Host-parasite relationships of Hoplolaimus columbus on Cotton and soybean.

Hoplolaimus columbus suppressed growth and pod yield of soybean in greenhouse tests. Although populations of H. columbus decreased in short-term experiments, increases occurred in long-term studies. The nematode caused extensive damage to the cortical parenchyma and occasionally to the endodermal-vascular region of both cotton and soybean roots. The nematode frequently entered secondary root primordia. Roots of soybean parasitized by H. columbus at high inoculum levels were severely damaged. The relationship of populations of H. columbus and stunting of soybean and cotton is discussed.