Pre-harvest desiccation of castor crop using 2,4-D and glyphosate

Castor is an industrial crop that depends on mechanization of harvest for increased production. The presence of green leaves and fresh fruits at harvest time affects the combine operation. Defoliation and desiccation are thus a requirement for efficient mechanized harvest. Desiccation was evaluated in castor crop sprayed with combinations of 2,4-D and glyphosate. The 12 treatments were combinations of two doses of 2,4-D (670 and 1340 g ha−1 of the a.i.) with three doses of glyphosate (1440, 1880, and 2160 g ha−1 of the a.i.), the same doses isolated, and a control treatment. The herbicides were sprayed at 90 days after emergence, and irrigation was continued until the harvest 21 days later. It was found that 2,4-D promoted full desiccation at any dose regardless of association with glyphosate, and the plants were killed one week after spraying. Glyphosate did not promote complete desiccation of castor plants in the doses tested. Seed yield was not affected in any treatment.