Integrated Management of Tomato Late Blight ( Phytophtra infestans Mont.) of Tomato ( Lycopersicon esculentum MILL.) at Ataye and Shewarobit Districts, Eastern Amhara, Ethiopia

Abstract

Field experiments were conducted at Ataye and Shewarobit districts during 2017/18 main cropping season to evaluate the fungicide against late blight on tomato varieties under natural conditions and to assess the integrated effect of fungicides (Ridomil MZ 68%WP, Metalaxy (0.25%), More720Wp and Mancozeb) and tomato varieties (Margoble and Melkasalsa) against late blight and yield. The experiments were arranged randomized complete block design in factorial with three replications. Fungicides were applied two weeks intervals starting from the onset of the disease. The integration of varieties and fungicides exhibited significant difference at (p<0.05) in disease parameters, and yield. Significantly, the lowest Percentage severity index (PSI) (28%) with AUDPC (592.67%-days) and the highest yield (50.3 t/ha) were recorded from Melkasalsa variety treated with Ridomil MZ 68% WP at Ataye while the lowest PSI (35%) with AUDPC (630%-days) and the highest yield (43 t ha-1) were recorded from Melkasalsa variety treated with Ridomil MZ 68% WP at Shewarobit. On the contrary the highest PSI (60.7%) with highest AUDPC (1373.17%-days) and the lowest yield (27 t ha-1) were obtained from untreated Margoble at Ataye, while the highest severity (69.3%) with highest AUDPC (1248.33%-days) and the lowest yield (22 t ha-1) were obtained from untreated Margoble at Shewarobit. As compared to yield losses from protected plots with Ridomil MZ 68%WP, the highest fruit yield loss of 44.9% at Ataye and 47% at Shewarobit were recorded from unsprayed Margoble variety. The best management of late blight and the higher yield were obtained from integration of two varieties treated with Ridomil MZ 68% WP. Thus, it is recommended to use tomato varieties with sprays Ridomil MZ 68% gave the highest protection against late blight and the highest yield benefit. However, further extensive studies have to be undertaken for late blight management options through integration of varieties and frequency of fungicide applications that may contribute to sustainability of tomato production in the country.