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.

Tuta absoluta is a key pest of tomato crops originating from South America. The consequences of X-radiation on this species were studied under laboratory controlled conditions. The effect of radiation on adult emergence was evaluated exposing male and female pupae to increasing X-rays. Adult emergence decreased as doses of X-radiation increased, with the appearance of deformities such as malformed wings and bent legs at doses C350 Gy. Besides, males and females obtained from irradiated pupae were out crossed with untreated counterparts to explore the effects of X-radiation on inherited sterility. (a) Irradiated male 9 untreated female crosses. Both fecundity and fertility of the untreated females were reduced by radiation, and the effect was stronger as the doses increased. Neither the longevity of parental males and F1 adults nor the sex ratios of the F1 and F2 generations were affected by X-radiation (F1 and F2: first and second generation of descendants of irradiated adults). Inherited sterility effects were manifested by a significant reduction in the F1 fecundity, F1 fertility, and the amount of larvae and pupae produced. Doses of 200-250 Gy could be used to induce inherited sterility in T. absoluta males. (b) Untreated male 9 irradiated female crosses. The minimum dose at which irradiated females were completely sterile was 200 Gy. The present study is the first study in T. absoluta that provides the starting point for implementing the inherited sterility in this species.

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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.