Differences in Population Increase, Host Preferences and Frequency of Morphological Variants Among Isolates of the Banana Race of Radopholus similis

Abstract

Physiological differences and morphological variations of the banana race of Radopholus similis (Cobb) Thorne were studied. Population increase of 6 isolates from different banana growing areas was measured in carrot disk cultures at two intervals. The Honduran isolate presented the lowest reproduction rate at 45 and 75 days, while the Panama-Armuelles and the Ecuadorian isolates showed the highest for the same periods respectively. Four isolates of R. similis were inoculated into nine different crops under greenhouse conditions. The Honduran isolate presented the highest population increase in sorghum, cowpea and pigeon pea seven weeks after inoculation as compared to the Panamanian and Ecuadorian isolates. Okra, corn and tick trefoil (Desmodium ovalifolium) were poor hosts of the nematode whereas tomato, sweet potato and sour orange were nonhosts. Observations on the morphology of female tails of R. similis revealed differences in the frequency of pointed and rounded tails within 1