A cultura da soja é extremamente importante para a economia brasileira, por isso formas para aumentar o rendimento de grãos devem ser consideradas. Uma proposta para aumentar produtividade pode ser a aplicação de micronutriente via foliar. O objetivo do trabalho foi avaliar a resposta da cultura da soja sob diferentes concentrações de boro (B), aplicadas via pulverização foliar, em diferentes estádios de desenvolvimento sob sistema de plantio direto. O delineamento experimental utilizado foi blocos ao acaso com parcelas subdivididas. Os tratamentos constituíram de quatro doses de B (0, 150, 300 e 450 g ha-1) aplicadas no estádio vegetativo (V6) e no reprodutivo (R2). Foi avaliado o número de legumes por planta, número de grãos por legumes, massa de mil grãos e a produtividade em kg ha-1. Os dados foram submetidos à análise de variância e comparados pelo teste Tukey a 5% de significância e análise de regressão. A adubação foliar com B promoveu aumento na massa média de grãos quando aplicado em R2 e no número de grãos por legumes (2,43 grãos para dose ajustada de 320 g ha-1 de B). No entanto, a produtividade (3200 kg ha-1) não apresentou comportamento diferenciado independentemente da dose e do estádio fenológico de aplicação.   Palavras-chave: Glycine max (L), Absorção de nutrientes, Micronutriente.

-The objective of this work was to evaluate the natural resistance of soybean cultivars to Chrysodeixis includens. For this, four commercial soybean cultivars recommended for the Southern region of Brazil were used: BR 36, NA 5909 RG, BMX Turbo RR, and Benso 1RR. In the laboratory, larvae were subjected to the antixenosis feeding assay, in which they were free or not to choose among old leaves, new leaves, and pods. Neonate larvae were subjected to two antibiosis tests: in the first one, they were fed with leaves from the middle third of the plants of the four cultivars; and, in the second one, with leaves or pods of the NA 5909 RG cultivar. Chrysodeixis includens larvae prefer leaves over pods and old leaves over new ones. The Benso 1RR cultivar extends the development cycle of C. includens, but only BMX Turbo RR will reduce the population growth of larvae in the next generations.Index terms: integrated pest management, IPM, lepidopteran pests, plant resistance, Plusiinae. Resistência natural de cultivares de soja à lagarta-falsa-medideiraChrysodeixis includens (Lepidoptera: Noctuidae) Termos para indexação: manejo integrado de pragas, MIP, lepidópteros-praga, resistência de plantas, Plusiinae.

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The objective of this study was to evaluate the effect of botanical oils on adult mortality and oviposition repellency of Anastrepha fraterculus in peach, apple and red cattley guava fruits. The fruits were treated by the dip method for 15 seconds with botanical oils of Ruta graveolens (0.05%), Cymbopogon citratus (1%), Cymbopogon winterianus (10%), Carapa guianensis (25%) and distilled water was used as a control. The experiments were carried out in a completely randomized design with twenty replicates. After being treated, the fruits were dried at room temperature, placed in separate plastic containers (750 mL) and transferred to a room at 25±2 °C. Each fruit was exposed to two fruit fly couples for 48 hours. After this period, the amount of dead insects was recorded. On apple fruits kept in containers with sterilized vermiculite, the effect of the treatments on A. fraterculus biology was evaluated for 36 days, and data were collected on the amount of pupae in the second generation. C. winterianus oil presented mortality rates of 100 and 80% of adults in peach and apple fruits, respectively. C. citratus oil caused a significantly different mortality rate compared to the control in peach fruits, whereas C. guianensis oil caused A. fraterculus mortality in red cattley guava and apple fruits. The mortality of A. fraterculus in fruits treated with R. graveolens oil did not differ from the control treatment. The botanical oils of C. winterianus and C. guianensis protected apple fruits by preventing A. fraterculus proliferation, and there was a significant reduction of the amount of pupae in the second generation. Botanic oils presented potential for suppression of fruit flies; however, further studies are necessary to test and make them feasible under field conditions.

Grape orchards are highly affected by oviposition of fruit flies on grape berries, which compromises the productivity and quality of the grapes. The goal of this study was to evaluate the susceptibility of American, European, and hybrid grape genotypes to Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) under laboratory conditions (25 ± 2ºC, 60 ± 10% RH, and 14-hour photophase). The assays were conducted by evaluating oviposition preference through choice and no-choice (antibiosis) tests. The choice test was set up using circular arenas (diameter: 300 mm) with 10 grapes per genotype. The no-choice test was set up using 150 grapes per genotype which were placed inside plastic boxes (417 x 297 x 289 mm). After exposure of the grapes to one or two couples of fruit flies per genotype in choice and no-choice tests, respectively, the grapes were transferred to transparent plastic containers (750 mL). The number of eggs per grape and its viability were evaluated. The no-choice test also evaluated the biological cycle of the fruit flies. The assays were conducted in a completely randomized design with 15 replicates. The most preferred grapes for oviposition by A. fraterculus were Cabernet Sauvignon, Niagara Rosada, and BRS Cora, while C. capitata mainly preferred Isabel Precoce grapes. We observed the complete development of fruit flies in the Moscato Embrapa grapes, but this only occurred with C. capitata. All genotypes evaluated were considered susceptible to A. fraterculus and C. capitata. However, the fruit flies expressed differences in preference for oviposition and host quality.

No abstract

Control of Anastrepha fraterculus (Diptera: Tephritidae) is usually accomplished with synthetic insecticides, which can be a problem considering exportation of fruits. This study aimed to evaluate mortality and offspring effects on A. fraterculus using peach, strawberry guava and apple fruits treated with andiroba (Carapa guianensis) oil. Higher mortality rate was observed when compared to control on strawberry guava and apple fruits treated with andiroba oil (18.4 % and 35.0 % points more than the control). The mean number of pupae observed in the offspring was inferior to the control on strawberry guava and apple fruits treated with andiroba oil (100 % control) and, on peach fruits (68.3 % fewer pupae). Andiroba oil shows promising results as an alternative product to control A. fraterculus. Studies are still needed especially considering the effectiveness of andiroba oil under field conditions.

In recent decades, soybean has been one of the most widely grown crops in Brazil. The soybean looper, Chrysodeixis includens (Walker, [1858]; Lepidoptera: Noctuidae), is one of the main defoliating pests of soybean that cause damage and affect the cost of production. The overall objective of the present study was to characterize the resistance of C. includens to diamide insecticides. To this end, the baseline susceptibility of C. includens to flubendiamide, chlorantraniliprole, and cyantraniliprole was characterized to estimate their concentrations for diagnostic monitoring of resistance in populations collected in commercial soybean crops in southern Brazil during the 2018/19 season. Under field conditions, evaluations were made of the residual activity of three diamide insecticides: chlorantraniliprole + lambda-cyhalothrin, teflubenzuron, methoxyfenozide, and bifenthrin for discrimination between flubendiamide-susceptible and resistant C. includens. Chrysodeixis includens was more tolerant to cyantraniliprole than to flubendiamide and chlorantraniliprole. The field populations had a higher survival rate than the susceptible population. The resistant population showed a resistance ratio to flubendiamide of 70.1-fold. Under field conditions, the residue of the study insecticides, except for bifenthrin, enabled discrimination between flubendiamide-susceptible and resistant C. includens. The data indicate the need to study the cross-resistance relationships between insecticides to improve the rotation recommendation. They also reinforce the importance of using other good management practices, e.g., the use of insecticides based on pest sampling and the choice of other control methods to prevent C. includens from becoming resistant to diamide insecticides.