Effect of herbicides on weed infestation in mango (Mangifera indica L.) nursery.
Saini J. P., Singh V. K.
Author Affiliation: Central Institute for Subtropical Horticulture, Rehmankhera, Lucknow - 227 107, India.
Tropical Agriculture 78 : 200-205
Abstract : A field experiment was conducted in Lucknow, Uttar Pradesh, India for two years to evaluate the effect of four herbicides, glyphosate, paraquat, atrazine, and Sencor [metribuzin] on the effect of weeds in a mango (Mangifera indica) nursery. Glyphosate was sprayed at 7.5 ml and 10 ml litre-1 three times, at 20 days prior to sowing, at sowing, and 20 days after seed germination. Paraquat was sprayed at 3.0 ml and 4.0 ml litre-1 20 days after germination. Atrazine at 2.0 kg and 3.0 kg ha-1 and sencor at 0.5 kg and 1.0 kg ha-1 were applied at sowing. Glyphosate at 20 days prior to sowing and the weed-free treatment significantly increased seedling leaf number, photosynthetic rate (Pn), chlorophyll content, nitrate reductase activity (NRA), protein, and total sugar levels. Paraquat significantly increased seedling leaf number, temperature, transpiration rate, and chlorophyll a content, while post application of glyphosate and higher concentrations of atrazine, sencor, and paraquat significantly decreased Pn, but they increased leaf temperature and transpiration rate. Glyphosate application at 10.0 ml litre-1 at 20 days prior to sowing completely controlled Saccharum spontaneum, Crotalaria medicaginea, and Trichodesma indicum in the rainy season while in the following winter, it controlled S. spontaneum, Medicago lupulina, and Erigron bonariansis [Conyza bonariensis]. At sowing it did not completely control S. spontaneum. Paraquat controlled Dichantheum annulatum, Fimbristylis tenera, Launea pinnatifida, and T. indicum but did not completely control S. spontaneum and did not affect winter weeds except E. bonariansis. Atrazine and sencor both completely controlled D. annulatum, F. tenera, T. indicum, and L. pinnatifida in the rainy season and only M. lupulina in the following winter. Higher concentrations of atrazine and sencor were more effective. Generally, all the herbicides decreased the weed population and their dry weight.