WVPP Resistance to Gall Rust Study

Det Vogler and Annie Mix

In 2006 the WVPPCA sent seeds from 100 families to the US Forest Service Placerville, CA Research Center where they were sown for the study. These seedlings will be outplanted and exposed to the gall rust inoculum to see if families vary in resistance/susceptibility. Det and Annie sent the following progress report.

The Willamette Valley ponderosa pine seedlings are still in supercells and surviving fairly well out in the lathhouse. We plan to plant them in the ground spring 2010. They are going to be planted in the midst of a Pinus radiata trial for gall rust susceptibility, or perhaps resistance.

The radiata trial was planted in 2006 and is entering its fourth season of being showered with Western Gall rust spores. One-third of the radiata pines were systematically removed in 2008 and another third were removed in 2009. This procedure is according to a study

design of Bill Libby's, which allows one to maintain the structure of the test while thinning to promote space for the residual trees, which would be crowded out by now. These are radiata pine and many are over 5 meters tall so you can imagine how the plantation would look if we didn't thin. By waiting until after the second thinning, we are ensuring that there will be a good source of inoculum within the plantation. Then, we will interplant the Willamette Valley ponderosa pine in the spaces left where trees were removed, and then remove the remaining one-third of the radiata in 2010, leaving only Willamette Valley ponderosa.

Det Vogler and Annie Mix are tree/plant pathogen geneticists with the US Forest Service in Placerville, CA.


Last Updated 02/28/10