Goosegrass [Eleusine indica (L.) Gaertn.] and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] are problematic weeds in bermudagrass and creeping bentgrass turf. Increased incidences of herbicide resistant weed populations and severe use restrictions on formerly available herbicides have increased need for selective, postemergence control options for these weeds in creeping bentgrass and bermudagrass turf. This weed management exigency has led turf managers to utilize less effective, more expensive, and more injurious options to manage goosegrass and smooth crabgrass. Although potentially injurious, topramezone can control these weeds, especially goosegrass, at low doses. Low-dose topramezone may also improve bermudagrass and creeping bentgrass response. An initial investigation of three 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting herbicides in different turf types showed that Kentucky bluegrass, perennial ryegrass, and tall fescue were highly tolerant to topramezone, while creeping bentgrass and bermudagrass could tolerate topramezone doses that may control grassy weeds. Further investigation suggested that frequent, low-dose topramezone applications or metribuzin admixtures could enhance weed control and may conserve turfgrass quality. A novel mixture of topramezone at 3.7 g ae ha-1 and metribuzin at 210 g ai ha-1 controlled goosegrass effectively and reduced bermudagrass foliar bleaching associated with topramezone 10-fold compared to higher doses of topramezone alone in 19 field and 2 greenhouse trials. In an attempt to further enhance bermudagrass tolerance to topramezone, post-treatment irrigation was applied at various timings. When bermudagrass turf was irrigated with 0.25-cm water at 15 or 30 minutes after herbicide treatment, bermudagrass injury was reduced to acceptable levels when following low-dose topramezone plus metribuzin but not when following high-dose topramezone alone. Goosegrass control was reduced significantly by post-treatment irrigation in all cases, while irrigation reduced goosegrass control by low-dose topramezone plus metribuzin to below-commercially-acceptable levels. Novel, low-dose, frequent application programs containing topramezone or siduron were developed for season-long crabgrass or goosegrass control on creeping bentgrass greens. Greens-height creeping bentgrass quality was preserved following five biweekly treatments of siduron at rates between 3,400 to 13,500 g ai ha-1 and topramezone at 3.1 g ha-1. Siduron programs controlled smooth crabgrass and suppressed goosegrass while topramezone programs controlled goosegrass and suppressed smooth crabgrass. In laboratory and controlled-environment experiments, goosegrass absorbed three times more 14C than bermudagrass within 48 hours of 14C-topramezone treatment. Bermudagrass also metabolized topramezone twice as fast as goosegrass. Metribuzin admixture reduced absorption by 25% in both species. When herbicides were placed exclusively on soil, foliage, or soil plus foliage, topramezone controlled goosegrass only when applied to foliage and phytotoxicity of both bermudagrass and goosegrass was greater from topramezone than from metribuzin. Metribuzin was shown to reduce 21-d cumulative clipping weight and tiller production of both species while topramezone caused foliar discoloration to newly emerging leaves and shoots with only marginal clipping weight reduction. These data suggest that selectivity between bermudagrass and goosegrass is largely due to differential absorption and metabolism that reduces bermudagrass exposure to topramezone. Post-treatment irrigation likely reduces topramezone rate load with a concomitant effect on plant phytotoxicity of both species. Metribuzin admixture decreases white discoloration of bermudagrass by decreased topramezone absorption rate and eliminating new foliar growth that is more susceptible to discoloration by topramezone. / Doctor of Philosophy / Goosegrass and smooth crabgrass are problematic weeds in bermudagrass and creeping bentgrass turf. Increased incidences of herbicide resistant weed populations and severe use restrictions on formerly available herbicides have increased need for selective, postemergence control options for these weeds in creeping bentgrass and bermudagrass turf. Although potentially injurious, topramezone (Pylex™) can control these weeds, especially goosegrass, at low doses. Low-dose Pylex™ may also improve bermudagrass and creeping bentgrass response. An initial investigation evaluating tembotrione (Laudis®), Pylex™, and mesotrione (Tenacity®) in different turfgrass species showed that Kentucky bluegrass, perennial ryegrass, and tall fescue were highly tolerant to Pylex™ at rates ranging from 0.75 to 2.25 fl. oz./A, while creeping bentgrass and bermudagrass were low to moderately tolerant to Pylex™. Further investigation suggested that frequent, low-dose (less than 0.25 fl. oz./A) Pylex™ applications or metribuzin (Sencor®) admixtures could enhance weed control and may conserve turfgrass quality. A novel mixture of Pylex™ at 0.15 fl. oz./A and Sencor® at 4 oz. wt./A controlled goosegrass effectively and reduced bermudagrass injury to near acceptable levels and significantly less than Pylex™ applied alone at 0.25 fl. oz/A. In an attempt to further enhance bermudagrass tolerance to Pylex™, post-treatment irrigation was applied at different timings. When bermudagrass turf was irrigated at 15 or 30 minutes after herbicide treatment, bermudagrass injury was reduced to acceptable levels when following Pylex™ at 0.25 fl. oz./A plus Sencor® at 4 oz but not when following Pylex™ applied alone at 0.5 fl. oz./A. Goosegrass control was reduced significantly by post-treatment irrigation in all cases, while irrigation reduced goosegrass control by low-dose Pylex™ plus Sencor® to below-commercially-acceptable levels. Novel, low-dose, frequent application programs containing Pylex™ or siduron (Tupersan®) were developed for season-long crabgrass or goosegrass control in creeping bentgrass greens. Greens-height creeping bentgrass quality was preserved following five biweekly treatments of Tupersan® at rates between 6 and 24 lb./A and Pylex™ at 0.125 fl. oz./A. Tupersan® programs controlled smooth crabgrass and suppressed goosegrass while Pylex™ programs controlled goosegrass and suppressed smooth crabgrass. The data from these studies indicate that utilizing low-dose Pylex™ in combination with Sencor® can impart acceptable bermudagrass safety while also controlling goosegrass effectively. For creeping bentgrass greens, the low-dose, frequent application of Tupersan® is the safest legal option for golf course superintendents to control smooth crabgrass effectively, while having some ability to suppress goosegrass.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-15T17:40:46Z No. of bitstreams: 1 JOÃO JONES DA SILVA - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1781652 bytes, checksum: 5ecbeafd5b48184bce3785273190c6dd (MD5) / Made available in DSpace on 2018-05-15T17:40:46Z (GMT). No. of bitstreams: 1 JOÃO JONES DA SILVA - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1781652 bytes, checksum: 5ecbeafd5b48184bce3785273190c6dd (MD5) Previous issue date: 2015-09-29 / A Região Nordeste do Brasil é caracterizada por clima semiárido, sendo os volumes precipitados normalmente inferiores à evaporação e, tornando o uso da irrigação imprescindível para uma produção agrícola sustentável, entretanto, o manejo inadequado da irrigação atrelado às condições locais, tem favorecido os processos de salinização e sodificação de solos, promovendo a degradação e o abandono de extensas áreas anteriormente produtivas. Entre as áreas afetadas por sais nessa região, destaca-se o Perímetro Irrigado de São Gonçalo - PB em situação de degradação de solos com problemas de sais, isso ensejou a propositura de estudar métodos e técnicas visando o melhoramento das características físicas e químicas do solo. O experimento foi instalado em área previamente identificada como possuidora de solo salino-sódico no Perímetro Irrigado de São Gonçalo, e para a recuperação fez-se da aplicação dos métodos e da técnica da fitorremediação com Erva-Sal (Atriplex numulária L.), Capim-pé-de-galinha (Eleusine indica L.), Salsa - Brava (Ipomoea asarifolia L.) e Gesso agrícola. A pesquisa constou de oito tratamentos, com quatro repetições, os tratamentos foram submetidos a um delineamento em blocos casualizados (DBC), com os seguintes tratamentos: i) cultivo de atriplex; ii) cultivo de capim-pé-galinha, iii) cultivo de salsa, iv) solo com gesso; v)aplicação de gesso agrícola associado ao cultivo de atriplex; vi)aplicação de gesso agrícola associado ao cultivo de capim pé-de-galinha; vii)aplicação de gesso agrícola associado ao cultivo de salsa e viii) solo sem manejo (testemunha), numa área total de 62 m² conduzido em campo, em parcelas de 1,40 x 1,40 m. Com esse estudo pretende-se recuperar solo afetados por sais, utilizando um método alternativo, mais viável economicamente e sustentável através de plantas capazes de extrair os sais em excesso do solo. / Brazil's Northeast region is characterized by semi-arid climate, and the precipitated volumes usually lower than the evaporation and, making use of vital irrigation for sustainable agricultural production, however, inadequate irrigation management linked to local conditions, has favored processes salinization and sodification soils, promoting the degradation and abandonment of extensive formerly productive areas. Among the areas affected by salts in this region, we highlight the Irrigated Perimeter of São Gonçalo - PB in soil degradation situation with salt problems and this gave rise to the filing of study methods and techniques aimed at improving the physical and chemical characteristics ground. The experiment was installed in previously identified area as saline-sodic soil possessed in the Irrigated Perimeter of São Gonçalo, and the recovery was made of the application of methods and phytoremediation technique with herb-salt (Atriplex moneywort L.), grass crow's foot bath (Eleusine indica L.), Salsa - Brava (Ipomoea asarifolia L.) and Agricultural Gypsum. The survey consisted of eight treatments, with four replications, the treatments were subjected to a randomized block design (RBD), with the following treatments: i) atriplex cultivation; ii) grass-foot-chicken farming, iii) salsa culture, iv) soil with gypsum; v) application of gypsum associated with atriplex cultivation; vi) application of gypsum associated with grass growing chicken's foot; vii) application of gypsum associated with the parsley cultivation and viii) soil without management (control), a total area of 62 m² conducted under field conditions in portions of 1.40 x 1.40 m. With this study we intend to recover salt affected soil, using an alternative method more economically viable and sustainable through plants capable of extracting soil excess salts.