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Abstract
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The potato tuberworm Phthorimaea operculella (Zeller), also known as potato tuber moth (PTM) is one of the major and key pests of crops belonging to the family Solanaceae has emerged in Iran as a serious problem on potatoes, Solanum tuberosum L. In recent years increased efforts have been focused on biological control of the pest using entomopathogenic nematodes belonging to the families Steinernematidae and Heterorhabditidae. These obligate insect parasitic nematodes are capable of parasitizing many important key pests including PTM. An infective is a modified third-stage juvenile is developmentally arrested and well-adapted for long-term survival and host finding which carries symbiotically bacteria from genus Xenorhabdus in its intestine. Bioassay of the pre-pupa and pupa were conducted at different concentrations of infective juveniles of Steinernema feltiae per PTM individual including 1, 5, 10, 50 and 100. The entire experiments replicated twice. The effects of EPN concentrations on PTM pre-pupa and pupa mortality (P<0.05) was significantly different. Highest (84.44%) and lowest (38.09%) rate of pre-pupa mortality were recorded at 100 and 1 IJs/Pre-pupa, respectively and for pupa these rates (25.71% and 2.85%) were recorded at the same concentrations. The results showed that S. feltiae is a promising candidate to involve in further investigation as a bicontrol agent of PTM. Infective juveniles of S feltiae by having the intermediate host finding strategy are able to find sessile and mobile host stages of PTM, this attribute makes this species suitable to involve in IPM of pest with overlapped life stages.
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