The withdrawal of the natural vegetation in order to implement an agriculturist system provokes disequilibrium in the soil. This study had as objective: evaluate changes in the chemical and physical characteristics of the ground and in the total organic carbon level of a ground that has experienced different systems of use: remainder of Atlantic Bush, cacao (Theobroma cacao), and pasture (Brachiaria decumbens). For each use, samples were collected, in the depths of 0 - 10 and 10 - 20 cm. The chemical and physical analyses had been proceeded, and the determination of the total organic carbon, nitrogen and match in the soil. The substitution of the natural vegetation for the cacao and pasture systems caused changes in the level of clay in the layer of 0 ¿ 10 cm and in the levels of clay and silte in the second layer 10 - 20 cm. To the chemical characteristics evaluated (0-10 cm), it was observed that the levels of Ca+2, Mg+2 and P were higher, and in the cacao system, while the pasture showed higher pH and levels of K+ and lower CTC. The attributes Al+3 and m decreased and V increased. 10-20cm the cacao and pasture systems showed changes just related to the level of Ca+2, and for the cacao system,higher P level. The TOC and chemical attributes in the second layer showed significant correlations just for the pasture area.

Among ten valid species within Rotylenchulus genus, R. reniformis is the economically most important. Polyfagous, the reniform nematode has been detected associated to high value crops in Brazil. However, variability among or within Rotylenchulus spp. populations has been poorly understood and studied. Identification of Rotylenchulus species is based on morphological characters of immature females and presence of males, but there is a lack of biochemical researches. The objectives of this study were to morphometrically characterize one R. reniformis population associated to commercial melon (Cucumis melo) crop grown in Baraúnas municipality, Rio Grande do Norte State; to compare L, V and s mean values to the other populations characterized as R. reniformis, from different Brazilian and North American states, and African countries; to identify the parasitic race and to develop a protocol to define the a-esterase phenotype. The results confirmed the specific population identification focused in this research which confidence interval mean values of L, V and s enclosed mean values from the other populations. The Baraúnas-RN population was characterized as race A. The used protocols did not allow to characterize an a-esterase phenotype for R. reniformis.

Studies on availability of suitable and economic diets for adults and larvae of the South American fruit fly Anastrepha fraterculus (Wiedemann, 1830) were carried out at the Entomology Unit of the FAO/IAEA Agriculture and Biotechnology Laboratories in Seibersdorf, Austria with the aim to find the best diets to fit in a large scale mass rearing production. The best diet for adult was the combination of Hydrolysate Corn Protein + Yeast Hydrolysate Enzymatic + Sugar (3:1:3). This diet resulted in the highest numbers of egg/female/day, spermatozoid in the spermathecae, percentages of egg hatch, the lowest mortality rate of adults and the highest average mating duration compared with the standard adult diet based on Yeast Hydrolysate Enzymatic + Sugar (1:3). Among eleven larval diets tested, diets based on sugarcane and sugarbeet bagases plus 7% brewer yeast, 8% sugar, 0.2% sodium benzoate, 0.8% of hydrochloric acid and 60% water (adjusted), yielded the highest percentages of egg hatching, pupal recovery, pupal weight and adult emergence. There was no statistical difference with the standard larval diet based on wheat germ 3%, corncob 15%, corn flower 8%, brewer yeast 6%, sugar 8%, sodium benzoate 0.23%, hydrochloric acid 0.63%, nipagin 0.14% and water 59% (adjusted). The significant performance of these adult and larval diets open discussion for future researches on improvement of rearing techniques required for the establishment of sterile insect technique (SIT) program focused on the South American fruit fly.

Aiming to evaluate crisp head lettuce cultivars adapted to summer, showing tip burn¿s tolerance caused by calcium deficiency, an experiment was conducted in Santana da Vargem, MG, comprising the Lucy Brown, PSR 1114, PSR 1115, PSR 0110, PSR 5338, PSR 1530, PSR 0398 and Raider cultivars. A randomized complete blocks design with three replications was used. Total and commercial fresh mass, stem length and tip burn¿s tolerance caused by calcium deficiency were evaluated. The total fresh mass ranged between 538.8 and 894.4 g.plant-1, being PSR 1114; PSR 1115; PSR 5338 and Lucy Brown superior to the others, with 822.2; 833.3; 850.0 and 894.4 g plant-1, respectively. For commercial fresh mass and stem length there were no significant differences among the evaluated cultivars. Regarding tip burn¿s tolerance significant differences were observed. The Lucy Brown cultivar showed the highest incidence of this physiological disorder.

This study had the objective of surveying the apicultural potential in the municipality of Petrolina flora (9o9'S; 40o22'W), aiming at identifying the nectariferous or polliniferous species visited by Apis mellifera. The observations were carried out from January 2004 to May 2005, in areas of hyperxerophilous Caatinga native vegetation and of irrigated fruit crops of Embrapa Tropical Semi-Arid. Fifty one species were observed, belonging to 42 genera and 25 botanic families. The families Leguminosae, Anacardiaceae, Convolvulaceae, Rubiaceae and Sterculiaceae were the most visited species by Apis mellifera, including 47.08% of the total visited plants. Among the species visited by Apis mellifera, 41.17% are herbaceous, showing the importance of this stratum as an apicultural source. Regarding the flora resource used as food source by the bees, it was found that A. mellifera made several visits for exclusive nectar extraction to 72.55% of the plants considered nectariferous. Among the remaining plants, it was found that in 19.60% the bee collecte pollen, being these species considered polliniferous, and in 7.85% there was pollen and nectar withdrawal. Among the herbaceous species, Borreria verticillata (L.) G.Mey., Diodia teres Walter (Rubiaceae), Waltheria rotundifolia Schrank (Sterculiaceae), Merremia aegyptia (L.) Hallier, Jacquemontia confusa Meisn. (Convolvulaceae), Hypenia salzmanni (Benth.) Hanley (Lamiaceae) distinguished as nectariferous source during the raining season, while the arboreal species Schinopsis brasiliensis Engl. and Myracrodruon urundeuva Allemão. are considered apicultural source for the dry season.

The objective of this study was to evaluate the effect of the synthetic compound Thiazolidines-2,4- dione on the ¿in vitro¿ development of Monosporascus cannonballus, the causal agent of the melon sudden wilt (vine decline) and Trichoderma sp., the biocontroller agent of the referred pathogen. The work was done through two experiments. In the first experiment the following concentrations of the composition were used: 0, 25, 50, 75, 100, 125, 150, 175 ìg.mL-1, combined with four isolates of M. cannonballus. The evaluated variables were mycelial growth inhibition (MGI), mycelial growth rate (MGR) and area below mycelial growth curve (ABMGC). In the second experiment the effect of the same concentrations of the synthetic compound were analyzed regarding a Trichoderma sp isolate. In the first experiment, there was a significant interaction between concentrations andisolates. High correlation coefficients confirmed the agreement of combination among the variables. The progress curves of the variables, according to compound concentrations, were adjusted by polynomial models. The most efficient concentration was 75 ìg.mL-1,, for inhibiting the mycelia growth until the experiment end, except for the Mc4 that showed TCM of 5.07. Regarding other isolates, Mc 3 was the least resistant, as with concentration of 50 g.mL- 1showed TCM of 2.36, while Mc1, Mc2 and Mc4 presented a higher growth rate, being 8.48; 8.08 and 8.97, respectively. The recommended dosage of the compound for the inhibition of M. cannonballus development when measured in vitro is 153 ug.mL .Neither concentrations influenced the mycelial development of Trichoderma sp.,as it didn¿t differ from control (P=0,05), demonstrating the potential of this synthetic compound as a complementary form of Monosporascus cannonballus control, together to the Trichoderma spp.

Water shortage and saline soils of the Brazilian semi-arid northeastern region are limiting factors to the development of many plants. Jurema preta (Mimosa tenuiflora (Willd.) Poiret) is a small, multiple use tree that abundantly colonizes unfavorable sites, including environments with severe water stress. This work had the objective of investigating the tolerance of jurema preta seeds to water and salt stresses during germination. Seeds germination in polyethylene glycol (PEG-6000) and sodium chloride (NaCl) solutions was analyzed under five different osmotic potentials (0.0; -0.3, -0.6, -0.9 and -1.2MPa), in order to simulate water and salt stress, respectively, in four 100-seed replications for each treatment. Seeds were placed into 10cmx10cmx4cm boxes, and germination accomplished in BOD germinator adjusted to 30oC. The number of germinated seeds was monitored every 24 hours, and percentage and speed of seed germination were generated from these data. Mean percentage germination in the control treatment was ~95%, reducing to 63-53% at -0.9 to -1.2-MPa PEG solutions, and to 27- 9.5% at NaCl solutions at equivalent osmotic potentials. Velocity of germination index was more affected, and decreased up to 1/8 of the control, at -0.6 MPa. Jurema preta seeds showed lower tolerance to NaCl than to water stress, and this species can be classified as a glycophyte.

Different substrates were tested, aiming to verify the ones that provided better development conditions for the mandacaru without thorns (Cereus hildemannianus K. Schum.). The work was carried out in the period from January to December 2005 in room temperature at Embrapa Semi-Árido, Petrolina, Pernambuco State, Brazil. A randomized blocks design, in a 5 X 3 factorial with five treatments and four replications, was used. The treatments consisted of five different substrate compositions and three plant types. Bud number, length, weight and dry matter of the flowers, besides weight, length and diameter of the roots were evaluated 360 days after planting. The substrates composed by sand, soil and cattle manure, presented the highest percentages of mandacaru buds growth.

A study was carried out to evaluate the influence of the elephant-grass x leucena intercropping, in aspects like productivity, crude protein contents and tillering of the intercropped elephant grass, besides trying to find the best planting density of this intercropping, aiming both highest grass productivity and better produced forage quality. The experiment was carried out at the Fazenda Experimental Vale do Curu, located in Pentecoste- Ceará, using a completely randomized blocks design with four treatments and four replications. The used treatments were: elephant-grass x leucena intercropping in the following spacings: 1.00m x 0.25 m; 1.00m x 0.50m; 1.00m x 0.75m and 1.00m x 1.00m, between the lines and plants, respectively. Cuts were done each 60 days, being six cuts during the experimental period. Leucena and capim-elephant were cutted 40cm and 10cm above ground 10 cm above the soil. The intercropping using leucena did not influence elephant-grass crude protein contents. The smallest tillers number and the biggest dry matter production of the grass occurred in spacing 1.00m x 0.25m, being this the indicated for this intercropping.

Oils of andiroba (Carapa guianensis Aubl.), copaiba (Copaifera sp.), Eucaliptus globulus Labill. and Eucaliptus citriodora Hook., neem (Azadirachta indica A. Juss), eugenol, souari nut (Caryocar brasiliense Camb.), rosemary (Lippia gracillis HBK.), and cedar (Cedrela fissilis Vell.) were evaluated in adults of Sitophilus zeamais Mots. (Coleoptera: Curculionidae). In the non-choice test, 20 g of corn grains per plot were treated with 50¿L of each oil and homogenized for two minutes. The plot was infested with eight 0 to 15 days-old S. zeamais adults. The E. globulus, eugenol, rosemary, and neem oils caused 100% mortality in S. zeamais adults. Except for copaiba, all oils caused mortality above 87% and the reduction in emergence of 100%. In the free-choice tests, arenas consisting of two plastic containers symmetrically interconnected to a central box by two plastic tubes were used. Twenty grams of non-treated corn (control) were placed in one of the boxes and the same amount of grain treated with 50¿L of each oil comprised the other treatment. Sixteen non-sexed S. zeamais adults (0-15 days old) were released in the central box. The rosemary, E. citriodora, eugenol and copaiba oils were the most repellent for S. zeamais adults, with repellence percentage varying from 97.3 to 87.7. Rosemary, andiroba, neem, and cedar reduced S. zeamais emergence in 100%, while the reduction caused by the other oils ranged from 72.7 to 97.9%.