Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/1994
Publication Date: N/A
Citation: Interpretive Summary: The ability of the plant-parasitic nematode Tylenchorhynchus zambiensis to feed and reproduce on various crop plants was evaluated under greenhouse conditions. Various inbreds and hybrids of corn from the U.S. and Africa supported large populations of the nematode, but the nematode was weakly parasitic on corn and caused little damage. Nematode populations increased on wheat and soybean, but did not damage these crops. Nematode populations declined on alfalfa, red clover, white clover, and sunflower. These results show that although populations of the nematode can increase on corn, crop damage under field conditions probably will not occur. If nematode populations were to increase, crop rotation with alfalfa, clover, or sunflower would cause nematode populations to decline dramatically and would be an effective control.
Technical Abstract: The host suitability of five genotypes of maize (zea mays), alfalfa (Medicago sativa cv. Cimarron), red clover (Trifolium pratense cv. Mammoth), soybean (Glycine max cv. Bragg), sunflower (Helianthus annus cv. CCA82-2), wheat (Triticum aestivum cv. Pioneer 2508), and white clover (Trifolium repens cv. Dutch White) to Tylenchorhynchus zambiensis were evaluated in two greenhouse experiments. Plants were inoculated with 5,000 nematodes, and populations and effects on growth were determined 60 days after inoculation. The host status was determined by calculating a reproductive factor (R) where R = final populations (Pf)/initial population (Pi) and where R < 1 = non host; R = 1.1-4 = poor host; R = 4.1-10 = fair host; R = 10.1-20 = good host; and R > 20 = excellent host. Maize genotypes M017 X A634, MM603, ZM-1760, TGR1349, Natal 8-Row flint were excellent hosts for T. zambiensis. Although plant growth was minimally affected by T. zambiensis, highest numbers of nematodes per gram of dry root weight were recovered from M017 X A634. The maize genotype TGR1349 was the most susceptible of the maize genotypes evaluated, having a significant reduction in plant growth. Dry root weights in all the maize genotypes were higher in noninoculated controls compared to inoculated treatments. Wheat was a good host for T. zambiensis, but plant growth was not affected by the nematode. Alfalfa, red clover and white clover, were poor hosts for T. zambiensis. Soybean was a poor host in the first experiment but was a fair host in the second test. Sunflower was a non-host.