Abstract

Ginger (Zingiber officinale Rosc.) is an important spice crop grown in tropical and subtropical countries including Ethiopia. It is produced both for commercial and home use. But, since 2012 the first ginger wilt disease epidemic was reported and ginger disease is becoming the threat of national ginger production as a whole. In Ethiopia except R. solanacearum, information regarding the other types of diseases; like fusarium and pythium spp potentially threaten ginger production in other world was scanty. Therefore this study was conducted to detect and identify the major potential pathogens for ginger wilt epidemics. So, a survey was carried out from August-September in three consecutive years 2015 and 2017 in major ginger growing areas of SNNPR. The total numbers of farms visited from Bloso-Bombe and Hadaro-Tunto districts were 35 in 2015, 40 in 2016 and 30 in 2017 and Rhizome spacemen of diseased ginger was collected from the ginger field and identified using standard isolation techniques. Survey result showed that, during 2015 survey season the major and dominant disease identified was ginger wilt. But, in 2016 and 2017 field survey ginger leaf pot and wilt diseases were identified as the problem of ginger production at both Boloso-bombe and Hadaro-Tunto districts. At Boloso-Bombe the incidence of leaf spot was in the range of 0 to 100% in 2016 and 5 to 100% in 2017. At this district its maximum severity was not more than 60% in 2016. But, in 2017 it stretched to 85%. At Hadaro-tunto, the incidence of ginger leaf spot was within the range of 0 to 30% in 2016 and 95-100% in 2017. Also its maximum severity was 25% in 2016 and 95% in 2017. At both locations relative to 2016 and 2017, in 2015 the lowest incidence and severity of leaf spot was recorded. The identification result showed R. solanacearum was detected on 72.7% of specimens and 90.9% of specimens were positive for Fusarium oxysporum spp, but all specimens were negative to Pythium spp Therefore, besides studying their biology and dynamics, focusing on developing management option to these complexes of diseases is vital to increase ginger production and productivity in Ethiopia.

Keywords: Ginger; Bacterial wilt; Leaf spot; Pythium spp; Fusarium oxysporum spp