Pesticides in Vegetables

2002-03-01

Like nitrates, pesticide residues in vegetables and fruit have no taste or smell. Nor are there any visible signs, although large and perfect fruit and vegetables may perhaps be more suspect than poor-quality ones. (Cases are known of growers who pierce imitation caterpillar holes in cabbages before taking them to market, so they will appear "organic"!). Careful tests over many years seem to indicate that pesticides can safely be used on fruit and vegetables without damage to human health, provided growers follow the manufacturer's instructions.

The Key: Following Manufacturers' Instructions When Using Pesticides

Problems of toxic residues occur when the proper procedures are not followed. Common causes

of residue problems are that growers apply the wrong pesticide, or apply too much of it too soon before harvest. Sometimes this is from ignorance. Sometimes there is an outbreak of pests or disease shortly before harvesting. Farmers may abuse chemicals because they lack guidance in how to use them. In some cases, the pesticide they are using is not well suited to their pest problems, and is not very effective. In this case, farmers may spray pesticide repeatedly without killing the pest.

Education of Farmers Is Vital

Education of farmers is vital, so that they know how to handle and use pesticides safely. However, while this is a precondition of safe fruit and vegetables, it does not guarantee them. With farmers as with the rest of us, just because people know what they should do, does not guarantee that they will do it.

National Monitoring Systems to Detect Pesticide Residues

If produce offered to sale is to be free of pesticide residues, there must be some monitoring system. Crops must be regularly tested for pesticide residues. FFTC has held several training courses to help Asian countries set up monitoring systems, some based on chemical analysis, and some based on the cheaper but less accurate rapid bioassay. Whichever system a country uses, it must check enough samples so that consumers can feel confidence in the produce they buy.

A sound system of monitoring for pesticide residues is a strong marketing asset. Local growers of fruit and vegetables are having to compete with cheap imports. They will have a big advantage if they are backed by a national system of monitoring for pesticide residues. This will encourage Asian consumers to trust local produce. They will also be drawn to produce which is freshly picked, grown nearby in familiar ways on small-scale family farms.

Index of Images

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  Figure 1 Like Nitrates, Pesticide Residues in Vegetables Cannot Be Detected by Taste, Smell or Appearance