The tomato pinworm (TPV), Keiferia lyopersicella (Walsingham), is by far the most important pest of processing and fresh market tomatoes in the Guasave and Del Fuerte Valleys of Sinaloa, Mexico. This is especially true for late plantings, during the months of April, May and June. Damage to fruit can be as high as 40%, despite continuous use of broad-spectrum insecticides such as fenvalerate, methomyl and permethrin to control TPW. In view of this, Campbell's de M6xico recently initiated an integrated pest management (IPM) program for processing tomatoes. One aspect of this program was to determine the parasites of K. lycopersicella larvae and to assess their potential as bio-control agents for controlling this insect. Two fields of processing tomatoes in the northern part of Sinaloa, Mexico were surveyed. A field near Chino de los L6pez was sampled during 1985-86 and one near Tamazula was sampled during 1986-87. One hundred leaves mined by TPW were collected at random from each field weekly. Those leaflets having the TPW larvae inside were wrapped with cotton at the petiole and watered every two days to enhance development of TPW larvae or parasites. Each leaflet was kept individually in a petri dish until pupae of TPW or a parasite cocoon was observed. The samples were held in a rearing room at 26 ? 3?C and a photoperiod of 14:10 (L:D) (Lin & Trumble 1985). Data on emergence of adult moths and parasites were recorded. Larval population of TPW in foliage and in fruit were monitored from time of fruit set through harvest, by inspecting twenty five randomly sampled whole plants and one hundred fruit, respectively, from each field at weekly basis. At Chino de los L6pez site, a weekly spraying program with fenvalerate and methomyl was followed after 10 moths/ trap/night were captured on pheromone traps over a 10 day period. At the Tamazula site, permethrin was used on a calendar basis with two sprays per week. Two braconids were reared from TPW larvae: Apanteles scutellaris Muesebeck and Pseudapanteles dignus (Muesebeck). This appears to be the first record for A. scutella?is (as a parasite of TPW) from Mexico (P. M. Marsh, personal communication). These two species are common in California (Oatman 1970, Cardona & Oatman 1971) and Florida (Poe et al. 1975). Although both species of parasites were recovered from the two sites (Table 1), their impact varied with site and abundance of the host. At the Chino de los L6pez site, TPW was rare; average density never exceeded 0.8 ? 0.1 larvae per plant and at harvest about 3% of the fruits were damaged. P. dignus was the prevalent species at this site, averaging 12.1% parasitization; in contrast A. scutellaris accounted for a mean of only 1.1%. At the Tamazula site, the maximum host density averaged 40.5 ? 9.3 larvae per plant and at harvest about 80% of the fruits were damaged. A. scutella7is was the most prevalent species, parasitizing an average of 59.4% of the hosts, while P. dignus only parasitized a mean of 3.5%. These results are in general agreement with those of Oatman (1970) with respect to maximum parasitism reached by these parasites, when highest infestations of TPW occurred. In California, he found up to 100% parasitism