Forum global sur la sécurité alimentaire et la nutrition • Forum FSN

Re: Enabling rural cooperatives and producer organizations to thrive as sustainable business enterprises

Mohammed Shams Mekky Nagdy Mekky Mekky
Mohammed Shams Mekky Nagdy Mekky MekkyAgricultural Research CenterEgypt

The main weed control practices available in Egypt is hand hoeing or hand weeding, often exercised in late period after seeding or planting. Generally, at least 20% of the crop yield is lost due to delaying of first weeding. Unfortunately, this problem is not always stressed in working with farmers. They should be made more aware of the need to keep fields weed-free early in the crop life cycle. Small farmers cannot afford the use of selective herbicide, but they are also ignorant of other ways to reduce weed infestations through the application of integrated weed management which include the use of preceding crops in rotation to smother weeds, adequate land preparation for the control of weeds, and intercropping to increase crop density and to suppress weed growth in crop areas. In addition, preventive measures for weed control are poorly practices. Un-cleaned crop seeds, irrigation water and untreated green manure contain huge amounts of weed seeds, which commonly brought into crop area and increase the level of weed infestations. This problem is more acute in newly reclaimed areas in Egypt for example.
Artemisia is a well-known medicinal plant that has been utilized for a number of purposes. The need to reduce chemical inputs into agricultural systems has renewed the interest to use of allelochemical produced by plants in the genus Artemisia (Marco and Barbera, 1990). Many researchers studied the allelopathic effect of crops on weeds have appeared recently such as Artemisia annua, Chen et al, 1991 showed that artemisinin an allelochemechical isolated from Artemisia annua, gave the same level of growth inhibition as 2,4-D and glyphosate in mung bean phaseolus. Lydon, et al (1997), Kil and Yun (1992), Yun and Kil (1992), Duke et al (1987) and Chen and Leather (1990) suggested that artemisinin had potential to be used as natural herbicide, due to the sesquiterpenoid lactone peroxide constituent which can be extracted from annual wormwood (Artemisia annua) where under laboratory and plant residues field studies caused significant inhibition in germination and decreased seedling elongation of receptor plants, redroot pigweed (Amaranthus retroflexus L.), common lambsquarters, soybean and corn, lettuce (Lactuca sativa) and common purslane (Portulaca oleracea L.). Wormwood extract I50 was estimated by 15 mg dry weight/ml for redroot pigweed Mekky (2008). Putnam and DeFrank (1979 and 1983) and White et al (1989) showed that the wee-suppressive activity of several cover crops has been attributed to the release of allelochemical.
The objectives of this investigation was to study the allelopathic effect of aqueous or wormwood extracts by natural white vinegar at 5% and 2.5% acetic acid concentrations on germination of maize as well as biological agent for suppressing species as wild oat, canary grass, dentated duck, redroot pigweed purslane and deccan grass as allelopathic recepters.