Coffee Science - v.13, n.3, 2018
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/10546
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Item Incidence and severity of coffee leaf rust, cercosporiosis and coffee leaf miner in coffee progenies(Editora UFLA, 2018-07) Lima, Amador Eduardo de; Sampaio Junior, Hudinilson Gilberto; Castro, Elisa de Melo; Carvalho, Samuel Pereira de; Silva, Fabiano França da; Lima Junior, Sebastião de; Carvalho, Alex Mendonça deCoffee leaf rust is the main disease of this crop, however cercosporiosis and coffee leaf miner can also cause significant damage when they reach high levels of infestation. Plant genetic improvement for resistance is one of the best tools for controlling plant diseases. The objective in this work was to identify F 3 progenies of Coffea arabica with resistance to coffee leaf rust, which present a lower incidence and severity of cercosporiosis and coffee leaf miner. The treatments were constituted by 10 progenies, besides two cultivars coffee leaf rust susceptible, used as a control. The experimental design was a randomized block design (RBD), with two replicates, each block consisting of 12 plots randomly distributed, each corresponding to one treatments. The following characteristics were evaluated: coffee leaf rust intensity and severity, cercosporiosis and coffee leaf miner, plants vegetative vigor, grain maturity uniformity and plants height. The progeny averages were grouped by the Scott & Knott test at 5% probability. Progenies 27, 30 and 15 were selected, since they presented low incidence in relation to coffee leaf rust, cercosporiosis and coffee leaf miner, and will be used to continue the breeding program.Item Saprobic fungi as biocontrol agents of halo blight (Pseudomonas syringae pv. garcae) in coffee clones(Editora UFLA, 2018-07) Botrel, Dayana Alvarenga; Laborde, Marie Caroline Ferreira; Medeiros, Flávio Henrique Vasconcelos de; Resende, Mário Lúcio Vilela de; Ribeiro Júnio, Pedro Martins; Pascholati, Sérgio Florentino; Gusmão, Luís Fernando PascholatiHalo blight caused by Pseudomonas syringae pv. garcae is a limiting disease in coffee production. There are few efficient commercial products on the market to control this disease, and therefore, the prospection of different biocontrol agents is a promising alternative. The objectives in this study were (i) to select saprobic fungi with the potential to control halo blight in coffee clones, and (ii) to evaluate the contributions of induced resistance as control mechanisms. Plants were sprayed with Gonytrichum chlamydosporium, Phialomyces macrosporus, and Moorella speciosa 7 d before inoculation with Pseudomonas. syringae pv. garcae. The area under the halo blight progress curve (AUDPC) and plant growth parameters were evaluated. M. speciose and G. clamydosporium did not reduce the AUDPC and even reduced plant growth in none of the trails compared to the water control. P. macrosporus consistently reduced AUDPC by 42-72% and increased plant height by 40%. Thereafter, the contributions of induced resistance was evaluated for the P. macrosporus, selected as the most promising biocontrol agent.. In order to determine induced resistance, phenylalanine ammonia lyase (PAL), peroxidase (POX), and ascorbate peroxidase (APX) activity of plant leaves were measured at two time points after stress challenge. Enzyme activity evaluation demonstrated high activity of POX and PAL at seven days after treatment with the saprobe, and high APX activity after 14 days. The results of this study indicate that P. macrosporus has the potential to be used in the management of coffee halo blight in seedling production, and one mechanism likely involved is induced resistance.Item Coffee leaf miner incidence and its predation by wasp in coffee intercropped with rubber trees(Editora UFLA, 2018-07) Androcioli, Humberto Godoy; Hoshino, Adriano Thibes; Menezes Júnior, Ayres de Oliveira; Morais, Heverly; Bianco, Rodolfo; Caramori, Paulo HenriqueThe coffee leaf miner (CLM) Leucoptera coffeella has a wide distribution and causes significant losses in coffee plantations (Coffea spp.) in Brazil. Its occurrence can be mitigated in intercropped systems, with the rubber tree (Hevea brasiliensis ) adapting well to the consortium, while also providing extra income to the producer. We aimed to determine whether the afforestation influences the microclimate and affects the leaf miner incidence and its predation by wasp in coffee plants intercropped with rubber trees. The study was undertaken in state of Paraná, Brazil, using coffee plants intercropped with rubber trees planted in double rows (alleys) spaced at 13, 16 and 22 m between alleys, and compared to sole cropping coffee plots. From January 2008 to November 2010, the presence of CLM’s lesions including those with signs of wasp predation was monitored in coffee plants intercropped with rubber trees and in the non-consorted coffee. A higher CLM’s incidence was verified in monoculture coffee plots, while coffee plants located under and two meters away from rubber trees had the lowest incidences. CLM’s incidence in intercropping system got higher as it increased distance from the trees. The number of lesions with signs of predation by wasps was positively correlated with the number CLM’s lesions, indicating a density-dependent predator-prey relationship. The coffee plants intercropped with alley rubber trees reduce the CLM’s occurrence and can be a management’s tactic for this economically important pest.Item Physiological selectivity of insecticides to eggs and larvae of predator chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)(Editora UFLA, 2018-07) Soares, Andrea de Fátima Torres; Carvalho, Geraldo AndradeGiven the importance of green lacewings as agents of biological pest control, the present study aimed to evaluate the toxicity of insecticides used on coffee crops on the eggs and larvae of Chrysoperla externa. The insecticides tested were (g or mL a.i./L) chlorpyrifos (2.25), cartap hydrochloride (1.66), pyriproxyfen (0.33), profenofos/lufenuron (1.33/0.13), fenpropathrin (0.40), triazophos/deltamethrin (0.70/0.02) and zetacypermethrin (0.05). The insecticides, when applied directly on the eggs, caused no adverse effects on the duration of the embryonic period. After the application of triazophos/deltamethrin, pyriproxyfen, profenofos/lufenuron and zetacypermethrin, a reduction in egg viability was induced. The insecticides triazophos/ deltamethrin, chlorpyrifos, and profenofos/lufenuron reduced the survival of newly hatched first instar larvae from treated eggs. The first instar larvae that were treated directly were sensitive to the effects of the products used, with the effect of triazophos and chlorpyrifos/deltamethrin being high. The survival of the second instar larvae was reduced by zetacypermethrin, fenpropathrin, profenofos/lufenuron, and cartap hydrochloride. The products chlorpyrifos and triazophos/deltamethrin also did not allow second instar larvae survival. For treated third instar larvae, chlorpyrifos and triazophos/deltamethrin allowed survival of only 20.0 and 57.5%. Eggs and larvae of C. externa showed sensitiveness to insecticides chlorpyrifos and triazophos, being needed more studies in semi-field and field conditions for the confirmation or not of the toxicity aiming the conservation of this predator specie on the coffee agroecosystem.