The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ̳Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity), acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index). The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m - 1 ). Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.

The insect Dysmicoccus brevipes (Hemiptera: Pseudococcidae) has been reported as an important pest for several crops, especially coffee. The citrus essential oils can be obtained as by-products of the citrus-processing industry and have been tested as an alternative to control different insect groups. Therefore, the objective of this work was to determine the chemical composition and evaluate the toxicity of commercial sweet orange (Citrus sinensis), bitter orange (Citrus aurantium) and Sicilian lemon (Citrus limon) essential oils and pure monoterpene D-limonene on D. brevipes. The essential oils were analyzed by gas chromatography. Two bioassays were conducted; the first assessing the insect mortality in all oils and the second assessing the lethal concentrations (LC50 and LC95) of the most effective oils. The main components of the oils were D-limonene (83.33%) and Linalool (8.91%) (sweet orange); D-limonene (78.53%) and γ-terpinene (12.65%) (bitter orange); D-limonene (59.78%), beta-pinene (14.71%) and γ-terpinene (10.19%) (Sicilian lemon) and the compound D-limonene had 97% of purity. The highest mortalities were found with the use of the Sicilian lemon (98.68%) and sweet orange (94.11%)oils. The sweet orange oil presented lethal concentrations at 2.21% (LC50) and 3.55% (LC95), and the Sicilian lemon oil at 0.72% (LC50) and 2.91% (LC95). The main component of the sweet orange and Sicilian lemon essential oils was the D-limonene, and the Sicilian lemon oil was most effective oil to control D. brevipes.

The intensive cultivation of vegetables with frequent chemical fertilization may cause accumulation of nutrients in the soil. This, in turn, may reduce crop yields and damage the environment due to contamination of ground water and rivers. Thus, to increase the effects of P (0, 100, 200, 300 and 400 kg ha - 1 of P 2 O 5 ) and K (0, 60, 120, 180 and 240 kg ha - 1 of K 2 O) doses on the growth and productivity of radish cultivars (Sakata 19 and Sakata 25) in a soil with high levels of these nutrients, two experiments were conducted in randomized blocks with the factors cultivars and doses arranged in a 2 x 5 factorial design with three replications. Number of leaves per plant, leaf area, shoot and root dry mass, total and commercial productivity, percentage of cracked roots and P and K contents in the plant and in the soil were evaluated. The Sakata 19 cultivar performed better than the Sakata 25 in both experiments. The fertilization with P or K did not influence the growth and the productivity of both radish cultivars. Therefore, both cultivars of radish evaluated do not need to be fertilized with P and K when planted in a Latosol with high levels of these nutrients.

The incorporation of organic matter has been used to manage of diseases caused by soilborne pathogen, but there is a gap in the use of coffee residues on disease supressiveness. The objective of this study was to evaluate the effect of organic matter sources against cassava root rot caused by F. solani CFF109. Fertilization with coffee residue (CR), cattle manure (CM), earthworm excrements (EE) and goat manure (GM) resulted in suppression of cassava root rot. The treatments of CR and CM presented higher reduction in the cassava disease severity. There were changes in the soil microbial community structure by organic matter incorporation, mainly in total fungi and Gram-negative bacteria populations. The total organic carbon and magnesium are negatively associated with disease severity. The microbial quotient, alkaline and acid phosphatase activities were positively and the biomarker a-15:0 was negatively associated with disease severity. This study indicated that agro-industrial residues can be recycled for providing organic matter and nutrients with effect for management of plant diseases by suppressing soilborne pathogens. This is the first evidence that the industrial residue of coffee can be use in the management of cassava root rot, caused by F. solani.

The aim of the present study was to identify fungal pathogens associated with prickly pear rot and the main components of squamous rot on plantations in the semiarid region of the state of Paraíba, Brazil. Pathogens were identified morphologically. The determination of the main components of squamous rot intensity was based on the incidence and severity of the disease. Fifteen genera of fungi were associated with rot, including Scytalidium sp., which was found on all plantations. The analyses indicated that relative humidity and rainfall favored the intensity of rot more than temperature. At least three pathogens were found to be associated with a high incidence of rot in prickly pear species in the semiarid region of the state of Paraíba, Brazil, but Scytalidium sp. was the most widely distributed. Moreover, the disease caused by this fungus intensifies and progresses under conditions of high humidity at moderate temperatures.

Intensive corn farming quickly depletes soil organic matter in the nutrient-poor soils of the Brazilian semiarid region. Application of vermicompost, an excellent organic fertilizer, could help solve that problem. This study evaluated the effect of applying Eisenia fetida vermicompost in the seeding furrows, at 0, 2, 4, 6, 8, and 10 Mg.ha-1 application rates, on the green ear yield and grain yield of two corn cultivars. Treatments were replicated five times with split-plots (vermicompost application rates within plots) in a completely randomized block design. The number of mature ears, number of kernels per ear (cultivar BR 106), and 100-kernel weight (cultivar AG 1051) were not affected by vermicompost application rate. However, vermicompost application increased total number and weight of unhusked and husked marketable green ears as well as grain yield. Total number of green ears was higher in cultivar BR 106 than in cultivar AG 1051. Conversely, grain yield and total ear weight and marketable weight of unhusked and husked green ears was higher in cultivar AG 1051, but responses in the latter two traits were dose-dependent.

The use of biofloc technology (BFT) can improve fish production in regions with low water availability. Therefore, information on dynamics of water quality is essential for success in fish rearing. Thus, the objective of the present study was to evaluate the water quality for Nile tilapia farming in a system without water exchange, during the fingerling stage, using different sources of carbon and C:N ratios. A completely randomized experimental design was used in a 2x3 factorial arrangement, with two carbon (C) to nitrogen (N) ratios (10:1 and 20:1) and three carbon sources (sugar, molasses and cassava starch). The C:N ratio and carbon source affected the variables alkalinity, settleable solids (SS), turbidity and total suspended solids (TSS), showing significantly higher values at C:N ratio of 20:1 (P < 0.05). The best carbon source for microbial floc formation were the molasses and sugar, under C:N ratios of 10:1 and 20:1. The stability of the monitored water quality parameters occurred from 6 to 7 weeks of rearing. The growth performance of Nile tilapia in BFT system fertilized with different organic carbon sources was not significantly different (P < 0.05) between treatments. The use of molasses to fertilize BFT systems can reduce costs of production in regions where this product is available.

This study aimed to evaluate the performance, carcass yield and intestinal morphometry of 1- to 21-day-old broiler chickens fed a diet containing increasing levels of sunflower cake, supplemented with or without an enzyme complex (EC). We used 1200 Cobb 500 birds, which were distributed in a completely randomized design in a 2x5 factorial scheme and five levels of sunflower cake inclusion (0, 5, 10, 15, and 20%) in diets supplemented or not with EC. Each treatment consisted of 5 replicates. Animals were fed the experimental diets from 1 to 21 days of age and from 22 to 42 days all birds received the same feed based on corn and soybean meal. There was no interaction between the level of sunflower cake inclusion and presence of EC. From 1 to 21 days of age, the weight gain, final weight, and feed intake linearly decreased (P<0.05) with increasing sunflower cake inclusion level. At 42 days old, after animals consumed diets based on corn and soybean meal (from 22 to 42 days), the levels provided least 21 days did not influence the performance results. Animals receiving the EC in the first phase showed better results at the end of the experiment (P<0.05). Up to 21 days old, carcass yield decreased, and abdominal fat increased with the sunflower cake inclusion. The addition of EC in the diet improved the thigh, breast and carcass yield. Intestinal morphology after 21 days revealed that the three segments of the intestine had at least one type of change, such as a decrease in villus height and increase in crypt depth, with increased level of sunflower cake in the diet, affecting performance.

Our study was conducted in the experimental field of the Department of Technology and Social Sciences (DTCS) of the State University of Bahia - UNEB, Juazeiro - BA. The experimental design was comprised of randomized blocks, sub - subdivided in plots, with four replicates comprising the plots of three different shading methods, gray shading screen (GS), red shading screen (RS), and blue shading screen (BS), and the control treatment with no shading. The subplots comprised three mini - tomato cultivars (“Sweet Million”, “Red Sugar”, and “Shani”), and sub - subplots consisted of seven sampling times. The traits evaluated were: dry matter accumulation in leaves, stems, roots, and fruits, total dry matter, shoot length, root length, total number of fruits, and overall yield. The results of the growth analysis showed that dry matter accumulation in organs of mini tomatoes was similar in all treatments and that the highest total dry matter accumulation occurred under RS. In all treatments, fruit was the preferential drainage; however, the cultivar “Red Sugar” showed higher dry matter accumulation in other plant organs. “Red Sugar” also showed the highest number of fruits per plant; however, when we evaluated total productivity, “Sweet Million” and “Shani” showed similar, higher values than “Red Sugar”.

Changes in row spacing may result in changes in crop and weed behavior and crop-weed competition. A study was performed to determine the periods of weed presence and weed control in cotton sown with 0.76 m spacing between planting rows. Cotton cultivar FM 993 was sown on 01/08/2010 with the aim of reaching a density of 190,000 seeds ha-1. Treatments with either weed presence or weed control during the first 0, 5, 10, 15, 22, 29, 36, 43, 50, 57, 64, 71, and 190 days of cultivation were established to determine the period prior to weed interference (PPI), total period of interference prevention (TPIP) and critical period of weed control (CPWC). The weed species with high relative importance were Amaranthus retroflexus, Bidens pilosa, Eleusine indica, Digitaria horizontalis, Alternanthera tenella, and Commelina benghalensis. Considering a maximum yield loss of 5%, the PPI was established 11 days after cotton emergence (DAE), the TPWC at 46 DAE, and the CPWC between 11 and 46 DAE, for a total duration of 35 days. Considering a maximum acceptable yield loss equal to the standard deviation for the weed-free treatment, the PPI was established at 6 DAE, the TPWC at 55 DAE, and the CPWC between 6 and 55 DAE for a total duration of 49 days.