Natural Agriculture

Back to the Basics

By Diana J. Choyce
Oct 04 - 10, 1999

Keeping fruit crops fresh from picking to retail shelves is a well known problem. Doing it without chemical pesticides and preservatives is an even bigger problem. Doing it naturally would be the best solution for the growers, shippers, retailers and consumers. Can it be done? According to research being done by Lisa Skog and Prof. Dennis Murr, from the Department of Plant Agriculture'sVineland Research Station, and Brian McGarvey of Agriculture and Agri-Food Canada, it's a definite possibility.

Natural fruit "volatiles" are compounds already found in fruit and which enhance its flavor and aroma. But in high enough concentrations it can also produce antimicrobial agents which will protect the fruit from fungal attack and damage. In response to environmental stress, injury and microbal attack a fruit will speed up its production of certain volatiles.

"If natural fruit volatiles prove effective, then growers, distributors and consumers will all benefit," says Skog. "It could lead to a healthier product, less storage decay, longer shelf life and decreased losses during shipping." The result can also mean huge monetary savings for all involved in the fruit business. And even more important a very positive effect for both humans and their environment.

The main focus of researchers is to find an alternative to using chemicals such as methyl bromide for fumigating fruit, soil, and grain storage facilities. This chemical has been used extensively for years despite its obvious negative effect on consumers and their environment. After January 2001 the use of methyl bromide will no longer be available. This has put all research into natural options on the fast track. The use of volatiles looks to be very promising. They may prove be very effective in preventing latent infections from becoming active because they can penetrate the fruit surface. Since not all volatiles are effective, the focus has been on identifying the most useful ones. And then testing and evaluating their effectiveness, finding the best methods of application, and deciding on the precise amounts to be used. So far over 20 volatiles have been found with 5 identified as possible options.

The research is called biocontrol and involves many different levels of study. From introducing micro-organisms to prevent infection of economic crops by soilborne pathogens, to the use of applying fruit volatiles directly to the fruits. There is also research being done involving genetic altering of plants to achieve these ends. In many respects it is very similar to studies being done on humans to provide

ways to naturally fight off disease and infections. The world has become far too dependent on chemically based answers to all these problems. And all too often it has proven the old adage that "the cure is worse than the disease".

The use of natural means has been documented as far back as Roman times, when the lowly mustard seed was used to preserve foods. And in the early 1900's research was started on determining which components in the seed were producing these preservative properties. But the research was stopped as chemical methods came on the scene and were regarded as easier and cheaper to use. Things have now come full circle as we have finally admitted the need to revert to natural methods in order to preserve not only our foods but ourselves and our environment. Had these earlier studies been continued its possible that chemical pestisides may have never taken such a hold in the world of agriculture.

Another study is being done to effect a way to monitor fruit, to determine quality and ripeness based on the emissions of volatile gases. This electronic sensor monitoring system would be extremely helpful in harvesting, grading and sorting fruits. A better understanding of the maturation of fruits would also be helpful in predicting their shelf life and would be very useful to fruit retailers. It is already being used with great success on crops such as already with apples, blueberries, raspberries and blackberries, strawberries, tomatoes and melons.

On a side note, research is also being done that could provide a possible treatment for HIV. This project is in cooperation with the University of Yaounde, Cameroon, and the Cameroon government along with other agencies and institutions. The plant being studied is the wild tropical liana from the rain forest of Cameroon, Africa. Means of cultivating the plants, which are rich in michellamine B (a dimeric alkaloid), and delivering them to the National Cancer Institute for chemical extraction and study are the main focus. Given the large quantities needed in this research, special nurseries have also been started to possibly clone these plants.

Agricultural research will no doubt provide the answers to many many problems facing the need to feed the world populations. And providing safe, long term, and effective means of growing, picking, packing and shipping are of the upmost importance. The economic impact on developing countries in regards to import and export is of great concern. And as always the effect on both humans and their environments is and should be a long term goal. Huge amounts of time and investment will be necessary to solve these problems. It is comforting to see that we've finally come to realize that natural methods have always been and will always be the only alternatives we should be seeking.