J. R. A. Fontes

Assessment of rubber tree panels under crowns resistant to South American leaf blight

(3) In memoriam Abstract - The objective of this work was to assess the performance of panel clones under crowns resistant to South American leaf blight (Microcyclus ulei). The experiment was carried out with 18 panel clones crown-budded with Hevea pauciflora x H. guianensis, in a Xanthic Ferralsol (Oxisol) in Manaus, AM, Brazil. The following parameters were evaluated: dry rubber yield, plant nutritional status, and anatomical and physiological characteristics of the latex vessels. In the first three years of evaluation, the panel clones IAN 2878, IAN 2903, CNS AM 7905, CNS AM 7905 P1, and PB 28/59 showed the highest dry rubber yield potential, while the clones IAN 6158, IAN 6590, and IAN 6515 should not be recommended for crown budding. Higher potassium and copper foliar content in panel clones were associated to an increase in dry rubber yield. The simultaneous evaluation of anatomical and physiological characteristics of latex is fundamental for the selection of panel clones in the Amazon region. Crown budding is an efficient technology for South American leaf blight management in endemic regions.

Metolachlor e fomesafen aplicados via irrigação por aspersão em plantio direto e convencional

The aim of this study was to evaluate the efficacy of metolachlor (2.4 kg a.i. ha-1) and fomesafen (0.225 kg a.i. ha-1) applied via a center pivot on weed control in the common bean plant (Phaseolus vulgaris). The cultivar Perola was sown in July (winter). Metolachlor was applied with water volume of 5, 10, and 15 mm, and fomesafen with 3, 6, and 9 mm. The herbicides were also sprayed. Two checks were included: with and without weeds. The predominant weed in the no-till system was Bidens pilosa and in the conventional tillage, Artemisia verlotorum. In general, herbigation was more efficient than spray for weed control, regardless of the type of tillage system. Water volume of 5 or 10 mm for metolachlor, and 3 or 6 mm for fomesafen, yielded the best results, overall.