Host-Range, Distribution, and Bibliography of the Reniform Nematode, Rotylenchulus reniformis, with Special Reference to Puerto Rico

Abstract

The reniform nematode which comprises five described and several undescribed species has been recognized as a dangerous plant parasite. It is undoubtedly one of the most common nematode types in our soils and its populations are usually very high. It has been found associated with most of our agricultural crops including pineapple, coffee, pigeonpea, tobacco, sugarcane, ornamentals, and vegetables. Increasing interest in the study of this parasite has suggested the existence of several other species which still remain undescribed. In Puerto Rico, it is now evident that several species are present. This statement is based on differences observed in relation to morphological and pathogenic characteristics among different populations. A list of 201 different host plants from 15 countries, including Puerto Rico and Caja de Muertos, an adjacent Island south of Puerto Rico, is given. Most of them are the result of field observations, but in many cases the susceptibility of the host has been corroborated on greenhouse inoculation trials. Eighty-nine host plants were found in Puerto Rico, 15 of which are new hosts to Rotylenchulus spp., and 74 to R. reniformis. Differences in degrees of susceptibility have been recognized, pigeonpea being the most susceptible, and ornamental crotalaria only a carrier. In Puerto Rico, the nematode has been located in 40 localities in some of which several plants have been found to be hosts. Humidity, elevation, temperature, and soil pH do not seem to be limiting factors in relation to the occurrence and distribution of the nematode. It occurs more in loamic soils but clay or sandy soils with little organic matter harbor large numbers if a suitable host plant is present. A general list of publications regarding this nematode citing 89 papers is also included.