Biological and Physico-chemical Properties of Causal Agent of Virus Disease of Coccinia barteri (Hook. f.) Keay in Calabar, Cross River State

Abstract

The physico-chemical properties of the causal agent of virus disease of Coccinia barteri (Hook. f.) Keay were studied. The virus causing the disease was characterized using diagnostic tools such as host range, longevity in vitro, thermal inactivation point, dilution endpoint and aphid transmission. The virus was mechanically transmitted from the natural host (C. barteri) to the healthy test plants in the green house. In the biological properties, the virus was successfully transmitted by Aphis spiraecola (obtained from Chromolaena odorata (L.) R. M. King & H. Rob.) from infected Cucumeropsis mannii Naudin to a healthy C. mannii in a non-persistent manner and had a narrow host range limited to the family Cucurbitaceae. In the physico-chemical properties based on crude sap with an unknown virus concentration, beyond which infectivity was lost. It was readily inactivated by heating to 35 – 65°C for 10 minutes in determination of thermal inactivation point. The virus had a longevity in vitro of between 4 – 5 days beyond which it was non-infectious. Symptoms induced by the virus were leaf cupping, mottle chlorosis, blisters, stunted growth, rugosity, leaf malformation and mosaic patterns.