Passionfruit woodiness potyvirus (PWV) causes passion fruit woodiness disease (Taylor and Greber, 1973; Wang, 1983). The virus causes serious damages in passionfruit vines in all producing region, reducing leaf area, decreasing productivity, yielding fruit without commercial value and reducing the economic span of the orchard (Rezende, 1994; Gloria et al, 2000). First described by McKnight (1953), is a potyvirus with flexuous particles of 670 to 750nm in length and 12 to 15 nm in diameter and a genome consisting of a single stranded, positive-sense RNA (Taylor and Greber, 1973; Hollings and Brunt, 1981). PWV has a single type of coat protein (CP) of 33.0 kDa and induces pinwheels inclusions in the cytoplasm of infected cells. The virus is transmitted in a non-persistent manner by aphids Myzus persicae Sulz (Taylor, 1959) and Aphis gossypii (Greber, 1966), and mechanically by grafting or by contaminated cutting tools (Nattrass, 1944; Wang, 1983). It was discovered that the virus cannot be transmitted by seeds (Pio-Ribeiro et al 2000) Apart from passion fruits, PWV has wide range of hosts, composed majorly of Passiflora and Leguminosae species, but over 44 herbaceous plant species in 21 genera of 6 families are susceptible to PWV (Edwardson and Christie, 1991). Diagnostically susceptible host species, Passiflora edulis (passionfruit) show mosaic, rugosity and distortion of leaves, with yellow spots on older leaves, P. edulis f. flavicarpa (golden passionfruit) and P. edulis x P. e. f. flavicarpa (hybrid passionfruit) develop pale green to chlorotic ringspots together with leaf mosaic, while, P. lathyroides and P. vulgaris show chlorotic to necrotic local lesions and faint local lesions to veinal necrosis, respectively. Fruits of Passiflora species are frequently distorted, pericarp hardens and thickens, giving the disease the common name of `woody fruit'. Several strains of PWV have been recognized, distinguished by the severity of symptoms they produce in P. edulis. Between, 1966-71, Greber (1966; 1971) described two strains; a severe strain that is mild in P. suberosa but causes tip blight and a complete crop loss in P. edulis and a mild strain which occurs naturally in C. pubescens but causes a mild mosaic in P. edulis. All strains have reported to appear closely related serologically. Given the different nature of symptoms induced by PWV in Uganda, many strains may be available in the country; moreover, a mixture of strains could be infecting a single plant. Additionally, the possible diversity of strains and differences in property is bound to have important implications for serodiagnosis, epidemiology and economic effects of the virus, and therefore, in-depth understanding of the virus in Uganda is essential for a successful control. Given this background a trial has been setup at National crops resource research institute at Namulonge. The aim of the research is to establish the special and temporal spread, transmission and species composition and abundance of potential vectors of passion fruit woodiness disease.
High pop’n of thrips compared other pests.
All aphids observed were winged.
Purple passion fruit most affected by the virus.
The virus is spreading in a non persistent manner.
Virus infection was confirmed in the field characterized by mosaic, rugosity, distortion of leaves and distorted, hardened and thicken pericarp.