The screenhouse trees will eventually replace the 14 -acre Foundation Block, a collection of 200 varieties of citrus trees growing in a field at Lindcove since 1961. The open-air trees are now threatened by the citrus tristeza virus, which can be transmitted by aphids from diseased trees surrounding the research station. Last fall, four trees at the Lindcove Research and Extension Center tested positive for tristeza. None of the four was in the Foundation Block and all were removed and destroyed. Trees at the station are again being indexed for tristeza and results will be available shortly.
Nurseries use the budwood to grow new citrus trees for farmers.
The citrus tristeza virus was first detected in San Joaquin Valley orchards about 40 years ago. An aggressive eradication program was successful in keeping the disease at very low levels. However, because of concerns about the costs associated with removing infected trees, a petition led to a moratorium on mandatory tree destruction and a voluntary program was initiated. However, he said he is hoping to use the existing Foundation Block for a while longer. They need a chance to grow.