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AVOCADO PROFILE Compiled by FTF Volunteer Juan Guzman for farmers in Guinea
Temperature: Avocadoes are from the tropics, but can handle temperatures as low as OșC for a couple of hours. Soil: Variable, but imperative to have good drainage; standing water for more than two days may kill the trees. Very susceptible to salinity. Maturity: Some varieties lose all leaves at the time of flowering. The harvesting will take from six to nine months after flowering depending in the variety. Propagation: Avocados can be reproduced by seed or vegetatively or by grafting. The use of grafted trees is recommended for commercial production. This method allows for earliest possible production of fruit and assures that one retains the quality of the parental plant. Planting distance: Spacing depends on the variety. Generally speaking, 7-10 meters between plants is adequate. Time of planting: Avocados can be planted at any time during the year. However, water must be available during the early stage of the plant's growth. This means that dry season plantings must be watered initially. Weed control: Competition from weeds early in the development of the avocado can have a negative impact on the plant. Trees must be kept clean of weeds around the trunks for the first 2 years. Pruning: While small, the trees need little pruning, except for shaping and reinforcement of the frame work branches. All dead branches should be removed. Mature trees must have their tops trimmed to control height to a desirable 6-7meters and sides need to be pruned to avoid overcrowding. Fertilizer: Avocado trees will consume a medium amount of nitrogen, higher amounts of phosphoric acid, medium amounts of potash and some magnesium. A formula 4-9-3-1 at the rate of 60 g per tree is appropriate for young non-bearing trees, twice a year. At the time of fruit production, the consumption of nitrogen and potash increase, so a formula like 8-4-8-4 will satisfy the requirements at a rate of 1MT/ha, in two applications per year. (In these formulas, the chemical composition is N, P,O,, K,0, and Mg.) Yield: Yield differs among varieties, but 5 MT/ha may be an acceptable average crop. MARKETING Harvesting: Avocados should be harvested with the stem attached to the fruit. The fruit that can be reached by hand should be harvest with clippers, cutting the stems 6-7cm above the fruit. Those not reachable by hand can be harvested with a picking basket and a pole to avoid the mistreatment of the fruit. The picking season for avocados is dependent on the variety and may change from year to year according to the climate. But the fruit should reach the market firm, ready to ripen, and without shrinkage. To accomplish this, it is recommended that a maturity test be undertaken each year for each variety where samples are collected and deposited in a room at regular temperature. These avocados must ripen in about a week, without water loss. If the fruit loses water, wrinkling results and this is a sign of lack of maturity. In the USA, each variety has a different picking schedule organized by size, date, and weight. No standards have yet been set concerning oil content. The fruit should be deposited in round containers to avoid blemishing the fruit. These containers should be situated out of the sun while being filled and then taken immediately to a packing facility for cleaning, grading and packing. Packaging: Avocados are marketed in different sizes of boxes, in general not exceed 10 kg so as to avoid damage to the fruit during transport. This box will contain holes to permit the aeration of the fruit and to facilitate temperature control. Storage: Avocados for long transport need to be kept in low temperature to extend the shelf life of the fruit, but they must never reach freezing temperature because the fruit will be damaged. At an average temperature of 8-10șC, most fruit will keep for about 14-28 days. And this fruit will soften in about 2-3 days after removal from refrigeration. DISEASES Cercospora spot, caused by the fungus Cercospora perseae, eke., infects both the fruit and the leaf. This disease can be carried over from one year to another if control is not practiced. Leaf infections will produce defoliation. Fruit that is infected will have to be discarded. Control can be achieved with fungicides based in copper. Anthracnose, caused by the fungus Collecthotrichum gloesporiodes, penz., produces lesions on fruit, branches and leaves. Fruit that is infected will spoil, so will have to be discarded. Avocado scab fungus is present in areas with high humidity. Avocado root rot, Phytophtora ciannamoni, and ronds. can be a major problem. There is no known control available, except to keep the soil loose and well drained. This disease will kill the trees. Powder mildew: Oidium spp. Algea spot: Cephaleurus spp. INSECTS AND OTHER PESTS Mites: Oligonichus spp. The Scales insect, thrips, mirids and borer
may attack avocado trees. Control will depend on the policies of the local Ministry of
Agriculture. |