Epiphytology and control of Phytophthora infestans the late blight fungus, on tomato plants

Para previsão de epifitias e controle de Phyrophthora infestans (Mont.) De Barry em culturas de tomate (Lycopersicon esculentum Mill.), foi analisada a regressão entre grau de infecção e fenômenos macroclimáticos importantes na região temperada sempre úmida de Colombo, PR. Foi detectada uma equação passível de ser introduzida no sistema de produção local e, também, com bom poder de previsão, tal seja: Y = - 0,8671 + 0,0209 X1X2 , onde em uma sequência de dez dias, Y representa grau de infecção, e X1X2, a soma do número de chuvas iguais ou superiores a 0,1 mm vezes o número de temperaturas noturnas iguais ou superiores a 10 °C. Verificou-se que o produto X1X2 igual a 40 indica a proximidade de uma epifitia. Consequentemente, concluiu-se que a aplicação de defensivos deve ocorrer sempre que X1X2 estiver alcançando o valor 40. Experimentos de campo comprovaram o controle de epifitias, com base na equação acima apresentada.To predict and control Phytophthora infestans in tomato (Lycopersicon esculentum Mill.), all analysis was made of the regression between the degree of infection and important macroclimatic phenomena of the humid temperate region of Colombo. PR. The following equation, with good forecasting potential, appropriate to the local production system, was discovered: Y = - 0,8671 + 0,0209 X1X2, where during a sequence of ten days, Y represents the degree of infection. and X1X2 the sum of the number of rains equal or greater than 0.1 mm time the number of night time temperatures equal to or greater than 10ºC. It was found that the sum of X1X2 equal to 40 indicates the approach of an epiphyte. It was therefore determined that the application of fungicides should be made whenever X1X2 reaches the value of 40. Field trials proved epiphyte control using the equation presented above

Partial budget analysis of prepartum antimicrobial therapy and Escherichia coli J5 vaccination of dairy heifers and their effect on milk production and milk quality parameters

Abstract: This study aimed to determine whether prepartum antimicrobial and/or Escherichia coli J5 vaccination in dairy heifers influence the milk production, milk quality, and estimate their economic benefit. Thus, 33 dairy heifers were enrolled in four groups using a split-splot design. Groups were: (G1) prepartum antimicrobial infusion and vaccination with an E. coli J5 bacterin, (G2) prepartum antimicrobial infusion, (G3) vaccination with an E. coli J5 bacterin, and (G4) control heifers. Composite milk samples for somatic cell count, total bacteria count and milk composition were collected 15 days after calving and every 15 days until the end of the experiment. Bacteriological analysis was carried out at the end of study. The milk production and the incidence of clinical cases of mastitis, as well as the costs associated with them were recorded. The results demonstrate a reduction on clinical mastitis rates by preventive strategies, which implicated in lower volume of discarded milk (0.99, 1.01, 1.04 and 3.98% for G1, G2, G3 and G4, respectively) and higher economic benefit. Thus, in well-managed dairy herds the prevention of heifer mastitis by vaccination or antimicrobial therapy can reduce the amount of antimicrobials needed to treat clinical mastitis cases and the days of discarded milk

Agronomic, morphogenic and structural characteristics of tropical forage grasses in northeast Brazil

The objective of this study was to assess the agronomic, morphogenic and structural characteristics of tropical forage grasses during the establishment phase and throughout the second year in northeast Brazil. The treatments included 9 grasses: Brachiaria humidicola (koronivia grass), Brachiaria hybrid cv. Mulato, Brachiaria brizantha cvv. Piatã, Xaraés and Marandu, Brachiaria ruziziensis (ruzi grass), Brachiaria decumbens (signal grass), Panicum hybrid cv. Massai and Andropogon gayanus (gamba grass). The grasses were planted in a randomized complete block design with 4 replications. The following parameters were measured: total forage production, leaf:stem ratio, tiller population density, number of dead tillers, leaf emergence rate, phyllochron, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of leaf blade and life-span of leaves. In the establishment year, cv. Mulato produced the highest forage yields, followed by cvv. Xaraés and Massai, with gamba grass and koronivia grass worst. In the second year, cvv. Mulato, Xaraés and Marandu, and gamba grass showed highest forage production, while cvv. Massai and Piatã produced the least. All grasses showed a marked drop in production during the dry season. Cultivar Massai consistently had the highest leaf:stem ratio. The morphogenic and structural characteristics differed according to cultivar and season of the year. In general, leaf emergence rate, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of the leaf blade, number of live leaves per tiller and density of living tillers were higher in the rainy season, while the phyllochron and life-span of leaves were higher in the dry season. The results of this research highlight the potential of the Brachiaria cultivars Mulato and Xaraés, gamba grass and Panicum cv. Massai in subhumid Maranhão, northeast Brazil.</p