The objective of this work was to implement the actions of phytosanitary surveillance, based on the NIMFs N° 6 and 8 for South American Cucurbit Fruit Fly Anastrepha grandis (Macquart, 1846) to determinate the situation of the pest on the area described in the “Protocol for exportation of Cucurbita moschata (Calabacita) under “Approach Systems' signed with the Republic of Argentine and determinate the dynamic population of others species of the genus Anastrepha in the Department of Concepción (Districts: Loreto, Belén, Horqueta y Concepción).