Objetivou-se neste trabalho realizar o levantamento fitossociológico de plantas daninhas em áreas de reforma de cana crua, mantidas em pousio após a utilização de três sistemas de manejo do solo em duas regiões do Estado de São Paulo. O trabalho foi conduzido no ano agrícola 2007/2008, em áreas de produção comercial nos municípios de Novais-SP e Guairá-SP. A última colheita da cana foi realizada na primeira quinzena do mês de julho de 2007. Utilizou-se delineamento experimental blocos casualizados, cujos tratamentos consistiram dos três sistemas de manejo de solo: convencional, cultivo mínimo e plantio direto. Após os tratamentos de preparo de solo as parcelas foram mantidas em pousio por período de 150 dias. Realizou-se a amostragem em cada parcela procedendo-se a identificação, contagem e coleta toda a parte aérea das plantas daninhas presentes. Os dados foram interpretados estatisticamente por meio de análise de variância e teste de Tukey, em seguida calculados os índices fitossociológicos. O sistema plantio direto proporcionou menor massa seca e menor número de plantas daninhas que os demais sistemas de manejo de solo nas duas regiões de cultivo. A região de Guaíra apresentou maior infestação de plantas daninhas que a região de Novais, onde a espécie que mais se destacou, apresentando elevado IVR, em todos os tipos de manejo foi a Cyperus rotundus L. A importância desta espécie decresceu com a utilização de manejos mais conservacionistas. A similaridade entre plantio direto e convencional foi menor nas duas regiões.

Thrips (Enneothrips flavens) is a pest that causes severe damage and yield losses to peanut crop if not properly controlled. The main control method currently used by farmers is bi-weekly application of insecticides during crop development, which, in addition to its toxicity, is very costly. Thus, new sources of resistance must be identified in order to reduce the use of insecticides and effectively manage the pest. This study aimed to evaluate the occurrence and symptoms of E. flavens infestations in 12 accessions of 10 wild species of Arachis and nine amphidiploids, as well as to compare their morphoagronomic characteristics to those of commercial cultivars. To this end, we conducted experiments during two summer seasons, using a randomized block design with four replications. We conducted evaluations of the severity of infestation, noting visual symptoms of E. flavens and morphological and reproductive characteristics of the Arachis plants. Results indicated that wild accessions V 7635 (A. vallsii), V 13250 (A. kempff-mercadoi), K 9484 (A. batizocoi), Wi 1118 (A. williamsii), V 14167 (A. duranensis) and V 13751 (A. magna) are the most promising for obtaining useful new amphidiploids. Among the amphidiploids, An 12 (A. batizocoi x A. kempff-mercadoi)4x, An 9 (A. gregoryi x A. stenosperma) 4x, and An 8 (A. magna x A. cardenasii)4x showed high level of resistance to E. flavens. The identified thrips resistant wild and amphidiploid Arachis species may be used in future breeding program to produce thrips resistant peanut cultivars.

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Several genetically modified maize events expressing insecticidal proteins from Bacillus thuringiensis (Bt) have been commercially available in Brazil, intended to control of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae). The objective of this study was to evaluate the efficiency of transgenic (Bt) and conventional (non-Bt) hybrids in the control of fall armyworm, treated or not with insecticides throughout three late growing seasons. To this end, trials were conducted at three locations in the state of São Paulo, in a randomized complete block design, in factorial arrangements with 5x4, 5x4 and 8x4 factors, respectively. The first factor consisted of the number of commercial hybrids of different companies. The second factor was represented by the different control managements of insect (non-Bt hybrid with and without insecticide; Bt hybrid with and without insecticide). The damage caused by fall armyworm was evaluated on a visual 1-9 scale, from score 0 (no damage) to 9 (totally destroyed whorl), and grain yield (kg ha -1 ). The data were analyzed by analysis of variance and the means compared by the Tukey test at 5% probability for each parameter evaluated at each location. For the Bt hybrids, the damage scores attributed to fall armyworm were lower and the proteins Cry 1F, Cry 1A105 and VIP3Aa20 were the most efficient in reducing leaf damage. Insecticide applications proved efficient in reducing leaf damage caused by the pest. Application of insecticides to Bt hybrids generally reduced leaf damage, especially for Cry1Ab-producing hybrids, which were the least effective in reducing pest damage without insecticides.Index terms: Zea mays; Spodoptera frugiperda; pest management. RESUMODiversas tecnologias de milho geneticamente modificado (Bt) foram liberadas comercialmente desde 2007 visando principalmente o controle da lagarta-do-cartucho, Spodoptera frugiperda (Lepidoptera: Noctuidae). O objetivo deste trabalho foi avaliar a eficiência de híbridos transgênicos (Bt) e convencionais (não Bt) no controle lagarta-do-cartucho, submetidas ou não a inseticidas. Para isso, foram conduzidos ensaios em três localidades do estado de São Paulo nas safrinhas de 2009, 2010 e 2011, com delineamento experimental de blocos casualizados, em esquema fatorial 5x4, 5x4 e 8x4, respectivamente. O primeiro fator correspondeu ao número de híbridos comerciais de diferentes empresas. O segundo fator foi constituído pela utilização de diferentes manejos de controle do inseto. Para a avaliação dos danos ocasionados pela lagarta-do-cartucho, foram realizadas amostragens ao acaso de 20 plantas por parcela, aplicando-se uma escala de notas visuais, atribuindo notas que variam de 0 (sem dano) a 9 (cartucho totalmente destruído) e obtido a produtividade de grãos. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade, para cada parâmetro avaliado em cada localidade. Os híbridos transgênicos proporcionaram redução nas notas de danos atribuídas a lagarta-do-cartu...

ABSTRACT. Peanut is an oilseed crop of great importance for Brazilian agribusiness. A major factor affecting its production is pest incidence, mainly thrips. This study aimed to evaluate the potential for resistance to Enneothrips flavens in genotypes derived from the cross between IAC 503 and the amphidiploid (A. magna x A. cardenasii) 4x and to estimate the genetic and phenotype parameters in these genotypes, allowing for better targeting in the selection. The experiments were conducted in a Federer augmented block design with additional checks in two generations (F 3 and F 4 ) . Resistance to thrips was evaluated by its natural infestation and the symptoms of attacks by the insect. They were also evaluated using agronomic trait indicators of interspecific segregating with cultivated species. The results indicated that the selected progeny exhibited high resistance to thrips compared to commercial genotypes, and they had the amphidiploid as the insect resistance source. Some progenies selected as resistant also had good production traits, but with the degree of suitability to the A. hypogaea L. genotypes still low, the use of a backcross as an alternative for the introgression of resistance genes and the consequent recovery of adapted genotypes of superior recurring parents is suggested.Keywords: Arachis hypogaea L., thrips, resistance to insects, REML/BLUP. , assim como estimar os parâmetros genéticos e fenotípicos em tais genótipos, como auxiliares no processo de seleção. Os experimentos foram conduzidos no esquema de blocos aumentados com testemunhas intercalares em duas gerações (F 3 e F 4 ). A resistência ao tripes foi avaliada pela sua infestação natural e pelos sintomas de injúrias causadas pelo inseto. Foram avaliados também, caracteres agronômicos como indicadores da proximidade dos genótipos segregantes ao cultivado. Com base nos resultados, observou-se que as progênies selecionadas apresentaram maior resistência ao tripes quando comparadas aos genótipos cultivados, tendo o anfidiploide como fonte de resistência ao inseto. Algumas progênies selecionadas como resistentes, também apresentaram bons componentes de produção, porém, com grau de adequação aos genótipos A. hypogaea L. ainda pequeno, o que sugere o uso de retrocruzamentos como alternativa na introgressão de genes de resistência e consequente recuperação dos genótipos adaptados dos genitores recorrentes. Resistência a Enneothrips flavens Palavras-chave:Arachis hypogaea L., tripes, resistência a insetos, REML/BLUP.

In peanut, pests are controlled by application of insecticides throughout the crop cycle, boosting production costs. This study compared the control of thrips (Enneotrhips flavens Moulton) in 10 peanut genotypes by biological and synthetic insecticides in the field in tropical area in Southeastern Brazil (21°13’29.9’’S 48°54’33.0’’W). The experiment was arranged in a randomized block, 10 x 3 factorial design with three replications. The first factor corresponded to 10 peanut genotypes and the second to different insecticides (synthetic, biological and control). The plants were evaluated 36, 44, 51, 59, 65, 72, and 79 days after sowing to determine the number of thrips individuals and the damage on leaflets caused by E. flavens. The plant height (cm), branch length (cm) and pod yield (kg ha-1) were also determined. The data were subjected to analysis of variance and averages compared by Tukey’s test. In prior evaluation carried out before the start of the applications of insecticides (25 DAS), natural infestation of thrips was observed in all genotypes. The genetic variability of lines L. 386 and L. 314 and cultivar IAC 113 was not significant, whereas yield difference was not observed among treatments of insecticides and control, showing tolerance to E. flavens. The synthetic insecticide Engeo PlenoTM showed of 39% higher efficiency (as average) for controlling thrips in peanut. The insecticides Beauveria bassiana (Bals.) (AUIN®) and Metarhizium anisopliae (Metch.) (GR-INN®) have potential to control E. flavens in peanut, but further studies are needed to better define the application date and products doses.

Plant height has a deep influence on the productivity of many crops, as it involves susceptibility to lodging, crop-weed competition, and the achievement of favorable harvest index. Nevertheless, modellers have practically ignored related ecophysiological processes, especially those modulated by management practices. The aim of this study was to analyze and model the processes involved with the effects of management on rice (Oryza sativa L.) elongation. Data were collected in two greenhouse experiments (2010-2011) where three factors (floodwater level, N fertilization, sowing density) were arranged in a split-plot design with three replicates. The model proposed demonstrated its suitability in reproducing both the dynamics involved with tissue elongation in the different phenological phases and the effects of submergence and N luxury consumption on elongation rates. Relative root mean square error (RRMSE) ranged between 4.23 and 12.41% for different treatments and years. The inclusion of algorithms for the impact of agronomic practices on plant height in cropping system models would increase their suitability for scenario analyses and for in silico ideotyping studies, owing to the great interest shown by geneticists in related traits. Moreover, this study-performed with students of a Cropping Systems MS course-demonstrated once more the power of modeling within educational activities. In this case, models were not the subject of the teaching but tools for analyzing processes and formalizing new knowledge