Coffee Science - v.14, n.2, 2019

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12059

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Biological control: isolated and in mixtures and genetic control of Meloidogyne exigua in coffee
(Editora UFLA, 2019-04) Tolardo, Alex Lavado; Alves, Gleina Costa Silva; Silva, Gustavo Ferreira da; Pereira, Wellington José; Silva, Débora Zacarias da; Silva, Samuel Afonso Sampaio
Meloidogyne exigua is one of the most found species of nematodes in coffee plantations in the Brazilian Cerrado. Thus, the objective of the present study was to evaluate the efficiency of biological agents on two coffee cultivars. The experiment was carried out in a greenhouse using a completely randomized design. The treatments were arranged in a 2x3 factorial scheme, using repeated measures (two cultivars, 3 nematicides, and 2 additional controls), and were composed of two genotypes (Mundo Novo IAC 376-4 and IPR-100), three biological nematicides (B. methylotrophicus, B. subitilis, and T. asperellum), and two treatments including the three nematicides together, totaling 8 treatments and 2 controls, with 6 replicates each. The plants were inoculated with 3,780 eggs and J2s of the respective nematode. Throughout 150 days, the following variables were evaluated monthly: plant height, stem diameter, number of leaf pairs, and chlorophyll contents. At the end of this period (DAI), the reproductive factor (RF), egg mass and gall index were analyzed. About FR, the results were lower (<1) when using the cultivar IPR-100 when compared to the Mundo Novo genotype, denoting adequate genetic control. On the other hand, in the treatments with the susceptible genotype, high FRs were verified, ranging from 2.64 to 5.68 in the control. It was concluded that the bacterial mixtures were efficient in the control, and B. methylotrophicus contributed to higher plant height in the IPR 100 genotype.
Chemical control strategies of Commelina benghalensis in coffee crop
(Editora UFLA, 2019-04) Silva, Paulo Vinicius da; Barbosa, Gustavo César; Ferrari, Andréa; Tronquini, Sergio Mateus; Monquero, Patrícia Andrea
The present study aims to evaluate the control of C. benghalensis by herbicides applied in post-emergence and in pre-emergence sequentially in the infesting weed in the coffee crop. Two field experiments were carried out in a coffee crop, with natural infestation of C. benghalensis, the experimental design of both was completely randomized with 4 replicates. The first experiment, involving a single application of herbicides in post-emergence presented the following treatments: (1) saflufenacil (70 g i.a. ha -1 ); (2) glufosinate (400 g i.a. ha -1 ); (3) carfentrazone (20 g i.a. ha -1 ); (4) flumioxazin (120 g i.a. ha -1 ); (5) metsulfuron (6 g i.a. ha -1 ), and (6) witness (without application of herbicide). In the second experiment, the treatments were: (1) saflufenacil (70 g i.a. ha -1 ); (2) carfentrazone (20 g i.a. ha -1 ); (3) flumioxazin (120 g i.a. ha -1 ); (4) metsulfuron (6 g i.a. ha -1 ), all these treatments with a sequence of indaziflam (75 g i.a. ha -1 ), at 21 days after the application of the treatments (DAT) of pos-emerging; (5) Witness (without application of herbicides). In the first experiment the herbicides safluenacil and flumioxazin presented the best percentages of control in post-emergence with 90 and 85.25% respectively, at 7 DAT, keeping the control superior to 80% at 21 DAT. In the second experiment, the treatments saflufenacil and flumioxazin with indaziflam sequential, presented control of 80% and 82.5% respectively at 28DAA (Days After Application). The herbicides saflufenacil and fluxioxazin represent an option for the control of C. benghalensis in post-emergence and favor the performance of the sequentially applied indaziflam herbicide.
Management of coffee leaf miner: spray volume, efficacy of cartap hydrochloride and impact on parasitism
(Editora UFLA, 2019-04) Melo, Thiago Lima; Raetano, Carlos Gilberto; Nery, Moizés Silva; Cardoso, Adriana Dias; Moreira, Aldenise Alves; Leite, Suzany Aguiar; Jesus, Thamires Francisca de; Silva, Wesley Gil Oliveira; Castellani, Maria Aparecida
The leaf miner is a key pest of coffee and the use of insecticides for its control results in high water consumption. The objective in this study was to evaluate the quali-quantitative aspects of reduced spray volumes with and without the addition of adjuvant, the efficacy of the insecticide cartap hydrochloride in the control of the pest and its effects on the parasitism. Two experiments were carried out in coffee plantations in São Desiderio, BA. Initially, solution of Brilliant Blue tracer (0.15% p v -1 ) of the 43, 112, 146 and 309 L ha -1 volumes was sprayed with and without the soybean oil methyl ester adjuvant (0.25 % v v -1 ). Before spraying, water-sensitive cards were fixed to the plants and subsequently used for analyze the droplet spectrum in Gotas 1.0 software. The tracer deposit was determined by spectrophotometry. Posteriorly, the insecticide cartap hydrochloride (0.5 kg a.i. ha -1 ) was applied in the same volumes and types of spray used in the first test. Infestation rates of pest and parasitism were evaluated before and after application of the insecticide. The quali-quantitative aspects of the sprays were affected by the volume of spray applied, by the adjuvant and by the interaction of the factors. The intermediate volumes yielded better spraying quality without the presence of the adjuvante, with higher number and desity of drops. The spraying volume affected the depoisto the Brilliant Blue tracer in a linear and positive form. The efficacy of the insecticide was prolonged with the lowest volume spray and with adjuvant and its impact on parasitism varied with the volume applied and time after application.