I recently traveled to the Malaga area of Spain where there is quite a bit of new planting going on. The industry celebrated its industry in 2002 with the World Avocado Congress and we saw a considerable expansion of the industry then and more has occurred since then. More than 22,000 acres are in the ground. Much of the plantings are occurring on almond and olive ground which have become less profitable. Average grower acreage is similar to that of California's at about six acres per grower.
Production is along the southern coast of Andalucia and Valencia with some produced in the Canary Islands. Although a “Mediterranean” climate, it is both hotter and more humid on average than the California production area. Typically ‘Hass' is harvested two months earlier there than here. Scarcity of water in some areas, although in the Malaga area there are a series of dams and water is not limiting. Labor cost and availability are similar to that in California. Also, unlike California, the fruit snap harvested and any stems remaining are clipped at the packing house. This more efficient harvest system is also used in Australia. A discussion of the method is described in the November 2002, AvoResearch Vol 2, Issue 2.
The industry produces 150 M pounds, the bulk of which goes to France and Germany where they are willing to pay good prices for quality fruit. It is a short drive to Paris and Berlin and fruit arrives in good condition. The bulk of this export market is in France and three export companies dominate this export. Per capita consumption in Spain is only about one pound per year, 3.5 pounds in France and now the US is about 4.5 pounds.
There are over 12 nurseries supplying trees to the industry, but three dominate. As here, growers are looking at high density plantings at as close as six feet apart, in row. They are using the standard varieties , such as ‘Reed', ‘Lamb Hass', ‘Fuerte', ‘Zutano', ‘Bacon', ‘Pinkerton' and ‘Hass', but they are looking at newer varieties, such as ‘Carmen' and ‘Mendez'. There is still a good market for greenskins. They also have several rootstocks that we don't have, such as ‘Atkinson' used in calcareous soil and ‘Albaida' used in situations of Rosellinia fungus. This is a fungus similar to oak root fungus which they don't have as much as we do. Recently a long term trial was initiated evaluating over 10 scion varieties on five rootstocks, including ‘Dusa' which is one of the most popular rootstocks now.
There is Phytophthora root rot there, but it is not as extensive as in our industry. They also don't seem to have much of a problem with black streak, leaf blight, bacterial canker, and stem blight. These are diseases associated with poor water management and poor water quality. Some of the water quality reports I saw were really quite good compared to many of our waters. They do have a problem with Persea Mite which arrived there in 2005. It still is not under good biological control, but I saw an organic orchard that didn't spray, and the damage was acceptable. So something is finally kicking in.
Phytophthora disease control is done as here with mulches and phosphonates. One of the major sources of mulch was shells from the almond industry. With the eclipse of the almond industry, the shells have become very expensive and are going into other products. They are developing a yardwaste collection system, but it is not as close to the avocado orchards as to make it a cheap source.
The latest (2012) Department of Agriculture reports on county agricultural production can be found at
In a mandarin orchard today, I saw what appeared to be sun burn damage. The bark was missing on the top, south facing branches. It was old damage and was healing over along the edges. I mentioned it to the grower who told me it was roof rat damage. Several years prior when we had had a long dry winter, the rats had come out of the hills and were eating his fruit, as well as feeding on the cambium. I've seen this damage in trees near the edges of wild country, as well as along stream and river beds. At one orchard in Santa Paula, the feeding had actually spread Phytophthora in the canopy of lemon trees. For control measures go to:
- Author: Ben Faber
- Author: Robert Vieth
The white sapote is a relative of citrus. However, it is too distant botanically for the fruit to resemble, be graft compatible, or hybridize with citrus. The white sapote should not be confused with other fruit termed sapote (aka zapote) which only signifies a soft, sweet fruit in the Nahuatl Indian language. The white sapote is a native of central Mexico and appears to be well adapted to any area in California in which oranges can be grown. The fruit is slightly larger than a baseball. The thin, smooth skin is green, yellow, or orange in color. The smooth textured pulp, contained around* 5 to 7 moderate sized seeds, is pleasantly flavored (banana + peach). For some tastes the fruit of many of the cultivars lacks sufficient acidity to offset the sweetness, nevertheless a market for fresh fruit would likely exist if it were not for its poor handling characteristics. No market has been established for preserved products such as jelly, juice or wine. The enormous productivity in combination with a potentially mature height of 30 to 50 feet and an extensive lateral root system make the white sapote a problematical choice for the home garden.
The citrus fruit family, Rutaceae, includes about 900 tropical and temperate species of which citrus are the most commercially important. Other less well known Casimiroa species having edible fruit are the woolly-leafed sapote (C. tetrameria) and matasano (C. sapote).
The seedling white sapote tree grows to 50 feet under ideal conditions; however, many grafted cultivars tend to grow more slowly and can be held between 15 and 20 feet.
The leaves are mostly evergreen, palmately compound with 5 to 6 inch leaflets, and sometimes hairy on the underside. The odorless greenish yellow flowers are 4 or 5 parted and born in axillary panicles The flowers are hermaphrodites; however, the stigmas may prematurely abort. Cross pollination sometimes improves fruit set. The 2 to 6 inch ovoid fruits are borne 6 to 9 months after pollination, generally in October and November. The fruit is soft when ripened and has a smooth consistency with a delicate banana flavor with hints of peach. In poorer varieties and overripe fruit, the bitter overtone predominates along with an unpleasant resinous flavor. Although tree ripened fruit has the best flavor, the fruit is readily bruised and damaged when ripe. Some cultivars can be picked early and ripened to good flavor while others become overly bitter.
The white sapote is hardy northward to Chico except for the desert areas. Frost damage occurs at about 22oF; however, young trees can be damaged at 30oF.
The white sapote prefers well draining soils but will tolerate almost any soil. For healthy trees, the pH should be between 5.5 and 7.5. Salty soil conditions should be avoided.
Spacing and training
The terminal bud should be removed from young trees in order to encourage branching.
The white sapote prefers regular, deep watering. Shallow watering will encourage surface roots which can be a nuisance for the home gardener.
White sapotes prefer regular applications of nitrogen fertilizer. Minor nutrient deficiencies (not a major problem) can be treated as with citrus.
The main purpose of pruning is to control size and secondarily shape.
Pests and Diseases
In California the tree is generally pest free. Black scale, mealy bugs and aphids are occasional problems which are best checked by controlling ants. Snails will damage the fruit. Phytophthora and armillaria are not problems.
Seedlings are considered too variable to be reliable producers of good fruit. Clonal reproduction is normally done by grating and budding as with citrus. Grafted trees bear in 3 to 4 years.
Harvesting and Storage
The poor handling characteristics of the fruit have limited its commercial potential. The very thin skin provides little protection against bruising which is aggravated by the fact that if picked when underripe the fruit will not ripen to full flavor and pick up an unpalatable bitterness. Overripe fruit also becomes bitter. Careful selection of cultivars can mitigate these drawbacks.
Orchard costs should be approximately the same as oranges or less.
White sapotes are seldom available in markets. Development of better handling cultivars would appear to be essential if a market for fresh fruit is to be established. Just as important is the establishment of other uses, for example, those which would allow use of bruised fruits. One challenge is that the delicate flavor of white sapote is easily lost if mixed with other fruits such as lemon to provide a better acid, sweetness balance.
With the proliferation of pests and disease that might appear in mulch used in orchards, it might appear that the practice will become more limited unless the material can be guaranteed to be safe. Polyphagous Shot Hole Borer and Asian citrus Psyllid are just two examples of pests that might appear in a mulch from an unknown origin. There are many other examples, though, and new threats keep coming. Composting is a process that can insure a quality product, but composts tend to be too expensive to be used as a mulch. There is a new solar processing technique that is being evaluated in the Central Valley that might produce a product that could be used as a mulch.
The proliferation of low-cost, high-efficiency and durable solar panels makes it possible to set up solar-powered composting systems that reduce reliance on alternative forms of power and avoid very expensive grid hook-up costs.
This type of technology lends itself to a more stable site layout, which can then utilise conveyors for material movement, further reducing reliance on diesel-powered equipment. A potato piler, a standard piece of equipment in the potato storage industry, is an ideal prototype for compost conveyors.
Static piles can easily be watered using simple irrigation systems that save water and further reduce diesel reliance. When combined with the already proven technology of a compost cap, reductions of VOCs and greenhouse gases can be substantial.