In the previous Michigan State University Extension article, “Combating root-knot nematodes in daylilies: Experimental results – Part 1,” the team of MSU explored pre-plant dipping practices to best control northern root knot nematodes (Meloidogyne hapla). To recap, northern root knot nematodes are detrimental to many crops in Michigan, including bare-root ornamentals like daylilies, and can cause significant economic losses. Daylilies are typically a three-year crop and fumigation can be an effective management tool in reducing nematodes in the first year of production. However, in the subsequent years of that production cycle, fumigants cannot be reapplied thereby allowing northern root knot nematode populations to reestablish and infest the plants. Our first trials explored root dipping practices to combat northern root knot nematodes, and they have since begun exploring fumigant alternatives that can be reapplied each year of production.
In 2018, a field trial was established with ‘Going Bananas’ daylilies to test nematicides and composts (Table 1) compared to an untreated and fumigated control over the course of the three-year production cycle. They monitored plant growth and nematode populations in roots and soil.