Repositório RCAAP

The ocurrence of predator ladybeetles (Coleoptera, Coccinellidae) in an orange orchard, in Montenegro/RS, was verifi ed to follow a seasonal pattern. The monthly samples obtained between January to December of 2002, from 30 trees of an orchard treated ecologicaly, resulted in 14 species of identifi ed coccinelids. In a general way, the coccinelids were more frequent between July to September (Winter season), where 81% are from Coccidophilus citricola Brèthes, 1905. In spite of the large number of individuals that occur on winter, seven from fourteen species presented, individually, population peaks on Spring season.

Data about 310 animals (150 younger steers (YS) fi nished between 12 and 14 months; 70 young steers (Y) fi nished between 20 and 22 months; and 90 cull cows (CC) from three to ten years were analyzed. The data were charted and analyzed in a MS Excel 97 spreadsheet. ADG was 1.004, 0.931 and 0.967 kg/day for YS, Y and CC, respectively. FC was 7.26; 10.55 and 11.61 kg MS ingested/kg weight gain, respectively for YS, Y and CC. Profi t was 25.19, 21.70 e 27.96 % for 151.6, 73.6 and 64.7 days of feedlot for YS, Y and CC, respectively. YS showed higher average daily gain and better feed : gain ration than Y and CC. The fi nishing of the different animal categories in a feedlot regimen resulted in an satisfactory economic return.

Soybean rust, a new disease in Brazil caused by Phakopsora pachyrhizi, occurred in the 2002/2003 crop season in the main producing regions. In order to avoid significant yield losses and unnecessary sprays, it is necessary to determine the better moment to spray fungicide. This work compared different spray moments to control soybean rust, spraying pyraclostrobin + epoxiconazol (0,5 L/ha c.p.) in the following treatments: 1 - sprayed in R4 growth stage; 2 - 4 days after first aplication (DAF); 3 - 9 DAF; 4 -14 DAF; 5 -19 DAF; 6 - 23 DAF; 7 - control (water). The cultivar was Fepagro-RS 10, planted in January 10th of 2003, and set up in randomized blocks, with 4 repetitions. The first lesions of rust were visible 4 DAF, in the control treatment. The yield (kg/ha) and the weight of 100 seeds (g) were measured. The treatments in R4 and, 4, 9, 14, 19 and 23 DAF showed, respectively, 15, 17, 17, 8, 11 and 8% higher yield that control, and 12, 14, 7, 7, 5 and 1% higher weight of 100 seeds that control. The treatments in R4 and 4 DAF were more efficient with no statistical difference between them. Taking a decision-making practical conceming whether to spray the fungicide or not, the treatment 4 DAF would be more suitable because it was performed when the first symptoms appeared in the field.

Soybean crop systems have been traditionaly based on the application of herbicides, frequently above the recommended dosages. The use of herbicides may be detrimental to the process of biological nitrogen fixation in legumes, dueto direct effects on rhizobia or indirect effects on the host plant. Two experiments were performed in greenhouse, in pots with soil, intending to evaluate the effects of dosages of herbicides and their residual effects over strains of Bradyrhizobium and over soybean nodulation. In both experiments, soybean seeds were inoculated with the strains SEM IA 587 (Bradyrhizobium elkanii), SEM IA 5074 and SEMIA 5079 (Bradyrhizobium japonicum). In the first experiment, the herbicides alachlor, imazaquin, metolaclhor and metribuzin were applied in the recommended dosage (1x) and in a dosage ten times greater (I 0x), besides a standard treatment without herbicide application. The number and dry matter of nodules and the dry matter and nitrogen content of soybean shoots were determined 30 and 55 days after the seeds germination. In the second experiment, the herbicides alachlor, imazaquin and metolaclhor were applied, in the recommended dosage, in the soil that had already received that dosage, in the previous experiment. In the soil where no herbicide had been applied, it was made an application of twice the recommended dosage. The soil that had received the dosage 10x received no further treatrnent, in order to evaluate the residual effect of the herbicides in soybean nodulation, 80 days after their application. As control treatments, soil was seeded with soybean inoculated with the Bradyrhizobium strains, with no herbicide. The experiment was harvested 40 days after soybean seeding and the number and mass of nodules and the dry matter of shoots were analyzed. The application of the recommended dosages of the herbicides had no effect, while the application of the dosage 10x was prejudicial to all variables analyzed. The Bradyrhizobium strain SEMIA 587 was more efficient and more tolerant to the applied herbicides. SEMIA 5079 was the most sensitive strain. The herbicide metribuzin was the most toxic, fallowed by metolachlor. The reapplication of the recommended dosage had no effect, showing that the herbicides were expressivelly dissipated 80 days after their application.

The common bean cultivar Irai, type I, was grown during the latter season of 2001 in Santa Maria-RS, in four plant populations (200, 300, 400, and 500 thousand plants ha-I) with the objective of observing the behavior of some traits through growth analysis. The experimental design was randomized blocks with four replications. lt was observed that the specific leaf area increases from flowering untilthe beginning of fi lling grain. The increment in the leaf arca index since flowering is dueto expansion of the leaves, and not because an increase in the number of the leaves. The increase of the plants per area unit accelerates the leaf senescence, and brings up the specific area index without changes in leaf area index. Also, causes a higher speed of soil covering, improving the bean plant competition capacity with weeds. 

lt has been shown that ley farming is technically and economical viable. For such end, medium - and long - temi production systems integrating grain production with perennial should be indentified. The objective of this five-year study was to assess the soybean performance after pastures. Five production systems were eva'luated: system 1 (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/ soybean, and oat + grazed common vetch pasture/corn); system III [perennial cool season pastures (fescue + white clover + red clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + ryegrass + white clover + red clover + birdsfoot frei -0H)); and system V (alfalfa as hay crop). The plot under systems III, IV, and V retumed to system I after the summer of 1996. The treatments were allocated in a complete randomized block design, with four replications. In the overall year mcan thc lowest soybean grain yield was obtained in system III, independently of the previous crop (white oat and/or wheat). Soybean grain yield was similar in the remaining ley forming proction systems. No difference was found among the systems under for the remaining agronomic traits of soybean.

The objective of th is study was to determine soybean plant height and yield, during a eigth-year period, in production systems of grain crops and annual winter and summerpastures. Six production systems were evaluated: system I (wheat/soybean, black oat + common vetch pasture/com); system II (wheat/soybean, black oat + common vetch + ryegrass pasture/com); system III (wheat/soybean, black oat + common vetch pasture/pearl millet pasture); system IV (wheat/soybean, black oat 4 common vetch + ryegrass pasture/pearl millet pasture); system V (wheat/ soybean, white oat/soybean, and black oat + common vetch pasture/pearl millet pasture); and system VI (wheat/ soybean, white oat/soybean, and black oat + common vetch + ryegrass pasture/pearl millet pasture). Treatments were randomly distributed in blocks and replicated four times. Soybean presented higher yield after wheat, in the systems VI, V, IV, I, 111, and II, than after white oat. Nevertheless, soybean yield, in the three last systems, was not different from the yield of soybean cultivated after white oat, in system V. Soybean after white oat, in system VI, did not differ from soybean after wheat, in system II.

From 1995/96 up to 1999/00, in Passo Fundo, RS, Brazil, crop production systems including winter and summer annual pasture under no-tillage were assessed. Six production systems were evaluated: system I (wheat/ soybean, black oats + common vetch pasture/com); system II (wheat/soybean, black oats + common vetch + ryegrass pasture/corn); system III (wheat/soybean, black oats + common vetch pasture/pearl millet pasture); system IV (wheat/soybean, black oats + common vetch + ryegrass pasture/pear) millet pasture), system V (wheat/soybean, white black/soybean, and oats + common vetch pasture/pearl millet pasture); and system VI (wheat/soybean, white black/soybean, and black oats + common vetch + ryegrass pasture/pear) millet). Two types of analysis were applied to the net return of production systems: mean-variance and risk analyses. The systems 1 and II presented h igher net return per hectare by the mean-variance analysis. The system II was the best production system to be offered as alternative to the farmers for profit and lower risk standpoints by the stochastic dominance analysis.

The objective of this trial was to demonstrate economic retum of rearing young beef calves in oat andItalian ryegrass pasture managed under leveis of 352, 422 and 507 kg ha' of green leaf biomass (GLB), correspondingto low, medium and high biomass, respectively. The trial was held from May to October of 2003. Forty four bullcalves of Charolais breed and its crosses with Nelore, with average initial age of nine months and 153 kg of initialliveweight. Economic computations used values from March of 2004, in a market census at Santa Maria. Resultaindicate, as other works, increase in value of urea and formulated fertilizer in last years, increasing costs of pastureestablishment, especial ly those of cool season species. Total operational costs were 384.92 kg ha' of LW. Enlargingutilization period from 85 to 106 days allowed higher live weight gains per hectare and, as a consequence, higherprofitability. Resulta indicate that the treatment gaving the higher return from invested capital is the medium GLB.Rearing calves in cool season pasture is an economically feasible investment.

The aim ofthis study was to verify microbiological quality and the physical-chemical characterization from 21 pasteurized goat milk strains. The Most Probable Number (MPN) of Total (TC) and Fecal coliforms (FC), total bacteria counts, fat, total solid, nonfat sec extract e density were detennined. It was possible to find TC in two strains (9.5%) (0.9 and 110 FCU/mL) and one strain (4.76%) with FC (2.1 FCU/mL). The total bacteriacountsreached a maximum of 2,5 x 106 cfuhnL. Two goat milk strains (9.5%) had density (1034,2 e 1035,8 g/L) higher than admitted. The nonfat sec extract presented variability and one strain (4.76%) presented lower value than admitted. Of the 21 pasteurizado goat milk samplcs analyzed, 14 (66,7%) presented satisfactory standard. All the samples had presented fat above of 3%, that were classified as integral milk. Seven strains were considered unsatisfactory, that didn't respect the criterias of TC and FC (1/7), mesophilic bacteria (5/7), density (2/7) and ESD (117) for pasteurized goat milk.

The soil seed banks in croplands represent management difficulties dueto the presence of spontaneous species that compete with the crops. Literature generally refers to this diverse group of species as "weed." This group includcs sceds of species with ecological and cconomic value, desirable as green manure, forage, or other uses. Knowing the composition and the dynamics of these seed banks can contribute to improve the integrated weed management and natural reseeding. Management practices can contribute to reduce the weed soil seed banks, but at the same time it should p.reserve the sceds from plants that show some potential use. The objective of this work is to review some aspects of th is subject, providing indications of management on the search for sustainable agriculture.

Adequate soil preparation increases pineapple yield and reduces 'production costs and contribute to sustainable agricultura. The conventional tillage (harrowing and grading) is more recommended as it facillitates planting end growth roots, but these benefits do not supersede those achieved through more conservationist and sustainable tillage, how strip-tillage and no-tillage. In RS, the size midle ploughing pineapple (1 ha) end cost of soil preparation is relatively low (1 a 2% total cost ploughing). Since there are no prof of gain nona ef these preparation, in mechanized areas could be used the conventional preparation with maintenance of coverage on the surface, by associates the facillities created to planting and growth of roots, as advantages inhrent strip-tillage and no-tillage. To facillitate harrowing, grading and planting and to avoid biomass incorporation, bafore these operations, the covering may be heaped and after scattered uniformly between the pineapple lines. In soi Is previously planted with pineapple, bafore harrowing ploughing old biomass must be fragmented and dried trough exposition to the sun for decontamination; if the excess be harmful management, one portion of it can be incorporated. In the strip-ti I lage and no-tillage used at steep areas, the covering biomass could be man ipulated on the same form and its maintenance on surface, is still more important also to erosion control. Considerations about sustainable agricultura, soil preparation effects on productivity, mealybug incidcnt, water storage, soil temperature, characteristics fhisical-chemistry and organic matar grade, also are done in the paper.

Throughout their evolution plants developed reaction mechanisms against pests and diseases. Adaptation and resistance are translated into changes in the metabolism of the plant cell, among which is the synthesis of defense proteins expressed through specific genes, activatcd by complex mechanisms. Thcse proteins play many roles in the resistance and survival of the plant, either directly, by fighting the aggressive agent or indirectly by keeping the cell structure and functions. Reaction mechanisms and substances involved in the defense processes have been gone through incense research. Knowing how plants protect themselves is fundamental to get, through bioengineering, more resistant growing varieties which can increase the production and quality of food. This review focus on the plant and insect interaction, including substances from chemical compounds and molecules made through the processing of proteins seen as insecticide coxins.

This is the first report of occurrence of Pseudomonas syringae in papaya in Rio Grande do Sul State. The disease was verified on seedlings with 5 to 7 cm of height and 4 to 6 definitive leaves, about 15 days after the emergency, initially on 'Golden' and after on Sunrise Solo, S. Solo - Diva and S. Solo - M5 cultivars. Disease shows up as small water-soaking leaf spot, begins in the borders of the leaves, and increases in size and develops to brown necrotic lesion and irregular shape. Very often a chlorotic halo is formed between the necrotic and healthy tissue.

The planting period indicated is that where the pineapple, planted at bigger density and at smal ler period possible, produce fruits of good quality and commercial value (>1kg), with smaller cost possible at period favourable to commerce. In others regions the climate (temperature, rainfall etc.) soil moisture, available sprouts, labour force and market define the better period to planting, what in some places is alone the year round. However, in Maquine, Rio Grande do Sul state, Brazil, in June, July and August the air average temperature is 16°C and temperature lower than 21°c, leaf and root has little growing. Sprouts established in this period have their initial growth prejudiced. They stay exposed to plagues, diseases and weeds and the soil is less protected against erosion; increase the cycle and costs of the production. So, the pineapple in RS state may be establish from Aug./Sep.to Mar./Apr. But, whem establishy em Sep./Oct./Nov. and cultivate at high levei technological, a large percentage of the plants willflourish in the first winter. They will produce smal I fruits with harvest at full harvest period and with lower prices. Planting at Dec./Jan./Feb. have a tendency to flourish in the second winter, increase the cicie and costs production. Whitin of the period at what is possibile to plant, Mar. is the best period. There is of sprouts available, temperature and soil moisture allow good establishment of the sprouts and production of good quality fruits and good commercial value at period favourable to commerce (nov./dec.) at short cycle (20-21 months). 

The study of green manure species secking the soil protection, improvement of your chemical conditions, as well a weed control, has crucial imponance to reach the balance in a production system. An experiment was deve loped to evaluate the behavior of different green manures in soil covering and competition with weed species. The statistical design was complete randomized blocks with three replications. The treatments consisted of nine summer green manures, Crotalaria juncea, Vigna unguiculata, Canavalia ensiformis, Cajanus cajan (dwarf), Caj anus cajan, Lablab purpureum, Stizolobium deeringianum, Stizolobium cinereum, Stizolobium aterrimum. The percentage of soil covering, green manure population and weeds, the relationship between soil covering and plant population, were evaluated. The production of biomass (green and dry matter) during the flowering, were evaluated. Canavalia ensiformis was the specie that presented the major velocity and soil covering percentage along the period. Crotalária juncea, cajanus cajan (dwarf) and Stizolobium deeringianum, provided an increase in the weeds and soil covcring percentage along the time. Stizolobium cinereum tended to result in the smallest weeds population.

One of the difficulties faced for the development of the fish farming is the lack of studies about theadversities of this activity, as wel I as of researches that guide the formulation of actions and of public politics andprivate for the sector. The present work seeks to characterize the fish fanning of the northwest area of the State ofRio Grande do Sul, aiding in the development of the activity and guiding rescarch demands and appropriatetechnical attendance. The information were obtained through applied questionnaire in 250 fish farmers, being theanswers analyzed in tables of double entrance. h was verificd that most of the producers do not have the fishfarming as the main activity, small fish farmers that use the technology in a reduced way prevailing. Thecommercialization concentrates on the Easter week, presenting a little market in other periods of the year. Theprincipal identified problem was the market lack consolidated to absorb the production, hindering the permanenceof the producers in the activity.

The present paper compares and characterizes the said conventional and organical cultivation systems implanted in july, 2001, in two orchards with a quarter hectar each in which Valência' orange trees were budded on Poncirus trifoliata rootstock, at Centro de Formação de Montenegro - RS. The orchards were installed at the distante of 300 m between them, with spacing among trees of 2,5 m and among tines of 5,5 m. Around each orchard a line of Cameroon grass was planted, as well as a line of Pinus elliotti to protect the trees against winds. In each orchard were applied in five blocks, with 5 trees each, from which were collected preliminary data in relation to growth, fruit bearing and attacks of certain plagues and diseases. The management of the conventional orchard comprehended activities accomplished for convencional system of cultivation of oranges, while organical proces- ses, which were commended by Cooperativa de Citricultores Ecológicos do Vale do Caí (ECOCITROS), were used in the organical system. Tree years after the stablishment of the orchards, we are able to asseverate that in the convencional orchard, trees grcw plus, but they were more suscetible to citrus canker attacks. In organical orchards, fru its bore less and there were no records of citrus canker attacks.

This work was carricd out at Depressão Central/RS (alt.46m, lat.30°05"S, long.51°40'0), to determine the effect ofsoil tillagc systems on the persistente of Desmodium incanum DC. in field crops established on natural grassland. In arandomized complete block design three tillage methods were used as plots: direct drill (DD), minimum tillage (MT) andconventional tillagc (CT). Surveying of cover-abundance, frequency and soil secd bank (soil core samples and germination) of D.incanum were carricd in: autumn and spring of 2002 and 2003, and autumn of 2004. A very low amount of seeds was registered.D. incanum frequency and cover-abundance were higher in the DD than MT and CT, of which the latter shówed ver> , Iow valucs.In DD and MT, the relationship between frequency and cover-abundance with vegetation sampling dates were described bynegative linear regressions. Positive linear regressions were recorded between frcquency and cover-abundance with pH andorganic mattcr of soil surface. In solte of the gradual reduction in persistente, D. incanum showed ability to persist for unti I fouryears, in soil tillagc systems under Iow disturbancc such as direct drill.

With thc objective to evaluate the effects of pruning and hand fruit thinning to control altemate bearing and ameliorate fruit quality of 'Montenegrina' mandarins (Citrus deliciosa Tenore), buddcd on 'Caipira' Orange, was conducted the present study in a seven-year old private orchard, located in Butiá-RS, southem Brazil (29°57'S - 51°40W). The following treatmcnts were applied: A) Control I (trees with heavy fruit load); B) Control 2, trees not bearing fruits; C) Hand thinnig in February of 66% of fruits on heavy loaded trees; D) Pruning in December, of heavy loaded trees; E) Pruning in December of heavy loaded troes plus hand thinning of 33% of the fruits; F) Pruning in December, of no bearing trees.The treatmcnts were applied in a randomized block design with four replicatcs and 3 plants as experimental unit. Thc averagc time required for pruning, thinning and harvesting the fruits of each tree, and weight of fruits classified in three categories were determined. An average price of R$ 0.38/kg for fruits of first plus second category and R$ 0.08/kg for the fruits of third category was considered. We concluded that pruning and hand thinning of 33% of the fruits, on heavy loaded trees, enhances growers income and reduces altemate beteing.