Thiamethoxam in soybean seed treatment: Plant bioactivation and hormesis, besides whitefly control?

Amid concerns on the myriad of existing chemical stressors in agroecosystems, pesticides and particularly neonicotinoid insecticides are in the forefront. Despite that, these neurotoxic compounds remain the dominant group of insecticides in worldwide use with the added versatility of use in seed coatings. Such use sparks environmental concerns counterbalanced by their reported insecticidal efficacy and potential plant bioactivation. Nonetheless, this alleged double benefit and interconnection expected with neonicotinoids has been little explored particularly when the whole plant phenology is considered. Regardless of the expected efficacy against targeted insect pest species, like whiteflies, neonicotinoids may spark dual effect on plants - negative at higher concentrations, positive at low concentrations, which is consistent with the hormesis phenomenon that may be expressed as a plant bioactivation. This effect may also cascade to the targeted insect species, what deserves attention. Therefore, soybean seeds treated with increasing concentrations of the neonicotinoid thiamethoxam were followed throughout their development in greenhouse, recording the plant response and yield, besides their effect in whiteflies (Bemisia tabaci MEAM1). Thiamethoxam application was correlated to leaf contents of thiamethoxam and its metabolite clothianidin. Plant hormesis was found for leaf area and root growth, but not for other plant morphological or physiological parameters, nor plant yield. The insecticide concentration-dependency compromised whitefly population growth without evidence of cascading any plant-mediated hormesis to the insects. Thus, although plant hormesis was recognized with thiamethoxam in treated soybean seeds in relevant parameters, no evidence of plant bioactivation was observed to justify its use with such a secondary objective, nor did this hormesis impair whitefly control.

Economic injury level for the coffee berry borer (Coleoptera: Curculionidae: Scolytinae) using attractive traps in Brazilian coffee fields.

The currently existing sample procedures available for decision-making regarding the control of the coffee berry borer Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) are time-consuming, expensive, and difficult to perform, compromising their adoption. In addition, the damage functions incorporated in such decision levels only consider the quantitative losses, while dismissing the qualitative losses. Traps containing ethanol, methanol, and benzaldehyde may allow cheap and easy decision-making. Our objective was to determine the economic injury level (EIL) for the adults of the coffee berry borer by using attractant-baited traps. We considered both qualitative and quantitative losses caused by the coffee borer in estimating the EILs. These EILs were determined for conventional and organic coffee under high and average plant yield. When the quantitative losses caused by H. hampei were considered alone, the EILs ranged from 7.9 to 23.7% of bored berries for high and average-yield conventional crops, respectively. For high and average-yield organic coffee the ELs varied from 24.4 to 47.6% of bored berries, respectively. When qualitative and quantitative losses caused by the pest were considered together, the EIL was 4.3% of bored berries for both conventional and organic coffee. The EILs for H. hampei associated to the coffee plants in the flowering, pinhead fruit, and ripening fruit stages were 426, 85, and 28 adults per attractive trap, respectively.

[Efficacy and safety of cefprozil versus cefaclor in the treatment of acute otitis media in pediatric patients] / Avaliação da eficácia e da segurança do cefprozil versus cefaclor no tratamento de otite média aguda em crianças.

OBJECTIVE: To evaluate the efficacy and safety of two oral cephalosporins, cefprozil and cefaclor, in the treatment of acute otitis media in children.METHODS: Forty children with clinical diagnosis of acute otitis media were randomized in two groups. Twenty-one children were given cefprozil at the dose of 30/mg/kg/day, in two equally divided doses every twelve hours, for ten days. Nineteen children were given cefaclor at the dose of 40/mg/kg/day in three divided doses every eight hours, for ten days. Efficacy evaluation of the antibiotic was analyzed by the presence or absence of symptoms, fever and otoscopic abnormalities while the safety and tolerability were evaluated by spontaneous information for possible adverse events.RESULTS: There was a significant decrease in the number of observed alterations between days 3 and 5 of treatment among those of the cefprozil group in comparison to the cefaclor group, while between days 10 and 14 of treatment the observed cure rate was clinically similar in both groups. Both medications presented adequate safety profiles. Only three children receiving cefprozil presented mild adverse events, such as nausea and vomit, none of which required treatment interruption.CONCLUSIONS: The clinical efficacy of both cephalosporins was similar although a more rapid activity was observed for cefprozil between days 3 and 5 of treatment. The favorable clinical results, the low incidence of adverse events and the twice a day dose regimen suggest that cefprozil is one more antimicrobial of choice for the treatment of acute otitis media in children, when this therapeutic is indicated.