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.
A trial planted in Oxnard involved eight different pollinizer varieties at three different distances from 'Hass' tree rows. Yield data collected from 2002 – 2005 suggest that the presence of pollinizer varieties in close proximity enhance the total number of fruit harvested from ‘Hass'. The influence of pollinizers on yield diminishes as the distance from the pollinizer variety increases. Differences were detected between pollinizer varieties in terms of influencing ‘Hass' yield. The highest ‘Hass' yields were observed when ‘Fuerte', ‘Zutano' and ‘SirPrize' were used as the pollinizer. The lowest cumulative yield was observed when ‘Harvest', an A-Flower type was used. Small but significant differences were also detected in percent dry weight, fruit and seed length/width ratio and seed size. For a more complete description of the trial see: