Management of the potato tuber moth by Tunisian farmers : a report of on-farm monitoring and a socioeconomic survey

Populations are low during the cold and rainy winter period, but increase to significant levels during the hot and dry summer months. Tubers are damaged both in the field (particularly if the harvest is delayed) and in traditional, rustic stores. The efficiency of Tunisian farmers" control tactics is highly variable - cases of total loss have been found. Experienced farmers have developed integrated control strategies which combine cultural practices with the use of insecticides. High hilling, well-timed irrigation, early harvest, rapid handling and storage, and well-designed stores using local materials provide adequate control when combined with a single insecticide treatment as the potatoes are being stored. Less toxic pyrethroids have replaced Parathion as the insecticide most commonly used by farmers. The biological insecticide Bacillus thuringiensis has given good results in experiments. Farmers must also check frequently for increasing pest populations and sell their produce before damage reaches a level that would affect the price. The development of decision rules, based on entomological research results and farmers" socioeconomic constraints, can help extensionists disseminate an improved integrated pest management program. This will require information on pest, crop, and market situations, based on routine observations by entomologists and economists. (Author abstract, modified)