Prevalence and Assessment of Disease Incidence and Severity in Citrus Orchards of Sub Zoba Hamelmalo

DOI: https://doi.org/10.55434/CBI.2021.9105

Abstract

Citrus (Citrus spp. L.) production in Eritrea covers over 2409 ha of the land but the average potential of production is 91 q/ha to 150 -170 q/ha. This low yield might be due to lack of knowledge on management practices, adverse environmental factors and different diseases caused by various pathogens. Moreover, there is no proper recorded data on the identification of diseases on citrus and its intensity, hence, this survey: to identify the prevailed diseases; assessment of disease incidence, severity and calculate the ‘Area Under Disease Progress Curve’ (AUDPC).  A survey was carried out in three orchards in each five citrus producing villages (Fredarb, Tsebabo, Hamelmalo, Wazntetand Genfelom) from sub-zoba Hamelmalo.  The fungal diseases found on citrus were brown spot, sooty mold, gummosis, black spot, scab and melanose; the bacterial infection was canker; and viral diseases were leprosis and cholorotic dwarf. The highest percentage of disease incidence was recorded Fredarb with 77.16% and the lowest was found in Genfelom with 47.29 % in the same month.  The highest percentage of diseases severity was found in Hamelmalo with 40.02%.  On the other hand, the least percentage of disease severity was found in Genfelomwith 25.04%. The influence of epidemiological factors showed that they could be some of the reasons to develop and spread the mean disease incidence (65.6%) in February, 2018. The AUDPC was recorded highest (2829) in the orchard 3 of Hamelmalo, and lowest (1152) in orchard 3 of Tsebabo. A decreasing trend of temporal disease data from the first month to the third month was estimated in the orchard 2 and orchard 3 of Fredarb, orchard 2 of Genfelom, orchard 1 of Hamelmalo, all orchards of Tsebabo and in both orchard1 and 3 of Wazntet villages.