Eugenia stipitata

Eugenia stipitata

The araza (Eugenia stipitata McVaugh 1956) is an arboreal species belonging to the Myrtaceae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Subkingdom Tracheobionta,
Spermatophyta Superdivision,
Division Magnoliophyta,
Class Magnoliopsida,
Subclass Rosidae,
Order Myrtales,
Myrtaceae family,
Genus Eugenia
Species E. stipitata.
The subspecies is recognized within it:
– Eugenia stipitata subsp. sororia McVaugh.

Etymology –
The term Eugenia is in honor of the general, diplomat and patron Eugene of Savoy (1663-1736).
The specific epithet stipitata comes from the Latin “stipitatus, a, um”, i.e. equipped with a stipe, in reference to the short peduncle of the inflorescences.

Geographic Distribution and Habitat –
Eugenia stipitata is a plant native to an area that includes: Bolivia, northern Brazil, Colombia (Putumayo), Ecuador (Napo) and Peru (Loreto and Ucayali).
The species is believed to originate far west in the Amazon basin, perhaps in the Peruvian Amazon. Most wild populations are found on old, non-flooding terraces in tropical, white, highly leached podzolic soils, distributed specifically in the area between the Marañón and Ucayali rivers and where the Amazon River begins and up to Iquitos (ssp. sororia ) and in the Brazilian state of Acre (ssp. Stipitata). It is found only in the western Amazon and does not appear to have been widely spread by indigenous peoples, although some of the best varieties appear to have been selected by the indigenous peoples of Peru around Iquitos. The reason is that in locally grown material there are varieties of 12 cm in diameter and 740 g in weight, compared to wild populations which do not exceed 7 cm in diameter and 30 g in weight. Less frequently, some species are also found in Bolivia, Brazil and Colombia. It is cultivated as an exotic species in other tropical areas of South America, as well as in Central America and Florida. Specimens have also been introduced in other places in the tropics, such as Malaysia.
It still exists in the wild today in many areas of the Loreto department, in Peru, where it reaches 10 meters in height in the Marañón river basin. They have also been identified in the Ucayali river basin, near the province of Requena. Although it was believed to have originated in Brazil (where it is called araca-boi or Peruvian guava), the specimens present were introduced from Peru.
Its habitat is that of rainforest and humid forests up to about 650 m altitude.

Description –
Eugenia stipitata McVaugh is a plant that grows in the form of a shrub or small evergreen tree, 3-12 m tall.
The foliage is very branched, with a reddish brown bark that tends to flake; the young branches are covered with brownish down.
The leaves are located on a short petiole, they are simple, opposite, ovate-elliptical with an entire margin and a pointed apex, 8-16 cm long and 3-8 cm wide, of an intense green color and slightly pubescent on the upper part, light green, pubescent and with scattered stiff hairs 0.5 mm long below. The young leaves are initially reddish in color.
The flowers are formed in the axillary position; they are solitary or gathered in racemose inflorescences, on a short peduncle, with dichotomous ramifications 0.5-1 cm long, carrying 2-5 pairs of bisexual flowers, on a 1-2 cm long pedicel. The calyx is composed of 4 free ovate sepals, 0.4-0.5 cm long, of a yellowish green color and retroflexed after opening, 4 obovate petals of white color, 0.8-1 cm long and about 0 .5 cm wide, quadrilocular ovary, style about 1.1 cm long and 80-130 stamens about 0.6 cm long.
The long-styled shape of the flower, while not completely preventing self-pollination, favors cross-fertilization.
The fruit is an almost spherical berry of 5-10 cm in diameter, initially green in colour, then yellow when ripe, with a thin and pubescent epicarp (the “skin”) and juicy and aromatic pulp, including that which surrounds the seeds, of light yellow colour.
The seeds, 5-15 in number, are slightly compressed oblong in shape, 0.5-2 cm long and 0.5-1.5 cm wide.

Cultivation –
Eugenia stipitata is a shrub or small evergreen tree with a densely branched habit and no apical dominance whose fruit, despite having a very acidic flavour, is generally much appreciated and is often collected in nature and also grown in home gardens.
The plant has been proposed for commercial production and is often grown as an ornamental plant.
Outside the tropical and subtropical areas, due to its compact shape and early flowering, it could be grown in large containers to be sheltered in bright greenhouses during the colder months, using a fertile, acidic draining soil, kept almost constantly humid, but without stagnation. Finally, its ornamental characteristics should not be underestimated.
For cultivation, take into account that it is a plant of humid or humid tropical plains, where it is found at altitudes of up to 650 meters. It grows best in areas where annual daytime temperatures are between 70 and 80 degrees F, but can tolerate 60 to 90 degrees F.
It prefers an average annual rainfall of between 2,000 and 3,500 mm, but tolerates 1,500 – 4,000 mm, and can also tolerate a period of seasonal drought of up to 2 months.
It grows in full sun and light shade and, from a soil perspective, prefers rich, well-drained clay soil, but will tolerate poorer clay oxysols, provided they are well drained, and will also tolerate the stress of acidic soil. It prefers a pH between 5 and 6, tolerating 4.5 – 6.5.
In general the plant prefers well-drained soil, but tolerates limited flooding, although some trees appear to adapt to flooding over time.
It is a relatively slow growing plant.
In the first year, and in some cases also in the second or third year, it can be associated with annual crops. The tree is useful for agroforestry systems and growth in the shade of taller trees appears to be greater than under less intense shade. We recommend pruning young trees, seeking the formation of three or four heavy branches. In addition, annual pruning and general cleaning should be carried out.
In fertilization trials, chemical fertilizers had no influence on fruit formation (between 20 and 40%, average 25%) or total yield, which justifies not recommending their use in the region .
This plant produces fruit year-round and provides 2-4 harvests per year due to the short period (about 84 days in San José de Guaviare, Colombia) between fruit set and harvest. Arazá can be classified as a Climateric fruit with high respiration rates but moderate C2H4 production rates. The climacteric behavior of arazá reflects that of the genus Psidium but differs from that of the non-climacteric fruit of the genus Eugenia. The development of arazá fruits in the conditions of the Colombian Amazon took 55 days in the climatic conditions of the Colombian Amazon. For arazá fruits, the harvesting criteria are the same as for guava: size, color and, to a lesser extent, consistency. If arazá fruits are allowed to ripen on the tree, the subsequent post-harvest shelf life is approximately 72 hours, due to anthracnose and other causes of decay. The fruit is harvested green, to avoid softening and bruising. Fresh fruit is transported to the processing unit in plastic trays with no more than three layers of fruit.
The arazá is still in an early stage of domestication and therefore it is difficult to correctly estimate any quantitative comparisons for improvement. Furthermore, the genetic basis is not well studied and knowledge of management practices is limited, making realistic projections difficult. Productivity can be slightly higher if optimal growing and harvesting conditions are further studied. The success of arazá as a widespread crop will depend above all on technological developments that facilitate its acceptance in markets outside its endemic region. Any improvement or selection program will have to involve parameters such as appearance, colour, smell, palatability and resistance of the fruit to transport and storage.
As for parasites and fungi, the species suffers heavy attacks from fruit flies, which reduce the normal density of plantations if sophisticated biological control measures are not adopted. The fruit fly attacks both green and ripe fruits: the larvae feed on the pulp and can completely destroy the fruits in sufficient numbers. They often appear at the same time as the larvae of (Conotrachellus sp.). The larvae of (Atractomerus imigrans) feed on the seed, while the larvae of Conotrachellus feed on the pulp. The weevil (Plectrophoroides impressionicolli) feeds on shoots, tender leaves and flowers. The black bee eats the peel, pulp and sometimes even the seed of the fruit. Finally, in the case of mushrooms, arazá is susceptible to anthracnose.
Reproduction occurs by seed, which must be planted quickly after extraction from the pulp as it has a limited duration of germination, in draining, acidic soil, kept humid at a temperature of 24-28 °C. Germination times from 2 to 8 months, which can be shortened by scarification, and first fruiting, in the best cultivation conditions, after about 2 years. To preserve particular characteristics, grafting is used.
Seeds have the best germination when extracted from fully ripe fruits. Germination success is maintained at 80% for up to 60 days when the seeds are kept in water.
The seeds are recalcitrant. After 40 days in cold storage, they lose more than 70% of their vitality. Accordingly, seedbeds must be established within the first five days after harvesting the seeds. The seedbeds are kept completely in the shade; the seeds are planted 2 cm apart and covered only lightly, as greater coverage inhibits germination. Partially decomposed soft wood is recommended as a seedbed while the use of earth is not recommended. Germination is not uniform and can take up to 80 days; under the conditions described, the germination rate can reach approximately 100%.
The seedlings are kept in the seedbed until they reach a height of between 7 and 10 cm. They are then transplanted into 6 to 8 kg polyethylene bags filled with a 10% mixture of soil and manure. The plants remain in the bags for up to a year; six months in the shade and 6 months in partial shade. After a year the plants are transplanted to their permanent site. In San Roque, distances of 3 x 3 m were adopted, with holes 50 cm deep and 30-50 cm in diameter. The soil is mixed with 0.50 kg of manure. It is recommended to remove weeds from the cultivated area every month and add organic material to the soil. Experimental fertilization results suggest that organic manure fertilizer is preferable to chemical fertilizers.

Customs and Traditions –
Eugenia stipitata is a plant known by various common names; among these are: araza (English); araçá, araçá-boi (Brazil); arazá, arazá-buey (Peru); arasá, arazá, guayabo amazonico (Spanish).
Its fruits have aroused great interest for their organoleptic characteristics suitable for the industrial production of juices, concentrates, jams, ice creams and for flavoring various drinks, while they are not very suitable for fresh consumption due to the high acidity of the pulp.
The fruit has a high content of vitamin A, B1 and C, proteins and carbohydrates, it also contains calcium, iron, magnesium, potassium and zinc. Cultivable in humid tropical regions with high average temperatures, well-distributed annual rainfall and humidity above 80%, even on very poor soils. Often economically depressed regions that could have an economic return with its cultivation and related industrial processing, which should preferably be carried out in the place of production due to the rapid perishability of the ripe fruit and susceptibility to mechanical damage during transport. The almost continuous fruiting throughout the year is a further incentive to increase cultivation.
The climacteric fruit contains a high level of acidity, with an average pH of 2.4 for the juice, giving it good quality for processing. Furthermore, it contains a high level of nitrogen and potassium. Dry weight contains 8-10% protein, 5-6.5% fiber, 65-72% other carbohydrates and a small amount of calcium, 0.16-0.21%, 10-12 ppm of zinc and also some phosphorus, potassium and magnesium. Per 100 g of fruit there are approximately 775 mg of vitamin A, 9.84 mg of vitamin B1, 768 mg of vitamin C (which is double that of an orange). The fruit pulp contains 4% dry matter, 11.9% proteins, 49.2% sugars (glucose 3.1%, fructose 33.9%, sucrose 17.2%), 4% ash, 39% total dietary fiber, amino acids and minerals. The main constituents of the E. stipitata fruit oil are sesquiterpenes of which the main component is germacrene B and which gives the fruit an antioxidant activity. Furthermore, the ethanolic extract of the fruit showed antimutagenic and antigenotoxic properties which suggest that this fruit could function as a preventive agent against cancer.
Fresh fruit can be used directly but is preferable with added sugar due to its high acidity. In Colombia, the economic interest of this fruit has increased since the end of the 20th century, and currently the fruit is sold by growers’ associations and even in supermarkets, while exports to the United Kingdom have only just begun. The United States is registering arazá for fresh sale. Another use of this fruit tree is to reclaim exhausted land and also for ornamental purposes.

Preparation Method –
Eugenia stipitata is a plant that is meeting a certain interest, especially for food and agroforestry purposes.
In edible use, raw fruit is transformed into juices, ice creams and sorbets.
The thick, very succulent pulp is aromatic and has an acidic flavour. The fruit quickly loses flavor and aroma when cooked, so it is best to boil it quickly if used to make jam.
It is very rich in vitamin C, double the amount of an average orange.
However, the fruits do not tolerate long transport.
In the medicinal field, some eat the unripe fruit to eliminate parasites.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://www.inaturalist.org/guide_taxa/285500
– https://cdn.floridamuseum.ufl.edu/Herbarium/f9fdcadb-fc2f-4a79-8340-e44f04c12bef/

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.