Root lesion nematodes (Pratylenchus penetrans) in conjunction with the fungal pathogen Verticillium dahliae create the disease complex, potato early die, which can drastically reduce potato (Solanum tuberosum L.) yields. In Michigan, this disease complex is often managed using broad-spectrum soil fumigants such as methyl bromide, metam sodium and 1,3- dichloropropene, which can be harmful to applicators as well as soil and environmental health. Since the phase-out of methyl bromide in 2005, alternative control tactics to soil fumigants have become increasingly important to potato growers. In this thesis I investigated the use of (1) manures and manure-based composts and (2) non-fumigant nematicides and fungal-based biocontrols and their efficacy in reducing potato early die incidence. In laboratory trials, poultry manure and a blend of poultry and dairy manure compost (Layer Ash Blend) provided significant control of root lesion nematodes with 0% survivorship at rates of 5% (vol/vol) or higher. In field trials, I did not observe significant (P < 0.05) reductions in nematode populations regardless of treatment but did see a reduction in germinating V. dahliae microsclerotia in plots treated with poultry manure. Of the nematicides tested, Salibro treatments significantly reduced root lesion nematode and V. dahliae populations. From this research, it is clear that non-fumigant alternatives are possible for Michigan potato growers.
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