The lychee (Litchi chinensis) and the longan (Euphoria longana) are exotic subtropical fruit crops native to Southeast Asia. Demand for lesser known uncommon fruit crops, such as lychees and longans, is expanding in the US in large part due to growth of Asian and Hispanic ethnic minority populations who readily search out the fruit in specialty stores. Demand is also growing among health-conscious consumers who seek exotic fruit dishes. Historically, the demand was primarily satisfied by frozen or canned fruit, but demand for fresh fruit is increasing.

Israel, Taiwan, South Africa, and more recently, China are also sources of fresh lychee fruit. Domestic supplies (Florida) are available from May into early July, Mexico ships from June into late July, and recent imports from China and Taiwan extend availability to September. Taiwanese fruit is shipped via ocean freight and undergoes extended cold treatment to control fruit fly pests, which changes the color from red to brown. The first Chinese fresh fruit to arrive in mid-1998 was brown due to the extended cold treatment and was sold at relatively low prices.

Over the past ten years, Australia has successfully established a new lychee industry with something over 2,500 acres planted. The majority of this fruit is consumed internally, but Australia has plans for export to growing Asian markets. Spain is also in the process of establishing new lychee plantings with interest in the export market.

The undocumented imported lychee and longan fruit in California is a source of a number of exotic fruit pests, including oriental fruit fly, lychee fruit borer, and Asian fruit fly. According to CDFA Division of Plant Industry, longans are hosts for fruit flies (including Bactrocera dorsalis and Ceratitis capitata), mealybugs, and scale. The demand is so great, however, that fruit importers have taken to smuggling the precious fruit from Canada where phytosanitary restrictions on imported fruit are lighter. In 1995, longans led the list of fruit interceptions on the Canadian border by USDA Plant Protection and Quarantine in Blaine, WA, with 42,437 pieces, followed closely by lychees with 26,579 pieces of fruit. Thirty-six percent of the intercepted pests were oriental fruit fly. The largest intercepted shipments in 1996 involved refrigerated semi-trucks with one shipment containing 11,000 pounds of longans and another with 17,000 pounds of longans. Rich Jackowski, the USDA PPQ Regional Operations Support Officer in Sacramento, reported that longans were valued at $8 per pound in Seattle and "even higher in Los Angeles."

Fresh lychee and longan fruit production offers a promising new crop for coastal California growers. Development of a domestic California commercial production capability for lychees and longans would markedly reduce the demand and economic attractiveness for importing fresh fruit contaminated with exotic pests. California fruit would also have competitive advantages over imported fruit in the market place because of the effects of post-harvest treatment and shipping time on fruit quality.

Wholesale prices in Los Angeles for fresh lychees in recent years have ranged from $4.00 per pound at the beginning of the season and falling to $1 - $2/lb. when volumes are at peak supply. The Taiwanese and Chinese fruit often tend to be lower in price because of the discoloration which occurs during cold treatment. But Taiwanese - Americans seek out the fruit because do not feel that the flavor or quality are adversely affected by the discoloration.

Imported fruit which arrives by air from Israel is much smaller in volume, but is generally of higher color and largely goes to more traditional outlets and up-scale markets and restaurants. The Taiwanese and Chinese fruit generally enters different market channels from the Israeli fruit. The fruit from Florida or Mexico may enter either of these market channels.

Longans by comparison are generally more exotic than lychees and relatively little has traditionally entered U.S. market channels. The longan is closely related to the lychee and is similar in growth and fruiting habit but is lesser known than lychee in world trade. Longans are, nevertheless, highly prized in the market place, and demand for both lychee and longan is high.

Several key elements are important in the establishment of a new tree fruit industry including:

• Genetic resources
• Nursery Production
• Production Systems
• Postharvest
• Marketing

There is a tradition of back yard and small orchard plantings of lychees, longans, and other non-traditional subtropical fruits in California, dating back to the early 1900s. Today, lychees and longans from small plantings in So. California appear in specialized markets in the greater Los Angeles area, and small commercial plantings are beginning to appear in some areas. There is, however, little sound technical information on cultivars or orchard management to guide prospective new growers.

Lychees and longans are subtropical fruits, and in key production areas in China they are grown in citrus production areas. In the area where they originated in China, winters are cool and dry, and summers are warm and humid. Experience thus far in California indicates that lychee and longan are generally adaptable to avocado or citrus growing areas.

A number of critical growth and development responses of lychee and longan are affected by complex interactions among temperature and humidity at different stages of the growth cycle. California’s coastal climates are dramatically affected by proximity to the ocean but latitude, altitude, and aspect have marked effects on climate as well.

Lychees and longans flower and fruit best with warm summer conditions, but a certain amount of winter chilling is necessary for flower bud development. Most cultivars need between 100 and 200 hours of standard chilling (32° - 45° F). Hawaiian lychee production is often limited by insufficient winter chilling. Cool winters with relatively low rainfall are ideal for lychees. High winter rainfall and poorly drained soils may aggravate root rot diseases. But Australian growers have been successfully cultivating lychees on raised mounds in higher winter rainfall areas.

Longans are somewhat more cold-tolerant than lychees and overall are considered to be somewhat more resilient than lychees. The trees become more winter hardy as they age. Lychee trees have survived temperatures below 25° F when fully hardened off. Young trees may be killed by a light frost in some circumstances, and there may be marked advantages to establishing young plantings in an old orchard. There are trees in San Diego County that are over 90 years old with no sign of decline.

Scattered plantings exist as far north as Santa Cruz, yet no effort has been made to develop commercial plantings. The longan tree is tougher and less demanding with respect to climate and soil conditions than the lychee, and it fruits in cooler and drier areas. However, the exact environmental conditions required for high yields of longan in California are not well defined.

Much is known about lychee and longan culture and management in diverse subtropical environments such as China, Australia, New Zealand, South Africa, Hawaii, Israel, and Florida. Lychees and longans grow well in many parts of coastal California, but no effort has been made to do the research and development necessary to establish these as commercial orchard crops. Old, small, isolated plantings exist in several areas of California from Santa Barbara County south to the Mexican border. The specific management requirements for lychee and longan have not been adequately developed for California to project successful cultivation to a commercial scale.

Cultivar selection is important and Brewster and Mauritius lychee, the most common commercial cultivars in Florida, have also been successful in other growing areas, including Mexico. Additional lychee cultivars are also available which may offer unique adaptation, fruit quality, or market alternatives to prospective growers. Additional promising lychee cultivars include:

Among longan cultivars, Kohala is the most common Florida cultivar with good fruit quality characteristics and wide adaptation in other growing areas. Additional promising longan cultivars also include Biew Kiew, Sri Choompo, and Diamond River.

Planting Density of both lychee and longans has been quite variable traditionally. Mature trees may attain 35 to 45 ft. in diameter, and traditional spacing varies 25 - 35 ft. between trees. Recent work in Israel and Australia, however, suggests that trees can be aggressively pruned to a 12 ft. to 16 ft. diameter. Although yield per tree is less, overall yield per acre increases, and trees are easier to maintain and to harvest.

Trees should be planted on raised mounds where soil drainage is questionable. This will provide drainage during the high rainfall, cooler winter months. There are numerous reports that lychee prefers somewhat acid soils and is somewhat prone to iron and zinc deficiency on high pH soils. Longans may be more tolerant of soil pH and may not show deficiencies. Both lychee and longan are grown on calcareous soils in Florida, but it is worthwhile to lightly acidify sites that have a neutral or alkaline pH.

Incorporation of 1-2 lb. of soil sulfur per 100 sq. ft. will acidify soil pH by approximately 0.5 to 1 pH unit on medium textured soils. These amounts of sulfur will be adequate for acidifying many coastal California soils with pH of 7 or higher. Alternatively, a drench or foliar spray of chelated iron may be used to correct chlorosis from pH- induced iron deficiency.

Fertilizer is not applied at planting to allow the plant to become established and the root system to develop somewhat prior to fertilizing. Fertility requirements also will vary from site to site. Annual application of a complete fertilizer will build phosphorus and potassium to optimum levels for young trees in years two, three and four. There are reports that nitrogen (N) is used on a regular basis, primarily in the early years (years 2-4), to support vegetative growth. For bearing trees, some N may be applied at harvest to help push the flush which comes at or shortly after harvest, and then no subsequent fertilizer is applied to vigorous, bearing trees.

Irrigation Management is critical for newly planted trees, many of which may have poorly developed root systems as a result of air-layering propagation. Irrigation will also be important for managing newly developing and bearing orchards for optimum production. Generally speaking, CIMIS data can be used to guide irrigation scheduling, and water use generally will be similar to avocado. Specific irrigation requirements will be site specific. There are reports from Australia that withholding irrigation and light stressing of bearing trees may actually aid fruit set by limiting vegetative vigor. These types of reports will need to be evaluated in similar growing conditions in California.

Pest Management information for lychee and longan is available for a broad range of pests in many types of growing conditions. It is unclear, which disease or insect pest may present serious problems in California growing conditions.

We have recently initiated research, which will evaluate trial plantings of commercial and experimental cultivars of lychees and longans on 20 sites, covering a range of geographical zones from northern San Luis Obispo County to southern San Diego County. This project is financed with a grant from the Pest Exclusion Branch of the California Department of Food and Agriculture (CDFA). There is considerable interest in the development of commercial lychee and longan production to aid in the reduction of imported fruit, which also introduces diverse exotic pest species.

This initial three-year research effort will establish small orchards of commercial and experimental cultivars of lychee and longan on promising sites. Initial baseline information will be collected on adaptation and fruiting patterns of lychee and longan cultivars. Data will also be collected on soil and climate characteristics that may ultimately be related to success with fruit production.

As part of the project, information will be compiled on lychee and longan wholesale and retail fruit handlers in California, and fresh fruit price and volume data will be tabulated and summarized. The market information will aid growers and fruit handlers in analyzing promising market windows for California lychee and longan. The cumulative data, information, and experience will support the establishment of new commercial orchards of lychee and longan in California.

It is important to evaluate several lychee and longan cultivars in diverse growing conditions in promising growing areas to determine the limits of adaptation of the potentially important new crops. There is also a need to assist the nursery industry in efficiently preparing to provide ample supplies of appropriate germplasm and growing advice to potential new growers. The combination of attractive market demand and the adaptation of the crops make lychees and longans promising candidates as new fruit crops for coastal California. Specific information on sound orchard management in California and the limits to adaptation of these promising fruits is needed.

There are a number of extensive reports available on lychee and longan production from a number of sources. One of the most complete documents on lychee production in California is available from California Rare Fruit Growers (CRFG). See Lychee (1996) CRFG Website at

Other information on lychee and longan is also available from many sources over the Internet. Contact either of the authors for additional information on lychee and longan production.