Abstract

Andrew F. O and Owunari Great

The degree of Okra mosaic virus (OKMV) at different growth stages of okra plants was studied using a
netted barrier method. In a two factor RCB design with three replications, a 2 m high netted barrier were
laid out in unit plots of 2 x 2 m using eight treatments: T1- Netting up to 7 days after seedling
emergence (DAE); T2- Netting up to 14 DAE; T3- Netting up to 21 DAE; T4- Netting up to 28 DAE; T5-
Netting up to 35 DAE; T6- Netting up to 42 DAE; T7- Netting up to last harvest; T8- No netting (untreated
control) . The number of Podagrica unifoma (Jac.) and Podagrica sjostedti (Jac.) were recorded weekly
and the number of virus infected plants from all the plants of each replication. It was observed that by
preventing the vectors (P. unifoma (Jac.) and P. sjostedti (Jac.)) of okra mosaic virus (OKMV) by the use
of 2 m high net barrier around the okra plots, until the plants became more than 21 days old after
emergence, decreased the populations of P. unifoma (Jac.) and P. sjostedti (Jac.) and virus infected
plants of both the resistant and susceptible okra varieties. Low virus infection in plots netted for 21
days after seedling emergence or more resulted in 25 - 50% increased yields in both tolerant and
susceptible varieties. These observations by this study showed that virus infection in okra plants at
growth stages earlier than four weeks has more severe effect on the physiological performance of okra
plant and subsequent reduction in growth performance and yield of okra. Therefore some effective
control measure is very necessary at early growth stages of okra plant.