Many pests and diseases can affect the coffee plant or its fruits, the most dangerous being:

Artificial addition of manure or chemical fertilizers is seldom used in coffee farms. Sometimes just cut weeds and coffee cherry pulp deriving from crop processing are spread between rows. Of course soil depletion follows if many years of coffee growing are not alternated with different crops.

There are about 25 major species within Coffea, but the typical coffee drinking is likely to be familiar with just two: Coffea arabica and Coffea canephora (var. robusta). Arabica is autogamous, that is to say, capable of fertilising itself, whereas Robusta is allogamous.

Coffea Arabica:
Arabica represents approximately 70 percent of the world's coffee production. Typica and Bourbon are the two best known varieties of C. arabica, but many strains have been developed, including Caturra (from Brazil and Colombia), Mundo Novo (Brazil), Tico (Central America), the dwarf San Ramon and Jamaican Blue Mountan.

Coffea arabica is a spontaneous mutation of pre-existing races which doubled the number of chromosomes in the cell. As a result it has 44 chromosomes compared with 22 for most other coffee varieties.

The arabica plant is an evergreen, typically large bush with dark green, oval shaped leaves that can reach a height of 14 to 20 feet fully grown. On plantations the plants are kept at a height of about two to three metres to facilitate harvesting and nourish heavy bearing of berries

After planting, arabica trees mature in three to four years, when they produce their first crop. The arabica plant can continue to produce fruits for about 50 years although the fruit yield decreases significantly after about 30. Arabica trees prefer a seasonal climate of 60-75 degrees Fahrenheit and an annual rainful of 60 inches.

Primary, non-renewable branches grow from the trunk at an average distance of 15 cm. The plants have taproots that are not very deep. The bright green leaves are shiny on top and dull on the underside; they vary from 5 to 20 cm in length and come to a point. Its' branches carry bouquets of 5-12 small, white flowers with a jasmine-like fragrance that spreads throughout the plantations.

The five-petal flowers fade quickly as they wilt as soon as fertilisation has taken place. They are quickly replaced by others, however. Once fertilised they give way to the coffee cherry; these are oval-shaped berries with, usually, two beans side-by-side with their flat sides together. When only one bean develops from a cherry it is called a peaberry. Each tree can produce between 1 and 12 pounds of coffee a year, depending on soil, climate and many other factors. At high altitudes the plants generally blossom once, while in the lower-lying areas where there are no great seasonal changes the plants blossom several times a year - so that there are almost always fruits on the plants.

A hybrid of arabica, Maragogype - called the elephant bean because of its large size - originated from the Maragogype County in the Bahia state of Brazil. Today it is grown in Guatemala, Mexico, Nicaragua, Honduras, El Salvador, Brazil and Zaire.

Coffee canephora (var. Robusta):
Coffea canephora provides the robusta beans. Robusta, which can grow up to 32 feet in height as a shrub or tree, has a shallow root system. The fruits are round and take nearly a year to mature. The seeds are rounder and smaller than arabica beans. Robusta coffee was discovered in the Congo in 1898 and has become widespread since then - representing about 1/4 of the world's coffee production. It is grown in West and Central Africa, throughout Southeast Asia, and parts of South America including Brazil, where it is known as Conilon.

Robusta trees produce their first crop 3 to 4 years after planting and they remain fruitful for 20 to 30 years. The trees prefer equatorial conditions with tempratures between 75 and 85 degrees Fahrenheit and an annual rainfall of 60 inches.

Robusta tends to be a hardier, more disease-resistant bean than Arabica which is less expensive to maintain and produces a higher yield. Consequently Robustas are used for the less expensive canned and instant coffees.

Arabica coffee grows best at high altitudes (from 1500m to 2500m) while Robusta coffee prospers in lowlands such as rainforests. Before roasting, the colour of robusta beans are yellow to light brown in appearance whereas arabica are green with silver/blueish shades.

Some differences between Arabica and Robusta: