Costa Rica

Marietta College Biology and Environmental Science Department Field Trip 2005/2007

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In 2005, the class went to a banana plantation near the Biological Station at La Selva to see how bananas are cultivated in Costa Rica.  In 2007, we went to a pineapple plantation near the Biological Station at La Suerte.  Understanding banana and pineapple growing in Costa Rica is a necessary step in unraveling the tensions in land use and conservation in this small country; the two crops dominate the agricultural sector and account for a good deal of the land use.  Bananas and pineapples are to Costa Rica what corn and soybeans are to Indiana.  

Left:  Dr. Brown issues some last minute instructions and the class limbers up at La Suerte before loading into the stations Kia truck for the ride to the pineapple plantation.  We had some visiting educators along, plus the 14 of us, plus Israel (from the station) plus an assistant, so it was a full bus.

Right:  Israel has just parked the truck.

The plantation manager explains the process to the class.  

Here, he demonstrates how a pineapple is started from a crown twisted from the top of a mature fruit at harvest.

The class examines a mature - but not ripe fruit.  The fruits are picked at this stage because they are sturdy enough to survive shipping.  Timing of ripeness can be controlled in the shipping process by controlling the temperature and injecting plant hormones to accelerate ripening.

A view of the plantation.  The building in the background is the packing house.  Pineapples require relatively little infrastructure to grow.
View of one of the fields (right).  Young fruit stalks are visible.  Different fields are kept in different stages of development to account for the long time it takes a plant to reach maturity and produce fruit.  A field will produce up to 3 crops of fruit, then it will have to be replanted from the crown cuttings.

As with bananas, drainage is key.  These deep drainage ditches help channel away the tropical rainforest levels of rain that fall each year.  Pineapples need relatively dry soil to avoid problems with fungi and nematodes.

Right:  A field of young plants which has yet to produce fruit.

Landscaping cloth is used to anchor the soil of the drainage ditches.  The board provides a bridge so that workers can use the drainage ditch as a path; this is easier than walking through the field (a subsequent picture will show why).  Reducing soil erosion on open ground exposed to tropical rains is a real challenge; one of the biggest environmental complaints against pineapple production is the soil erosion it can cause.

The plants to the right in this photo have been harvested and the leaves cut back.  Pineapple plants can produce up to 3 crops of fruit.  It takes about 18 months to produce the first fruit, the second crop will follow a little over a year later.

Pineapples can be propagated from a number of sources.  The crowns above the fruit can be twisted off at harvest and replanted.  Lateral growths can be removed and planted, and exceptional plants can be marked at harvest and later be cut up with the sections allowed to re-root.  In some cases, and particularly with new cultivars, pineapples are propagated with tissue culture techniques, at least at first.

Her the flower stalk is beginning to form.  This view reveals the pineapple's place among the bromeliads, a varied group with many epiphytic members (including the "Spanish Moss" of the American Southeast.

Flowers of the pineapple start at the bottom and work their way upward.  Each flower produces a fruit; the pineapple we eat is comprised of many such fruits all pressed together in one structure.  

Pollination is not needed; if the flowers are pollinated then seeds will develop, and this is not desirable in fruit for market.  Normally, pollination would be done by hummingbirds;  in Hawaii, there are no hummingbirds, so this is not a problem.  In Costa Rica, there are a lot of hummingbirds, but the scale of the plantations would defeat the most industrious of hummingbirds - that, combined with the genetic similarity of the plants means that few seeds, if any are produced.

Close-up of flower.  Chemicals are applied (including acetylene, ethylene, and napthaleneacetic acid) to the fields to force flowering and ensure the whole crop matures at the same time to facilitate harvesting.  Low-tech ways of doing this include smoke (burning plant materials gives off ethylene) and adding calcium carbide granules to the base of the leaves.  Calcium carbide is added to waters in the old-style miner's lamps; acetylene is produced (which is burned in the lamp to provide light and absorbed by the plant to induce flowering).

Nearly mature fruits in the field.


Harvesting the fruit.  This harvest is being done by hand.  The sign warns that it's sometimes necessary to apply pesticides for the protection of the crop, and therefore only authorized personnel are permitted.  The top has some nonsense about how this protects the environment (medio ambiente)

Integrated Pest Management:  The Tican solution to 2-legged pests in the pineapple fields.  Note back-up dog at extreme right.


This is why workers don't walk through the fields.  The edges of the pineapple leaves bear sharp spines.


A close-up of the harvest.  These workers have some protection - goggles and gloves.  Some are wearing long sleeve shirts, but clothing that is tough enough to protect one from the spines probably is too hot to wear in the fields during the day - there isn't a lot of shade! 




Pineapples require numerous chemical applications. Fungicides are needed to prevent fungal infections.  Soils must be treated for nematodes in some areas.  Other pesticides are needed to control insect pests, and herbicides are applies to control competing plants.  Fertilizer is needed in large quantities.  Rain isn't a problem in Costa Rica; in drier areas such as Hawaii farms now use drip irrigation combined with palstic mulch sheets (these also keep out competing plants and thus reduce herbicide use).


Hopefully, the workers are wearing protective equipment as they spray, but again, such equipment is very hot to wear, and not every employer supplies it.

Despite the applications of herbicides, ferns grew lushly in some of the drainage ditches. I don't usually think of ferns as a particularly tough plant.




Packing pineapples for export is pretty straightforward (as opposed to canning, for instance).  The packing house, above, has a conveyor on which the incoming fruit is placed (below).

The fruit is sprayed to wash off any contaminants and kill any microorganisms.  The sheet on the window gives the concentrations and time for the chemical application.  The fruit is then rinsed and coated with a thin layer of wax to prevent desiccation.  The wax is dried by the blower in the image at lower left.

Below, the belt extends into the plant; if the packing house had been in operation when we visited workers would have been placing the fruit into boxes.

The boxed fruit, ready for export.

For more info:  Pineapple Lecture




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