1.12 and 11.2, 1.12 and 11.2 and 0.92 and 7.40. respectively. Total a.i. (kg/ha) of metalaxyl plus tolclofos-methyl applied in 1986 and 1987 were 1.34 and 3.36 and 1.12 and 2.24, respectively. Fungicides reduced pod rot severity on both cultivars at 28 wks prior to harvest; at harvest, however, none of the reductions were significant (P≤0.05). Yield increases were measured from 111579 kg/ha, but few increases were significant (P≤0.05). Fungicides generally reduced the number of Pythium propagules in soil at several sampling dates, but few of the reductions were significant (P≤0.05). In 1986 and 1987 populations of Pythium spp. in soil peaked at 60 and 75 days, respectively, then declined. At these peaks treated soils generally had fewer Pythium propagules than nontreated soils. Populations of Pythium spp. were not significantly reduced at harvest. Populations of R. solani were highly variable over the seasons and control was erratic from year to year. In combination with metalaxyl, tolclofos-methyl was no more effective than PCNB in reducing pod rot or populations of R. solani. Populations of R. solani at harvest were not significantly (P≤0.05) reduced by the fungicide combinations.
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Keywords: Metalaxyl, pentachloronitrobenzene, tolclofos-methyl, soil fungicides, peanut pod rot, Pythium spp, Rhizoctonia Solani, Arachis hypogaea, L
How to Cite:
Filonow, A. & Jackson, K.,
(1989) “Effect of Metalaxyl Plus PCNB or Metalaxyl Plus Tolclofos-methyl on Peanut Pod Rot and Soil Populations of Pythium spp. and Rhizoctonia solani”,
Peanut Science 16(1),
31 Dec 1988