In This Issue

Mechanical Harvester Demos to be Announced

There will be demonstrations of the olive industry sponsored mechanical harvester in the San Joaquin Valley this fall. Watch for an announcement from the California Olive Committee regarding location and time.

Fall Copper Sprays

Probably the most important spray an olive grower can apply is Copper immediately following harvest. Copper applied then and dissolved in subsequent rainfall protects the tree against both the "Peacock Spot Fungus" (AKA "Olive Leaf Spot") and the "Olive Knot" Bacterium. Here are some things to know about each disease and copper application.

Peacock Spot: For best effect, copper needs to be applied prior to winter rains - rain disseminates the fungus spores for subsequent new infections of leaves. No difference in control exists between the following copper products: Bordeaux (copper sulfate and lime), COCS, Kocide, Nordox, Micro-cop, and Copper Count N (we did not test all fixed coppers); the important point is to have copper on the trees prior to winter rains, and not as much what copper is selected.

In any one year, one copper treatment prior to winter rains (November) is as effective as two applications (November and January). However, where the double treatment is consistently used year after year, long term disease infection is suppressed.

Olive Knot: Copper, in ionized form, kills the Olive Knot bacterium. Recent research has shown that, in addition to the fall spray, an additional application in mid-March is very important in preventing knot (gall) development. This new strategy is suggested each year. If freezing temperatures occur, sufficient to cause splitting bark, an additional treatment following the freeze event is recommended in the interim.

Black Scale: An excellent time to control black scale is following harvest, as the insect is in an extremely susceptible stage for chemical treatment. In fall, there are also more chemical choices than when fruit are on the tree. Further, the orchard is accessible prior to winter rains.

If populations are heavy at harvest, we suggest a fall application be made. Also, remember that pruning to "thin out" olive trees next spring will maintain excellent control of this pest; black scale suffers substantial mortality in a dry, summer heat. Avoid dense trees.

Remember: Black scale treatments and fall applied copper can, in some cases, be combined after harvest. Check compatibility with your manufacturer first before combining these treatments.

Fall Weed Control

Residual, preemergence herbicides need to be applied to olives in October and November before winter weeds germinate. If applied late, following weed germination and growth, a contact herbicide needs to be included as a "knock-down." The 1999 Herbicide Label Status for Olives is located below.

1999 Herbicide Label Status for Olive

R = registered; NB = registered in nonbearing orchards and vineyards only.

Note, this is intended as a general guide only! Before use of any herbicide consult the label carefully. Labels change frequently and often contain special restrictions regarding specific use of a company's product.

Mark your Calendar for Next Year's "California Olive Day"

The "California Olive Day" is scheduled for March 9, 2000, at the Lampliter Inn in Visalia, CA. Watch for the agenda and registration materials in late winter.