Determination of Optimum Nativo SC 300 (Trifloxystrobin 100g/l + Tebuconazole 200g/l) Spray Frequency for Control of Rust (Puccinia allii Rudolphi) on Garlic in Bale Highlands, South Eastern Ethiopia

Garlic (Allium sativum L.) is one of the major allium crops grown in the highlands of Bale, south eastern Ethiopia. Rust, which is caused by Puccinia allii Rudolphi is the most important disease of this crop in these areas. There are different fungicides recommended for the control of garlic rust on Allium crops in different parts of the world. Nativo SC 300 (Trifloxystrobin 100g/l + Tebuconazole 200g/l) is one of the recommended chemicals for the control of this disease. To determine the optimum Nativo SC 300 spray frequency for the control of the disease a study was conducted at research station of Sinana Agricultural Research Center, south eastern Ethiopia. The fungicide was sprayed on garlic plots in three different frequencies. The frequencies were five times (every 7-days), three times (every 14-days) and two times (every 21-days) starting from the onset of the disease. The experiment was laid down in Randomized Complete Block Design with three replications. The lowest average rust severity level (1%) was recorded from plots which were treated with the fungicide five times at weekly interval whereas the maximum average severity level (83.3%) was recorded from the unsprayed plots. All fungicide treated plots gave significantly (p ≤ 0.05) higher total bulb yield than the untreated check plots. Among fungicide treated plots, the maximum total bulb yield (13.92 t/ha) was obtained from plots which were protected from the disease by spraying the fungicide three times at 14-days interval. Partial budget analysis revealed that application of Nativo SC 300 three times at 14-days interval gave the highest net benefit. Therefore, application of Nativo SC 300 (Trifloxystrobin 100g/l + Tebuconazole 200g/l) three times at 14-days interval starting from the onset of the disease results in not only high total bulb yield but also high net benefit on the chemical application.