This greenhouse study was undertaken to determine whether the addition of arbuscular mycorrhizal (AM) fungi to creeping bentgrass (Agrostis palustris), a common golf course turfgrass, can reduce damage by root parasitic nematodes. The study is divided into two complementary parts: prevention and treatment. In the former, AM fungi were added to bentgrass before the introduction of the nematodes; in the latter, AM fungi were added after nematodes. Prevention is designed to test the efficacy of AM fungi in preventing nematode infection and damage. Treatment is designed to test the efficacy of AM fungi in reducing nematode damage post infection. Grass seeds were planted in a sterilized soil: sand mixture and after 2, 3, or 5 weeks of growth one of 11 different applications or application combinations was applied. There were seven control or single factor applications (neither AM fungi nor nematodes added, AM fungi added at week 2, 3, or 5, nematodes added at week 2, 3, or 5) and four application combinations (AM fungi added at week 2 and nematodes at week 3 or 5 and nematodes added at week 2 and AM fungi added at week 3 or 5). The plants were grown for 12 weeks, harvested and the following data collected: aboveground and belowground plant biomass, AM fungal root colonization, root nematode damage, nematode population size, and leaf color.
Results/Conclusions
The presence of AM fungi in the soil before nematode introduction (nematode prevention) greatly reduces the size of the soil nematode population but does not improve plant performance. AM fungal application to an existing nematode infestation (nematode treatment) significantly increases aboveground biomass and darkens the color of leaves. We conclude that AM fungi can be effective biocontrol agents when added post nematode infection, combating nematode damage in golf courses that grow creeping bentgrass.