Rafael Narciso Meirelles

Comparative Biology of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) Reared on Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

ABSTRACT The braconid Diachasmimorpha longicaudata (Ashmead) is the most widely used parasitoid in biological control programs of tephritids in the Americas. Anastrepha fraterculus (Wiedemann) is a major fruit fly pest of exotic and native fruits in southern Brazil. However, life history parameters such as longevity, sex ratio, preoviposition, oviposition and post-oviposition periods, fecundity and fertility of D. longicaudata using A. fraterculus as host, have not been determined. These parameters were compared to those derived from the better known host, Ceratitis capitata (Wiedemann), the Mediterranean fruit fly. In the laboratory, A. fraterculus was at least as suitable a host for D. longicaudata as C. capitata. Female parasitoids derived from A. fraterculus were larger and had a higher net reproductive rate (R0). The mean numbers of superparasitism records were higher in A. fraterculus larvae (1.6 ± 0.22) than in C. capitata (0.4 ± 0.07). Other variables did not differ between hosts. Given suitable environments D. longicaudata may become established in A. fraterculus populations or successfully mass-reared on this host species and released.

Moscas frugívoras associadas a mirtáceas e laranjeira "Céu" na região do Vale do Rio Caí, Rio Grande do Sul, Brasil

This study aimed at recognizing frugivorous flies species in Myrtaceae: Eugenia uniflora L., Campomanesia xanthocarpa Berg. Psidium cattleianum Sabine, Psidium guajava L. and Acca sellowiana (Berg.) Burret., as well as in Citrus sinensis (L.) Osbeck (Rutaceae), at Vale do Cai region, Rio Grande do Sul. Fruits were collected at the maturation stage of each fruit species between October 2004 and July 2005, and at the laboratory they were placed in pots with sand and were kept at 12h photoperiod, 80 ± 10% RH and 25 ± 1oC. Pupae were individualized and their characteristics were recorded. In Tephritidae only Anastrepha fraterculus (Wied.) was recorded and in Lonchaeidae, Neosilba n. sp. 3, Neosilba zadolicha McAlpine & Steyskal and Neosilba certa (Walker). These last two species were recorded for the first time in Rio Grande do Sul. Only on P. cattleianum all species were recorded. Results show that A. fraterculus is the most frequent fruit-fly species found attacking the studied fruit plants in Vale do Cai region.

Side-effects of pesticides used in the organic system of production on Apis mellifera Linnaeus, 1758

This study aimed to evaluate the effects of pesticides, used in the organic system, on Apis mellifera under laboratory conditions. Four multiple (0.25x, 0.5x, 1x and 2x) concentrations as recommended by they manufacturers of the following products: Rotenat CE®, Pironat®, Biopirol 7M®, Organic neem®, Natuneem® and lime sulfur were tested by topical application and ingestion. Of all the products and concentrations tested, only the lime sulfur (5000 ml 100L-1 and 10000 mL 100L-1 of water) by ingestion, and Rotenat CE® (1200ml 100L-1 of water) on topical application were considered slightly harmful for A. mellifera, as the classification of IOBC/WPRS for the laboratory tests.

Thermal Requirements and Annual Number of Generations of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) Reared in the South American Fruit Fly and the Mediterranean Fruit Fly (Diptera: Tephritidae)

Abstract Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is the most widely used parasitoid in biological control of Tephritidae programs around the world. Nevertheless, we have little information about the use of these parasitoids against Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae). This study was conducted to evaluate the thermal requirements for the development of D. longicaudata in 2 of its hosts, A. fraterculus and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Third instars of each fly species were exposed for 1 h to 50 couples of the parasitoid. Subsequently, the larvae were placed individually in glass jars maintained in chambers at temperatures of 15, 18, 21, 25, 28, and 31 °C, at 60 ± 10% RH and a photoperiod of 14:10 h L:D until the emergence of D. longicaudata. The rate of development of D. longicaudata, in both hosts, increased as temperature increased. The development period of egg-to-adult phases was used to estimate, by the hyperbola method, the lower development threshold (Dt) and the thermal constant (K) of D. longicaudata. Dt and K were, respectively, 7.83 °C and 322.58 degree days for individuals that developed in C. capitata, and 12.5 °C and 227.27 degree days for those that developed in A. fraterculus. Adult longevity was inversely proportional to temperature. The results indicated that D. longicaudata may not develop in Rio Grande do Sul in the winter, because it is very common that minimum temperatures in the months of Jun and Jul fall below the Dt. In the 4 fruit-producing regions of the state of Rio Grande do Sul, the average numbers of generations of D. longicaudata per year were estimated in A. fraterculus and C. capitata, respectively, as follows: Porto Alegre (11.16 and 13.12), Pelotas (7.97 and 10.89), Bento Gonçalves (6.99 and 10.05), and Vacaria (4.84 and 8.28).

PARASITISM OF FRUIT FLIES (TEPHRITIDAE) IN FIELD, AFTER THE RELEASES OF Diachasmimorpha longicaudata (ASHMEAD) (HYMENOPTERA: BRACONIDAE) IN RIO GRANDE DO SUL

Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) was introduced in 1994, in Northeastern Brazil, to evaluate its use in biological control programs of fruit flies. However, the effects of this specie on parasitism rates on the population of native parasitoids and fruit flies in Southern Brazil conditions are unknown. The objective of this study was to evaluate the impact of releases of D. longicaudata on the parasitism rates on loquats, peach trees, strawberry guava trees, and persimmons in an experimental area in the city of Eldorado do Sul, Rio Grande do Sul, in southern Brazil. In the first year of the study, fruits were collected and stored in the laboratory to obtain pupae. The flies or parasitoids that emerged were counted and identified. In the second year, adults of D. longicaudata were reared in the laboratory on Anastrepha fraterculus (Wied.) and larvae were released in the field (1.700 insects/ha) at each harvest time and the parasitism was evaluated in the same manner as in the first year. In the third year, the procedure was the same as the first year, without any releases. A significant increase in the rates of parasitism was recorded in the second year except in the persimmon, in which no parasitoid was recovered in any year. In the second year the number of emerged fruit flies was also lower. In the third year, no D. longicaudata were recorded and parasitism rates of parasitism were statistically similar to those found in the first year. The native parasitoids collected were Aganaspis pelleranoi (Brethes), Doryctobracon areolatus (Szepligeti), Doryctobracon brasiliensis (Szepligeti) and Utetes anastrephae (Viereck). These species were found in at least one kind of fruit even in the years after the introduction of the exotic parasitoid, indicating that it was not harmful to these species. We conclude that D. longicaudata can help to reduce the population of fruit flies in Eldorado do Sul region, in Rio Grande do Sul.