Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Economic Entomology and Pesticides

Study the efficacy of three herbicides at different rates: Acetochlor (Harness 84% EC) at 0.5 L+ one hoeing and 1.0 L/feddan as pre-emergence, Cinosulfuron (Setoff 75% WG) at 25 g + one hoeing and 50 g/feddan and Fluroxypyr (Starane 20% EC) at 200ml + one hoeing and 200 ml/feddan as post-emergence. as well as Hand hoeing (twice) and Unweeded control on yield, yield components and quality characters of maize. Also, study the persistence of Acetochlor in maize grains and soil. The data revealed that Acetochlor at recommended rate (1.0L. /feddan.) gave lowest fresh weight (0.0gm./m2) of Portulaca oleracea L, Amaranthus hybridus L. and Xanthium pungens wallr, followed by Echinochloa colonum L, Corchorus olitorius L, Euphorbia geniculata L. and Brachiaria eruciformis L. during the two seasons, the all herbicides treatment were more effective on Amaranthus hybridus L and Xanthium pungens wallr than other tested weeds. The most effective treatment on ears weight was achieved by Cinosulfuron with the hoeing as compared with Acetochlor and Fluroxypyr treatments. No phytotoxicity was observed to herbicides treatments in maize in two seasons that Indicating the safety of these herbicides on the plant photosynthesis. Insignificant differences were recorded between Cinosulfuron at the recommended rate and plus hoeing on oil percentage in 2013 and protein in 2014. Residue analysis of Acetochlor (0.5 and 1.0 L. /feddan) at harvest of corn grain showed that no detectable amounts of Acetochlor residues, so corn grains could be safely marketed for human consumption after treatment with Acetochlor under the normal field conditions. The dissipation of the herbicide residues in/on crops depends on environmental condition, type of application, plant species, dosage, and interval between applications

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