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71.
R. S. C. Christiano M. Dalla Pria W. C. Jesus Junior L. Amorim A. Bergamin Filho 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(1):1-7
The combined effect of temperature (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 42°C) and leaf wetness duration (0, 4, 8 12, 16,
20 and 24 h) on infection and development of Asiatic citrus canker (Xanthomonas citri subsp. citri) on Tahiti lime plant was examined in growth chambers. No disease developed at 42°C and zero hours of leaf wetness. Periods
of leaf wetness as short as 4 h were sufficient for citrus canker infection. However, a longer leaf duration wetness (24 h)
did not result in much increase in the incidence of citrus canker, but led to twice the number of lesions and four times the
disease severity. Temperature was the greatest factor influencing disease development. At optimum temperatures (25–35°C),
there was 100% disease incidence. Maximum disease development was observed at 30–35°C, with up to a 12-fold increase in lesion
density, a 10-fold increase in lesion size and a 60-fold increase in disease severity. 相似文献
72.
Flávia Q. de Oliveira Arlindo L. Boiça Junior Maria de Lourdes Z. Costa Patricia A. Sanches Julio M. M. Walder Jacinto de L. Batista 《Phytoparasitica》2014,42(4):475-483
This study aimed to verify the preference and infestation level of Anastrepha fraterculus (Diptera: Tephritidae) [South American fruit fly] in fruits of guava cultivars and to correlate them to variables such as peel coloration, soluble solids and pH of fruit cultivars. The following cultivars were used: Pedro Sato, Paluma, Cascão and Século XXI. The infestation was evaluated in cages, considering two scenarios: no-choice and multiple choice. In both tests, evaluations of the fruit attraction to insects were conducted for a period of 1′, 3′, 5′, 10′, 20′, 30′, 1 h, 2 h, 6 h, 12 h and 24 h. The visit of A. fraterculus on the assayed cultivars in relation to the time was studied by logistic regression. After 10 days, the number of larvae in each fruit was recorded. In the multiple choice test, the visit proportions were significantly higher in the fruits of cvs. Século XXI and Pedro Sato than in those of cvs. Paluma and Cascão. In the no-choice test, the visit proportions were significantly lower in the Paluma fruits. In both tests, the rate of fruit infestation by A. fraterculus did not differ among cvs. Pedro Sato, Paluma and Cascão, whereas the fruits of cv. Século XXI were more infested. The indexes of pH did not interfere with the infestation of A. fraterculus, whereas a high rate of soluble solids and low color angle appear to be crucial for discriminating the fruits of the most susceptible cultivars. Infestation rate of Século XXI fruits displayed significant correlations with: °Brix (r= 0.7078) and color angle (h) (r= –0.9499) of guava fruits under the multiple choice conditions. 相似文献
73.
Canopy height and N affect herbage accumulation and the relative contribution of leaf categories to photosynthesis of grazed brachiariagrass pastures 下载免费PDF全文
J. I. Yasuoka C. G. S. Pedreira V. J. da Silva M. P. Alonso L. S. da Silva F. J. Gomes 《Grass and Forage Science》2018,73(1):183-192
The effects of three canopy heights (10, 25 and 40 cm) and two N rates (50 and 250 kg ha?1 year?1) on herbage accumulation (HA), participation of leaf categories in the leaf area index (LAI) and photosynthesis of grazed “Mulato II” brachiariagrass (Brachiaria brizantha × B. decumbens × B. ruziziensis) were investigated during two summer growing seasons in Piracicaba, São Paulo, Brazil. The HA and LAI increased linearly from 8560 to 13600 kg DM ha?1 year?1 and 2.3 to 5.5 m2 m?2, respectively, as canopy height increased. Mulato II brachiariagrass maintained at 10 cm canopy height showed greater proportion of young leaves, but was less productive than taller canopies. Taller canopies had greater proportion of mature leaves in the LAI as well as greater photosynthesis. The greater N rate contributed to increased LAI, leaf and canopy photosynthesis rates and HA but did not affect the LAI composition. The total leaf area is more important to HA than the proportion of young leaves in the LAI, as taller canopies were more productive, suggesting that maintaining Mulato II brachiariagrass at 25 or 40 cm is advantageous for this grass. 相似文献
74.
Rilner Alves Flores Talles Victor Silva Virgínia Damin Renata de Castro Marques Carvalho Débora Regina Marques Pereira Jonas Pereira de Souza Junior 《Communications in Soil Science and Plant Analysis》2018,49(6):725-734
Aspects related to micronutrients management are still poorly studied and need to be clarified to guarantee sustainable production. In this way, the study aimed to evaluate boron (B) fertilization effects on nutrition and production of common beans. The parameters measured were relative chlorophyll index, dry mass, boron transport, utilization and absorption efficiencies, B content, and B accumulation in plant tissues. The study showed that the dry mass production was negatively affected by B application, with linear dry mass decrease following the increase of B doses. Accordingly, it was found that the common bean cultivar Esplendor presented high absorption capacity of boron, and can reach 175 mg kg?1. However, the high absorption caused phytotoxicity and reduced dry matter production by up to 30%, reflecting the efficiency of boron use by the plant, which was reduced in up to 75%. 相似文献
75.
Leandro Paiola Albrecht Alfredo Junior Paiola Albrecht André Felipe Moreira Silva Fábio Henrique Krenchinski Henrique Fabrício Placido Ricardo Victoria Filho 《Journal of Crop Science and Biotechnology》2018,21(3):211-216
Susceptibility to chlorimuron varies according to soybean genotype. STS® (sulfonylurea-tolerant soybean) presents a high tolerance to some sulfonylureas; this feature is determined by semi-dominants alleles, Als1 and Als2. Experiments were conducted in the field for four seasons with two cultivars for season to evaluate the selectivity of chlorimuron rates in post-emergency (V4) of glyphosate-tolerant and sulfonylurea-tolerant soybean. Data analysis made it possible to infer that there was no significant effect on the productivity of the cultivars when they received application in post-emergency, of chlorimuron at the doses used (0, 15, 30, 45, 60, 75, and 90 g ai ha-1). The maximum recommended rate for non-STS cultivars of chlorimuron is 20 g ai ha-1, or 4.5 times less than the maximum rate employed in this study. The soybean cultivars CD 250 RR/STS, CD 236 RR/STS, CD 2630 RR/STS, and BMX Turbo RR/STS were tolerant to the application, in post-emergency (V4) of the herbicide chlorimuron, until the rate of 90 g ai ha-1. 相似文献
76.
V. F. Silva G. V. França J. W. S. Melo R. N. C. Guedes M. G. C. Gondim Junior 《Journal of pest science》2017,90(1):207-215
The control of hidden pest species with pesticides depends on the accurate timing of the application to reach the life stages during their only moment of vulnerability, which is when the pests (temporarily) leave their hiding places. A curious case involves the colonization of the coconut perianth, a bract-protected region of the fruit, by the coconut mite Aceria guerreronis. The coconut bracts apparently provide protection against the direct action of acaricides used against the coconut mite. Furthermore, some acaricides target mite eggs and/or immatures in addition to adults, leading to enhanced mortality and/or compromised progeny production, but only if reaching these stages. In this study, we developed methods for assessing the likely protection provided by the coconut bract against the acaricides used for managing the coconut mite. We also assessed the efficacy of the acaricides currently registered for use against this species. Our results support the notion that coconut bracts provide protection to the coconut mite against direct acaricide action. Some acaricides (abamectin and fenpyroximate) were effective only with the removal of the coconut bracts, whereas others (hexythiazox and spirodiclofen) were not effective even with bract removal. Coconut mites sheltered by bracts were protected against the acaricides over time, but the acaricides seemed to induce mite dispersion. In addition, the preventive application of some acaricides reduced the chances of the perianth colonization by the coconut mite. Among the acaricides used, two (hexythiazox and spirodiclofen) are registered as ovicides, but only one (spirodiclofen) acted on eggs, preventing hatching of approximately 40 % of the eggs. The acaricide impacts on coconut mite management are discussed. 相似文献
77.
Carine de Freitas Souza Cristine Rampelotto Bruno Bianchi Loureiro Fernanda Alves Pereira Adriane Erbice Bianchini Carine Dahl Corcini Antonio Sergio Varela Junior Tatiana Emanuelli Leila Picolli da Silva Sílvio Teixeira da Costa Kalyne Bertolin Monique Tomazele Rovani Paulo Bayard Dias Gonçalves Berta Maria Heinzmann Bernardo Baldisserotto 《Fish physiology and biochemistry》2018,44(4):1253-1264
In aquaculture, nutrition and supplemented diets have been shown to affect broodstock reproductive performance. In this study, we investigated the effects of dietary supplementation with Cymbopogon flexuosus essential oil (CFEO) microcapsules on reproductive-related parameters in silver catfish (Rhamdia quelen) male broodfish. Adult male broodstocks were separated into three groups according to the concentrations of supplemented CFEO (0.0?=?control; 1.0 or 3.0 mL per kg of diet). After 20 days under experimental conditions, the animals were euthanized and the gonads were harvested for gonadosomatic index, sperm analysis, oxidative stress, and histopathology; testosterone levels were measured in the plasma; gene expression of prl, smtl, pomca, and pomcb was assessed in the pituitary gland by real-time PCR. The results showed no alterations on reproductive parameters in R. quelen males treated with Cymbopogon flexuosus essential oil compared to the control-diet animals. In conclusion, CFEO microcapsules supplied for 20 days in the concentrations of 1.00 or 3.00 mL per kilogram of diet did not affect the reproduction criteria evaluated in this study in male silver catfish. 相似文献
78.
Mírian Peixoto Soares da Silva Marta Simone Mendonça Freitas Paulo Cesar Santos Almy Junior Cordeiro de Carvalho Tiago Silva Jorge 《Journal of plant nutrition》2019,42(5):417-427
This study aims to describe macronutrient and boron deficiencies in pepper grown in a hydroponic system in the presence of a substrate during the vegetative and fruiting phases. The experiments were carried out into a greenhouse, and consisted of a randomized block design with eight treatments: complete solution (control) and nitrogen (-N), phosphorus (-P), potassium (-K), calcium (-Ca), magnesium (-Mg), sulfur (-S) and boron (-B) deficient solutions, with four repetitions for each assay. Visual diagnoses of certain macronutrient and boron deficiencies can be applied by farmers to aid in soil management, since they are observed in leaves, while N, P, Ca, S and B deficiencies led to roots symptoms. Pepper fruits showed nutritional deficiency symptoms when grown under N, K, Ca, Mg, S and B deficits. The appearance of nutrient deficiency symptoms in pepper plants occurs in the following order: N, K, P, Mg, S, Ca and B. 相似文献
79.
Giovano Neumann Jurandir Joaquim Bernardes Junior Valdecir Neumann Robie Allan Bombardelli 《Reproduction in domestic animals》2021,56(6):829-836
We conducted a study to assess the accuracy of nearest neighbour (NN) and multiple hypothesis tracking (MHT) methods—which are opposite extremes in computational complexity—in determining the percentage of motile sperms and the number of sperms tracked in simulated data of fish sperm movements, and to evaluate the resulting number of tracking errors and analysis duration. Sperm tracking and swimming path assembly were assessed in 36 video clips (1 s length at 100 fps) of emulated Rhamdia quelen sperm kinetics at different densities (50, 100, 200 or 300 spermatozoa in the field of view) and motility rates (30, 60 or 90%). The MHT method accurately estimated the percentage of motile sperms, whereas NN underestimated it by up to 6.59%. Increase in sperm density reduced the number of sperms tracked from both trackers. With more than 50 sperms in the field of view, NN and MHT tracked 73% and 92% of the ground-truth sperm count, respectively. Both trackers showed a quadratic increase in tracking errors with increasing sperm density. The maximum percentage of errors at 90% motility was 12% for NN and 4.7% for MHT. The MHT tracker required up to 150 s to track 300 sperms, whereas NN completed the tracking procedure in less than 0.5 s. On maintaining a density of up to 100 sperms in the field of view, it was possible to obtain high accuracy, low number of tracking errors and an acceptable analysis duration with both tracking methods. 相似文献
80.
Isabela Ramsdorf Gomes Patinni Cristiane Alves de Andrade Cid Naudi Silva Campos Larissa Pereira Ribeiro Teodoro Sinomar Moreira Andrade Cassiano Garcia Roque Carlos Antônio da Silva Junior Paulo Eduardo Teodoro 《Journal of Agronomy and Crop Science》2020,206(6):806-814
Most of the Brazilian soils, especially in Cerrado biome, have high acidity and toxic aluminium, making the application of limestone an indispensable technique to obtain high yield in soybean crop. The hypothesis of this study was that contrasting base saturation provides changes in water-use efficiency (WUE) and agronomic traits of soybean populations. Thus, we evaluated the WUE and agronomic performance of F3 soybean populations under different base saturation levels. Each experiment was conducted in a randomized complete blocks design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10) for two crop seasons. Segregating populations were obtained by bulk method. In the first experiment, F3 populations were evaluated without correction of base saturation (V = 30%), while in the second experiment, limestone was applied three months before sowing to increase base saturation to 60%. The traits evaluated were as follows: calcium, magnesium and potassium contents, water-use efficiency (WUE), plant height, first pod height, main stem diameter and grain yield. Our findings indicate that WUE and agronomic performance of F3 soybean populations depends on the saturation condition. We identified the P4 and P9 populations as the most promising for use in breeding programmes aiming at higher tolerance to abiotic stress caused by low base saturation in soil. 相似文献