Now is the Time...
by Eunice Messner

PRUNING: If you are a fan of Gary Matsuoka (Laguna Hill Nursery) and read his educational ad in the "Register" each Saturday, then you know that he advocates pruning fruit trees now. If you missed it - this what he said:
"This is the time of year that I finish pruning my fruit trees to control height, I used to perform this task in winter, but not any more.

Fruit trees, such as apple apricot, nectarine, peach and plum, stop growing in early fall and start producing flower buds at the base of leaves that have good sun exposure.
These buds will open next spring and become next summer's harvest. Up until recently it was traditional to prune these fruit trees in winter.
Because controlling the size of our fruit trees was usually of primary importance, we always cut off the
top branches, which are the branches with best sun exposure and subsequently, loaded with flower buds.
If the trees are cut back now, flower buds will form on the remaining branches, wherever there are leaves exposed to sun. In the winter I don't need to prune much, just a bit of corrective pruning, such as eliminating parallel and
crossing branches.

Older references always explained fruiting wood and fruiting spurs and how to develop and preserve them. Modern research shows that mindless machine hedging doesn't compromise the fruiting wood as long as the timing is proper.
In the spring my 8 foot tall fruit trees bloom and set fruit. By summer they have grown substantially. In July I trim off most of the new growth, usually 3 -4'. By fall they have grown another 3-4', which I am pruning now. There is no fruit on new growth, so my pruning doesn't affect the current crop. With proper timing my trees produce a heavy crop on a small, compact tree."

GLASSY-WINGED SHARPSHOOTERS ON CITRUS (Copied from U.C, Extension, San Diego County, Avocado and Citrus Notes)

"Glassy-winged sharpshooters entered California in 1990 and are now found throughout Southern California and southern part of the San Joaquin Valley in high populations. They have the potential to hitch-hike to Northern California and other states on nursery stock, fruit, and inside the passenger compartment of cars and trucks. The real devastation caused by these insects is their role in spreading Pierce's disease in grapes, a disease caused by the xylem-inhabiting bacterium Xyella fastidiosa. We have always had Pierces's disease in grapes in San Diego Count, but it has spread rather slowly via the blue- green sharpshooter as a vector. Now, with the glassy-winged sharpshooter, we have a much more efficient vector of the disease. If you have been reading the newspapers about the Pierce's disease epidemic in Temecula, this information is not new to you. (You can also understand why we do not recommend planting wine grapes in the western areas of San Diego County).

What about citrus? The insects have increased to enormous populations in Pauma Valley this summer, and so far we do not have a disease for them to spread. Are the insects causing any harm to the trees just by their presence? The first symptom that you see when you look at citrus trees with heavy populations is the white residue on the leaves and fruit. This residue consists of the mineral salts in the xylem fluid that is excreted through the bodies of the insects. Basically, this residue is the fertilizer that you just put on the trees, plus other minerals from the soil The second symptom is the steady stream of small droplets pouring out of the insect bodies. The insects are extracting a small amount of carbohydrate from the xylem fluid, thus a lot of water moves through the insects in order for them to get enough food to survive. Each insect produces about 10 ml of liquid a day. If a tree has 1000 insects, then 10
liters of water is lost each day just due to insect feeding! An effect on fruit size is strongly suspected. This is the second year that we have seen abnormally small fruit in the Valencias. This is difficult to prove because large trials comparing pesticide-treated trees vs. non-treated must be conducted; but Phil Phillips (our IPM advisor in Ventura County) managed to do such a trial on lemons, and he did show that a heavy insect infestation resulted in small fruit.
Also contributing to small fruit is the high nitrogen found in the leaf analyses of several groves. The nitrogen should be about 2.5%, but several analyses showed the leaves were in the 2.9 -3.1% range. Not only does this lead to small fruit size, but also high nitrogen is known to cause re-greening in Valencias, a problem also seen in Pauma Valley this year."