In the past decade, important achievements have been made in the field of biological controls for plant diseases and insect pests related to food crops. As university researchers began to focus on nonchemical approaches to these problems, a number of innovative solutions have been discovered.
One of the most successful developments arose from the necessity to find a substitute for the chemical methyl bromide, which is used to treat a number of plant diseases but causes ozone depletion in the atmosphere. Scientists began studying a fungus known as trichoderma and discovered that it attacks and devours a wide range of pathogenic fungi around host plants and trees.
Actually, trichoderma species were identified and reported as common soil fungi back in 1930. They were termed opportunistic, avirulent plant symbionts – that is to say the plants become hosts for the fungi, which act to protect them from plant diseases in return for carbohydrates provided by the host plant.
They were found to be effective against a wide range of pathogenic organisms, including  those causing stem rot (Fusarium spp, Pythium spp and Rhizoctonia solani), onion rot (Botrytis cinerea) and late blight (Phythopthora), and Sclerotium rolfsii and white mold (Sclerotinia).
Costa Rica has also done its fair share of research and development in the use of trichoderma as a biological control for agricultural crops, and the fungi are now being used to protect a wide range of food crops in the tropics. Over the years, the National Training Institute (INA) has developed educational programs for sustainable agriculture that include the use of biological controls for organic farming. As a result of this program, numerous laboratories across the country now produce biological controls for agriculture.
Trichoderma is just one of many new biological controls that have been developed to protect plants from disease and insect pests. Gardeners can take advantage of these new biological controls and move away from the use of risky chemical pesticides for home food production.
For information on products such as trichoderma and classes, contact INA at 2232-4422, extensions 556, 339 and 381, or Laboratorio Dr. Obregón at 2293-0394. I’ll be reviewing more of these natural biological controls with hopes of helping readers find natural solutions for their home gardens.
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For more information on tropical gardening,contact Ed at thenewdawncenter@yahoo.com or visit www.thenewdawncenter.info
