Long-term suitability of an alternative host for rearing the sugarcane stalk borer parasitoid Tetrastichus howardi.

The continuous utilisation of an alternative host may influence parasitoid performance across successive generations due to conditioning in natal hosts. Tetrastichus howardi (Olliff) has successfully been reared using Tenebrio molitor L. pupae as a feasible alternative host. However, the extended rearing of T. howardi on this alternative host may impact the biological features of the parasitoids. Parasitoids were reared using T. molitor pupae for 30 consecutive generations. Quality criteria were assessed during the generations F5, F15, and F30, offering pupae of the target pest, Diatraea saccharalis (Fabr.), and compared with the F0 generation (parasitoids reared in D. saccharalis pupae). Criteria included assessments of parasitism performance, host selection, and wing form variation in the parasitoid wasps. Additionally, we examined the fecundity of T. howardi females that emerged from both hosts, considering their age, egg loading before and after one oviposition, as well as parasitism of sugarcane stalk borer pupae. Rearing T. howardi using pupae of T. molitor did not affect its biological traits or preference for the target pest for 30 generations. After parasitism, the parasitoid left the host pupa inside the stalk, and one oviposition was enough to kill D. saccharalis pupae and obtain viable parasitoid progeny. Female sexual maturation and egg loading occurred 72 and 96 h after parasitoid emergence. Egg-loading recovery after parasitism did not happen within 24 h. T. howardi can be reared for up to 30 generations using alternative hosts without compromising its parasitism performance or egg loading.

Is a diet of Planococcus citri nymphs and adults suitable for Chrysoperla externa for use in biological control?

ABSTRACT Several studies have shown that the survival and reproduction of lacewings varies depending on the type of prey they consumed, especially during the first instar. In this study, we evaluated the effect of a diet consisting of Ephestia kuehniella (EK) and/or Planococcus-citri (PC) eggs offered to first instar Chrysoperla externa on subsequent development and survival. Larvae supplied only with P. citri (PC) nymphs had extended immature development, low survival, adults with lower weight and longevity, low fecundity and egg viability, and lower net reproduction rate (R0). Larvae submitted to the treatment EK+PC responded positively to the diet, showing results similar to those obtained in the control-EK treatment. Therefore, this mealybug supports suitable development and reproduction of C. externa when it is provided to second instar larvae after they fed on E. kuehniella eggs as first instars. As far as we know, this is the first report that demonstrates the effect of natural prey and alternatives on different larval stages of lacewings. This information is valuable in developing protocols for use of C. externaas a pest control agent.

Effect of Low-Temperature Storage on Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae).

We evaluated the effects of constant low-temperature storage on Diaeretiella rapae (McIntosh) (Braconidae, Aphidiinae). Diaeretiella rapae mummies were stored at 5 ± 1°C for 0-36 days. The percentage of D. rapae emergence varied (100-83%) after 0-32 days of storage. After 32 days, emergence reduced to 55%. According to our Probit analysis, 50% mortality (LT50) of the population of D. rapae was reached after 40 days of storage at 5°C. Storage for up to 32 days did not negatively affect emergence and survival. Cold exposure of D. rapae for 36 days did not influence morphological malformations, sex ratio, and emergence of the F1 generation. After 4-36 days of storage, D. rapae showed a gradual decrease in emergence, longevity, reproductive capacity, and F1 sex ratio. Diaeretiella rapae can be stored for up to 24 days at 5°C, at which time the percentage of parasitism and the F1 sex ratio remain above 38% and at 0.50, respectively.

Trichogramma in Brazil: feasibility of use after twenty years of research / Trichogramma no Brasil: viabilidade de uso após vinte anos de pesquisa

São apresentados os resultados dos estudos com Trichogramma no Brasil, especialmente aqueles desenvolvidos na ESALQ/USP, nas últimas duas décadas (1984-2004). O projeto, envolvendodesde a taxonomia, técnicas de criação, aspectos biológicos e comportamentais das pragas e dos parasitóides, dinâmica populacional das pragas, técnicas de liberação,estudos de seletividade, avaliação da eficiência, pode ser considerado um modelo e foi seguido por outros programas de controle biológico no Brasil e na América Latina. O programa gerou inúmeras publicações, permitindo a formação derecursos humanos na área, abrindo novas áreas de pesquisa e mostrando que o parasitóide pode ser usado no controle de pragas-chave do algodoeiro, cana-de-açúcar, grãos armazenados, hortaliças, milho, soja e tomateiro. As perspectivas do uso do parasitóides possibilitaram a criação de empresaspara comercializá-los no Brasil, transferindo mais facilmente a tecnologia ao usuário.

Results of studies with Trichogramma in Brazil are presented, especially those developed at ESALQ/USP in the past two decades (1984-2004). The project involved taxonomy, rearing techniques,biological and behavioral aspects of the pests and parasitoids, pest population dynamics, release techniques, selectivity studies, and efficiency evaluation. It can be considered a model project and has been adopted by other biological control programs in Brazil and Latin America. The program has givenrise to a number of publications, allowing the formation of human resources in this area and openingnew research areas. The results indicated that the parasitoid can be used to control key pests in cotton, sugarcane, stored grain, vegetables, corn, soybean, and tomato. The perspective of using the parasitoidhas stimulated the creation of companies to commercialize it in Brazil, thus more easily transferring thistechnology to users.