Using Elbon rye for Biological Control of Root Knot Nematodes; a Gardening Experiment.

Elbon Rye in Raised Bed, March, 2018

Last summer, 2017, our tomatoes produced a small number of very small fruit. Part of the issue was the incredible number of “stinkbugs”that invaded and damaged both the tomato fruit and the tomato plants. Another issue was nematodes.

There are many beneficial microscopic nematodes found in soil; however, Meloidogyne spp – commonly called root knot nematodes – are incredibly damaging to root systems. These roundworms are very difficult to control once in the soil. Fumigation techniques require the use of highly toxic chemicals – something we will not use. Over winter, decided to try to selectively reduce the root knot nematodes. A method of biological control is using Elbon rye – a nematode trap plant. Another biological control is to use marigolds (Tagetes spp) in warmer weather.

We used marigolds around our Pepper plants last year, and saw some “reduced” nematode activity on plants closest to the marigolds. (Peppers are in the same family as tomatoes, so they will be targeted by the same pathogens.) Over the winter months, we planted the Elbon rye as a trap crop to hopefully reduce the numbers and thereby reduce damage to the Spring tomatoes. Once a nematode enters the Elbon rye root system, that nematode is unable to leave.

The tomatoes will be planted in about 3 weeks, once the likelihood of another frost is minimized (we keep frost cloth on hand for both late Fall and early Spring vulnerable plants like tomatoes). We are hoping for 2 changes; 1) improved yield (testing the same tomatoes from last summer), and 2) fewer damaged roots. If root damage is noticed early in the season (we are planting seeds so it’s easy to set out a new crop, that just reduces the amount of time that fruit will set because fruit will not set on plants when the temperature consistently exceeds 90 to 95 degrees Fahrenheit.

Watch for updates later this Spring or into Summer.