INFLUENCE OF IMAZETHAPYR ON WEED CONTROL AND PRODUCTIVITY OF GROUNDNUT ( ARACHIS HYPOGAEA L . ) AND SUCCEEDING SORGHUM ( SORGHUM BICOLOR L . )

Productivity of oil seed crops in India is needs to be improved to achieve sustained productivity under different production system. Groundnut (Arachis hypogaea L.) is an important oil seed crop of India. Weed menace is a major constraint in groundnut production and it aggravate after seed emergence. Among various weed management practices chemical method has become cost effective and timely control of weeds (Verma et al., 2015). It is grown throughout the year and thus weed management plays an important role for its successful cultivation. Depending upon the nature, density and period of occurrence of weeds, cause yield loss of 40-80 %. Keeping the crop weed free through manual hand weeding and hoeing, though effective, it has several limitations such as timely availability of adequate labour and difficulty in using mechanical weeders during rainy season etc. The only and the best alternative, seems to be application of herbicides at proper time and optimum dose. At present, pendimethalin 30 EC @ 3.3 ml/L is applied as pre-emergent followed by one hand weeding at 40 days after sowing (DAS) was recommended in groundnut growing areas. It is found to be effective for weed control upto 20-25 DAS. However, critical period of crop-weed competition in groundnut was upto 40-45 DAS (Verma et al., 2015). The herbicides applied as pre-emergence may fail to provide weed control for the entire growing season due to herbicide dissipation and mode of action in the dry weather conditions. Presently,there is no effective post emergent broad spectrum herbicide for groundnut. The post-emergence herbicide like imazethapyr can be used effectively for controlling weeds in groundnut. Imazethapyr belongs to Imidazolinones a broad spectrum herbicide applied on foliage and soil. The chemical formula of Imazethapyr is [2-{4, 5 dihydro-4 methyl-4-(1methylethyl)5-oxo-1H-imidazol-2-yl}-5-ethyl-3 Pyridine Carboxylic acid. In India, it is recommended for, soybean, pigeonpea, sunflower etc. as post emergent herbicide in India (Hari Ram et al., 2013). In this regard, an experiment was conducted to evaluate Imazethapyr 10 % SL for its dose and time of application on weed control and productivity of irrigated groundnut and its phytotoxic effect on succeeding sorghum.