Determination of Tralkoxydim and Tribenuron- Methyl Residues in Wheat Plant, Soil and Its Effect on Aphids Infestation and on Fresh Yield.

Abstract

The field experiment was conducted at Fayoum Governorate to determine the effect of Tralkoxydim 10% EC and Tribenuron-methyl 75% residues in two wheat varieties (Cids-7 and Giza-164) against infestation of aphids; Schizaphis graminum (Rondani) and Rhopalosiphum padi (L.) during 1998-1999 and 1999-2000 seasons. Results indicated that the two studied varieties were highly susceptible to the infestation with aphid R. padi and less susceptible to S. graminum. The Giza 164 variety was less susceptible to R. padi (34.95, 30.66 and 16.71, 12.36 individual/plant) than Cids 7 variety (94.05, 86.56 and 39.81, 32.36 individual/plant) by contrast, the former variety was more less susceptible to S. graminum than the second one (1.21, 0.83; 3.48, 2.66 individual/plant and 0.98, 0.58; 2.25, 1.71 individual/plant), with untreated and treated during two successive seasons respectively.The times for 50% loss of initial Granstare in soil were 50.97 and 49.33 days for Giza 164 and Cids 7, respectively. The loss of initial Granstare concentration in the leaves of Giza 164 and Cids 7 were (4.52 & 5.19 ppm). The Granstare residue became undetected in grains of the two varieties after 170 days.At the end of experiment, about 99.64 and 99.66% loss of initial Grasep in the soil in both two varieties. After 95 days, only 0.91 and 1.12 ppm of Grasep reached to the grains of Giza 164 and Cids 7 varieties, respectively. At the end of experiment (155 days) there were no Grasep residues in the grains of the two varieties. These results indicated that the effect of Granstare and Grasep herbicides on growth was greater in Cids 7 than in Giza 164 varieties and Granstare + Grasep used to control weeds and give a good yield comparing with untreated wheat plants.