Reduce volume application of 2,4-D [herbicide] using controlled drop applicators in rainfed rice (Oryza sativa)
1985
Llagas, M.A. | Mercado, B.L. | De Datta, S.K. (International Rice Research Inst., Los Banos, Laguna (Philippines). Dept. of Agronomy)
Reduced volume application of 2,4-D [(2,4-dichlorophenoxy) acetic acid] in rice (Oryza sativa L. 'IR 36') using controlled drop applicators (CDAs) Micronherbi and Birky were evaluated. The CDAs were compared with hydraulic VLV-50 and the conventional hydraulic flat-fan knapsack sprayer. The effect of droplet size, droplet count per unit area, dose, and formulation on the biological efficacy of 2,4-D low volume application was also determined. Field trials showed that CDAs performed comparably to the conventional hydraulic flat-fan knapsack sprayer and hydraulic VLV-50. In greenhouse studies, 2,4-D amine regardless of application rate or volume, reduced the fresh weight of Ipomoea triloba L. Weed control did not vary between 2,4-D rates and among spray volumes. 2,4-D isopropyl and isobutyl ester formulations were more active than the dimethylamine salt, particularly when CDAs were used. Formulation had no effect on weed control when the conventional knapsack sprayer was used. Droplet size did not affect 2,4-D amine activity. However, large drops (318 and 400 m) were effective in controlling I. triloba when using amine formulation. With IBE, 200 m drops were as effective as the 400 m. IPE activity was unaffected by droplet size. At the lowest dose (5.64 mg), IPE was the most effective while at each of the high doses, all formulations performed similarly
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