Management of the Mediterranean Fruit Fly, Ceratitis capitata (Wied.), in the Gharb area in Morocco

Full text: The Gharb is one of the most fertile regions of Morocco. The annual rainfall is 500 mm and the temperature varies from 11deg C in January to 24 deg.. C in July-August. Fruit production in the Gharb area covers 16,544 ha and generates an annual production of 466,680 Tonnes. The Mediterranean fruit fly (medfly); Ceratitis capitata is a major pest of cultivated and wild fruit trees. It causes 11,000 Tonnes/year of losses in citrus production and prevents export to main markets. Early varieties, such as clementine and navel are subject to higher infestation than late varieties like maroc late. The monitoring using Maghreb-Med trap has confirmed those results. Management of medfly is solely based on chemical treatments. Currently, and in order to determine the need for treatment, growers use Maghreb Med traps baited with trimedlure and a toxicant. At 2 to 3 flies/trap/day, a mixture of a proteinous bait attractant and a pyrethrenoid insecticide is sprayed in every fourth row. However, in the period of high activity, growers may treat every row using pesticide only. The number of applications can reach 10 per cycle of production, which leads to an average cost of USD 220/ha. This generates an increase of production costs, elimination of non-target organisms, toxic effects on consumers and the environment, and finally denial of export certificate because of high chemical residues. The DPVCTRF; the Moroccan official organisation for plant protection; in collaboration with GTZ; the German technical co-operation organisation, developed a management programme based on spot treatment. It consists of the application of a mixture of proteinous baits and pesticide on a weekly basis, using only 16ml/ha, as a spot treatment applied to the lower foliage of the tree. The spraying is applied from early fruit maturation until three weeks after harvest. This method allowed to decrease the cost of controlling medfly to an average of USD 30 /ha, instead of USD 220/ha, using conventional method. Preliminary results indicated that, although the number of flies and the infested fruits are not significantly different in the conventional method and the spot treatment method, the latter is more economical and is less harmful for natural enemies and the environment. Therefore, promotion plans were initiated with the extension service in Gharb area to advertise and motivate growers to apply the spot treatment method for medfly control. Although this operation was considered successful], innovative actions are needed to reduce the cost of medfly management and to minimise the risk of pesticides residues in fruits. In this regard, integrating SIT within the management programme offers an alternative to purely chemical control and complements the management programme developed using spot treatment. (author)