Resumo -O objetivo deste trabalho foi avaliar o desenvolvimento de estágios imaturos e parâmetros reprodutivos de adultos de Grapholita molesta em dietas naturais, constituídas de ramos e frutos de pessegueiro 'Vanguarda', frutos de macieira 'Gala' e 'Fuji', e em dieta artificial à base de milho. O delineamento experimental foi inteiramente casualizado. Considerou-se cada inseto uma repetição e, no estudo dos parâmetros biológicos dos adultos, cada casal foi considerado uma repetição. Foi calculada a tabela de vida de fertilidade. O tempo para o desenvolvimento das lagartas foi menor em ramos e frutos do pessegueiro, em comparação a frutos de macieira e dieta à base de farinha de milho. Quanto à sobrevivência das larvas, não houve diferença entre as dietas. Com base na tabela de vida de fertilidade, os frutos da cultivar Fuji foram mais adequados ao desenvolvimento de G. molesta do que os da Gala. Os ramos de pessegueiro foram mais adequados ao desenvolvimento do inseto do que os frutos. A dieta à base de farinha de milho foi adequada para a criação dos insetos em laboratório. As dietas avaliadas afetam a taxa de sobrevivência, o desenvolvimento e o potencial de crescimento populacional de G. molesta. Termos para indexação: Grapholita molesta, Malus domestica, Prunus persica, criação em laboratório, tabela de vida. Development and reproduction of the oriental fruit moth in apple and peachesAbstract -The objective of this work was to evaluate the immature stages development and the reproductive parameters of Grapholita molesta adults reared on shoots and fruit of 'Vanguarda' peach, on fruit of 'Gala' and 'Fuji' apples, and on a diet formulated with corn meal. The experimental design was completely randomized. Each insect was considered one replicate; and for the biological parameters of adults study, each couple was considered a replicate. The fertility life table was calculated. The time for larvae development was shorter in peach shoots and fruits, in comparison with apple fruit and corn meal diets. There were no differences for larvae survival, in the comparison between diets. Based on fertility life table, 'Fuji' apple fruit are more appropriated to the G. molesta development than Gala ones. Peach shoots were more suited for insect development than fruit. The corn meal-based diet is suitable to rear G. molesta in laboratory. The evaluated diets affect survival rate, development and growth potential of G. molesta population.
The oriental fruit moth Grapholita molesta is one of the major pests of stone and pome fruit species in Brazil. Here, we applied 1226 SNPs obtained by genotyping-by-sequencing to test whether host species associations or other factors such as geographic distance structured populations of this pest. Populations from the main areas of occurrence of G. molesta were sampled principally from peach and apple orchards. Three main clusters were recovered by neighbor-joining analysis, all defined by geographic proximity between sampling localities. Overall genetic structure inferred by a nonhierarchical amova resulted in a significant ΦST value = 0.19109. Here, we demonstrate for the first time that SNPs gathered by genotyping-by-sequencing can be used to infer genetic structure of a pest insect in Brazil; moreover, our results indicate that those markers are very informative even over a restricted geographic scale. We also demonstrate that host plant association has little effect on genetic structure among Brazilian populations of G. molesta; on the other hand, reduced gene flow promoted by geographic isolation has a stronger impact on population differentiation.
In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as survival strategy during the winter (May–August). In our study, we evaluated the effect of diapause on biological characteristics of the species for 4 months in laboratory. Newly hatched larvae of G. molesta were induced to diapause changing the photoperiod and temperature (T) (12 ± 1°C), relative humidity (RH) (70 ± 10%), and a photophase of 12 h and, when they started diapause in the prepupal stage, the conditions were kept for 4 months. Afterwards, the insects were induced to finalize the diapause process at T 25 ± 1°C, RH 70 ± 10%, and a photophase of 16 h. We evaluated the duration and viability of the larval stages and pupae, pupae weight at 24 h and sex ratio (sr), periods of preoviposition, oviposition, and postoviposition; adult life span (males and females); fecundity (daily and total); embryonic period duration and eggs viability, comparing the data with insects nondiapause. The results show that diapause greatly affected the viability of pupal–adult stages of the population (21.8%) when compared with insects’ nondiapause (80.0%). Total fecundity (83.0 eggs) and mean life span (12.0 d) of insects diapause was significantly lower compared with insects nondiapause (173.0 and 17.0), respectively. However, these differences were not observed in the sr, which was similar to insects diapause (sr = 0.41) and insects nondiapause (sr = 0.49). The diapause induced for 4 months negatively affects reproduction and life span of adults of G. molesta.
The Bonagota salubricola (Meyrick) is a major pest in apple orchards in Brazil, and chemical control has been the primary tool for insect management. To support the development of an insect resistance management (IRM) program, baseline studies of the susceptibility of a reference (laboratory) B. salubricola population were conducted; seven wild B. salubricola populations were monitored for susceptibility to insecticide; and the toxicity of some new chemicals to third-instar larvae and adults was evaluated by a leaf dip and ingestion bioassay, respectively. Neonates from the susceptible (laboratory) population exposed to insecticide showed an LC50 ranging from 0.34 (spinetoram) to 30.19 (novaluron) µg of a.i. ml(-1) (88.8-fold variation), so the diagnostic concentrations for an IRM program in Brazil based on the LC99 were as follows: 19.0 µg of a.i./ml chlorantraniliprole, 510.0 novaluron, 72.0 phosmet, 4.1 spinetoram, 12.8 spinosad, and 110.0 tebufenozide. Based on the LC99, significant differences were not observed in the susceptibility of the field and laboratory populations to chlorantraniliprole, phosmet, spinetoram, spinosad, and tebufenozide insecticides, but there were significant differences in the survival rates of the two populations to novaluron insecticide (3.3%). All insecticides at the diagnostic concentrations showed high toxicity to third-instar larvae (mortality rates between 73 to 97%). Phosmet, spinetoram, and spinosad insecticides were toxic to B. salubricola adults (mortality >85%), while chlorantraniliprole, novaluron, and tebufenozide insecticides caused mortality below 5%. The evaluated insecticides showed high toxicity to different developmental stages of B. salubricola, so the diagnostic concentrations may be used in IRM programs in Brazil.
RESUMO -O objetivo deste trabalho foi avaliar a eficiência e os efeitos subletais de um inseticida à base de nim (10 g.L -1 de azadiractina A) sobre a lagarta-enroladeira Bonagota salubricola em laboratório. Nos bioensaios, foi utilizado o produto à base de azadiractina NeemAzal-T/S ® nas concentrações de 0,06%; 0,09%; 0,12%; 0,16%; 0,18% e 0,20% do produto comercial (p.c) e uma testemunha (água destilada). A dieta artificial foi cortada em cubos e imersa nas caldas das respectivas concentrações do produto, e, em seguida, lagartas recém-eclodidas foram transferidas para tubos de vidro, contendo os cubos de dieta tratados. Quando a dieta artificial foi tratada com concentração de 0,20% do produto comercial, houve 100% da mortalidade aos 6 dias após a inoculação. Por outro lado, as concentrações de 0,16 e 0,18% prolongaram a fase larval, reduziram a viabilidade de pupas e afetaram negativamente a fecundidade do inseto. Termos de indexação: Azadiractha indica, nim, lagarta-enroladeira. EFFICIENCY AND SUBLETHAL EFFECTS OF NEEM ON Bonagota salubricola (MEYRICK) (LEPIDOPTERA: TORTRICIDAE)ABSTRACT -The objective of this study was to evaluate the efficiency of control and sublethal effects of neem insecticide (10 g.L -1 of azadirachtin A) to the leafroller Bonagota salubricola at laboratory condition. In the bioassays, it was used an azadirachtin based product (NeemAzal-T/S ® ) at concentrations of 0.06%, 0.09%, 0.12%, 0.16%, 0.18% and 0.20% of the commercial product (c.p.) and a control (distilled water). The artificial diet was cut in cubes and immersed in the syrups of the respective product concentrations, soon afterwards recently-emerged caterpillars were transferred to glass tubes, containing the diet cubes treated. When the artificial diet was treated with a concentration of 0.20% of the commercial product, the mortality was 100% at the 6 th day after inoculation. Additionally, concentrations of 0.16% and 0.18% extended the larval stages, reduced pupae viability and negatively affected the fecundity of the insect.
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