Two fruit ßy species (Diptera: Tephritidae) of economic importance occur in Argentina, the Mediterranean fruit ßy, Ceratitis capitata (Wiedemann), and Anastrepha fraterculus (Wiedemann). Here, we compared the relative abundance of these fruit pests in 26 fruit species sampled from 62 localities of Argentina in regions where C. capitata and A. fraterculus coexist. In general, C. capitata was predominant over A. fraterculus (97.46% of the emerged adults were C. capitata), but not always. Using the number of emerged adults of each species, we calculated a relative abundance index (RAI) for each host in each locality. RAI is the abundance of C. capitata relative to the combined abundance of A. fraterculus and C. capitata. Some families of fruit species were more prone to show high (Rutaceae and Rosaceae) or low (Myrtaceae) RAI values, and also native plants showed lower RAI values than introduced plants. RAI showed high variation among host species in different localities, suggesting a differential use of these hosts by the two ßies. There were localities where A. fraterculus was not found in spite of suitable temperature and the presence of hosts. Most host species showed little variation in RAI among localities, usually favoring C. capitata, but peach, grapefruit, and guava showed high variation. This suggests that these fruit species are suitable for both fruit ßies but more favorable to one or the other, depending on local environmental conditions (e.g., relative humidity and degree of disturbance) of each locality.

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Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most devastating pests of tomato. We studied whether partially sterile T. absoluta males and fully sterile females were capable of suppressing wild populations of this moth in semi-controlled conditions. After irradiating T. absoluta pupae with 200 Gy, emerged males and females were released at 10:1 (treated:untreated) and 15:1 over-flooding ratios inside field cages containing tomato plants. The number of eggs and larvae produced was recorded once per wk during 3 mo. An over-flooding ratio of 10:1 caused a decline in larvae production compared with the untreated control cages, but these differences were not statistically significant. Using an over-flooding ratio of 15:1, the moth population in the cages with irradiated insects decreased significantly compared with those in the untreated control cages. In addition, the possibility of combining inherited sterility and a natural enemy as a strategy to manage this pest was investigated. We studied in no choice and choice tests the predation behavior of females of the egg predator Tupiocoris cucurbitaceus (Hemiptera: Miridae) on eggs derived from the following parental T. absoluta crosses:  U ×  U (control),  U ×  I and  I ×  U (where U = untreated, I = irradiated). In the no choice test, females of the T. cucurbitaceus readily consumed T. absoluta eggs regardless of their origin. In the choice test, T. cucurbitaceus females consumed similar numbers of eggs of untreated parents and eggs oviposited from crosses in which the male had been irradiated. However, the mirid females preyed on significantly more eggs-roughly 20% more-from irradiated females than on eggs from untreated females. We conclude that it is possible to achieve a certain level of suppression of a T. absoluta wild population through the release of irradiated insects, and that it is technically feasible to combine the use of the predator T. cucurbitaceus with inherited sterility to control this moth pest.

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Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a key pest of tomato crops. Tupiocoris cucurbitaceus (Spinola) (Hemiptera: Miridae) is a neotropical predator capable of consuming T. absoluta eggs. We evaluated the life history traits of T. cucurbitaceus on three different diets: T. absoluta eggs from irradiated parental males and untreated parents, and Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) eggs (control). The nymphal development of T. cucurbitaceus was reached in 13 days with a similar survival for all diets (58-65%). Mirid female longevity and oviposition period were statistically similar when the diets consisted of T. absoluta eggs from untreated parents and S. cerealella eggs, although the number of nymphs laid was larger with the second diet. Moreover, mirid females feeding on T. absoluta eggs from untreated parents lived longer and laid double number of nymphs than when fed on T. absoluta eggs from irradiated parental males. The highest intrinsic rate of increase (r m ) was observed for the S. cerealella eggs diet, while differences were not observed between the two types of T. absoluta eggs. These results indicate that the mirid could develop and reproduce by feeding exclusively on both types of T. absoluta eggs. As conclusion, the use of more environmentally friendly strategies to control this pest, such as the biological control and inherited sterility, is possible through the release of T. cucurbitaceus and irradiated T. absoluta individuals.

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