Herbicide application on Genetically Modified Maize influences bee visitation

Brazil is one of the world’s largest producers of maize (Zea mays L.). Cry proteins derived from the bacterium Bacillus thuringiensis (Bt) have been widely used in transgenic maize due to their toxicity and specificity against insects that damage crops. In addition, these plants have been stacked with different herbicide tolerance genes. Non-target insects end up being exposed to Bt proteins and herbicide applications. There is little information on the effects of Bt transgenics and their cultural practices on the behavior of pollinators in genetically modified crops. The aim of this research was to verify the impact of genotypes of genetically modified maize, Herculex®, PowerCore®, and the conventional isohybrid, pulverized or not with herbicides (atrazine, glufosinate-ammonium and nicosulfuron) in bee populations. In order to evaluate the presence of insects, a zig-zag tour was carried out throughout the experimental field, ascertained from visual analysis and direct counting of six plants per plot (the dimensions of the plots were 2.5 x 10 m with five maize lines spaced 0.50 m between rows and 0.36 m between plants) randomly, 18 days after spraying herbicides in the area. Apis mellifera (L.) (Hymenoptera: Apidae), Tetragonisca angustula (L.) (Hymenoptera: Apidae) and Trigona spinipes (F.) (Hymenoptera: Apidae) were the pollinator species identified in the crop. It was observed that the incidence of pollinator insects varied according to cultivars and herbicides tested; however, the PowerCore® genotype experienced more visitation of pollinating bees independently of the herbicide treatments.

Sustainable intensification using irrigation and N fertilization for pasture production in Tocantins, Brazil.

Cattle raising is among the main Brazilian economic activities. Currently, there are 169 million hectares covered by tropical grasslands and 30% of this area is degraded. In the last 40 years, the area occupied by grasslands in Brazil increased only 17% while the meat production increased 114% and that fact was only possible due to national effort and investments on agricultural research, development and innovation. To verify the influence of irrigation in a pasture of Panicum maximum cv. Massai was carried out a field research testing rainfed and two irrigation depths (SO and 100% of evapotranspiration) and 300 kg ha-1 year-1 of N-urea, during one year at the periods Jun-Sep, Oct-Nov, Dec-Mar and Apr-May, in Tocantins state, Brazil. The parameters are one animal unit (AU) corresponding to 450 kg of liveweight, a daily dry matter intake of 11.25 kg. The accumulated dry matter (kg ha-1 day-1 ) obtained by the 100% depth was significantly higher than the others in almost all periods analyzed, and during Jun-Sep the treatment 50% depth showed no significant difference when compared to 100% depth suggesting seasonality probably related to low temperatures. The results revealed the potential to achieve a stocking rate of 6.44, 4.20 and 3.51 AU ha-1 year-1 with 100%, 50% depths and rainfed treatment, respectively. Despite promising results, further studies on physiology, phenology and economy must be done to confirm the feasibility of using irrigation for pasture production in Tocantins

Sustainable intensification using irrigation and N fertilization for pasture production in Tocantins, Brazil.

To verify the influence of irrigation in a pasture of Panicum maximum cv. Massai was carried out a field research testing rainfed and two irrigation depths (SO and 100% of evapotranspiration) and 300 kg ha-1 year-1 of N-urea, during one year at the periods Jun-Sep, Oct-Nov, Dec-Mar and Apr-May, in Tocantins state, Brazil