Dynamics of Concomitant Populations of Hoplolaimus columbus, Scutellonema brachyurum, and Meloidogyne incognita on Cotton
Kraus-Schmidt, H.; Lewis, S.A.
Journal of Nematology 13(1): 41-48
1981
ISSN/ISBN: 0022-300X PMID: 19300720 Document Number: 168902
Cotton seedlings grown in a greenhouse and a growth chamber were inoculated with S. brachyurum, H. columbus and M. incognita, singly and in all possible combinations, at 2 initial population (Pi) levels (100 and 300/100 cm3). S. brachyurum alone was not pathogenic to cotton at these population levels. It fed primarily as an ectoparasite, but matured and reproduced within the root when it penetrated. Populations of S. brachyurum increased in the presence of H. columbus, but were suppressed by M. incognita. H. columbus suppressed dry shoot weights of cotton (P = 0.05) at a Pi of 300/100 cm3 soil. Simultaneous inoculation of H. columbus with either M. incognita or S. brachyurum increased H. columbus populations over treatments with H. columbus alone, both at 60 and 90 days after inoculation. M. incognita suppressed cotton shoot weights significantly (P = 0.05) at both Pi levels. Inoculation with S. brachyurum increased M. incognita populations 60 days after inoculation, while H. columbus suppressed populations of M. incognita. Most larvae of M. incognita did not develop to maturity in the presence of H. columbus. Giant cells aborted and were necrotic 20-25 days after inoculation. Since M. incognita and H. columbus feed on different tissues, the inhibition of M. incognita may have resulted from a physiological effect of H. columbus on the host.