Júlio Marcos Melges Walder

Análise quantitativa e distribuição de populações de espécies de Anastrepha (Diptera: Tephritidae) no campus Luiz de Queiroz, Piracicaba, SP

The distribution of females of Anastrepha species per trap was strongly clustered, with five traps (6%) capturing 50% of the total of females. Only Anastrepha fraterculus (Wied.) and A. obliqua (Macquart) were dominant species. A. fraterculus was by far the most frequent species (80.2% of the females), and the most constant, occurring in 98.0% of the samples. In decreasing order of frequency, A. obliqua (12.6%), A. pseudoparallela (Loew) (3.1%), and A. bistrigata Bezzi (2.1%) comprised the other major species. The remaining species showed frequency lower than 1%. The high value of the Simpsons index (0.660) as well as the low values of Shannons index (0.7518) and the equitability index (0.4597) resulted from the high frequency of A. fraterculus.

A New Generation of X Ray Irradiators for Insect Sterilization

ABSTRACT Recent fears of terrorism have provoked an increase in delays and denials of transboundary shipments of radioisotopes. This represents a serious constraint to sterile insect technique (SIT) programs around the world as they rely on the use of ionizing radiation from radioisotopes for insect sterilization. To validate a novel X ray irradiator, a series of studies on Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) were carried out, comparing the relative biological effectiveness (RBE) between X rays and traditional &ggr; radiation from 60Co. Male C. capitata pupae and pupae of both sexes of A. fraterculus, both 24–48 h before adult emergence, were irradiated with doses ranging from 15 to 120 Gy and 10–70 Gy, respectively. Estimated mean doses of 91.2 Gy of X and 124.9 Gy of &ggr; radiation induced 99% sterility in C. capitata males. Irradiated A. fraterculus were 99% sterile at ≈40 – 60 Gy for both radiation treatments. Standard quality control parameters and mating indices were not significantly affected by the two types of radiation. The RBE did not differ significantly between the tested X and &ggr; radiation, and X rays are as biologically effective for SIT purposes as &ggr; rays are. This work confirms the suitability of this new generation of X ray irradiators for pest control programs that integrate the SIT.

Gamma radiation in papaya harvested at three stages of maturation

Papaya is a fragile, perishable fruit, highly accepted worldwide. To keep the quality of papaya from harvest to the consumers, conservation techniques are often used; among them is the application of gamma irradiation. The objective of this work was to evaluate gamma irradiation in papayas harvested at three degrees of maturation, in order to increase shelf life. Papayas were harvested in perfect quality conditions and selected by skin coloration into three distinct degrees of maturation: maturation 0, or beginning of yellow coloration; maturation 1, yellow stripes more developed, and maturation 2, one third yellow. Half of them were irradiated with 0.75 kGy, while the other half became control treatment. They were analyzed in four periods of conservation, which were 1 DAI (days after irradiation refrigerated at 11 ± 1°C), 14 DAI, 14 DAI + 3 DRT (room temperature at 24° ± 2°C) and 14 DAI + 6 DRT. The papaya maturation degree at harvest did not influence the radiation effect. Irradiation maintained firmness of papaya and, therefore, delayed ripening; modified the green color of papaya to a lighter, more intense tone, which determined more homogeneity in the development of the skins yellow color (greater values of L* and croma). There was no effect of irradiation in papaya weight loss, occurrence of diseases, croma of flesh color, pH and total soluble solids contents.

Gamma irradiation in the control of pathogenic bacteria in refrigerated ground chicken meat

ABSTRACT: This work evaluated the effect of gamma radiation on reducting the population of Staphylococcusaureus , Escherichia coli and Salmonella typhimurium in ground chicken breast stored under refrigeration. Theexperiment included a control and 4 doses of gamma radiation (2.0, 4.0, 6.0 and 8.0 kGy) along with 5 periodsof storage under refrigeration (1, 7, 14, 21 and 28 days). Samples of ground chicken breast were inoculatedwith Staphylococcus aureus (ATCC 14458), Escherichia coli (ATCC 11105) and Salmonella typhimurium (ATCC0626), irradiated at temperatures between 4 and 8 o C and stored under refrigeration (5 o C) for 28 days. Theincreased radiation dose and period of storage under refrigeration caused a reduction of Staphylococcus aureus ,Escherichia coli and Salmonella typhimurium populations in the ground chicken breast. Mean radiation D valuesdetermined for Staphylococcus aureus and Escherichia coli were 0.41 and 0.72 kGy, respectively. Gammairradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kGy keptthe ground chicken breast within the microbiological limits established by the Brazilian legislation, for up to 28days under refrigeration.Key words: gamma irradiation, pathogenic bacteria, chicken meat, refrigeration

Biodiversidade de moscas-das-frutas do gênero Anastrepha (Diptera, Tephritidae) no campus da ESALQ-USP, Piracicaba, São Paulo

Biodiversity of fruit flies of the genus Anastrepha (Diptera, Tephritidae) at the ESALQ-USP campus, Piracicaba, Sao Paulo. The aim of this study was to determine the number of species of Anastrepha Schiner at the campus and to verify the association between host plant species and Anastrepha species in this area. A total of 23,277 females of Anastrepha collected in McPhail traps was examined, and 18 species belonging to nine species groups were recorded. A total of 563 fruit samples representing at least 23 plant species from nine families was collected in 47 capture sites. A total of 10,243 females was identified. Of the 18 Anastrepha species captured in traps, only six emerged from fruit samples: A. bistrigata Bezzi, A. fraterculus (Wied.), A. obliqua (Macquart), A. pseudoparallela (Loew), A. serpentina (Wied.) and A. sororcula Zucchi. A. fraterculus infested the greatest diversity of hosts. The preferred hosts of A. obliqua were plant species of the family Anacardiaceae. A. pseudoparallela, and A. serpentina only infested species of Passifloraceae and Sapotaceae, respectively. A. fraterculus is recorded for the first time in sapodilla (Manilkara zapota L.) in Brazil.

Fermentation of irradiated sugarcane must

Bacillus and Lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. As microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. Must from sugarcane juice was inoculated with bacteria of the genera Bacillus and Lactobacillus. The contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation. After ethanolic fermentation by the yeast (Saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. Treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. The acidity produced during the fermentation decreased as the dose rate of radiation increased. Conversely, the yeast viability increased as the dose rate of radiation increased. Gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.

Mass-rearing of Mediterranean fruit fly using low-cost yeast products produced in Brazil

Ceratitis capitata is one of the most important pests of fruits for exportation, and Sterile Insect Technique (SIT) has been the most efficient and environmental friendly technique used to control fruit fly populations around the world. A key goal in achieving a successful SIT program is a mass rearing system producing high quality insects at low cost. Providing adults with an artificial diet containing hydrolysed protein has been the major obstacle for bio-production facilities in Brazil, because it is expensive and has to be imported. Two other commercial products, autolysed yeast (AY) and yeast extract (YE), of domestic origin and low cost, were tested as substitutes of the imported hydrolyzed protein. To compare their efficiency we observed the female fecundity, adult survival and egg viability of flies raised on diets containing one of each of the different protein products. Flies reared on the domestic yeast products had equivalent or superior performance to the flies reared on imported protein. Both AY and YE can be a possible substitute for imported hydrolyzed protein for C. capitata mass-rearing, as they are cheaper and are readily available in the national market.

Dispersion patterns of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in citrus orchards in southeast Brazil

Abstract We studied the dispersion patterns of the exotic endoparasitoid, Diachasmimorpha longicaudata (Ahsmed) (Hymenoptera: Braconidae), in 1999 (summer) and in 2000 (winter) in a citrus orchard in southeast Brazil. Different population densities of D. longicaudata were released in the centre of the orchard, and their dispersion was determined by using yellow, sticky, rectangular traps, placed in various distances and heights around the release point. Our results suggest that during summer, climatic conditions did not affect dispersion. However, in winter, dispersion rates were positively affected by temperature, and negatively by rainfall. Both estimated dispersal distance and surface were higher in summer than in winter for all release densities. Dispersion peaked at 2000 parasitoids ha−1 in summer and 8000 parasitoids ha−1 in winter. The importance of our results for the biological control of fruit flies by augmented or innoculative releases of D. longicaudata in southeast Brazil is discussed.

SEXUAL BEHAVIOR AND DIEL ACTIVITY OF CITRUS FRUIT BORER Ecdytolopha aurantiana

Males and virgin females of the citrus fruit borer Ecdytolopha aurantiana Lima, displayed two flight peaks during a 24-hr period, one at dawn and the other at dusk in an orange grove near Gavião Peixoto, São Paulo, Brazil. During the day, when temperatures were highest and relative humidity lowest, most individuals rested on leaves in the lower and middle crown. Moths rapidly moved higher in the crown after sunset, and many were observed flying above the tree canopy. This behavior was mainly associated with mating. Males and virgin females marked with fluorescent powder of different colors were observed in the dark with the aid of a black light. Mating was observed only in the upper crown of citrus trees from 6:00 to 9:00 PM, with a peak (64%) between 7:00 and 8:00 PM. Males of E. aurantiana were captured in traps baited either with virgin females or female extracts, suggesting the use of a long-range sex pheromone. At close distance (1–2 cm), males and females displayed a short-range communication behavior, with males exposing hairpencils and vibrating their wings. Females were frequently stimulated to contact the body of a male before copulation. The mean duration of copulation was 1 hr 40 min.

Efeitos da radiação gama na esterilização e comportamento da mosca-do-caribe, Anastrepha suspensa (Low) (Diptera:Tephritidae)

Pupae of Anastrepha suspensa (Loew) were irradiated 2 days before adult eclosion in an air atmosphere with 15, 20, 25, 30, 50 and 70 Gy of gamma radiation (Co-60). The radiation effects on sterility and other parameters of quality and behavior of males and females of caribfly were established. Males became fully sterile with a dose of 50 Gy and females laid no eggs when exposed to 25 Gy. Radiation had no significant effect on adult eclosion, sex ratio, flight ability and irritability, but female mortality was affected significantly by radiation, showing higher survival rates in low dosage treatments. The mating behavior of the males was reduced significantly by increasing the radiation doses.