RESUMO
Studies were conducted in the laboratory and in the greenhouse with the objective of evaluating nymph development, adult body weight gain, and damage of different species of pentatomids feeding on fruit (hereafter referred to as siliqua) of canola, Brassica napus (L.) var. oleifera. Nymphs of Nezara viridula (L.) were able to reach adulthood feeding on siliquae (93.3% survivorship), while nymphs feeding on siliquae that had their seeds removed showed arrested development, only reaching the 4th instar and did not complete development to adulthood. Adults of N. viridula gained body weight feeding on canola siliquae, particularly during the first two weeks of adult life, dropping weight thereafter. Adults of another species of pentatomid, Diceraeus furcatus (F.), also gained body weight, while adults of Euschistus heros (F.) lost weight. N. viridula adults caused significantly greater damage to seeds (shrunken and with rotten aspect) within siliqua and to the siliqua walls (whitish spots with lesions in the form of starbursts, called rosettes) compared to D. furcatus and to E. heros. The amount of damaged seeds caused by N. viridula adults during the first week of adult life was greater (ca. 60%) compared to those of older females 32 days of age (27%). Damage symptons caused by the feeding activity on siliqua walls (commonly known as rosettes) reached up to 10% of the total area with similar injury rates for N. viridula adults of different ages. The majority of N. viridula (70%) caused rosette, while only 20% of E. heros and 5% of D. furcatus produced similar damage.
RESUMO
This study evaluated intra- and interspecific variation regarding the susceptibility to insecticides of key pentatomid pests of soybean (Glycine max L.) and maize (Zea mays L.) crops in Brazil. To perform bioassays, populations of Euschistus heros (F.), Diceraeus (=Dichelops) furcatus (F.), Nezara viridula (L.), and Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae) were collected in soybean fields in Southern Brazil during the 2020/2021 crop season. Then, stink bugs were exposed to doses of commercial insecticides commonly applied for its control in dip-test bioassays using fresh green bean pods. In general, all stink bug species and populations studied were susceptible to acephate, acetamipridâ +â bifenthrin, imidaclopridâ +â bifenthrin, and ethiprole, with mortality ratesâ >â 80%. Most populations of E. heros and D. furcatus, considered the main stink bugs that attack soybean and maize, respectively, presented low or intermediate susceptibility to acetamipridâ +â α-cypermethrin, ζ-cypermethrinâ +â bifenthrin, dinotefuranâ +â λ-cyhalothrin, and bifenthrinâ +â carbosulfan. Except for bifenthrinâ +â carbosulfan (mortalityâ <â 57%), secondary stink bugs species that attack soybean (N. viridula and P. guildinii) showed pronounced susceptibility to all insecticides tested, with mortality ratesâ >â 70%. In summary, the populations of E. heros and D. furcatus showed diminished susceptibility to various insecticides formulated with the mixture of neonicotinoidsâ +â pyrethroids, whereas N. viridula and P. guildinii were most susceptible to the insecticides evaluated. The implications of these findings to integrated and resistance management programs are discussed.
Assuntos
Heterópteros , Inseticidas , Animais , Brasil , Glycine max , Zea maysRESUMO
This study evaluates the effects of combinations of pyrethroids and neonicotinoids on the control of stink bugs at different stages of soybean crop development. The experiment was set up in a factorial randomized block design (4×6: 4 treatments and 6 stages) with 4 repetitions. The following treatments were tested during the V6/V7, R2, R4, R5.1, R5.5 and R 6 phenological stages: 1 control (no application), 2 thiamethoxam + λ-cyhalothrin, 3 acetamiprid + α-cypermethrin, and 4 dinotefuran + α-cypermethrin. Infestation, number of damaged seeds, number of pods, number of pods per plant, and yield (kg/ha) were evaluated. Stink bug infestations were smaller when applications commenced during the vegetative stages (V6-V8). Pod numbers and yields were highest in the dinotefuran + α-cypermethrin treatment with applications from V6/V8 to R4. The active ingredients dinotefuran + α-cypermethrin reduced stink bug populations and increased yields and could therefore be considered in integrated pest management (IPM) programs for soybean crops.(AU)
O objetivo deste trabalho foi avaliar o efeito de combinações de piretroides com neonicotinoides no controle de percevejos em diferentes estádios de desenvolvimento da cultura da soja. O delineamento experimental foi em blocos randomizados, em esquema fatorial 4×6 (4 tratamentos e 6 estádios) com 4 repetições. Os produtos utilizados foram: 1 testemunha (sem aplicação), 2 tiametoxam + λ-cialotrina, 3 acetamiprida + α-cipermetrina, e 4 dinotefuran + α-cipermetrina, e as aplicações foram realizadas a partir dos estádios fenológicos V6/V7,R2, R4, R5.1, R5.5 e R6. Avaliaram-se a infestação, número de grãos danificados, número de vagens, número de vagens por planta e produtividade (kg/ha). A infestação de percevejo foi menor quando se iniciou a aplicação precocemente nos estádios vegetativos (V6-V8).O número de vagens e produtividade foi superior no tratamento dinotefuran + α-cipermetrina nos estádios V6/V8 até R4. Os ingredientes ativos dinotefuran + α-cipermetrina apresentaram resultados positivos na redução da população de percevejo e proporcionaram incremento no rendimento de grão, podendo ser utilizado como opção em programa de manejo integrado de pragas (MIP) na cultura da soja.(AU)
Assuntos
Glycine max , Controle de Pragas , Cimicidae , Piretrinas , Neonicotinoides , FungosRESUMO
This study evaluates the effects of combinations of pyrethroids and neonicotinoids on the control of stink bugs at different stages of soybean crop development. The experiment was set up in a factorial randomized block design (4×6: 4 treatments and 6 stages) with 4 repetitions. The following treatments were tested during the V6/V7, R2, R4, R5.1, R5.5 and R 6 phenological stages: 1 control (no application), 2 thiamethoxam + λ-cyhalothrin, 3 acetamiprid + α-cypermethrin, and 4 dinotefuran + α-cypermethrin. Infestation, number of damaged seeds, number of pods, number of pods per plant, and yield (kg/ha) were evaluated. Stink bug infestations were smaller when applications commenced during the vegetative stages (V6-V8). Pod numbers and yields were highest in the dinotefuran + α-cypermethrin treatment with applications from V6/V8 to R4. The active ingredients dinotefuran + α-cypermethrin reduced stink bug populations and increased yields and could therefore be considered in integrated pest management (IPM) programs for soybean crops.(AU)
O objetivo deste trabalho foi avaliar o efeito de combinações de piretroides com neonicotinoides no controle de percevejos em diferentes estádios de desenvolvimento da cultura da soja. O delineamento experimental foi em blocos randomizados, em esquema fatorial 4×6 (4 tratamentos e 6 estádios) com 4 repetições. Os produtos utilizados foram: 1 testemunha (sem aplicação), 2 tiametoxam + λ-cialotrina, 3 acetamiprida + α-cipermetrina, e 4 dinotefuran + α-cipermetrina, e as aplicações foram realizadas a partir dos estádios fenológicos V6/V7,R2, R4, R5.1, R5.5 e R6. Avaliaram-se a infestação, número de grãos danificados, número de vagens, número de vagens por planta e produtividade (kg/ha). A infestação de percevejo foi menor quando se iniciou a aplicação precocemente nos estádios vegetativos (V6-V8).O número de vagens e produtividade foi superior no tratamento dinotefuran + α-cipermetrina nos estádios V6/V8 até R4. Os ingredientes ativos dinotefuran + α-cipermetrina apresentaram resultados positivos na redução da população de percevejo e proporcionaram incremento no rendimento de grão, podendo ser utilizado como opção em programa de manejo integrado de pragas (MIP) na cultura da soja.(AU)
Assuntos
Glycine max , Controle de Pragas , Cimicidae , Piretrinas , Neonicotinoides , FungosRESUMO
BACKGROUND: The abundance and contribution of the neotropical brown stink bug, Euschistus heros (F.), and the redbanded stink bug, Piezodorus guildinii (West.), to the composition of insect pests of soybean, Glycine max (L.), fields have changed both spatially and temporally in neotropical soybean production areas. Therefore, we assessed the competitiveness of each species in direct competition experiments following an additive series. We performed mixed (adult) insect infestations in soybean plants and evaluated the fitness of each species and the soybean yield. RESULTS: While the competitive ability of E. heros was significantly compromised by increments in conspecifics and heterospecifics (i.e. P. guildinii), the competitive ability of P. guildinii was compromised by the presence of heterospecifics (i.e. E. heros). The reproductive output of P. guildinii remained unaffected by increments in E. heros or of P. guildinii. Intriguingly, despite the fact that P. guildinii apparently lost the competition with E. heros, almost no pod production was observed in any plant colonised by the former. CONCLUSIONS: The higher abundance of E. heros in neotropical soybean fields seems to result from higher competitive ability than its heterospecific competitor P. guildinii, which may prevent the higher losses caused by P. guildinii. © 2016 Society of Chemical Industry.
Assuntos
Glycine max/parasitologia , Heterópteros/fisiologia , Animais , Brasil , Comportamento Competitivo , Feminino , Heterópteros/crescimento & desenvolvimento , Masculino , Dinâmica Populacional , Especificidade da EspécieRESUMO
O conhecimento de Pentatomoidea no Estado de São Paulo é aqui atualizado. São registradas 92 espécies em 89 gêneros pertencentes as famílias Acanthosomatidae, Canopidae, Cydnidae, Pentatomidae, Phloeidae, Scutelleridae, Tessaratomidae e Thyreocoridae. Comparando com os dados apresentados na primeira edição do Biota SP em 1999, foram adicionadas 41 espécies além de 13 correções nomenclaturais e taxonômicas efetuadas. O Estado de São Paulo apresenta uma riqueza total ao redor de 25% das espécies conhecidas para o Brasil e ao redor de 3% da fauna mundial de Pentatomoidea. Com o incremento dos estudos em famílias pouco conhecidas no país, estes números certamente serão ampliados. Pentatomidae resultou no táxon mais numeroso no estado, com 80% de espécies registradas.
Pentatomoidea knowledge in São Paulo state is here updated. Two hundred and two species in 92 genera belonging to Acanthosomatidae, Canopidae, Cydnidae, Pentatomidae, Phloeidae, Scutelleridae, Tessaratomidae and Thyreocoridae are registered. Forty one species were added and 13 taxonomical and nomenclatorial corrections were made comparing with the data presented in the first edition of the Biota SP in 1999. Pentatomoidea species richness of São Paulo state is around 25% of the species known to Brazil and around 3% of the world fauna. The increase of the studies in scarcely known families in Brazil will certainly raise these numbers. Pentatomidae was the most numerous taxon in São Paulo state, with 80% of the registered species.