1National Horticultural Research Institute, Ibadan, Nigeria.
2Department of Agricultural Biology, University of Ibadan, Ibadan, Nigeria.
*Present address:Box 232, Suite 202, 3148 Kingston Road, Scarborough, Ontario MIM 1P4, Canada.
A single side dressing application of aldicarb, carbofuran, miral or oxamyl at 2(I) or 4(II) kg a.i./ha in early season resulted in significant yield increases of corn. Cob yields increased by 24, 27, 28 and 31% in respect of miral II, carbofuran I, aldicarb I and miral I; and in grain yields by 43, 50, 65 and 84% in order of oxamyl II, aldicarb I, miral II and miral I. Aldicarb and miral residues in treated grains were <0.01 and <0.02 ppm, respectively, at either rates. Aldicarb degraded rapidly in experimental loam sand from 0.02–1.00 ppm during the early four weeks following treatment to <0.01 ppm by the eighth week and till harvest in the wet season.
Treatment suppressed soil populations of Helicotytenchus dihystera, Hoplolaimus galeatus, Meloidogyne incognita, Criconemoides sp. and Pratylenchus sefaensis considerably. Miral and aldicarb were the most effective treatments against present nematode species. Response of the individual nematode species to rainfall and interactions with coinhabiting biomass were greatly diversified from untreated in the nematicides plots. Greater significant negative correlations were found between number or weight of cobs and numbers of H. galeatus than those with other contemporary species. This is the first report on residues of aldicarb and mirai in corn grains and soils.
corn, granular peeticides, yield, residues in grab and soils, nematode community, nematode biological interactions
