Nematropica (1997) 27, 41-52
R.K. Jansson and S.H. Lecrone (1997)
Effect of sweet potato cultivar on efficacy and persistence of entomopathogenic nematodes for control of Cylas formicarius
Nematropica 27 (1), 41-52
Abstract: Control of the sweet potato weevil, Cylas formicarius (F.), with different biological and chemical insecticide treatments was evaluated on two cultivars of sweet potato, Ipomoea batatas (L.) Lam. cvs. Jewel and Picadito, differing in susceptibility to C. formicarius. The effectiveness of two entomopathogenic nematodes, Steinernema carpocapsae (Weiser) All strain and Heterorhabditis bacteriophora (Poinar) HP88 strain, were compared with that of two chemical insecticides made in combination. Weevil control and nematode persistence (recycling) were evaluated. Weevil counts did not differ between cultivars nor among biological and chemical insecticide treatments during the first sampling period. On the second sampling period, numbers of live and nematode-infected weevils were higher on Jewel' than on 'Picadito'. Weevil counts were lowest on plants treated with All followed in increasing order by those treated with chemical insecticides, HP88 and nontreated plants. Root damage and percentage marketability did not differ between cultivars; however, lower damage scores and higher percentages of root marketability tended to be found on plants treated with 13P88 nematodes and chemical insecticides than on those treated with All nematodes and on nontreated plants. Interactions between sweet potato cultivar and biological and chemical insecticide treatments were significant suggesting that weevil control achieved by each insecticide treatment was affected by cultivar. Recovery of nematode-infected larvae was higher in plots planted with 'Jewel' than in those planted with 'Picadito'. Recovery of both nematodes was comparable up to 137-140 days after the last application, albeit recovery was also affected by the nematode x cultivar interaction. Although recovery was comparable between nematode strains in plots planted with 'Jewel', recovery of All was higher than that of HP88 in plots planted with 'Picadito'.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Richard K. Jansson
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
