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Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world's most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 ± 1°C, 70 ± 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pêra and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SF (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements. [ABSTRACT FROM AUTHOR]

Foraging animals must often decide among resources which vary in quality and quantity. Nectar is a resource that exists along a continuum of quality in terms of sugar concentration and is the primary energy source for bees. Alternative sugar sources exist, including fruit juice, which generally has lower energetic value than nectar. We observed many honeybees ( Apis mellifera scutellata ) foraging on juice from fallen guava ( Psidium guajava ) fruit near others foraging on nectar. To investigate whether fruit and nectar offered contrasting benefits of quality and quantity, we compared honeybee foraging performance on P. guajava fruit versus two wildflowers growing within 50 m, Richardia brasiliensis and Tridax procumbens . Bees gained weight significantly faster on fruit, 2.72 mg/min, than on either flower (0.17 and 0.12 mg/min, respectively). However, the crop sugar concentration of fruit foragers was significantly lower than for either flower (12.4% vs. 37.0% and 22.7%, respectively). Fruit foragers also spent the most time handling and the least time flying, suggesting that fruit juice was energetically inexpensive to collect. We interpret honeybee foraging decisions in the context of existing foraging models and consider how nest-patch distance may be a key factor for central place foragers choosing between resources of contrasting quality and quantity. We also discuss how dilute solutions, such as fruit juice, can help maintain colony sugar-water balance. These results show the benefits of feeding on resources with contrasting quality and quantity and that even low-quality resources have value.

Studies on population dynamics and vertical distribution in the soil of Scaptocoris carvalhoi Becker were carried out in a pasture area in Paraúna, State of Goias, Brazil, from November 2004 to October 2005. One meter-deep holes were excavated in the soil, except on the season of lower precipitation, when 2-meter holes were excavated (June, August and September 2005). On each evaluation, the specimens were collected and grouped according to the depth they were found in the soil profile (0-20, 21-40, 41-60, 61-80 and 81-100 cm). Nymphs occurred during the entire length of the study and were more abundant than adults. Adult population augmented with the increase of rainfall. Nymphs and adults were located in the top layer of the soil during the rainy season and were found deeper in the soil during droughts. However, adults were less tolerant to hydric stress and burrowed deeper into the soil at the beginning of the dry season, while nymphs burrowed deeper only at the end of the season. Results of this study are in accordance to other studies on various species of Scaptocoris, in other regions of Brazil.

Stenoma catenifer Walsingham is the major pest in avocado groves (Persea americana Mill.) in the Neotropical region. Management has been difficult for many reasons related to the reduced knowledge on its bioecology and the avocado growing systems. The goal of this work was to study the vertical distribution of S. catenifer in avocado plants, the gagging effect of infested fruit on its survival, and the losses caused. The experiments were conducted in a commercial grove located at the São Tomás de Aquino, State of Minas Gerais, Brazil, during the 2001/2002 and 2002/2003 growing season. S. catenifer was observed especially at the lower and central part of the plant, and the inner canopy was the least attacked in comparison with the north, south, east and west quadrants. These results may be important indicators for the use of am adequate sampling procedure. The highest percentage of attacked fruit had one to four larvae; in some cases up to eight individuals per fruit were found. The losses caused by the borer varied during the agricultural season, with figures close to 5% in a single evaluation, and the harvest loss may reach 27%. The bagging of infested fruit caused mortality of S. catenifer, as observed through the evaluation carried out four days later.

Agroecosystems consist on complex trophic relationships among host plants, herbivores and their natural enemies. This article reviews the research of plant volatiles in Brazil, in order to determine multiple resistance mechanisms of economically important crops and to contribute to the understanding of insect-plant interactions. Most pest management programs, including chemical and biological control, do not consider the impact of these chemicals on herbivores and their natural enemies. Alternative control methods are being developed in order to improve our understanding on the endogenous mechanisms of plant induced defenses against phytophagous arthropods. The use of plant volatiles technology as an additional tool in integrated pest management programs would offer a new and environmentally sound approach to crop protection. This technique involves the development of baits that attract beneficial organisms and the manipulation of biochemical processes that induce and regulate plant defenses, key factors in the improvement of control programs against economically important pests. The elucidation of the mechanisms involved in the indirect defenses of plants will result in useful tools for biological control of crop pests.

The objective of this work was to characterize the sexual behavior of the citrus leafminer, Phyllocnistis citrella Stainton, as the foundation for the isolation, identification, and synthesis of the complete sex pheromone of this species. Mating occurred in a time window of 2h, starting 1h before the onset of photophase. The large majority of tested insects mated in the first two days after emergence, with no significant difference between mating at day 1 and day 2. A stereotypical courtship and copulation behavior were described for this species. When mating was successful, the copulation was recorded in average for 49.6 min. In Y-olfactometer tests conducted at the time of mating activity, males were strongly attracted to caged virgin females as well as to extracts from putative pheromone glands.