EFFECT OF THE DOSES OF HERBICIDES IN THE CHEMICAL CONTROL OF THE HELIOTROPO (Hedichium coronarium) IN CORDILLERA, CHIRIQUI, PANAMA. 1993.

Abstract

In Cordillera, Boqueron, Chiriqui, weed killers and a mixture of them at different doses were evaluated bioeconomically on Heliotropo weed (Hedichium coronarium). a split plot arrangement in a ramdomized complete block design with three replications was used. The ages of sprouting were the main plot and weed killers were the subplot. Weed killers were picloram + 2,4-D anime at 1.0% and 1.5%, equivalent to 0.25 + 0.96 and 0.38 +1.44 kg a.i./ha; dicamba + 2,4-D anime at 1.0%, 1.5% and 2.0%, equivalent to 0.48 + 1.44; 0.72 + 2.16 and 0.96 + 2.88 kg a.i./ha, and a mixture of 2,4-D anime (6 lb) + (picloram + 2,4-D anime) in proportion of 3:1 at 1.0% and 1.5% equivalent to 2.40 + 0.064 and 3.59 + 0.096 kg a.i./ha and the producer's practice composed by diesel + 2,4-D anime (6 lb) in proportion of 2:1 at 1.0%. At 120 after sprayed the herbicides, it was found significant difference (P<0.04) among ages of sprouting and differences highly significant (P<0.0001) among weed killers and applied doses. All evaluated treatments were better than the producer's practice. The best treatment was picloram + 2,4-D anime at 1.5% sprayed to plants of 22 and 60 days of sprouting with 92.2 and 98.8% of effectivity. Picloram + 2,4-D anime at 1.0% sprayed to plants of 60 days of sprouting killed 89% of the plants. Dicamba + 2,4-D anime at 1.0%, 1.5% and 2.0% had moderated effectivity on Heliotropo weed. Mixture of 2,4-D anime (6 lb) + (picloram + 2,4-D anime) had 84.0% of effectivity, which is considerated as good. The producer's practice killed only 36% of Heliotropo weed but at a low cost.