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Made available in DSpace on 2020-12-12T02:18:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Yield losses due to Groundnut ringspot virus – GRSV (genus Orthotospovirus) infection have been observed across major peanut (Arachis hypogaea L.) growing areas in Brazil. However, effective management systems capable of minimizing GRSV damage are not yet available. The aim of the present study was to verify the effectiveness of the pyraclostrobin (a strobilurin fungicide reported as a potential activator of natural, large–spectrum plant defense mechanisms) in the management of GRSV in peanuts. Two independent field experiments were carried out in commercial peanut areas with a natural occurrence of GRSV. A completely randomized block design was used with a 5 × 2 factorial scheme, including four replicates, five peanut cultivars (‘Runner IAC 886’, ‘IAC OL4’, ‘IAC 503’, ‘IAC 505’, and ‘Granoleico’) and two treatments (with and without pyraclostrobin application). At 80 and 100 days after sowing, visual disease severity scores and the number of infected plants were evaluated, followed by virus quantification in the leaf tissues and yield. The cultivars ‘Granoleico’ and ‘IAC 503’ displayed the highest levels of GRSV susceptibility. Pyraclostrobin was found to be effective in reducing the number of GRSV–infected plants, as well as in attenuating disease severity. In addition, pyraclostrobin was able to promote significant yield increase. Even though the mechanism(s) of pyraclostrobin action against GRSV remain elusive, this fungicide can be regarded as a potential component for viral disease management programs in peanuts. Apta Polo Regional Centro Norte, Rodovia Washington Luis, Km 372, C. Postal 24, CEP 15830-000 Universidade de Brasília, UnB Embrapa Hortaliças Departamento de Produção Vegetal FCAV/Unesp Instituto Taquaritinguense de Ensino Superior–ITES Centro de Grãos e Fibras IAC Departamento de Produção Vegetal FCAV/Unesp

Entre os fatores ambientais, a deficiência hídrica tem efeito em diversos processos morfológicos e fisiológicos das plantas, podendo afetar o crescimento e o desenvolvimento das culturas, refletindo na produtividade. Diante disso, objetivou-se avaliar as características fisiológicas de genótipos de amendoim submetidos à deficiência hídrica. Realizou-se um experimento em blocos inteiramente casualizados, com os tratamentos dispostos em esquema fatorial 12 × 2, tendo como tratamentos 12 genótipos e duas condições hídricas, em cinco repetições. Para avaliar o efeito do estresse, aos 25 dias após a emergência (DAE), as plantas de amendoim permaneceram sob deficiência hídrica por quatro dias, enquanto as testemunhas foram mantidas a 70% da capacidade de campo. Aos 29 DAE, foram realizadas as avaliações de fotossíntese, transpiração, teor relativo de água, teor de cera epicuticular e massa seca das plantas. A taxa fotossintética foi menor para todos os genótipos sob deficiência hídrica, exceto para a linhagem 870, que demonstrou maior tolerância à seca. Para a transpiração, as cultivares Runner IAC 886, IAC OL3, IAC OL4 e as linhagens 573, 599, 870 não foram afetados pela deficiência hídrica. Entre os genótipos, há variação na quantidade de ceras epicuticulares sob condições hídricas. Com relação ao comportamento anatomofisiológico dos genótipos, concluiu-se que as linhagens 573 e 870 são altamente tolerantes à deficiência hídrica, as cultivares IAC OL3, IAC OL4, Runner IAC 886 e as linhagens 599 e 967 são moderadamente tolerantes e IAC 503, IAC 505 e IAC Tatu-ST e as linhagens 322 e 506 são mais sensíveis ao estresse hídrico durante a fase de florescimento.

Made available in DSpace on 2020-12-12T01:44:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 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. Laboratory of Entomology APTA North Center Department of Crop Production FCAV/Unesp Grain and Fiber Center Agronomic Institute of Campinas (IAC) Plant Protection Center Agronomic Institute of Campinas (IAC) Department of Crop Production FCAV/Unesp

Made available in DSpace on 2021-06-25T10:57:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Trinexapac-ethyl (TE) has recently been shown to have a stimulatory effect on the initial growth of Eucalyptus seedlings. However, the optimal dose and seedling age at which TE should be applied has not been assessed. The objective of our study was to evaluate the effects of sub-doses of TE on the initial growth of eight Eucalyptus clones. The experiment was conducted in an open area. The treatments were arranged in an 8 × 3 factorial scheme, meaning eight Eucalyptus clones and three doses of TE (0, 15 and 30 g a.i. ha-1) sprayed at 70 days after planting. Plant height, stem diameter, shoot and root dry mass, and leaf area were evaluated. Eucalyptus clones differed in their growth regardless TE application. TE did not negatively affect the growth of any clones but doses used in our study were not sufficient to give a significant positive effect on growth when applied at 70 days after planting. We suggest that older Eucalyptus seedlings need higher doses of TE to reveal potential stimulatory effects on growth of the plants. Sao Paulo State University UNESP FCAV Department of Biology Applied to Agriculture Sao Paulo State University UNESP FCAV Department of Biology Applied to Agriculture

Made available in DSpace on 2022-04-29T08:36:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Instituto Nacional de Tecnología Agropecuaria Narrowing row spacing was expected to improve peanut crop performance, but the responses varied depending upon the evaluated environment and the growth habit of the plant. To clarify apparent inconsistencies, two cultivars with contrasting growth habits were sown at 52 cm and 70 cm row spacings in field experiments carried out in four environments. Vegetative and reproductive traits were evaluated. The leaf area index was always higher in the 52 cm than in the 70 cm row spacing, independently of the growth habit. Similarly, the light attenuation coefficient (k) was higher under narrow than under wide rows, but the cultivar with procumbent growth habit had a larger k and increased slightly the intercepted radiation respect to the erect type. These responses of the procumbent cultivar were driven by its lateral arrangements towards neighboring rows and its longer cycle duration. Narrow rows contributed to intercept approximately 14% more radiation than wide rows. These responses determined an improved biomass production through increases in the crop growth rate during the pod set period, with subsequent increases of the radiation use efficiency of this phase. Narrow row spacing enhanced seed and pod yields independently of the growth habit, but the relative importance of each seed yield component varied between cultivars. Seed numbers were more relevant for the erect growth habit, concurrently with the marked increase in total flower numbers of this cultivar. Seed weight was more relevant for the procumbent growth habit. On one hand, the erect growth habit caused a larger relative variation in seed and pod yields across environments than the procumbent one, particularly at narrow row spacing. On the other hand, the erect growth habit showed the lowest yield under wide rows. The small differences in biomass production between growth habits but the large difference in harvest index (procumbent > erect) contributed to an enhanced and more stable seed yield of the procumbent type, particularly when grown under narrow rows and linked to the large seed size of the runner cultivar. Results suggest that farmers should consider reducing row spacing as a way to increase peanut yield in the region under analysis. Estación Experimental Agropecuaria Manfredi del Instituto Nacional de Tecnología Agropecuaria (INTA) Department of Crop Production FCAV/Unesp Facultad de Agronomía de la Universidad de Buenos Aires and Consejo Nacional de Investigaciones (CONICET) at INTA Pergamino Department of Crop Production FCAV/Unesp

Made available in DSpace on 2021-07-14T10:33:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-02. Added 1 bitstream(s) on 2021-07-14T11:32:55Z : No. of bitstreams: 1 S1808-16572019000100242.pdf: 346490 bytes, checksum: cccf378ab784e6bbd234d3b733c67497 (MD5) A presença de mosca-das-frutas é o maior obstáculo à produção de goiabas, sendo o monitoramento populacional de fundamental importância para seu manejo. O objetivo deste trabalho foi avaliar a eficácia de iscas atrativas para mosca-das-frutas em goiabeiras, produzidas em um sistema orgânico. Foram instaladas armadilhas McPhail contendo 400 mL de solução, em quatro repetições e distribuição em blocos randomizados, em seis tratamentos: isca Mosca® (5%); isca Samaritá Tradicional® (5%); levedura Torula®; Bio Anastrepha® (5%); Ceratrap® e suco de goiaba (50%), com 3 avaliações semanais. Os dados da captura foram submetidos à análise de variância e às médias comparadas (Tukey 5%). Os valores de Mosca por Armadilha por Dia (MAD) foram calculados. A correlação entre moscas e as variáveis meteorológicas foi avaliada e o custo mensal das iscas foi calculado. Foram coletados 37.917 indivíduos do gênero Anastrepha e 122 moscas da espécie Ceratitis capitata, sendo a Anastrepha spp. o principal gênero de mosca-das-frutas da região. O produto Ceratrap mostrou-se superior, seguido pelas iscas Torula, Isca Mosca e Bio Anastrepha; a Isca Samaritá e o suco de goiaba apresentaram os menores resultados de captura. O padrão de captura de fêmeas foi semelhante ao total. Verificou-se uma queda na uniformidade de atração de todos os tratamentos, sendo o Ceratrap o que apresentou maior constância após sete dias. As correlações entre os fatores meteorológicos e a flutuação populacional foram positivas e significativas apenas para a precipitação. Os tratamentos mais onerosos (Ceratrap e Torula) também foram os mais eficientes e seletivos, sendo o produto Ceratrap o que demandou menor mão de obra. Fruit flies are the biggest obstacle in guava cultivation, with the monitoring of population a fundamental aspect for their management. The objective of this study was to assess the effectiveness of attractive lures for fruit flies in guava trees, produced in an organic system. McPhail traps were installed with 400 mL of solution, in four repetitions, and distributed in randomized blocks in six treatments: Isca Mosca® (5%); Isca Samaritá Tradicional® (5%); Torula® yeast; Bio Anastrepha® (5%); Ceratrap® and guava juice (50%), with 3 weekly reviews. Data on capture were subjected to analysis of variance, and averages were compared (Tukey 5%). The values of fly trap per day (FTD) were computed. The correlation between flies and meteorological variables were evaluated, as well as the monthly cost of lures. A total of 37,917 individuals from the genus Anastrepha and 122 species of flies Ceratitis capitata were collected, being Anastrepha spp. the main genus of fruit fly in the region. The Ceratrap product proved to be superior, followed by Torula, Isca Mosca, and Bio Anastrepha; Isca Samaritá and guava juice presented the lowest results. The standard trapping of females was like the total. The uniformity of attraction presented a drop in all treatments, and Ceratrap was more constant after seven days. The correlations between meteorological factors and population variation were positive and significant only for precipitation. The most expensive treatments (Ceratrap and Torula) were also the most efficient and selective, and the Ceratrap product required less manpower. Agência Paulista de Tecnologia dos Agronegócios Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias

Among the factors that may influence the germination process of seeds, water deficiency is considered the most important. The present study aims to evaluate the physiological response of peanut genotypes to water deficiency. The experiment was conducted in a completely randomized design with four replications in a 12 x 7 factorial scheme with 12 peanut genotypes and seven polyethyleneglycol 6000 concentrations corresponding to osmotic potentials of 0.00; -0.10; -0.20; -0.40; -0.60; -0.80 and -1.00 MPa. The data were submitted to analysis of variance and Tukey’s test at a 5% probability level and, when significant, to analysis of variance adjusted to a quadratic polynomial curve. The germination percentage, seed vigor evaluated by the speed germination index, mean germination time, root length and root dry matter of some genotypes were affected by the osmotic potentials. Among the genotypes, there is a differential response related to the water deficiency level. In relation to the physiological response of the seeds, the lineages 506, 599, and 870 and the cultivar IAC Tatu-ST have a higher tolerance of water deficit. The peanut genotypes begin to suffer the effects of water deficiency at the osmotic potential of -0.4 MPa. Entre os fatores externos que podem influenciar o processo germinativo das sementes, a deficiência hídrica é considerada o mais importante. Dessa forma, o objetivo do presente trabalho foi avaliar a resposta fisiológica de sementes de genótipos de amendoim submetidos à deficiência hídrica. O experimento foi conduzido em esquema fatorial 12 x 7, tendo como tratamentos sementes de 12 genótipos de amendoim submetidos a sete concentrações de polietilenoglicol 6000, nos potenciais osmóticos correspondentes a 0,00; -0,10; -0,20; -0,40; -0,60; -0,80; -1,00 MPa. Constatou-se que os genótipos são afetados pelos potenciais osmóticos e, entre os genótipos, há resposta diferenciada em relação ao nível de deficiência hídrica. Em relação à resposta fisiológica das sementes, as linhagens 506, 599, 870 e a cultivar IAC Tatu-ST possuem maior tolerância à deficiência hídrica. Todos os genótipos de amendoim começam a sofrerem os efeitos da deficiência hídrica a partir do potencial osmótico de -0,4 MPa para a maior parte das características avaliadas.

A interferência de plantas daninhas em convivência com o amendoim afeta o crescimento e desenvolvimento das plantas, podendo causar perdas superiores a 80% na produtividade da cultura. Dentre as principais espécies daninhas problemáticas nas áreas de produção de amendoim, tem-se observado aumento significativo das plantas trepadeiras, principalmente, da mucuna e cordas-de-viola. Diante disso, objetivou-se com este trabalho avaliar o impacto da competição da mucuna-preta no desenvolvimento das plantas e na produtividade do amendoim. O experimento foi conduzido em campo no delineamento em blocos casualizados, com 5 repetições. Os tratamentos foram constituídos por seis densidades de mucuna-preta (0, 1, 2, 3, 4 e 5 plantas/m2) em competição com a cultivar de amendoim IAC OL3. Durante os estágios reprodutivos R1 a R7, foram realizadas avaliações da radiação fotossinteticamente ativa interceptada pelas plantas daninhas e pela cultura do amendoim. Ao final do período experimental (130 DAS), foi realizada a colheita manual do amendoim e da mucuna-preta. Em seguida, foi determinada a massa seca da parte aérea da mucuna-preta e do amendoim. Determinou-se, também, o número e massa das vagens e sementes do amendoim. Os dados obtidos foram submetidos a análise de variância pelo teste F e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Com base nos resultados obtidos, verificou-se que a massa vegetativa da mucuna-preta, independente da densidade de plantas, proporcionou sombreamento no amendoim, reduzindo, em média, 90% a interceptação da radiação fotossinteticamente ativa pela cultura, 70% a massa vegetativa do amendoim e 76% a produtividade de vagens e sementes do amendoim. Diante disso, conclui-se que a mucuna-preta é uma planta bastante agressiva em competição com a cultura do amendoim e causa sérios prejuízos na densidade de uma ou mais plantas /m2.

A identificação das espécies de plantas daninhas que infestam as áreas agrícolas é importante para a tomada de decisão durante a escolha do método de controle. Diante disto, o objetivo do trabalho foi identificar e quantificar as principais espécies de plantas daninhas presentes em área de produção de amendoim no município de Jaboticabal – SP. O delineamento experimental foi em blocos casualizados. As avaliações foram realizadas aos 15, 30, 45, 75, 90, 105 e 130 dias após a semeadura, utilizando-se o método do quadrado vazado. Em cada avaliação foram realizadas 2 amostragens/parcela, totalizando 8 amostragens por tratamento. As plantas coletadas foram seccionadas rente ao solo, identificadas, acondicionadas em estufa de circulação de ar a 70ºC e, após 96 horas, foi determinada a massa seca das plantas. Com base nas informações obtidas nas amostragens, foram estimados os parâmetros fitossociológicos, frequência, frequência relativa, densidade, densidade relativa, abundância, abundância relativa, dominância, dominância relativa e determinou-se o índice de valor de importância. Verificou-se que a comunidade infestante na cultura do amendoim apresentou 17 espécies, em 17 gêneros e 9 famílias. O maior número de plantas daninhas foi encontrado na família Poaceae. Concluiu-se que nesta área, as espécies que predominaram foram Alternanthera tenella Colla, Digitaria sp. e Amaranthus sp.

O amendoim é comumente semeado em áreas de renovação de canaviais, por isso, a cultura passou a herdar as mesmas plantas daninhas infestantes da cana-de-açúcar, dentre elas, a Ricinus communis, popularmente conhecida como mamona. Em virtude da carência de informações sobre o impacto dessa espécie, objetivou-se avaliar densidades de mamona em competição com a cultivar de amendoim ‘IAC OL3’, visando determinar a interferência dessa planta daninha na interceptação da radiação fotossintéticamente ativa, e consequentemente, no desenvolvimento das plantas e produtividade da cultura. O experimento foi conduzido em delineamento em blocos casualizados, com 5 repetições. Foram realizados seis tratamentos, que consistiram das densidades de mamona (0, 1, 2, 3, 4 e 5 plantas/m2) em competição com a cultivar de amendoim ‘IAC OL3’. Durante os estágios reprodutivos (R1-R8), foram realizadas avaliações de interceptação da radiação fotossinteticamente ativa. Aos 130 dias após a semeadura (final do experimento), foi determinada a massa seca das plantas daninhas e do amendoim, e realizou-se a colheita das vagens e sementes, extrapolando os dados para kg/ha. Em seguida, os dados obtidos foram submetidos a análise de variância pelo teste F, e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade. Com bases nos resultados obtidos, verificou-se que a mamona na densidade de uma ou mais plantas/m2 reduz, em média, 35% da interceptação da radiação fotossinteticamente ativa, 20% da massa vegetativa e pode causar perdas superiores a 60% da produtividade de vagens e sementes do amendoim.

Made available in DSpace on 2020-12-12T01:10:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 An increased incidence and severity of Orthotospovirus species has been observed in the peanut crop. The typical symptoms of the virus, usually known as ringspot in peanut and spotted wilt in other crops, include mosaic, chlorotic ring-shaped spots, necrosis, and plant stunting. This study aimed to verify the occurrence of this virus in peanut growing areas in the São Paulo State, Brazil, identify the predominant virus species, and determine losses resulting from the presence of this virus. Surveys were carried out in four peanut commercial areas sown in the municipalities of Santa Adélia and Cândido Rodrigues in the 2014/2015 season using the cultivar Granoleico. The following parameters were evaluated: plant stand, number of plants with symptoms, and severity of these symptoms through a scoring scale of visual symptoms. The results showed that the predominant virus species is Groundnut ringspot tospovirus (GRSV). Also, the lower the stand is, the higher the percentage of plants with virus symptoms. The mean incidence of GRSV in commercial peanut areas is 40%, with mean losses estimated at 38% when GRSV is present and 64% when there is the presence of virus and reduction in plant density. Agência Paulista de Tecnologia dos Agronegócios APTA Polo Regional Centro Norte Universidade Estadual Paulista UNESP APTA Polo Regional Centro Norte Instituto Agronômico de Campinas IAC Universidade de Brasília UNB UNB Universidade Estadual Paulista UNESP

Herbicide resistant is associated with morphological, physiological and metabolic alterations in weeds. These alterations may reflect changes in the nutritional status of resistant plants and their growth it can be inferred in greater adaptability and competitive ability of the resistant biotypes. Thus, the objective of this research was to determine the dry matter and macronutrient accumulation and distribution by glyphosate-resistant and susceptible plants of Digitaria insularis (sourgrass), growing under mineral nutrition standard conditions. The experimental design was completely randomized, with eleven treatments and four replicates. The treatments consisted of evaluation periods at 15, 30, 45, 60, 75, 90, 105, 120, 135, 150 and 165 days after emergence (DAE). The average time for maximum theoretical accumulation (PtMax) and for inflection points of dry mass and macronutrient were lower for susceptible (133 DAE; 99 DAE) than for resistant biotype (141 DAE; 105 DAE). However, considering the average time obtained by susceptible, dry mass (g) and macronutrients (mg) accumulation was always higher for resistant biotype. The decreasing sequence of nutrient accumulation was similar for both sourgrass biotypes: K, N, Ca, Mg, P and S.

The cotton leafworm is an important defoliating pest of cotton in Brazil, and occurs in all regions where the crop is cultivated. The purpose of this study was to evaluate the effect of larval densities of A. argillacea after different infestation periods on the yield components of four cotton cultivars. The experiment was carried out in Pindorama, SP, Brazil, in the 2008/2009 growing season. The cultivars IAC-25, DeltaOPAL, Fibermax 966 and Fibermax 993 were artificially infested with A. argillacea larvae at three times (30, 60 and 90 DAE) and four densities (0, 2, 4, and 6 larvae per plant). The average boll weight (g), fiber percentage (%), 100-seed weight (g) and yield (kg·ha-1) were evaluated. With increasing infestation density of A. argillacea, the cotton yield of the cultivars decreased. The presence of larvae significantly reduced the weight of 100 seeds of cultivar Fibermax 966. Initial infestations reduced the boll weight of IAC-25 and DeltaOPAL, while cultivars Fibermax 966 and Fibermax 993 were most affected by late infestations. Early infestation compromised fiber percentage of cultivar DeltaOPAL and late infestations were most harmful to cultivar Fibermax 966. Early A. argillacea infestation reduced the yield of DeltaOPAL, while infestations 60 DAE caused the most damage to IAC-25, and the other cultivars were not affected by the moment of infestation.

The objective of the present study was to determine the periods of interference of velvet bean on ratoons of sugarcane cultivar 'RB855536' and to identify its potential for decreasing the crop yield and the quality of the harvested product. The experiment was arranged in a randomized block design, with 18 treatments divided into two groups and four replicates per treatment. In the first group, the sugarcane was kept free from velvet bean interference for nine different periods, beginning at bud sprouting: 0-15, 0-30, 0-45, 0-60, 0-90, 0-120, 0-150, and 0-180 days after budding (DAB) and 0-harvest. In the second group, sugarcane was grown in coexistence with velvet bean during the same periods described for the first group. The critical period of interference prevention for velvet bean in ratoons of sugarcane cv. 'RB 855536' lasted 138 days, from 50 DAB (pre-interference period [PIP]) to188 DAB (total period of weed interference prevention [TPIP]). Velvet bean interference caused a 50% decrease in sugarcane yield and negatively affected the quality of the harvested product. RESUMO: Objetivou-se determinar os períodos de interferência da mucuna-preta na soqueira cana-de-açúcar, cultivar 'RB855536', e o potencial de redução na produtividade da cultura e na qualidade do produto colhido. Foi utilizado o delineamento experimental em blocos casualizados, com quatro repetições por tratamento, aplicando-se 18 tratamentos divididos em dois grupos. No primeiro, a cultura permaneceu livre da interferência da mucuna-preta desde a brotação até nove épocas do seu ciclo de vida: 0-15, 0-30, 0-45, 0-60, 0-90, 0-120, 0-150, 0-180 dias após a brotação (DAB), 0-colheita. No segundo grupo, a cultura permaneceu em convivência com a mucuna-preta desde a brotação até os mesmos períodos descritos anteriormente. O período crítico de prevenção à interferência da mucuna-preta na soqueira da cultura da cana-de-açúcar ´RB 855536´ abrangeu 138 dias do ciclo da cultura, de 50 DAB (PAI) a 188 DAB (PTPI). E a redução da produtividade da cana-de-açúcar em decorrência da interferência da mucuna-preta foi de 50%, afetando negativamente a qualidade do produto colhido.

Weed interference is one of the main factors responsible for reducing the productivity of the peanut crop. Among weed control methods, the chemical is considered one of the main tools, however, the herbicides registered for this crop are scarce. The objective of this study was to evaluate the selectivity of herbicides applied in post-emergence in Runner peanut cultivars. For this, an experiment was performed in an 11x5 factorial scheme, meaning 10 herbicides plus one control (without herbicide) and five peanut cultivars, with four replicates. Visual evaluations of phytointoxication were carried out at 7, 14 and 21 days after application of the herbicides. At the end of the experiment, was determined the dry mass of aboveground and root parts. Based on the results obtained, it is concluded that the herbicides 2,4-D (1.50 L ha-1), mesotrione (0.3 L ha-1), saflufenacil (0.75 L ha-1), imazapic (175 g ha-1) and S-metolachlor (1.75 L ha-1) have potential to be used for all the peanut cultivars studied. Herbicides hexazinone (2.50 kg ha-1), amicarbazone (2.00 kg ha-1), tebuthiuron (2.00 L ha-1), clomazone (2.00 L ha-1) and sulfentrazone (1.20 L ha-1) must not be indicated, at these doses, for post-emergence spraying in the evaluated cultivars. The genotypes do not react equally to certain products, therefore, there is a need for further studies the at field conditions to attest the responses obtained in the present study and verify that the yield potential is not affected.

The cotton leafworm, Alabama argillacea (Hubner, 1818) (Lepidoptera: Noctuidae) is a major defoliating pest that reduces yield and quality of the crop. The purpose of this study was to evaluate the effect of different levels of defoliation caused by different larval densities of A. argillacea on four cotton cultivars in three different plant ages. The experiment was conducted at an experimental station of the Agencia Paulista de Tecnologia dos Agronegocios (APTA), Polo Centro Norte, in Pindorama, SP, Brazil. The experiment was arranged in a factorial randomized block design with 4 replicates: four cultivars (DeltaOPAL, IAC-25, Fibermax 996 and Fibermax 993) x four larval densities (0, 2, 4, and 6 larvae per plant) x three infestation times (30, 60 and 90 days after plant emergence). Fortnightly evaluations carried out based on the production of squares, flowers, fruits and bolls per plant. It was found that the higher infestation level of A. argillacea , the lower was the production of buds per plant and consequently the production of fruits and bolls of the four varieties. Early infestation (30 and 60 DAE) reduced the production of reproductive structures per plant in cultivars more than late infestation (90 DAE).

Eucalyptus plants are sensitive to stress factors in the initial growth phase. The plant growth regulator trinexapac-ethyl can provide gains to eucalyptus plants, a phenomenon known as hormesis. Thus, the aim of this work was to evaluate the effect of trinexapac-ethyl on the initial growth of two Eucalyptus urograndis clones (Clone 1 = I-144 and Clone 2 = 1407). The experiment was performed during 90 days after planting (DAP) of eucalyptus, in 100 L pots, with a randomized complete block design. The treatments were arranged in a 2 × 3 factorial scheme, with two eucalyptus clones and three trinexapac-ethyl doses (0, 30 and 60 g i.a. ha-1), with four replications. Fortnightly, plants height and stem diameter were evaluated. At 90 DAP, the leaf area and plants dry matter (DM) were evaluated. Clone 1 obtained leaf area and total DM 53% and 58% larger than Clone 2, respectively. The higher dose of trinexapac-ethyl provided mean gains of 30% in stem DM and total DM in Clone 1. For Clone 2, both doses of the product caused mean gains of 70% in stem DM, leaf DM and total DM. In conclusion, trinexapac-ethyl has a positive effect on the initial growth of E. urograndis, Clones I-144 and 1407. Clone I-144 showed higher growth than Clone 1407, regardless trinexapac-ethyl application. However, the Clone 1407 obtained more expressive gains with the application of trinexapac-ethyl, compared to Clone I-144.

The objective of this study was to evaluate the selectivity of fluazifop-p-butyl and haloxyfop-R methyl ester on Eucalyptus urograndis (clone GG100), as well as the use of fluazifop-p-butyl for control of Panicum maximum and Urochloa brizantha. Two experiments were conducted in 15-liter capacity pots, in a completely randomized design with four replications. The first experiment consisted of seven treatments, in which fluazifop-p-butyl and haloxyfop-R methyl ester were sprayed at 15, 30 and 37 days after planting (DAP) and a control plot without application. In the second experiment, the treatments consisted of a factorial 4 × 2 (four application periods and two weed species), in which three seedlings of P. maximum or U. brizantha were transplanted per pot. In both experiments, at 90 DAP, plant height, stem diameter, leaf area and total dry matter of eucalyptus were evaluated. In the second experiment, besides the morphological parameters, the percentage of weed control was evaluated. The data was submitted to analysis of variance by F test, and the means compared by Tukey test at the level of 5% of probability. Both herbicides did not cause visual effects of phytointoxication in eucalyptus, but haloxyfop-R methyl ester was not selective to clone GG100 (E. urograndis). Fluazifop-p-butyl was selective to clone GG100, providing better control in the first application period (15 DAP) but only for P. maximum, which negatively affected the initial development of eucalyptus, while U. brizantha was not efficiently controlled with the usage of fluazifop-p-butyl.