Biology and Population Dynamics of the American Vine Moth and the Potential Biocontrol with Trichogramma pretiosum.

The American grapevine moth (AGVM), Lasiothyris luminosa (Razowski & Becker) (Lepidoptera: Tortricidae), was recently registered as a new pest for table grapes in the Northeast region of Brazil. In the present study, two approaches were made aiming to aid information to support management strategies for the new pest control: (i) study AGVM biology in the laboratory and its population dynamics in the field and (ii) evaluate Trichogramma pretiosum Riley as a potential biological control method against L. luminosa. The AGVM population dynamics showed a similar trend in the three grapevine monitored vineyards. The larvae started occurring at 30 days after pruning (DAP), pre-bloom stage, with a peak population between 54 and 78 DAP, following a decrease until harvest. The AGVM females larva, pupa, and egg-adult period were longer than males. The egg-adult period was 42.1 and 45.2 days for male and females, respectively. Trichogramma pretiosum was able to parasitize L. luminosa eggs. The T. pretiosum egg-adult period was 10.2 days with a 98.5% pupa survivorship at 25 °C. The release of T. pretiosum in the vineyards resulted in 65.5 to 73.2% AGVM egg parasitism. Our findings bring the first biological and population dynamics information for L. luminosa, which can help developing efficient approaches to monitor and control the pest in grapevines. The release of T. pretiosum in the vineyard is a potential biological control option to AGVM.

Temperature-dependent development of two neotropical parasitoids of Liriomyza sativae (Diptera: Agromyzidae).

We studied two species of neotropical parasitoids that occur naturally in northeastern Brazil and are associated with Liriomyza sativae (Blanchard): Opius (Gastrosema) scabriventris Nixon (Hymenoptera: Braconidae) and Chrysocharis vonones (Walker) (Hymenoptera: Eulophidae). We evaluated the influence of seven temperatures on the duration of the egg-adult period and on the survivorship of the immature stages of the parasitoids. A temperature increase from 15 to 30°C shortened the egg-adult period of O. scabriventris and C. vonones. However, at 32°C, the developmental time for the braconid was prolonged, and no difference was observed for the eulophid, compared with 30°C. The highest temperature, 35°C, proved to be lethal for both species. At 15°C, C. vonones pupal survivorship was drastically reduced, whereas that of O. scabriventris was unaffected. At most temperatures, the eulophid had an egg-adult period shorter than or similar to the braconid, except at 15°C. The threshold temperature (Tt) of the egg-adult period for O. scabriventris was 7.3°C with a thermal constant (K) of 257.1 degree days (DD). For C. vonones the Tt was 7.4°C for the total cycle and 6.2°C for the pupal stage, with a thermal constant of 246.3 and 140.3 DD, respectively. These data allow an estimate of 29.4 annual generations for O. scabriventris and 30.5 for C. vonones in a melon production region in northeastern Brazil, values that are equivalent to 4.9 and 6.0 more generations than the host. These results demonstrate that both species have potential for application in biological control programs against the leafminer fly L. sativae.