Influence of Soil pH and Oxygen on Persistence of Steinernema spp
Kung, S.P.; Gaugler, R.; Kaya, H.K.
Journal of Nematology 22(4): 440-445
1990
ISSN/ISBN: 0022-300X PMID: 19287743 Document Number: 364764
Survival of infective juveniles of Steinernema carpocapsae [Neoaplectana carpocapsae] and Steinernema glaseri [N. glaseri] gradually declined during 16 weeks of observation as the tested soil pH decreased from pH 8 to pH 4. Survival of both species of Neoaplectana dropped sharply after 1 week at pH 10. Survival of N. carpocapsae and N. glaseri was similar at pH 4, 6 and 8 during the first 4 weeks, but N. carpocapsae survival was significantly greater than N. glaseri at pH 10 for 16 weeks. N. carpocapsae and N. glaseri that had been stored at pH 4, 6 and 8 for 16 weeks, and at pH 10 for 1 or more weeks were not infective to Galleria mellonella larvae. N. carpocapsae survival was significantly greater than that of N. glaseri at oxygen : nitrogen ratios of 1:99, 5:95, and 10:90 during the first 2 weeks, and survival of both nematode species declined sharply to less than 20% after 4 weeks. Survival of both nematode species significantly decreased after 8 weeks as the tested oxygen concentrations decreased from 20 to 1%, and no nematode survival was recorded after 16 weeks. N. carpocapsae pathogenicity was significantly greater than that of N. glaseri during the first 2 weeks. No nematode pathogenicity was recorded at oxygen concentrations of 1, 5, and 10% after 2 weeks and at 20% after 16 weeks.