Biological control of late leaf rust disease [Pucciniastrum americanum (Farl.) Arthur] in raspberry (Rubus idaeus L.) using two biological products: Bacillus subtilis (Fungizard®) and Larrea tridentata botanic extract (CleanCrop®) under screenhouse conditions

Abstract

espanolRESUMEN El objetivo del presente estudio fue evaluar la idoneidad de cepas nativas de Trichoderma para el control biologico de la roya tardia de la hoja (RTH), en una plantacion organica de Rubus idaeus, bajo condiciones de malla sombra. Se evaluaron cuatro tratamientos: T1) Trichoderma sp. cepa Clombta; T2) Trichoderma sp. cepa Chlorolota; T3) Co-aplicacion de ambas cepas de Trichoderma (Clombta + Chlorolota) y T4) Control, el cual consistio en la aplicacion de dos productos biologicos: Bacillus subtilis (Fungizard®) y extracto botanico de Larrea tridentata (CleanCrop®)]. Se evaluo la severidad de la enfermedad, el indice de severidad de la enfermedad (IS) y el area bajo la curva de progreso de la enfermedad (ABCPE). La co-aplicacion de Trichoderma sp. cepas Chlorolota y Clombta (de 43,44 a 35,73%) redujo la severidad de RTH al mismo nivel que el Control (de 44,61 a 34,33%). Para el IS, Trichoderma sp. cepa Chlorolota (64,13) y la Co-aplicacion (61,11) mostraron valores similares al Control (59,84). La co-aplicacion de ambas cepas de Trichoderma obtuvo el menor ABCPE (71,2), al mismo nivel que el Control (68,7). Sin embargo, Trichoderma sp. Chlorolota (72,1) logro el mismo ABCPE que la Co-aplicacion. El uso de Trichoderma sp. Chlorolota o su Co-aplicacion con la cepa Clombta fueron capaces de reducir la RTH en R. idaeus. EnglishABSTRACT This study aimed to evaluate the suitability of native Trichoderma strains for the biological control of Late Leaf Rust Disease (LLRD) in an organic Rubus idaeus plantation under screenhouse conditions. Four treatments were evaluated: T1) Trichoderma sp. strain Clombta; T2) Trichoderma sp. strain Chlorolota; T3) Co-application of both Trichoderma strains (Clombta + Chlorolota) and T4) Control, which consisted in the application of two biological products: Bacillus subtilis (Fungizard®) and Larrea tridentata botanic extract (CleanCrop®)]. Disease severity, disease severity index (DSI) and Area Under the Disease Progress Curve (AUDPC) were evaluated. The Co-application of Trichoderma sp. strain Chlorolota and Trichoderma sp. Clombta (from 43,44 to 35,73%) reduce the LLRD severity at the same level than the Control (from 44,61 to 34,33%). For DSI, Trichoderma sp. train Chlorolota (64,13) and the Co-application (61,11) showed similar values than those from the Control (59,84). Co-application of both Trichoderma strains showed the lowest AUDPC (71,2), at the same level that the Control (68,7). However, Trichoderma sp. Chlorolota (72,1) achieved the same AUDPC that the Co-application. The use of Trichoderma sp. Chlorolota or its Co-application with Trichoderma sp. strain Clombta was able to reduce the LLRD in R. idaeus.