The Fungicide and Variety Integration Effect on Late Blight (Phytophthora infestans) Disease of Potato (Solanum tuberosum L.) in Western Amhara Region, Ethiopia

Abstract

Potato is suffered by many abiotic and biotic factors. Among biotic factors late blight disease (LBD) is the most important. The study was conducted during 2017 at Adet and Debre-Tabor to determine and evaluate the combination effect of varieties and fungicides, to reduce LBD intensities and increase yield. Four potato varieties and three fungicides with untreated check were used in factorial randomized complete block design with three replications. Lowest disease severity 11.11% was obtained from Belete and Gudene at Adet and Belete at Debre-Tabor. Similarly, the lowest AUDPC (9.33 and 89.83 %-days) were expressed from Gudene + Saboxyl 72% at Adet and Debre-Tabor, respectively, whereas, the maximum PSI and AUDPC were obtained from untreated plots. In average up to 359.81% yield increases were recorded from Abalo + Saboxyl 72% WP. The highest marginal rates of return (2,886.50 % and 3,786.35%) were obtained from Saboxyl 72% treated plots of Abalo & Guassa at Debre-Tabor and Adet, respectively. Therefore, an application of Saboxyl 72% with different varieties was effective at both locations to reduce the yield loss of potato and could be recommended to manage LBD. The combination of Saboxyl 72% with Gudene, Belete and Guassa were highly hinder LBD development at both locations. Even though, its yielding capacity was relatively lower Gudene could be recommended for production without fungicide. Variety Belete and Guassa could be recommended for production in combination with Saboxyl 72%, since they have best performance with relatively lower disease reaction at Adet and Debre-Tabor, respectively. Contribution/Originality:This study contributes in the existing literature to fill the gap of the current state of knowledge of late blight disease management of potato. This study is one of very few studies which have investigated potato late blight disease management in Western Amhara Region Ethiopia. INTRODUCTIONPotato (Solanum tuberosum L.) ranks 3 rd after rice and wheat in terms of human consumption (Devaux et al., 2014; FAOSTAT, 2015) and it is the primary non-grain food commodity in the world (Waga et al., 2016). Among root and tuber crops, potato ranks first in volume of production and consumption, followed by cassava, sweet potato and yam (Egata et al., 2016). It is a high potential contributor to national food security (Gildemacher et al., 2009;Bitew and Abera, 2018). In Ethiopia, potatoes are a source of both food and cash income in the densely populated highlands, where 90% of the population resides (Gildemacher et al., 2009;Abebe et al., 2013). Its high yielding capacity, early maturing, and excellent food value give the potato great potential for improving food security,

Integrated Management of Late Blight Potato (Phytophthora infestans, (Mont) de Bary) Disease through Potato Varieties and Fungicides in Lay-Armachiho District, Ethiopia

“…Potato late blight disease symptoms were first appeared 45 days after planting (DAP) in almost all treatments after flowering and the fungicides spray was started at this time. This result agreed with the findings of Gebremariyam et al [26] that the first symptom appeared on susceptible variety Abalo within 41 days after planting. The first disease incidence data were recorded after 7 days of the spray of the fungicide (52 DAP) and continued until the end of the final disease incidence data of 80DAP.…”

“…AUDPC and final severity were positively and highly significantly correlated (P < 0.01, r � 0.96 * * ). Similar findings have been reported by Gebremariam et al [26] and Ayda [37]. In most cases, the negative correlation of total yield with late blight development was found to be stronger with the final severity than with AUDPC.…”

“…However, Ridomil significantly (P < 0.05) reduced the progress of the disease as compared to Mancozeb fungicide on Jalene and Belete varieties. Similarly, Gebremariam et al [26] also reported that late blight incidence was higher in susceptible local potato varieties than in resistance varieties, and fungicides application significantly reduced late blight incidence as compared to local control plots. Our results are in line with Shiferaw and Tesfaye [28] who reported that the application of fungicides minimized the infection of late blight than the control plots.…”

“…Yield and final severity were negatively and highly significantly correlated (P < 0.01, r � −0.89 * * ) indicating the negative effects of late blight on the total yield of potato varieties. Gebremariam et al [26] also reported that all disease parameters had a negative correlation with tuber yields of potatoes. Applying Mancozeb and Ridomil fungicides gave the highest yield, lowest late blight incidence, severity, progress rate, and AUDPC values for the respective potato varieties.…”