This work aimed to evaluate the repellent and deterrent effect of the application of concentra- tions of neem and chinaberry oil on bean leaves on the leaf beetles Diabrotica speciosa (Germar) and Cero- toma arcuata (Olivier). The concentrations of neem oil tested were 0.625, 1.25, 2.50, 5.00, 10.00 and 20,00 mL, corresponding respectively to 1, 2, 4, 8, 17 and 33 ppm of azadirachtin A and the concentrations of china- berry oil used were the same used to neem oil, corresponding, however, to 1.875, 3.75, 7.50, 15.00, 30.00 and 60.00 mg mL-1 of chinaberry extract, respectively. For the free-choice tests, glass containers were used as are- nas, whereas for the no-choice tests Petri dishes were used, where in both one insect per treatment was released in the center. Attractiveness was evaluated in predetermined time periods, in addition to the leaf consumption, at the end of the experiment. Neem oil is repellent to D. speciosa and C. arcuata, with more efficient results at the 5.00, 10.00 and 20.00 mL concentrations. All concentrations of neem oil reduce leaf consumption of both insects, except in the no-choice test with D. speciosa, in which only the 10.00 and 20.00 mL concentrations are deterrent. Chinaberry oil provides high repellent activity on both leaf beetle species, and the 10.00 and 20.00 mL concentrations stood out. The 10.00 and 20.00 mL concentrations of chinaberry oil are deterrent to D. spe- ciosa and C. arcuata.

The management when done so improperly can cause changes in the physical, chemical and biological soil properties. The aim of this study was to evaluate the behavior of physical attributes in a dystrophic Oxisol under different vegetation covers and managements in the city of Chain southern state of Piauí. The experimental design was randomized using a split-plot with four types of cropping systems and four sampling depths, with three replications. Cropping systems were studied: Nim (Azadirachta indica), elephant grass (Pennisetum purpureum), Brachiaria decumbens and Native Forest sampling depths 0-0.10, 0.10-0.20, 0.20-0, 30 and 0.30-0.40 m. The effects of hedges and management on soil physical properties in different soil depths were recorded from the analysis of variance and treatment means compared by Tukey p <0.05. Determinations were carried out density, macroporosity, microporosity, total porosity, and resistance to penetration in all cropping systems. The elephant grass and native forest had the lowest values of penetration resistance and bulk density, higher values of total porosity and macroporosity, reflecting better physical condition of the soil. The area with Nim and Brachiaria was influenced by animal trampling, thus causing increase of soil density and hence the resistance to penetration.

The objective of this work was to study the effects of N and K2O doses applied through fertigation in soil fertility and nutritional status. The experiment was carried out during April, 2002 until March 2004, on Experimental Farm of the Empresa de Pesquisa Agropecuária of the State of Rio Grande do Norte (EMPARN), Brazil. The statistical design was in a completely randomized block with 4 replication, using for composition of treatments Plan Puebla III experimental matrix, treatments being composed of combination of two factors: nitrogen and potassium doses in the form of urea and potassium chloride, respectively. In all 10 treatments, defining the interval for N (256 to 4874 g plant-1 year-1) and K2O (258 to 4872 g plant-1 year-1) were applied through fertigation with microsprinkler irrigation system. The contents of nutrients in the soil presented great variation and tended to decrease with time. The doses of N decreased the pH and contents of Ca and Mg although increased the availability of P in soil and favored its absorption by plant. A negative gradient in concentration of nutrients under fertigation was observed from the soil surface. The K content in leaf 14 were increased with increase in doses of K2O via fertigation presenting high correlation with number of fruits. The application of K in soil increased the contents of Cl and Mg in leaf 14 and decreased the contents of Na, while the application of N in soil increased the contents of Mn in leaves.

The inadequacy of sewage systems and water shortages in semi-arid Northeast is encouraging the reuse of water in the production of agricultural crops. This study aimed to analyze the effect of treated do- mestic sewage in the initial development of three melon cultivars in Mossoró-RN. The experiment was mounted on a split-plot in randomized blocks with plots cultivars of melon (Yellow Tikal, Cantaloupe type Harper and Gália) and the split-plots the proportions of water supply and domestic sewage (T1 - 100% water supply T2 - 50% of water supply and 50% of domestic sewage, T3 - 25% of water supply and 75% of domestic sewage and T4 - 100% domestic sewage) in three replicates. In the experimental period were analyzed for physico-chemical and microbiological characteristics of sewage and water supply. At 20 days after sowing was measured plant height, stem length, root length and stem diameter. The results showed that the fertirrigation of melon cultivars with domestic sewage minimizes the effect of water scarcity in semiarid. The development of cultivar Gália seedlings was not affected by application of primary domestic sewage. The T2 and T4 were the most suitable for the production of cultivar Gália seedlings.

The use of Silicon on the plants cultivation is one the most used strategy in order to reduce the negative effects of soils salinity. The goal of this work is to evaluate the influence of Silicon on minimizing the negative impacts due to salinity of irrigation water in the Jatropha curcas plants growth. The experiment was carried out at the National Center of Cotton Research, in a completely randomized design and treatments ar- ranged in a factorial 4 x 4 x 6, performed by four levels of salinity of irrigation water (0,43; 2,5; 5,0; and 7,5 dS m - 1 ), four levels of Silicon (0; 221,76; 443,52; and 665,28 mg L - 1 ) and six evaluation periods (40, 55, 70, 85, 100 and 115 days from emergence) with three replications. The analysis of variance, the F test and the polyno- mial regression to 0.05% significance were used to evaluate the data. hight plant, diameter stem plant, number of plant leaves, leaves plant area, total dry matter, dry matter roots plants e dry mass stem plants, dry mass of shoots and roots of Jatropha curcas were not affected by salinity of water at 115 days after sowing. The leaves number and leaf area were influenced by Silicon.

The objective of this study was evaluate the morphological variability and existing production between peanut genotypes collected from small farmers in seven counties in Recôncavo of Bahia, in addition to selecting the most promising materials. Peanut seeds (60 genotypes) were collected along the ethnobotanical survey. Each genotype was collected from a zoned farmer in the study area. Experimental design was a randomized block with four replications. For morphological analysis of growth characteristics were evaluated: main stem height, number of leaves and number of branches also have assessed them components of plant production and productivity, which were evaluated: the volume of fresh and dried vegetable, fresh vegetable pasta and dried, the diameter and length of vegetables, total number of vegetables, total number of grains and the weight of 100 grains. The data were subjected to analysis of variance and means were compared by the Scott- Knott test at 5% probability. Although not shown variability the vegetative morphological characteristics, yield characteristics are indicative of the existence of variability, and why it has become possible to preselect seven peanut genotypes collected from farmers in the Recôncavo of Bahia, which may be considered important descriptors for the distinction of superior genotypes.

The effect of plant aqueous extracts in the control of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. the causal agent of guava anthracnose in, was evaluated in vitro with 1, 2 and 3% aqueous ex- tracts of Azadirachta indica, Nerium oleander, Ocimum gratissimum, Syzygium aromaticum. The experiment was installed in a complete randomized desing in a 3x4 factorial scheme (doses x extracts). For the evaluation, it was calculated the percentage of fungal inhibition. The experiment in vivo was conducted by applying Syzy- gium aromaticum and Azadirachta indica aqueous extract at 2 and 3%, respectively, in three different storage conditions: refrigerated with and without plastic film (PVC), and at ambient conditions. The experiment was installed in a completely randomized design, in a 2x3 factorial scheme (extracts x storage conditions). We evaluated the external appearance and severity of disease, loss of weight and Brix degrees. Syzygium aromati- cum extract at 2% provided 100% of fungal mycelial growth inhibition, and Azadirachta indica extract at the highest dosage (3%) inhibited 20.22%. In fruits, there was not significant statistical difference between the ef- fect of extracts on the external appearance and severity of disease, loss of weight and Brix degrees. In relation to the storage conditions, the ones with plastic film and refrigerated differed from the other conditions obtain- ing better external appearance and less severity of disease, lower loss of weight and higher Brix degrees.

Organic fertilizing promotes changes in the physical, chemical and biological attributes of soil making it more productive. The objective of this study was to evaluate the effect of different amounts of hairy woodrose (Merremia aegyptia L.) and their times of incorporation on the chemical attributes of an Alfissol Eutrophic cultivated with lettuce. The experiment was conducted from April to June 2006 at the Universidade Federal Rural do Semi-Árido (UFERSA) in Mossoró-RN. The experimental design was complete randomized blocks with treatments arranged in a 4 x 4 factorial with 3 replications. The first factor consisted of four amounts of hairy woodrose incorporated into the soil (2.2, 4.4, 6.6 and 8.8 t ha-1 dry matter) and the second factor was the four times of their incorporations (0, 10, 20 and 30 days before transplanting lettuce). The soil pH remained alkali, decreasing with the amounts of hairy woodrose incorporated into the soil and with the times of incorporation. The contents of N, Ca and Mg in the soil increased with increasing amounts of hairy woodrose and with the times of incorporation in soil. The levels of available P and K increased with increasing amounts of hairy woodrose incorporated into the soil. However, in relation to the incorporation times, they were optimized at 16 and 14 days, respectively, after the manure incorporation. The utilization of hairy woodrose as organic fertilizer, generally, indicated improvement in soil chemical attributes in relation to the original values evaluated before its incorporation.

The objective of this study was to evaluate the reaction of soybean (Glycine max) cultivars to brown spot (Septoria glycines) under different crop management methods. In this study the effects of the following crop management techniques were evaluated on five soybean cultivars (Msoy9001; Msoy8411; Conquista; Emgopa313; A7002): (a) fungicides and hormones, and; (b) time of planting (October, November and December). The experiment was set in Cristalina, GO, Brazil, in a randomized complete block design with eight replications in a factorial scheme (5 x 3 x 4). The chemical control of brown spot was tested as following: 1) Tetraconazol (T) (0.35 L ha-1) Thiophanate methyl + (TM) (0.4 L ha-1); 2) Stimulate ® [indolbutiric acid 0.005%, kinetin 0009% and giberelic acid (GA3 0.005%) (0.10 L ha-1)] + T (0.35 L / ha) + TM (0.4 L ha-1); 3) T (0.5 L ha-1), and; 4) control without any product. For each plot was evaluated the disease severity and incidence, and yield of seeds. Msoy8411 and Emgopa-313 planted in November presented the lowest amount of disease, and the highest seed yield. Considering the analysis of all cultivars, the chemical treatments that significantly reduced disease were Tetraconazol (0.5 L ha-1) and the chemical combination [Stimulate ® (0.10 L ha-1) + Tetraconazol (0.35 L ha-1) + Thiophanate methyl (0.4 L ha-1)].

Boron deficiency in sunflower cultivation can cause decreased production, mainly by the fall of the inflorescence diameter. Most soils, especially in the tropics present low content of boron (B) available. To ascertain the response of sunflower to boron application in different orders of tropical soils with different tex- tures, we carried out an experiment under controlled condition. Were applied to the soil samples collected in the layer 0-20 cm, four doses of B as boric acid (H3BO3) in solutions at concentrations of 0.0; 0.04; 0.08 and 0.16 mol m-3. The soils were: PAC - Argissolo Acinzentado; PVe - Argissolo Vermelho eutrófico; PVA - Argissolo Vermelho-Amarelo; RL - Neossolo Litólico; RY - Neossolo Flúvico; VX - Vertissolo Háplico. The experimental design used was a randomized blocks in factorial scheme 4 x 6 (doses x soils) with four replica- tions and one plant per pot. Quantification of B content was performed by extraction method with barium chlo- ride solution of 5.0 mol m-3 subjected to heating with microwave radiation and determining the B content in the soil was performed by colorimetric technique using the azomethine-H reagent. The contents at levels sufficient to allow the soil B established independent of the dose added, a yield exceeding 90% yield on. The highest dry matter yield of sunflower was associated with the B concentration in the soil between 0.04 and 0.08 mol m-3 and there was a decrease with higher concentrations.