Vol. 2, Issue 6 (2018)
Weed management in conventional and organic potato production
Author(s): SP Singh, S Rawal, VK Dua, S Roy, MJ Sadaworthy, SK Charkrabarti
Abstract: It is widely known that losses caused by weeds have exceeded the losses from any category of agricultural pests such as insects, nematodes, diseases, rodents, etc. The potential crop yield loss without weed control was estimated by 43%, on a global scale. Despite the annual investment of US$ 40 billion for the application of 3 million metric tonnes of pesticides, plus the use of various biological and other non-chemical controls worldwide, global crop losses remain a matter of concern. Concerted efforts were made to implement integrated pest management programmes in principal food and cash crops. As a result of these developments, losses due to insect pests in several agricultural crops have shown a declining trend. Even then during 2007-08, insect pests inflicted a loss of about US$ 21.5 billion in major agricultural crops. Most critical period of crop-weed competition for potato is 25-30 days from planting. Metribuzin, an s-triazine or triazinone, is one of the oldest potato herbicides and is still widely used in potato production. Metribuzin controls a range of broadleaf weed species and suppresses many additional grasses. Resistance to triazine herbicides has developed in 69 species worldwide, limiting activity and requiring a combination of control practices for these weeds. Herbicide Bentazone (Basagran) was found very effective when applied @ 1 litre/ha at 4-6 leaf stage of weeds in potato crop. This herbicide did not show any toxic effect on potato plants. Weeds are considered the biggest problem facing organic farming, where weed control is more expensive compared to synthetic herbicides whose use is prohibited in organic (clean) agriculture. Weed management is the most difficult part of organic crop production and it is the major reason for organic crop yields being 50% lower than conventional yields. Lower yields and higher costs for weed control labor are two of the major reasons that organic produce must be sold with high price premiums. The growers in organic farming should keep these three points in mind: 1) start clean stay clean successful, 2) Prevention is always better than treatment and, 3) One year's seeds will lead to seven year's weed infestation. Successful and sustainable weed management systems are those that employ combinations of techniques rather than relying on one method. The objectives of this paper are to review some safe weed control methods for potato production.