Estratégias de controle químico da ferrugem em cafeeiros sombreados na Venezuela :
During the years of 1988/89 and 1989/90 trials were carried out in Córdoba, State Táchira in Venezuela, to study strategies of chemical control of coffee leaf rust under shade, on eight-year-old plants of cv. Mundo Novo at 650 m of altitude. Eight treatments were distributed in a randomixed complete block design with six replications involving the application of triadimefon at 0.175. and 0.350 kg i.a./ha, triadimenol at 0.350 l i.a./ha and copper oxychloride at 1.25 and 2.50 kg i.a./ha different times. Fungicide dosages were calculated based on the leaf area of the plants at the rate of 400 l/ha. The disease incidence and number of fallen leaves were evaluated at 20 day intervals and yield was evaluated both years per year. The standard treatment, copper oxychloride 2.50 kg i.a./ha applied five times from May to September, was the most efficient treatment yielding 450 percent of fruit yielded in nontreated controls. The other control strategies yielded approximately 50 percent of the standard treatment and 240 percent more than the check treatment. Except the standard treatment, considering all the parameters studied, triadimefon (0.350 kg i.a./ha) applied in June and in September was the best strategy to control coffee leaf rust. The results of this study showed that on coffee under shade, the critical period to control coffee leaf rust, is from June to September. The strategies using half of the dosage of the fungicides triadimefon mixtured with copper oxychloride were not efficient to control coffee leaf rust. The correlation coefficient between the proportion of area under disease progress curve (PAUDPC) and the proportion of area under fallen leaves curve was positive and significant (r = 0.719, P ¥ 0.05); the correlation of PAUDPC of 1988/89 and yield of 1989/90 was negative and significant (r = -0.664, P ¥ 0.05).
| Main Authors: | , , |
|---|---|
| Format: | biblioteca |
| Language: | eng |
| Published: |
1994
|
| Subjects: | COFFEA ARABICA, HEMILEIA VASTATRIX, ENFERMEDADES FUNGOSAS, CONTROL QUIMICO, OXICLORURO DE COBRE, TRIADIMENOL, TRIADIMEFON, CULTIVO BAJO SOMBRA, |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|