Wladecir Salles de Oliveira

Assessment of the high-dose concept and level of control provided by MON 87701 × MON 89788 soybean against Anticarsia gemmatalis and Pseudoplusia includens (Lepidoptera: Noctuidae) in Brazil.

BACKGROUND Genetically modified MON 87701 × MON 89788 soybean (Glycine max), which expresses the Cry1Ac and EPSP-synthase proteins, has been registered for commercial use in Brazil. To develop an Insect Resistance Management (IRM) program for this event, laboratory and field studies were conducted to assess the high-dose concept and level of control it provides against Anticarsia gemmatalis and Pseudoplusia includens. RESULTS The purified Cry1Ac protein was more active against A. gemmatalis [LC(50) (FL 95%) = 0.23 (0.15-0.34) µg Cry1Ac mL(-1) diet] than P. includens [LC(50) (FL 95%) = 3.72 (2.65-4.86) µg Cry1Ac mL(-1) diet]. In bioassays with freeze-dried MON 87701 × MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of A. gemmatalis and up to 95.79% mortality for P. includens. In leaf-disc bioassays and under conditions of high artificial infestation in the greenhouse and natural infestation in the field, MON 87701 × MON 89788 soybean showed a high level of efficacy against both target pests. CONCLUSIONS The MON 87701 × MON 89788 soybean provides a high level of control against A. gemmatalis and P. includes, but a high-dose event only to A. gemmatalis.

Compositional equivalence of insect-protected glyphosate-tolerant soybean MON 87701 × MON 89788 to conventional soybean extends across different world regions and multiple growing seasons.

The soybean product MON 87701 × MON 89788 expresses both the cry1Ac gene derived from Bacillus thuringiensis and the cp4 epsps (5-enolpyruvylshikimate-3-phosphate synthase) gene derived from Agrobacterium sp. strain CP4. Each biotechnology-derived trait confers specific benefits of insect resistance and glyphosate tolerance, respectively. The purpose of this study was to compare the composition of seed and forage from this combined-trait product to those of conventional soybean grown in geographically and climatically distinct regions. Field trials were conducted in the United States during the 2007 growing season, in Argentina during the 2007-2008 growing season, and in the northern and southern soybean regions of Brazil during the 2007-2008 and 2008-2009 growing seasons. Results demonstrated that the compositional equivalence of MON 87701 × MON 89788 to the conventional soybean extended across all regions and growing seasons. Further evaluation of the data showed that natural variation (region and growing season) contributed more to compositional variability in soybean, particularly for such components as isoflavones, fatty acids, and vitamin E, than transgene insertion.

Compositional Variability in Conventional and Glyphosate-Tolerant Soybean (Glycine max L.) Varieties Grown in Different Regions in Brazil

The compositions of a diverse range of commercially available conventional and genetically modified (GM; glyphosate-tolerant) soybean varieties from maturity groups 8 and 5, respectively, grown in the northern and southern soybean regions of Brazil during the 2007-2008 and 2008-2009 growing seasons were compared. Compositional analyses included measurement of essential macro- and micronutrients, antinutrients, and selected secondary metabolites in harvested seed as well as measurement of proximates in both forage and harvested seed. Statistical comparisons utilized a mixed analysis of variance model to evaluate the relative contributions of growing season, soybean growing region, production site, phenotype (GM or conventional), and variety. The study highlighted extensive variability in the overall data set particularly for components such as fatty acids, vitamin E, and isoflavones. There were few differences between the GM and non-GM populations, and most of the variability in the data set could be attributed to regional and variety differences. Overall, the results were consistent with the expanding literature on the lack of any meaningful impact of transgene insertion on crop composition.

Balanço do nitrogênio (15N) da uréia nos componentes de uma pastagem de capim-marandu sob recuperação em diferentes épocas de calagem

In order to evaluate the use of urea nitrogen, the balance of nitrogen (15N) in Brachiaria brizantha pastures was obtained when urea was applied either incorporated or in the soil surface (in four applications beginning in November of 1998) and the lime was applied in two periods (March and August of 1998). The recovery and retention of the N-urea were obtained for each plant structure of the soil-pasture system, and indicated that the plant crown is a very important storage organ for the N applied via Urea. Liming in March favored forage mass production and improved the efficiency of N use when urea was incorporated. The incorporation of urea improved both, the recovery and retention of nitrogen in most Brachiaria structures. Difference in N recovery between the best (lime application in March with urea incorporated) and the worst treatment (liming in March with urea-N on the soil-surface) was around 50 kg N.ha-1 after one year.

Manejo de lepidópteros-praga na cultura do milho com o evento Bt piramidado Cry1A.105 e Cry2Ab2

The objective of this work was to evaluate the efficacy of the pyramided event (MON 89034), expressing Cry1A.105 and Cry2Ab2 proteins, in the control of the main lepidopteran maize pests in Brazil, Spodoptera frugiperda, Helicoverpa spp., and Diatraea saccharalis. The trials were conducted in four regions of the country, using the hybrid DKB 390, subjected to six treatments: hybrid containing the pyramided event, hybrid expressing only the protein Cry1A(b) (MON 810), and conventional hybrid (non Bt), all with and without integrated management for S. frugiperda. For the pyramided event, chemical control was not necessary in any of the evaluated locations. Significant differences were observed between treatments for larval damage and presence. In general, those variables were lower for the pyramided hybrid and higher for the conventional hybrid without chemical control. Under high infestation, chemical control reduced the damage caused by S. frugiperda and D. saccharalis both on the single protein event and on the conventional hybrid. Based on the damage caused by the insects, the pyramided event Cry1A.105 and Cry2Ab2 is efficient in the control of the main lepidopteran maize pests in Brazil.

Efeito residual de fertilizantes fosfatados solúveis na recuperação de pastagem de Brachiaria brizantha cv. Marandu em Neossolo Quartzarênico

Dois experimentos foram realizados, por um periodo de dois anos, para avaliar a resposta de um sistema solo-pastagem a fertilizantes fosfatados de diferentes velocidades de solubilizacao (superfosfato simples, superfosfato triplo e termofosfato magnesiano) associados ou nao a calagem. Nao houve diferenca em producao de forragem entre as varias fontes de fosforo, quando as adubacoes fosfatadas foram feitas nos dois anos. A associacao de fertilizantes pode ser vantajosa, porque o termofosfato promoveu as maiores producoes de forragem quando se suprimiu a adubacao fosfatada no segundo ano, enquanto as adubacoes com superfosfatos resultaram nas maiores producoes no primeiro ano. A calagem favoreceu a producao de forragem e proporcionou aumento nos teores de nutrientes e reducao do aluminio no solo. A resposta a adubacao foi melhor no segundo ano, porque a pastagem estava em recuperacao.

Control of glyphosate resistant hairy fleabane (Conyza bonariensis) with dicamba and 2,4-D

Os herbicidas mimetizadores de auxinas como dicamba e 2,4-D sao alternativas para o controle de buva resistente ao glyphosate. Com a possivel futura liberacao comercial de culturas resistentes ao dicamba e 2,4-D, a aplicacao destes herbicidas reguladores de crescimento sera uma provavel alternativa de controle de buva resistente ao glyphosate. O objetivo desta pesquisa foi modelar por meio de curvas de dose-resposta a eficacia do dicamba e 2,4-D isolados e dicamba em associacao com glyphosate para controle de uma populacao de buva resistente. Um estudo de doseresposta em casa de vegetacao foi conduzido em delineamento experimental inteiramente casualizado, sendo que as doses utilizadas para a construcao das curvas de dose-resposta foram de 0, 120, 240, 480, 720 e 960 g i.a. ha-1de para o dicamba e o 2,4-D isolados e dicamba associado com 540 g e.a. ha-1 de glyphosate. As doses utilizadas para o glyphosate isolado foram de 0, 180, 360, 540, 720 e 960 g e.a. ha-1. Os tratamentos herbicidas foram aplicados quando asplantas estavam no estadio vegetativo de 10 a 12 folhas e altura entre 12 e 15 cm. A buva apresentou baixa sensibilidade ao glyphosate, pois nao foi controlada mesmo na dose de 960 g e.a. ha-1 de glyphosate. O dicamba e o 2,4-D foram eficazes no controle da populacao de buva estudada. A buva responde de forma diferenciada ao 2,4-D e dicamba e sera importante determinaras doses apropriadas de cada herbicida para controle de buva resistente ao glyphosate em condicoes de campo. A associacao de glyphosate e dicamba nao foi antagonica no controle da buva e o glyphosate pode causar um efeito aditivo no controle, apesar da resistencia da populacao.Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosatedicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 g a.i. ha-1 for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a.e. ha-1. The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a.e. ha-1. Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a.e. ha-1 rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.

Residual herbicides in weed management for glyphosate-resistant soybean in Brazil

In agricultural production systems where the glyphosate-resistant soybean crop (Glycine max) is grown and the practice of crop rotation with alternative herbicides is not adopted, the exclusive and continuous use of glyphosate has led to the occurrence of resistant weed populations that may limit or compromise the benefits of this technology. Thus, the efficacy of weed management programs, including the use of residual herbicides (sulfentrazone, flumioxazin, imazethapyr, diclosulan, chlorimuron and s-metolachlor) applied in preemergence and followed by in-crop postemergence applications of glyphosate (PRE-POST) were compared to glyphosate postemergence only programs - POST. The study was conducted across nine locations during the 2009/2010 and 2010/2011 growing seasons. PRE-POST programs were efficient in the control of Amaranthus viridis, Brachiaria plantaginea, Bidens pilosa, Commelina benghalensis, Eleusine indica, Euphorbia heterophylla and Raphanus raphanistrum, with the level of control being similar when comparing the program with two applications of glyphosate POST. Some PRE-POST programs were not efficient in controlling Cenchrus echinatus, Ipomoea hederifolia and Ipomoea triloba. Sulfentrazone and diclosulam PRE-POST programs improved the control of Ipomoea triloba compared to sequential applications of glyphosate alone. No significant differences in soybean yield were observed between any of the herbicide treatments or study locations. The use of residual herbicides in preemergence followed by glyphosate in-crop postemergence provides consistent weed control and reducing early season weed competition. Furthermore, these programs utilize at least two herbicide modes of action for herbicide use diversity, which will be needed to stay ahead of resistance build-up, regardless of when weeds may appear.