Comparison of the host status of different rootstocks to ring nematode (Criconemoides xenoplax)

The objective of this project was to evaluate some of the commercial stone fruit rootstocks’ status as hosts for ring nematode (RN) (Criconemoides xenoplax).  This was done by inoculating rootstocks with a known number of RN and determining the increase in populations over time.  The reproduction factor (RF) was then calculated and used to rank the rootstocks according to their host status.

Seven rootstocks were evaluated.  All the rootstocks tested were hosts for RN.  However, there were differences and this information should be used when deciding on a rootstock in a specific situation.  The results support observations that poor hosts for Meloidogyne spp. (root-knot nematode), such as Flordaguard and Maridon, are good hosts for RN.  There also seems to be a trend that apricot rootstocks are less successful as RN hosts than rootstocks originating from peach and plum origin.

Based on their RF values the rootstocks tested were ranked as follows:

1. Flordaguard Very good host
2. Maridon Very good host
3. Kakamas Very good host
4. GF 677 Good host
5. Viking Host
6. Royal Host
7. Soldonné Host

One of the outcomes of this project is that we now have a reliable protocol to determine the RF values of RN for stone fruit rootstocks.  This protocol, with small adjustments, could also be used to determine the RF values for other nematodes.

In future all commercial stone fruit rootstocks should be tested and ranked for their nematode host status.  This will be a huge benefit to growers in making informed decisions when choosing a rootstock.