RESUMO
Tetranychus urticae is the main pest of strawberry crops and can cause up to 80% of productivity losses under high infestations. Aiming to search T. urticae management alternatives compatible with eco-friendly or organic-based food production systems, this study evaluated the lethal and sublethal toxicities of formulated derivatives from Annonaceae (rich in acetogenins) against this pest species. In addition, it also evaluated the selectivity of the most promising formulation to the predatory mites Neoseiulus californicus and Phytoseiulus macropilis, which are largely applied in biological control in Brazil. Among the derivatives tested, the emulsion from the ethanolic seed extract of Annona mucosa-ESEAm (major component: acetogenin bis-tetrahydrofuran rolliniastatin-1) caused pronounced mortality of T. urticae after 120 h of exposure (LC50 = 465.5 mg L-1), in a comparable or superior manner to an abamectin-based synthetic acaricide used as positive control (LC50 = 1243.4 mg L-1). Moreover, ESEAm exposure resulted in a significant decrease in the number of eggs laid by females and caused the most pronounced ovicidal action for T. urticae, with only 5% embryonic viability. However, ESEAm also showed high toxicity to the predatory mites tested, causing 100% mortality for both species after 120 h exposure, similar to abamectin. The interaction between these bioacaricides and biological control agents should be tested under field conditions to further assess the potential ecological selectivity of these derivatives.
Assuntos
Acetogeninas , Ácaros , Controle Biológico de Vetores , Tetranychidae , Acetogeninas/toxicidade , Animais , Brasil , Feminino , Comportamento PredatórioRESUMO
Studying the susceptibility of peach trees to Grapholita molesta (Busck) is one of the major steps in the development of pest-resistant peach varieties. This work evaluated the susceptibility of 55 genotypes of the "Prunus Rootstock Collection" ("Coleção Porta-enxerto de Prunus") of Embrapa Temperate Climate (Pelotas, Rio Grande do Sul, Brazil) to the natural infestation of G. molesta, assessed the oviposition preference of G. molesta in choice and no-choice bioassays, and estimated the biological parameters and the fertility life table on different Prunus spp. genotypes in the laboratory. Genotypes Prunus kansuensis (Rehder), I-67-52-9, and I-67-52-4 were the most susceptible to G. molesta infestation in the field (>60% of branches infested), while 'Sharpe' (Prunus angustifolia x Prunus spp.) and Prunus sellowii (Koehne) were the least infested (0% of branches infested). In choice and no-choice bioassays, G. molesta preferred to oviposit on P. kansuensis when compared with Sharpe. The Sharpe genotype also showed an antibiosis effect, resulting in negative effects on the fertility life table parameters when compared with the genotypes P. kansuensis and 'Capdeboscq.' The results found in the present study can provide information to initiate a long-term breeding program moving desired G. molesta resistance traits from the rootstock into the Prunus spp. cultivars.
Assuntos
Herbivoria , Mariposas/fisiologia , Oviposição , Prunus/genética , Animais , Brasil , Genótipo , Interações Hospedeiro-Patógeno , Larva/crescimento & desenvolvimento , Larva/fisiologia , Características de História de Vida , Mariposas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Prunus/fisiologiaRESUMO
Non-native insect pests are often responsible for important damage to native and agricultural plant hosts. Since Drosophila suzukii Matsumura (Diptera: Drosophilidae) has become an important pest in North America and Europe (i.e., in 2008), the global production of soft thin-skinned fruits has faced severe production losses. In the southern Neotropical region, however, the first record of D. suzukii occurred in 2013 in the south of Brazil. It has also been recorded in Uruguay, Argentina, and Chile. Despite its recent occurrence in the southern Neotropical region, the fast dispersion of D. suzukii has inspired local research efforts in an attempt to mitigate the consequences of this insect pest invasion. In this forum, we explore the current status of D. suzukii in southern Neotropical regions, discussing its future perspectives. Additionally, we attempt to draft activities and a research agenda that may help to mitigate the losses caused by D. suzukii in native and commercial soft-skinned fruits produced in this region. Currently, D. suzukii appears to be well established in the south of Brazil, but considering the entire southern Neotropical region, the invasion panorama is still underinvestigated. The lack of studies and regulatory actions against D. suzukii has contributed to the invasion success of this species in this region. Considering several peculiarities of both the pest biology and the environmental of this region, the authors advocate for the need of intensive and integrative studies toward the development and implementation of area-wide integrated pest management programs against D. suzukii in the southern Neotropical region.
Assuntos
Produtos Agrícolas , Drosophila/fisiologia , Controle de Insetos/métodos , Animais , Brasil , Drosophila/classificação , Dinâmica PopulacionalRESUMO
Drosophila suzukii (Matsumura) has been recently detected causing damage to strawberries in Brazil. Infestation in strawberry culture has often been observed jointly with the presence of Zaprionus indianus Gupta. This study investigated the susceptibility of strawberries at three ripening stages to infestation of D. suzukii and Z. indianus and their interaction. In the laboratory, strawberries cv. Albion at different ripening stages (green, semi-ripe and ripe) were exposed to D. suzukii and Z. indianus for 24 h in choice and no-choice bioassays. Additionally, we evaluated the effects of mechanical damage incurred artificially or by D. suzukii oviposition on Z. indianus infestation. In no-choice bioassay, there were no significant differences in fruit susceptibility to D. suzukii infestation at different ripening stages. However, in choice bioassay, D. suzukii adults preferred to oviposit on R fruit. The presence of mechanical damage did not increase susceptibility of fruit to D. suzukii oviposition. For Z. indianus, there was greater susceptibility of R fruit in relation to SR and G fruit in both the choice and no-choice bioassays. There was a significant and positive interaction of mechanical damage and damage caused by D. suzukii to R fruit and infestation by Z. indianus, which was not observed in SR and G fruit. Although infestation of Z. indianus is related to attack damaged or decaying fruit, this work shows that this species has the ability to oviposit and develop in healthy strawberry fruit with and increased infestation level when the fruit has damage to its epidermis.
Assuntos
Drosophila , Fragaria , Oviposição , Animais , Brasil , Feminino , FrutasRESUMO
Aganaspis pelleranoi (Brèthes, 1924) (Hymenoptera: Figitidae) is a koinobiont endoparasitoid of larvae of species of the genus Anastrepha and of Ceratitis capitata. It is a candidate for use as a biological control agent, as under field conditions, it may reach a parasitism rate of 62%. The objective of this study was to determine the effect of different constant temperatures on biological parameters of A. pelleranoi when parasitizing the larva of Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae), as well as to determine its thermal requirements. The study was conducted in environmental chambers at 18, 20, 22, 25, 28, and 30 ± 1°C; 70 ± 10% relative humidity; and a 12-h photophase. Females maintained at 18 and 20°C produced more progeny than females at other temperatures tested. The longevity of males and females was inversely proportional to temperature, ranging from 49.1 to 3.73 d for females and from 32.1 to 3.8 d for males at temperatures of 18-30°C, respectively. The duration of the biological cycle (egg-to-adult) was influenced by temperature, and ranged from 69.1 d at 18°C to 30 d at 25°C. No preimaginal development of A. pelleranoi occurred at 28 and 30°C. The relationship between temperature and the demographic parameters of A. pelleranoi showed a linear effect over the temperature range of 18-25°C. The lower temperature threshold and thermal constant were 11.69°C and 391.70 degree days, respectively.