The results allowed concluding that the management methods of weed ryegrass must be adopted in the period between 11 and 21 days after crop emergence, which is described as a critical period of control of this weed. The wheat grain yield loss competing with ryegrass reached 59% when grown with ryegrass. For ETL, the linear regression model of the rectangular hyperbola adequately estimates grain yield losses in the presence of ryegrass. The cultivar presenting the lowest values of ETL, that is, less capacity to live with the weed, was TBIO Alvorada. The other cultivars presented similar ETL values.

The weeds if not properly controlled have great ability to settle in agricultural systems, affecting crop production. The objective of this work was to determine the interference and level of economic damage in different density of crop. The treatments were composed of canola hybrids (Hyola 50, Hyola 76, Hyola 433, Hyola 571 CL, Hyola 575 CL and Diamond) and twelve infestation turnip density in crop. The variables evaluated to estimate the competitiveness of the hybrids were plant density, leaf area, soil cover and dry mass of the turnip. Grain yield, canola price, herbicide efficiency, and control cost were used to determine the weed's level of economic damage on the crop. The canola hybrids Hyola 575 CL, Hyola 50, Hyola 76 and Hyola 571 CL are more competitive with turnip. The values of economic damage levels range from 2.86 to 5.95, 2.43 to 5.05, 2.22 to 5.43 and 2.99 to 6.22 turnip plants m-2 for hybrids Hyola 50, Hyola 76, Hyola 571 CL and Hyola 575 CL, respectively, as a function of simulated variables. The increased grain yield, canola price, herbicide efficiency and lower control costs reduce the level of economic damage, justifying the adoption of control.

The increase in flower cultivation in recent years has been reflecting the higher incidence of soil pathogens that can cause serious problems. This study aimed to evaluate the biological control of Fusarium wilt in gerbera with Trichoderma asperellum. The evaluated treatments were: T1) Control, only sterile substrate; T2) Substrate + Fusarium oxysporum; T3) Substrate + Fusarium oxysporum + Trichoderma asperellum; and T4) Substrate + Trichoderma asperellum. For this, the pathogen was isolated from gerbera with disease symptoms and, subsequently, it was identified according to morphological characters. Furthermore, the degree of antagonism of T. asperellum against F. oxysporum was evaluated through the culture pairing test. For greenhouse evaluations, commercial autoclaved substrate was used and infested with corn grains infected by the pathogen. Morphological identification confirmed the pathogen species as Fusarium oxysporum. In the culture pairing test, it was found that T. asperellum did not present a high degree of antagonism. The plants cultivated on substrate infested by the pathogen had no visible symptoms of wilt, but the substrate infestation with the pathogen provided lower values of fresh and dry mass of shoots and roots. The treatment with T. asperellum obtained higher values of fresh and dry mass of both shoots and roots, and also more vigorous inflorescences in relation to the plants treated with the pathogen

The objective of this work was to determine the periods of interference of turnip, ryegrass and black oats infesting the canola crop. Two models of interference were studied: first, the canola cohabited with weeds for increasing periods up until 0, 7, 14, 21, 28, 35 and 42 days after the emergency (DAE) and throughout the cycle; second, the culture was kept free of the infestation for the same periods described previously. At 51 DAE, the variables related to canola and weed morphophysiology were determined. In the harvest of the crop, was measured the number of siliques, a thousand grain mass and grain yield. The physiological variables, photosynthetic rate, internal CO2 concentration, perspiration rate, stomach conductance of water vapors, carboxylation efficiency and efficient water use did not show significant variation. The dry mass was reduced by 79.21% when canola culture was always in competition with ryegrass, turnip and black oat weeds. The number of siliques and the mass of one thousand grains also decreased as the period of competition with the turnip, ryegrass and black oat weeds increased. The period before the interference (PAI) of the weeds ryegrass, turnip and black oats goes up to 25 DAE of canola. The critical interference prevention period (PCPI) for canola culture goes from 25 to 60 DAE. And the total interference prevention period (PTPI) is 60 DAE. Interference from weeds has reduced by 94.05% the productivity of canola grains when it has not received control of ryegrass, turnip and black oats.

The use of herbicides to anticipate harvesting in species with easy seed dehiscence may be an alternative to avoid maturation losses. However, the appropriate time for herbicide application is extremely important as it prevents the seeds from remaining in the field for long periods. The objective of this study was to evaluate the efficiency of the application of maturing herbicides in two distinct seasons, and their effects on the physical, physiological, and sanitary quality of canola seeds. A randomized block experimental design arranged in a factorial scheme (herbicide x season + control) with four replications was used. Hybrid 50 canola plants were matured with the herbicides: glufosinate, paraquat, glyphosate, diquat, saflufenacil, 2,4-D, and paraquat + diuron twice during the crop cycle, G3 and G4, and two controls without application for each epoch, with the first being harvested the day of product application, and the second kept in the field until the final crop cycle. Analyses of one thousand seed weight, electrical conductivity, emergence speed index, and a sanity test were performed. The application of maturing herbicides to canola increases the one thousand seed weight and rate of emergence speed. At the same time, it increases electrical conductivity and the incidence of fungi. Plants that remained in the field until the end of the crop cycle and did not receive herbicide application resulted in higher quality seeds. The most appropriate moment to apply maturation herbicides to canola is in the G4 season.

Canola (Brassica napus L. var. oleifera) is a winter growing option for producers, however, harvesting is the phase that requires the most care and decision making to avoid losses in productivity. One of the alternatives that can be used to solve this problem is the application of maturing herbicides. Thus, the objective of this study was to evaluate the physiological quality of canola seeds with the use of herbicides, applied in two seasons, for pre-harvest maturation of the crop. The experimental design was a randomized block design, arranged in a factorial scheme 7x2 + 2 (herbicide x season + control) with four replications. Hybrid 50 canola plants received ammonium glufosinate, paraquat, glyphosate, diquat, saflufenacil, 2,4 -D and paraquat + diuron at two times in the crop cycle (G3 -when the first ten the main stem silica has a width greater than 4 cm, and G4 -when the first ten silicas of the main stem begin to mature), in addition to two unselected controls, for each season, the first being harvested on the day of application of the products, and the second kept in the field until the final cycle of the culture. First germination, germination, seedling length, dry mass, cold test and accelerated aging tests were performed. Herbicides applied in the first season (G3) cause the greatest damage to the seeds, and the plants that remained in the field until the end of the crop cycle and did not receive herbicide application (additional control), result in seeds with better physiological quality. The treatments with diquat, paraquat + diuron and glufosinate of ammonium presented higher efficiency with respect to seed quality, being the best period to carry out the maturation practice in the canola crop in the G4 season.