THE LOQUAT
SCIENTIFIC NAME: Eriobotrya japonica
FAMILY: Rosaceae
Loquats grow well in many parts of New Zealand. The fruit is aromatic and refreshing. It can be eaten fresh, made into delicious jams and jellies, or into wine. Fresh fruit could possibly be exported to Japan.
LOQUAT
The loquat (Eriobotrya japonica) is a native of central China. It was introduced to ancient Japan and has long been cultivated for its fruit throughout China, Japan and India. However, it was brought to Europe for the beauty of its foliage rather than for its fruits, and is now grown in many countries as an ornamental broad-leaved evergreen. Wild trees can still be found in some parts of Japan. It is from the apple-pear-quince family (Rosaceae), but in New Zealand it is still not commonly grown for fruit.
The tree
The loquat is a large, evergreen tree, growing 5-6m tall and spreading an equal distance, but can be kept lower by pruning. It makes a handsome garden tree with its large shiny, deep green leaves which are silvery-grey underneath. It makes an ideal pot plant, both in warm countries and in cooler areas where it is easily protected in the winter.
Climate and soil requirements
Loquats are grown in many areas in New Zealand. Although the tree itself is hardy, it is by nature a subtropical plant; the young tree growth is frost-tender and severe frosts can kill the blossoms which emerge over autumn and winter. Once established, the foliage can withstand moderate frosts. A coastal climate suits loquats, but to produce good quality fruit some wind shelter needs to be provided as the fruit bruises easily, and can be damaged by the stiff serrated leaves.
Loquats grow well on most soils, particularly those which are deep and do not dry out too much. The tree would seem happy with similar soils to those suiting its close relative, the apple. On less fertile soils loquats respond well to NPK fertiliser.
Propagation
Loquats are easily propagated from seed, but the best quality fruit and the highest yields are obtained from trees budded or grafted from known varieties. The rootstock used is either seedling loquat, which will develop a rather large tree, or quince stock, which produces a smaller, more compact tree, well-suited to the home garden. It can also be propagated by layering.
Tree management and pruning
Young trees should be planted 5-6m apart. In cooler areas they will need protection from frosts for the first one or two years. They should be pruned to produce a clear trunk about one metre high, with 3-4 strong main scaffold branches forming an open vase. Little further pruning needs to be done until the tree starts bearing fruit, usually when 5-6 years old. Pruning is done in early summer after harvest, but before the autumn growth flush. Remove the defunct fruit stalk, then thin the lateral shoots below the old cluster by removing most of the shorter terminal shoots to carry the fruit in the following year. This summer pruning will help to keep the tree compact, and will reduce the number of fruit it carries and so increase the size.
Pests and diseases
Leaf roller caterpillar damages the skin of the closely-clustered fruit. This pest is easily controlled by insecticides such as carbaryl. Aphids occasionally attack leaves and flower clusters. The fruit is vulnerable to fruit fly when ripe, and birds are a major pest. Black spot (scab) sometimes causes black, scabby spots on the fruit, and can be controlled by pre-blossom sprays of half-strength bordeaux. Quince fleck occasionally affects loquats. However the most serious problem is Pseudomonas syringae pv. eriobotryae, a bacteria that was introduced on seed from Japan. This disease caused the DSIR trials to be destroyed in 1985.
Varieties
There are many local selections as well as varieties imported from Japan, Australia, USA and Europe.
Fruit flesh can vary from firm, yellow flesh with a bland taste, as in many Chinese and some Japanese types, to fruit with cream-coloured flesh, very juicy, with a slightly acid taste.
Flowering and fruiting
Loquats flower in late autumn and winter, forming clusters of up to a hundred sweet, intensely fragrant, white or cream flowers in long, down-covered panicles borne at the end of the current season's growth. Loquats are self-fertile and do not require cross-pollination to set fruit, but performance is improved by cross-pollination.
Each flower panicle can set a large number of fruit but, unless these are thinned, the fruit will be small and often scarcely worth picking. As they develop, they become less hairy and turn from green and cream to yellow and orange. Using gibberellic acid sprays before the flowers open, and spraying with NAA near full bloom, has produced seedless loquats experimentally in Australia. However, the fruit normally contains one or more large seeds and sometimes up to 10 seeds. The best varieties are those which naturally have relatively large fruit with few and small seeds. To make the fruit more acceptable, good management is needed to further increase the ratio of flesh volume to seed, and increase the overall fruit size. Fruit thinning is therefore important, and fruit should be thinned out by hand soon after they have set. This will also reduce the loquat's tendency to biennial bearing. If fruit-set is normally too heavy, some flower bunches can be removed as they appear, and, later on, fruit can be thinned from the remaining bunches, Only 3 or 4 fruit should be left per cluster. The yellow-skinned fruit can attain the size of a large plum and ripen in the spring, from late October onwards, making them one of the earliest fruits of the season. They should be picked when they have reached the full yellow or orange colour. Loquats are best removed from the tree by cutting through the stalk with scissors or secateurs. Handle them very carefully as their tender skin bruises easily. If the flesh is still firm at picking, the fruit will keep for a week or so in the refrigerator.
The fruit is aromatic and rather refreshing with a slightly apple-like flavour. Some varieties are sweetish, while others have a slightly acid taste. They are used as fresh fruit and for jams, or can be made into a delicious jelly.
Imported canned loquats are available in New Zealand so presumably they can be bottled. Loquat wine is very popular in Asia and a liqueur (Bermuda Gold) is made from loquats in the West Indies. There appears to be a potential export market for fresh loquats to Japan.
Loquats in Japan
When Dr Ichiro Kaijura from Japan was in the Waikato some years ago, he considered that the warmer parts of the Waikato appeared very suitable for loquat fruit production. He also felt that our existing genetic material was probably suitable for commercial exploitation. As with a number of our fruit trees, Dr Kaijura was amazed at the size and quality of fruit off trees that had never been trained, pruned, sprayed, manured or fruit-thinned. He gave us some useful information on how they grow loquats in Japan, which is summarised below. The months refer to Japan: add six months for New Zealand and Australia.
The loquat has been used as a refreshment or a table fruit in Japan since the eighth century, but those old loquat trees bore small fruits. Loquats did not become important fruit until the introduction of large-fruit strains from China about 1850. After this introduction, the production and acreage began to increase and the loquat became about the twelfth most important fruit produced in Japan, with a slightly lower acreage than cherries and damson plums. It is a valuable fruit, because it is sweet and has a good flavour. As well, it can be harvested at the beginning of summer during the off-crop season for the fruit market. In Japan it is used fresh and for canning (in sugar syrup). Bruised and low-grade fruit is used to make loquat wine.
Difficulties
However, despite the above advantages there are still some difficulties associated with growing loquats:
1. Low average yield (6 t/ha) in comparison with apples (35 t/ha), pears (26 t/ha) and persimmons (32 t/ha).
2. Unstable cropping, because young fruitlets develop in winter and suffer from cold injury. As a result, the best growing areas are those with a mild winter. (Note that in USA loquats are grown in California and Florida.) Flowering occurs during autumn and winter (mid-October until mid-March), and during the winter the loquat is sensitive to cold. Although wood and leaves are tolerant of low temperatures, flower buds, flowers and young fruits are killed at temperatures under -70C, -50C and -2.50 C respectively.
3.Labour requirement. They need a great deal of labour, especially to thin and bag the fruit. Sixty to seventy bisexual self-compatible flowers (min. 20, max. 100) develop in one cluster. The terminal flower at the central peduncle blooms first and the flowering continues successively to the central flower of the basal peduncle. The large number of flowers in a: cluster makes it necessary to thin the clusters (the middle to the end of October), and to thin the fruit (the end of March to the beginning of April).
Loquat fruit is round to ovate with yellow to orange skin and flesh. Loquats are 50-100gms in weight and mature from the beginning of May to the end of June. The seeds are large and occupy about 20% of the fruit weight. Large fruit size and small seeds are important goals in loquat breeding. After the introduction of large-fruited cultivars from China, many attempts were made to select the cultivars with the largest fruit and the smallest amount of seed.
Culture, pests and pollination
In Japan, loquats are propagated by veneer grafting on seedlings or quince stocks in the middle of March. The grafted seedlings are planted at intervals of six to seven metres. The first crop is obtained five years after grafting. Trees are pruned in September. Trees in commercial orchards can usefully be kept for about a hundred years. However, the tree crown is large and the root is shallow, and trees may be blown over in strong winds.
White root rot (Rosellinia necatrix) and canker (Pseudomonas eriobotryae) are serious diseases of loquat. Tanaka shows no symptoms of bud blight and Mogi shows no stem canker. Pear green aphid (Nippolachnus piri), the longhorn mulberry borer (Apriona japonica), and peach curculio (Rhynchites heros) are reported as pests.
All varieties benefit from cross-pollination and some require cross-pollination. In the USA, honey bees visit the flowers and are the primary pollinators.
This article first appeared in the TCA Journal in 1980. Since then, some the leading Japanese cultivars have been imported for trial in New Zealand. As with a lot of "new" fruits and nuts, it is possible that we do have material just as good, and maybe even better, among our seedling loquat population in New Zealand. It was intended that the imported cultivars would be trialled alongside the best New Zealand selections. Enough time has now passed for an evaluation of the results, but we have largely lost track of the material. Anyone with trial cultivars, or any member who feels he has a superior seedling, is asked to contact Research Coordinator Roy Hart so we can make further progress in the development of loquat fruit production in New Zealand.
Loquat Varieties
Dr Kaijura described a number of Japanese cultivars:
Tanaka is the oldest important cultivar. Tanaka fruit tastes a little sour, has good fruit appearance and a long shelf life, and is 75 gms in weight (maximum 150 gms). The trees show vigorous growth.
Mogi weighs about 50gms and is relatively sweet. In comparison with Tanaka, Mogi is easier to peel, matures earlier, but is more susceptible to bruising and to cold injury.
Tsukumo fruit weighs 60 to 70gms, matures at the same time as Mogi, is very sweet, and does not bruise easily during storage and marketing because its peduncle is difficult to remove.
Mizuho is a large-fruited cultivar of over 100gms, has a strong skin, is easily peeled, tastes very sweet, and yet is not insipid in taste. But sometimes green spots develop on the skin, giving it a bad appearance.
Togoshi has the best fruit quality, matures at the same time as Tanaka but is smaller (70 to 75gms).
Obusa is firmer-fleshed, larger and earlier maturing than Tanaka. This cultivar is tolerant of cold injury and diseases.
Nagasakiwase is the earliest maturing cultivar in Japan, even earlier than Mogi.
DATE: November 1996
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