NEWSLETTER ARTICLES

Small Farms and Specialty Crops

From our Central Coast Agriculture Highlights newsletter
June 1997 issue:

INITIAL RESULTS FROM BLACKBERRY
VARIETY EVALUATIONS
by Mark Gaskell

Trials were established in 1995 and 1996 to evaluate several commercial varieties of raspberries and blackberries at different sites along the Central Coast. The initial results from the establishment year raspberry production has been reported previously and these trials are ongoing. Blackberries produce little if any fruit during the establishment year, and this is the first season where reliable data is expected.

One of the key objectives of this project has been to identify varieties of raspberries and blackberries which may be managed to produce earlier or later than traditional production in this area. Traditionally, production of fresh market berries has been concentrated in a relatively narrow period between late May and September/October. Prices for fresh market raspberries and blackberries can be quite attractive in the early and late season (April-June and October-November). Imports from offshore production in Chile, New Zealand, and Guatemala typically dominate the market from October to June. Prices tend to be higher during this period.

Blackberry production on the South Central Coast has consisted of Ollalie blackberries during May and June. Some Ollalies are also grown in Watsonville, and in July and August there is also some production of Chester Thornless, Shawnee, and Cherokee blackberries in the Watsonville area. Some fresh market boysenberries are also grown in coastal areas as well as in the northern Central Valley.

Another key objective of these trials is to evaluate some of the more erect-growing blackberry varieties which are easier to manage in an intensive fresh market production system. Some of the varieties are also thornless which could be a desirable trait for ease of management. The blackberry varieties in the trial include Rosborough, Chester, Black Satin, Shawnee, Arapaho, Navajo, and Choctaw.

The thornless varieties are Arapaho and Navajo out of the University of Arkansas breeding program; Chester from the USDA/SIU program in Illinois; and Black Satin from the University of Maryland. Rosborough, an older low chill variety from Texas, and Shawnee and Choctaw from Arkansas are thorny varieties. Most of the varieties are erect-growing types; only Black Satin and Chester are semi-erect.

Data collected thus far in this area shows that all of the varieties are vigorous vegetatively, and many are flowering and, in some cases, fruiting in early May. Rosborough is the earliest with the first picking coming the last week in April. Rosborough has been producing 1 to 1-1/2 half-pint baskets (180 grams per half-pint) per week per plant for the last week in April and the first three weeks of May. This is equivalent to at least 200 flats per acre per week. Typically, Ollalieberries begin producing in late May along the coast, and thus it appears that Rosborough will fit very nicely into an early season production window which will lead into the Ollalie harvest. Several of the Arkansas varieties also have green fruit in May, so they eventually may offer additional production window options as well.

It may be possible in subsequent seasons to use pruning management to extend the harvest season even further. Winters are relatively mild and the low chill varieties may be induced to set flowers and fruit early. Pruning may also extend the harvest of one or more varieties later into the fall.

Rosborough is extremely vigorous, but also quite thorny. In Texas, it is managed in large hedges which are mowed to the ground every year or every other year. It can also be trained to a wire and pruned for extended, intensive production. At a later date I will have additional data on production cycles of the different varieties under coastal conditions.

Rosborough and an older sister variety, Brazos, form the backbone of the Central American winter blackberry export industry. This is important because it indicates that the fruit is already established in market channels and can be managed to ship well and endure 7 to 10 days in the wholesale market stream. Fruit are sweeter if allowed to ripen longer on the plant, however, and local sales and nearby markets would be preferred whenever possible for shippers of this type of blackberry.

We have observed relatively few pests thus far. Orange rust has been a problem in the late season for the raspberries, but blackberries have thus far been free of diseases. Redberry mite (Acalitus essigi) appeared in ripening blackberry fruit in large numbers in April and May. Fall and dormant season lime/sulfur application is helpful for controlling redberry mites, but we will be looking at combinations of sulfur followed by an attempt to establish various species of predatory mites. Little is known about the efficacy of predatory mites for redberry mite control in this area, and I will have something to report at a later date. Two-spotted mites are appearing in the raspberries, and it is likely that populations will continue to rise as the weather warms. There is data available on the value of Phytosielius persimilis for control of two-spotted mites in strawberries and brambleberries. Recommendations typically call for the application of persimilis mites at low rates at the first sign of two-spotted mites, so that predator populations will keep pace with the two-spotted mite pests. More later on production and production cycles for raspberries and blackberries on the Central Coast.

GARLIC WATER MANAGEMENT
by Mark Gaskell

Several growers have inquired recently about various aspects of garlic management related to irrigation and harvesting. It is important that water be adequate throughout the period of normal vegetative development. Water stress during vegetative development will adversely affect plant development and eventually bulb size. According to Oregon State University, water stress may also "de-vernalize" garlic bulbs leading to a reversal of the cold temperature bulbing induction and an interruption in bulbing.

Water requirements are similar along much of the coastal growing areas, typically varying from 0.5 to 1.5” per week depending upon the time of year. Inland areas away from the coast may experience periods of warm, dry weather when as much as 3” per week may be required. Garlic has a root system restricted to the top 6” to 10”, so little soil moisture storage should be assumed. Finer textured (clay-loam) soils will require less frequent irrigation than sandier soils. Friable soils are also preferred for garlic because they are less likely to cause bulb deformation. Fields should be checked regularly as they approach harvest according to Richard Smith, Farm Advisor in San Benito, Santa Cruz, and Monterey counties. Water should be cut off about one month prior to harvest or when 3 to 5 sheath leaves remain. This means sampling the field regularly and slicing through a few bulbs. At least two of the leaves will be lost in the harvest operation, and the remaining sheath leaves hold the cloves together. Shattering of cloves is often a sign that too few sheath leaves remain due to late watering or that bulbs were dried too rapidly following harvest.

Garlic for processing or dehydrating may be watered a bit longer according to Ron Voss, Vegetable Specialist from UC-Davis. And garlic for fresh market or braiding should be pulled a bit earlier when some of the leaves are still green. This will decrease the tendency for soil staining and allow more sheath leaves for protection in the post harvest and marketing chain. Sheath leaves may be removed to eliminate the soil stains. The longer the garlic stays in the soil, the more leaves need to be removed. This is the compromise between quantity and quality according to Voss who also acknowledges the importance of experience and the “art” in garlic growing. The garlic harvest is handled much like bulb onions. Bulbs are undercut prior to harvest or pulled by hand and arranged in windrows with leaves covering bulbs to prevent sunburn. Prior to grading and bagging, trim leaves and roots to about 1”. Garlic to be braided is often braided with limp green leaves or also with thoroughly dry leaves which are rewetted prior to braiding.