Although the brown stink bug, Euschistus heros (F.) is susceptible to entomopathogenic fungi, only a single formulation is currently available on the Brazilian market for its control. The objective of this work was to isolate entomopathogenic fungi with potential to control E. heros, evaluate their virulence, and determine effective conidial concentrations. Thirty six different fungal isolates were obtained from soil samples and diseased insects and pure cultures of each were established on potato-dextrose agar. Suspensions of 1 × 10⁸ conidia mL⁻¹ were prepared from each isolate and a 5 μL aliquot was inoculated on the dorsum of adult stink bugs (n = 8 replications of 5 bugs each). Three isolates caused 100% mortality of bugs over a 15-day observation period. These were identified by molecular techniques as belonging to the Beauveria bassiana species complex and designated UFSM-1, UFSM-2 and UFSM-26. Further bioassays determined the LC₅₀, LC₉₀ and cumulative mortality functions caused by these three isolates. Isolates UFSM-1 and UFSM-2 stood out as highly virulence, with an LC₉₀ of 5 × 10⁹ conidia mL⁻¹ in 9 days, compared to an LC₉₀ of 8 × 10¹⁰ conidia mL⁻¹ for strain UFSM-26. Application of 1 × 10⁸ conidia mL⁻¹ of UFSM-1 and UFSM-2 isolates killed 70% of stink bugs in nine days, whereas the same concentration of UFSM-26 killed only 12%. We conclude that isolates UFSM-1 and UFSM-2 warrant field tests as novel agents for biological control of E. heros.

This study aimed to evaluate the yield and seed quality of wheat, cultivar ‘Quartzo’, harvested after desiccation with two desiccants (glyphosate and paraquat) at two reproductive stages (11.2 and 11.3). The study used a randomized block experimental design in a 3 x 2 factorial arrangement (two desiccants and a control) and two growth stages of wheat, with four replications. The following were assessed: seed yield, thousand seed weight and seed quality (germination, first germination count, root and shoot weight, seedling dry and fresh weight, accelerated aging, electrical conductivity, cold germination, potassium leaching). Based on the results, it can be concluded that the use of desiccants on wheat at the two stages of development have not affected yield, but they have negatively influenced physiological seed quality. Generally, the herbicide glyphosate showed the lowest phytotoxic effect on seeds, and desiccant application at stage 11.2 resulted in higher physiological seed quality compared with application at stage 11.3.

RESUMO A aveia-branca (Avena sativa) é uma importante alternativa para cultivos de inverno no sul do Brasil. Contudo, elevados percentuais de acamamento limitam sua produtividade. Nesse contexto, a utilização de reguladores de crescimento pode ser uma opção para evitar o acamamento e obter maior produtividade. O objetivo deste trabalho foi avaliar o efeito de doses do regulador de crescimento trinexapac-ethyl sobre as características agronômicas da aveia-branca, bem como sua influência na qualidade fisiológica e sanitária das sementes. Um experimento foi conduzido em campo, onde foi avaliada a influência de quatro doses de trinexapac-ethyl (0, 50, 100 e 150 g i.a. ha-1) sobre a estatura de planta, o diâmetro de colmo, o percentual de acamamento e os componentes do rendimento. Um segundo experimento foi conduzido em laboratório, onde sementes provenientes do estudo em campo foram avaliadas quanto a qualidade fisiológica a partir da mensuração da germinação, primeira contagem da germinação, condutividade elétrica, comprimento e massa de plântulas, envelhecimento acelerado, teste de frio, índice de velocidade de germinação, índice de velocidade de emergência, massa seca de plântulas em campo e sanidade pelo método de Blotter Test. A utilização de doses crescentes de trinexapac-ethyl reduziu de forma quadrática a estatura, bem como o acamamento de plantas de aveia-branca. A dose de 100 g i.a ha-1 de regulador de crescimento proporcionou os melhores resultados para os componentes de produtividade em A. sativa. O uso do trinexapac-ethyl afeta negativamente a germinação e o vigor de sementes de aveiabranca, assim como a sua sanidade, reduzindo a capacidade de estabelecimento e desenvolvimento inicial da cultura.

Soybean (Glycine max L.) is one of the most economically important crops in Brazil and in the world. Among soil-borne plant pathogens that affect soybean, the root-knot nematodes (Meloidogyne spp.) cause serious damage to this crop in different growing regions of Brazil (Hartman et al. 2015). In Brazil M. javanica, M. incognita, M. arenaria, M. morocciensis, M. paranaensis, M. ethiopica and M. enterolobii are reported in soybean (Castro et al. 2003; Almeida et al. 2008), but M. luci has not been detected before. In November 2015, soybean plants (cv. Nidera 5909) exhibiting many galls on the roots were detected and sampled in areas from Palmeira das Missões (-27°49'41"S; -53°20'06"W) county, northwest Rio Grande do Sul State, Brazil. The identification of Meloidogyne was carried out by esterase phenotypes (n=30) (Carneiro and Almeida 2001), perineal patterns (n=20), morphological measurement of second-stage juveniles (J2) (n=20) and sequencing of the ribosomal DNA region D2-D3 of 28S (primer set: forward 5...