Estimation of damage caused by the burrowing Nematode, Radopholus similes (Cobb, 1893) Thorne, 1949 (Tylenchidae) (Guerot, 1970) on Musa germplasm in green house studies in Rivers State, Nigeria

To define the extent of damage that Radopholus similes alone can cause in plantain (Musa sp) CV Agbagba, an inoculation experiment was conducted under greenhouse (tropical) conditions using sword suckers of Musa Sp. as test plants. Three (3) inoculum levels of Radopholus similes 50, 250 and 500 nematodes were employed. There were 4 groups of potted plants filled with sterilized soil made up of 5 replicates each. The 1st group of 5 replicates were inoculated with 50 nematode vermiforms per plant while the 2nd and 3rd group had 250 and 500 nematode vermiforms per plant introduced into them respectively. The 4th group served as the control with no nematodes introduced. The period of observation was three (3) months. Damage was determined by accessing the nematodes reproduction rates. This was done by the extraction of nematode species from root samples. (Maceration – sieving method) for nematode count. Observations were made on the sensitivity of the genotype, root necrosis and plant growth parameter (freshroot weight, plant height, girth, dry root, green leaves etc). Results showed that infected plants showed a significant increase (P 0.025) in dry leaves and dry roots at all treatment levels while fresh root, plant girth and ok roots reduced mean values compared with recorded values of non-infected plants. The percentage difference between values of infected and their non-infested counterparts was 89.3 That mean values of dry leaves and dry roots of nematode infested plant recorded significantly (P 0.025) higher values than those of control showed that R. similes are damaging to plantains. Males and females of R.similis recovered at treatment levels 50, 250 and 500 were highly significantly (P 0.05) different from those recovered from control. Reproduction of nematodes occurred at all treatment levels. Plantain plants were severely damaged by R. similis as shown by increased dry roots, dry leaves and high occurrence of males (and females) which are useful growth parameters in determining susceptibility.