Dr. Menge recommends that all replanted groves be treated in July with fungicides registered to control Phytophthora species during the first two years the new trees are in the ground. The longer that I am on this job, the firmer is becoming my conviction that if a grower wants to change the existing variety on a given piece of land, the best approach is to replant the block to new trees rather than attempt to bud the older block over with a new variety. This belief is especially firm if the existing block is older than 25 years. If all goes well, budded trees may beat replants into production. However, things in general do not usually appear to go well with older, rebudded trees.
Young trees are vigorous, and once they come into production, produce high yields of big fruit.
In Kern County, the cost of removing old, existing trees, in some cases, can be offset by selling of the wood to cogeneration plants. Removing the old orchard can also give the grower a chance to correct some existing problems. Layered soils can be slip plowed or ripped, and groves that are infested with nematodes or fungi can be treated more effectively in the absence of living trees. While as of the date of this writing there still appears to be no sign of the dreaded El Nino, many growers in Kern County are preparing for the worst by paying particular attention to their Fall copper sprays. In Kern County, growers probably apply copper sprays as much as to prevent Septoria related stains on the fruit as to prevent brown rot.