J. Honorato Júnior, D. Debona, L. Zambolim, F. Rodrigues
{"title":"Factors influencing the performance of phosphites on the control of coffee leaf rust","authors":"J. Honorato Júnior, D. Debona, L. Zambolim, F. Rodrigues","doi":"10.1590/1678-4499.20200176","DOIUrl":null,"url":null,"abstract":"This study investigated the effect of different phosphites on the control of coffee leaf rust (CLR) caused by Hemileia vastatrix, considered the major disease affecting coffee yield worldwide. Three-month-old coffee plants were sprayed with two doses each of the phosphite solutions (standard and double), as follows: K (40% P2O5; 1.5 and 3 mL·L -1), K (30% P2O5; 3 and 6 mL·L -1), Cu (2.5 and 5 mL·L1), Mn+Zn (3 and 6 mL·L-1) and Na (3 and 6 mL·L-1) 24 h before being inoculated with H. vastatrix. Leaves were not washed or washed with deionized water after the foliar phosphites spray. Plants sprayed with water served as the control treatment. Inoculation was performed on the abaxial side of the first pair of expanded leaves using a camel hairbrush with a suspension of urediniospores (1 mg per leaf). All phosphites applied at the standard doses (from 1.5 to 3 mL·L-1) reduced the total number of pustules (TNP) per leaf by 28-69% regardless of washing treatment. The biggest reductions were observed for Cu phosphite, which decreased the TNP per leaf by 60 and 69% without and with leaf washing, respectively. A similar trend was observed when the double doses of phosphites (from 3 to 6 mL·L-1) were used, though Na phosphite without leaf washing and Mn/Zn phosphite without and with leaf washing were not efficient to reduce the TNP per leaf. Without leaf washing, only Cu and Na phosphites decreased CLR severity at the standard doses (53-61%), whereas all phosphites, except the Mn/ Zn phosphite, reduced CLR severity at the double dose. The CLR severity was decreased using K 30%, K 40% and Cu phosphites when applied at the standard doses with leaf washing (41-59%). With double doses, only Cu and Na phosphites decreased CLR severity by 55% for both treatments. In conclusion, the efficiency of the phosphites for CLR control varied according to the accompanying cation, dose and washing conditions. The Cu phosphite resulted in the best CLR control regardless of the dose used and the washing conditions.","PeriodicalId":9260,"journal":{"name":"Bragantia","volume":null,"pages":null},"PeriodicalIF":1.2000,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bragantia","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1590/1678-4499.20200176","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"AGRICULTURE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
This study investigated the effect of different phosphites on the control of coffee leaf rust (CLR) caused by Hemileia vastatrix, considered the major disease affecting coffee yield worldwide. Three-month-old coffee plants were sprayed with two doses each of the phosphite solutions (standard and double), as follows: K (40% P2O5; 1.5 and 3 mL·L -1), K (30% P2O5; 3 and 6 mL·L -1), Cu (2.5 and 5 mL·L1), Mn+Zn (3 and 6 mL·L-1) and Na (3 and 6 mL·L-1) 24 h before being inoculated with H. vastatrix. Leaves were not washed or washed with deionized water after the foliar phosphites spray. Plants sprayed with water served as the control treatment. Inoculation was performed on the abaxial side of the first pair of expanded leaves using a camel hairbrush with a suspension of urediniospores (1 mg per leaf). All phosphites applied at the standard doses (from 1.5 to 3 mL·L-1) reduced the total number of pustules (TNP) per leaf by 28-69% regardless of washing treatment. The biggest reductions were observed for Cu phosphite, which decreased the TNP per leaf by 60 and 69% without and with leaf washing, respectively. A similar trend was observed when the double doses of phosphites (from 3 to 6 mL·L-1) were used, though Na phosphite without leaf washing and Mn/Zn phosphite without and with leaf washing were not efficient to reduce the TNP per leaf. Without leaf washing, only Cu and Na phosphites decreased CLR severity at the standard doses (53-61%), whereas all phosphites, except the Mn/ Zn phosphite, reduced CLR severity at the double dose. The CLR severity was decreased using K 30%, K 40% and Cu phosphites when applied at the standard doses with leaf washing (41-59%). With double doses, only Cu and Na phosphites decreased CLR severity by 55% for both treatments. In conclusion, the efficiency of the phosphites for CLR control varied according to the accompanying cation, dose and washing conditions. The Cu phosphite resulted in the best CLR control regardless of the dose used and the washing conditions.
期刊介绍:
Bragantia é uma revista de ciências agronômicas editada pelo Instituto Agronômico da Agência Paulista de Tecnologia dos Agronegócios, da Secretaria de Agricultura e Abastecimento do Estado de São Paulo, com o objetivo de publicar trabalhos científicos originais que contribuam para o desenvolvimento das ciências agronômicas.
A revista é publicada desde 1941, tornando-se semestral em 1984, quadrimestral em 2001 e trimestral em 2005.
É filiada à Associação Brasileira de Editores Científicos (ABEC).