August 2005. Cook Islands asked about control of nematodes on noni, Morinda citrifolia. Information on the use of 'organic' methods was requested.
A good biological control agent is "BioAct WG" (conidia of Paecilomyces lilacinus). Good results were reported on various crops (tomato, gombo/okra, carrot, cucumber, basil). There was no knowledge of research done using BioAct on noni. But as the nematodes (eggs, larvae and adults) are drastically reduced in soil following its use, noni plants should be protected.
There is information about BioAct on the website of the manufacturer: www.prophyta.com/
Some info in French is also available on http://www.oesterlin.de.vu/
And a summary on nematode control methods can be found on Ecoport at:
In the Cook Islands, and countries with similar climates, root knot nematodes will not survive for more than a couple of months in soil which is free from living host plants. So, if the soil is cultivated and kept totally free of weeds for 2 months, it should be possible to grow clean noni in it more or less indefinitely, provided there is a 'clean' fallow strip, a few metres wide, around the edge.