ABSTRACT The use of pre-emergent herbicides is important for the current agricultural production systems that present weeds resistant to herbicides. Considering the complexity of using these products, the objective of this work was to evaluate their selectivity and residual weed control in soybean crops and their effect on the weeds Amaranthus hybridus, Bidens pilosa, Digitaria insularis, Eleusine indica, and Euphorbia heterophylla. The herbicide selectivity experiments were conducted under field conditions in the 2017/18 and 2019/20 crop seasons and the herbicide efficacy experiments were conducted under greenhouse conditions. The herbicides s-metolachlor and flumioxazin can be applied on day of the soybean sowing without causing significant grain yield losses. Diclosulam and sulfentrazone are safe for soybean crops when applied at least 14 days before sowing. The herbicides used proved to be good options for weed management systems for soybean crops; flumioxazin and sulfentrazone were the herbicides that promoted the best control for all evaluated weed species and ensured a residual effect of at least 30 days.

ABSTRACT Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae) is an important cassava pest due to the great potential damage and the increasing population in recent years. However, few studies about bioecology and control of the cassava lace bug have been conducted and their results don't provide adequate control strategies. An alternative to maintain the population below economic injury levels is through the adoption of host plant resistance. To improve the understanding about the bioecology and find new sources of resistance in cassava, the biological parameters and demographics of V. manihotae on five cassava genotypes (Santa Helena, MEcu 72, Col 22, Clone 02 and Clone 03) under controlled conditions (25±2°C, 14L/10D) were evaluated. Duration and viability of the stages, the period egg-adult, sex ratio, the pre-oviposition period, fecundity and longevity of male and female was determined, and a fertility life table was prepared. Insects fed on MEcu 72 showed increased nymphal, egg-adult, and pre-oviposition periods and reduced female fecundity and longevity in comparison to the other genotypes. Demographic parameters (Ro, rm, T, DT) showed a significant impact on the growth potential of V. manihotae fed on MEcu 72 indicating that the populations would diminish over time. The combined effect of these parameters indicated that MEcu 72 has resistance on V. manihotae specimens hindering their development.

RESUMO O objetivo deste estudo foi de avaliar a influência da adubação nitrogenada, do ambiente e cultivares no teor de proteínas, o volume de sedimentação com dodecil sulfato de sódio (SDSS) e no número de queda em trigo. O delineamento experimental foi em blocos ao acaso em esquema de parcelas subdivididas, em quatro repetições foram avaliadas cultivares de trigo IPR Catuara TM, BRS Gaivota, Quartzo e CD 120 em seis manejos do nitrogênio em quatro ambientes. Foram realizadas as avaliações do teor de proteínas, teste de sedimentação com dodecil sulfato de sódio, número de queda e produtividade de grãos. Foi realizada análise de variância conjunta para os quatro ambientes e as médias foram comparadas pelo teste de Tukey, p ≤ 0,05. O efeito do ambiente é superior ao efeito de nitrogênio e de cultivares sobre o teor de proteínas. O incremento no teor de proteínas reduz a produtividade de grãos das cultivares. O SDSS e o número de queda em trigo são influenciados pela interação entre cultivar e ambiente e também pelo manejo do nitrogênio. O teor de proteínas no grão tem baixa influência sobre o volume de sedimentação com dodecil sulfato de sódio, logo o manejo do nitrogênio em cobertura apresenta efeito menos acentuado para essa variável resposta. O número de queda não varia entre cultivares quando o ambiente é propício à germinação na espiga. A utilização de nitrogênio em cobertura influência o número de queda em trigo.

ABSTRACT The aim of this study was to evaluate the influence of nitrogen (N) fertilization, environment and cultivars on the protein concentration, sodium dodecyl sulfate sedimentation test (SDSS) volume and falling number in wheat. The experimental design was a randomized blocks in split plot scheme with four repetions. Four wheat genotypes were evaluated under six N managements in four enviroment (subplots). The wheat genotypes evaluated were IPR Catuara TM, BRS Gaivota, Quartzo and CD 120. Protein concentration, SDS sedimentation test, falling number and grain yield were evaluated. Combined analysis of variance for the four environment was performed and means were compared by Tukey test at p ≤ 0.05. The environmental effect is greater than the genotype and N effects on protein concentration. The increase in protein concentration reduces grain yield of the cultivars tested. SDSS and falling number in wheat are influenced by the interaction between cultivar and environment and also by the N management. The protein concentration of grain has low influence on SDS sedimentation volume, so the topdressing N management has less accentuated effect on this response variable. The falling number does not vary among cultivars when the environment is suitable to pre-harvest sprouting. The use of topdressing N influences the falling number in wheat.

ABSTRACT The application of an adequate rate and splitting of nitrogen is essential for wheat grain yield and protein content. The aim of this work was to adjust nitrogen management approaches regarding agronomic performance and protein content of wheat cultivars in various environments. Field experiments were conducted under no-tillage system on soybean mulch during the 2011 and 2012 growing seasons in Londrina and Pato Branco regions. The experimental design was a randomized block in split plot with four replicates. Four wheat cultivars (IPR Catuara TM, BRS Gaivota, Quartzo, CD 120) were tested with six nitrogen (N) management forms. Were evaluated: number of ears per unit area (NEA); plant height (PH); thousand-kernel weight (TKW); test weight (TW); grain yield (GY); and protein content (PC). The combined ANOVA (p ? 0.01) and Tukey’s test (p ? 0.01) were used. The interaction between cultivars and environments influence all yield components, GY and PC. The interaction management forms of N and environments affected the TKW, NEA, GY and PC. The results showed that in low-rainfall environments, nitrogen topdressing could be suppressed with no negative effects on GY or PC. Under ideal weather conditions, the GY of wheat cultivars was enhanced on application of 60 kg.ha–1 N of urea at the beginning of tillering as well 20 kg.ha–1 of N at booting. Matching the appropriate cultivars to the ideal growth environment is essential for achieving high GY values. The nitrogen forms on the topdressing do not influence the PC of cultivars in Pato Branco.

O fósforo (P) é um nutriente limitante na produtividade do feijoeiro e pode influenciar na composição química de sementes. O trabalho objetivou avaliar os efeitos da adubação fosfatada e de épocas de cultivo ('águas' e 'seca'), na composição química de sementes de duas cultivares de feijoeiro. O experimento foi realizado em Botucatu (SP), no delineamento de blocos ao acaso com cinco repetições. As cultivares de feijão 'Carioca Precoce' e 'IAC Carioca Tybatã' foram avaliadas no cultivo 'das águas' e 'da seca' sob seis doses de P2O5 (0; 30; 60; 90; 120 e 150kg ha-1) com aplicação de superfosfato triplo no sulco de semeadura. Amostras de sementes foram analisadas para determinação dos teores de N, P, K, Ca, Mg, S, Cu, Mn, Fe, Zn, açúcar total e redutor e proteína. A adubação fosfatada alterou a composição química das sementes, incremento nos teores de P e redução de Ca e Cu. Os teores de K e Fe apresentam ponto de mínima nas doses de 69,9 e 66kg ha-1 de P2O5, respectivamente. O cultivo na época 'da seca' favorece os teores de N, P e proteínas das sementes. A cultivar 'Carioca Precoce' apresenta maior teor de N e proteínas nas sementes em relação a 'IAC Carioca Tybatã'. Há interação cultivar e época de cultivo para o teor de S, Mn, Fe, Ca, Mg, Cu, açúcares totais e redutores.

Phosphorus is a limiting nutrient in common bean grain yield and may influence the chemical composition of seeds. The aim was to assess the effects of phosphorus fertilization and planting dates ('water' and 'dry') in the seeds chemical composition of two dry bean cultivars. A field experiment was carried out in Botucatu (SP) in a randomized block design with five replications. Two dry bean cultivars 'Carioca Precoce' e 'IAC Carioca Tybatã' were evaluated in growing 'water' and 'drought' in six levels of P2O5 (0, 30, 60, 90, 120 and 150kg ha-1) applying superphosphate at planting row. It was assessed seed samples to determine the levels of N, P, K, Ca, Mg, S, Cu, Mn, Fe, Zn, total and reducing sugar and protein. The phosphorus in the soil alters the seeds chemical composition, increasing contents of P and decreasing Ca and Cu contents. The K and Fe contents showed minimum point at a level of 69.9 and 66kg ha-1 of P2O5, respectively. It was observed that occurred increase in contents of N, P, and protein of seeds in the growing season 'drought'. The cultivar 'Carioca Precoce' showed higher N content and protein of seeds than 'IAC Carioca Tybatã'. There is interaction between cultivar and growing season for the content of S, Mn, Fe, Ca, Mg, Cu, total and reducing sugars.

Neste trabalho se objetivou avaliar a aplicação foliar de aminoácidos associada à aplicação de nitrogênio em cobertura, no desempenho produtivo e nas características agronômicas da cultura do milho, cultivado no período da safrinha. O delineamento foi o de blocos ao acaso, em esquema fatorial 4 x 4, com 4 repetições. Foram utilizadas quatro doses de nitrogênio em cobertura (0, 60, 120 e 180 kg ha-1) na forma de ureia e quatro doses de aminoácido (0, 8, 16, e 24 L ha-1) aplicadas via foliar. A cultivar de milho utilizado foi o Pioneer 305 31H. As variáveis analisadas foram teor de nitrogênio foliar, altura de plantas, altura de espiga, diâmetro do colmo, comprimento de espiga, número de fileiras de grãos por espiga, número de grãos por fileira, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O aminoácido não alterou as variáveis analisadas. O nitrogênio incrementou linearmente as variáveis altura de plantas, altura de inserção de espiga, número de grãos por espiga e número de grãos por fileira. O comprimento de espiga, a massa de mil grãos e a produtividade de grãos obtiveram, respectivamente, máxima resposta ao nitrogênio nas doses de 135,3, 157 e 149,5 kg ha-1.

The objective of this study was to evaluate the foliar application of amino acids associated with the application of nitrogen as topdressing on yield performance and agronomic characteristics of corn, cultivated during the latter season. The experimental design was a randomized block design in a 4 x 4 factorial, with 4 repetitions. Four doses of nitrogen (0, 60, 120 and 180 kg ha-1) as urea were used and four doses of amino acids (0, 8, 16, and 24 L ha-1) were applied on leaves. The maize cultivar used was Pioneer 305 31H. The variables analysed were: leaf N content, plant height, ear height, stem diameter, ear length, number of kernel rows per ear, number of kernels per row, number of grains per spike, weight of 100 grains and yield. The amino acids did not alter the analysed variables. Nitrogen increased linearly the variables plant height, height of insertion of ear, number of grains per ear and number of kernels per row. The length of spike, thousand grain weight and grain yield response to nitrogen obtained under maximum doses of 135.3, 157 and 149.5 kg ha-1, respectively.

El piojo harinoso de la yuca, Phenacoccus manihoti (Hemiptera: Pseudococcidae), se alimenta por succión de la savia de las plantas de yuca, causando daño directo por la succión de la savia y la toxicidad de la saliva e indirectamente, favoreciendo el desarrollo de fumagina. Para el establecimiento de un manejo integrado de plagas, es importante conocer la biología de este insecto. Por lo tanto, el objetivo de este estudio fue determinar las caracteristicas biológicas de Ph. manihoti en la yuca. El experimento se realizó con el cultivar Santa Helena. Las plantas se mantuvieron en un sitio semi-climatizado con una temperatura media de 25 °C. Se colocaron aproximadamente 20 huevos recién depositados en las cuatro hojas apicales. Después de la eclosión de los huevos, se dejó una sola ninfa del primer instar por hoja. Las cochinillas se evaluaron diariamente, registrando el tiempo de muda y la mortalidad de las ninfas y la fecundidad y la longevidad de las hembras adultas. A partir de los datos biológicos obtenidos, se realizó la tabla de vida de fertilidad. El estudio tuvo 90 repeticiones. La duración del huevo, ninfa del primer instar, segundo instar, tercer instar y longevidad de la hembra adulta fueron 7,7; 6,9; 4,9; 5,7 y 20,7 días, respectivamente. El ciclo de vida fue de 45,22 días, y la fecundidad fue de 247 huevos por hembra. La tasa reproductiva neta (Ro), tiempo generacional medio (T), tasa intrínseca de crecimiento (r m) y el tiempo de duplicación (D T) fueron 223,640 hembras/hembras, 36,500 días, 0,145 hembras/hembras/día y 4,780 días, respectivamente. La tasa máxima de aumento de la población fue en el día 36.

The cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) feeds by sucking the sap of cassava plants, causing damage directly by sucking the sap and contaminating the plant with its toxic saliva and indirectly by favoring the development of sooty molds. To establish an integrated pest management program, information about the biology of pest species is basic. Thus, the objective of this study was to determine some biological characteristics of Ph. manihoti on cassava. The experiment was conducted using Santa Helena cultivar which was kept in a semi-heated room at an average temperature of 25 °C. Approximately 20 newly oviposited eggs were placed on four apical leaves of each plant. After the eggs had hatched, only one first-instar nymph was left per leaf. The mealybug nymphs were examined on a daily basis; information on molting time was recorded and data on mortality and oviposition were used to construct a fertility life table. The experiment was conducted with 90 replicates. The average duration of the egg, first-instar, second-instar, third-instar nymph and the adult stages were 7.7, 6.9, 4.9, 5.7 and 20.7 days, respectively. On average, the total life cycle lasted 45.22 days, and each female was able to produce a total of 247 eggs. The net increase rate (Ro), mean generation time (T), intrinsic rate of increase (r m) and doubling time (D T) were 223.640 female/female, 36.500 days, 0.145 female/female/day and 4.780 days, respectively. The maximum rate of population increase occurred on the 36th day.