Management of Rust (Puccinia allii R.) through Host Resistance and Alternate Application of Fungicides on Garlic (Allium sativum L.) in North Wollo, Ethiopia

Abstract

Rust (Puccinia allii R.) is the major problem constraining garlic production in most areas of northern Ethiopia. Thus, this study was conducted during 2018 with the objectives to (1) evaluate the effects of integrated disease management through host resistance and alternate fungicide applications on rust epidemic and bulb yield; and (2) determine the economics of fungicide application in the management of garlic rust. Field experiments were
conducted in Gidan and Lalibella districts of North Wollo, Ethiopia, using three garlic varieties, namely Chelenko-1, Tseday, and a local cultivar. Nativo and Tilt fungicides were sprayed with alternate and alone applications during the 2018 cropping season. Treatments were arranged factorially in a randomized complete block design with three replications. Analyses of variance revealed that interaction effects of Nativo, Tilt, and their alternate applications with Chelenko-1 and Tseday varieties showed the lowest disease severity, area under the disease progress curve, and disease progress rate as compared to the unsprayed plots of all varieties. In Lalibella, the variety Chelenko-1 showed significantly higher (9 t ha-1)
yield and, exhibited 28 and 21% yield advantages over Tseday variety and the local cultivar, respectively. However, there was no significant difference among the fungicides tested on bulb yield in both districts, but lower relative yield losses were recorded in response to application of Nativo and Tilt alone. The economic analysis also confirmed that sole application of Nativo on Local and Tilt on both Tseday and Chelenko-1 showed higher net profit and marginal rates of return than other treatment combinations. Thus, the fungicides Tilt and Nativo alone were relatively effective against garlic rust and economically profitable in Lalibela and related agro-ecologies for the variety Chelenko-1. However, there was no
significant variation in garlic bulb yield of all varieties in Gidan, and the same fungicides with local garlic variety can be used for rust management and sustainable garlic production.