Interference and Economic Threshold Level for Control of Beggartick on Bean Cultivars

Abstract

-The aim of the study was to assess the interference and determine the economic threshold level of beggartick damage on bean crops. Treatments consisted of bean cultivars (IPR Uirapuru, BRS Supremo, BRS Campeiro, Fepagro 26, BRS Esplendor and IPR Tuiuiú) submitted to competition with ten beggartick populations. We evaluated plant population, leaf area, ground cover and shoot dry mass of beggartick. Dry mass of shoots of beggartick fitted better to the hyperbolic model, and grain yield losses due to beggartick interference were estimated satisfactorily by this model. BRS Esplendor and IPR Tuiuiú were more competitive than the others in the presence of beggartick. Sowing of BRS Esplendor, IPR Tuiuiú and Fepagro 26 increases the level of economic damage, justifying the adoption of control measures only for higher densities of beggartick. Increase in grain yield, commercial price of beans, herbicide efficiency and reduction in control cost decrease the threshold level for weed control, justifying application of control measures for lower densities of beggartick. Keywords: Phaseolus vulgaris, Bidens pilosa, interference. RESUMO -Objetivou-se com este trabalho avaliar a interferência e determinar o nível de dano econômico de picão-preto infestante da cultura do feijão. Os tratamentos foram compostos por cultivares de feijão (IPR Uirapuru, BRS Supremo, BRS Campeiro, Fepagro 26, BRS Esplendor e IPR

Bean yield loss in response to volunteer corn

“…For dry bean, at each volunteer corn plant per square meter, the reduction on dry bean yield ranged from 6.5 at 19.3% (Sbatella et al, 2016). The yield loss from volunteer corn in this study is substantially higher than level of yield loss from weeds such as Euphorbia heterophylla (Machado et al, 2015) and Bidens pilosa (Galon et al, 2016). According to these authors, the values of i were 5.5 and 2.4% for E. heterophylla when the weed emerged seven days before and simultaneously with the bean, respectively, and while to B. pilosa the values of i ranged from 3.4 to 12.8%.…”

“…Alms et al (2016) point out that the cost of herbicide control would be economically feasible even at volunteer corn density of less than one plant m -2 . The ET of volunteer corn in beans is extremely low when compared to other weeds, such as Bidens pilosa and E. heterophylla in beans (Machado et al, 2015;Galon et al, 2016).…”

“…The high losses of bean yield due to the increase of volunteer corn density, agree with found by Alms et al (2016), which verified a maximum yield loss in soybean of 71% for three plants m -2 of volunteer corn. The interference effects on bean yield from weeds is lower than volunteer corn, where the impact of high density of E. heterophylla (23 plants m²) reduce 54% of bean yield (Machado et al, 2015) and maximum losses for different bean cultivars ranging from 15.4 to 43.6% (density ranging from 0 to 50 plants m²) in competition with Bidens pilosa (Galon et al, 2016).…”

“…Previous studies have shown different threshold level of Euphorbia heterophylla and Bidens pilosa in bean crop (Machado et al, 2015;Galon et al, 2016), which can reduce crop grain yield in 60%. However, there is little information on yield losses and ET for volunteer corn on bean.…”

“…The weed management in bean crop occur basically with the use of herbicides, due to the high efficiency and lower cost compared to other control methods (Galon et al, 2016). The use of most sustainable production systems that reduce the risk of residues in food and the environmental impact on agroecosystems can become an important management tool.…”