Wednesday, June 29, 2011

Part 1: Are there pesticide-free vegetables?

Abe V Rotor

This item was originally written as a response to queries about how certain we are that our vegetables are, indeed, safe from pesticides.

In general, leafy vegetables (e.g. pechay) and fruit (tomato) vegetables receive more chemical spraying than do root (potato) and seed (mungo) vegetables, but this is not always true as we will see later.

As far as our problem on pesticide is concerned, I would rather classify vegetables into two: those that do not need spraying at all, and those which can not be raised economically without the protection of chemicals.

For the first category, here is a list of 30 common vegetables in their common and scientific names. Farmers simply find them resistant to insects, mites, nematodes, snails, fungi, including weeds, rodents and birds. These vegetables may also be found in the wild, or in the open spaces.

1. Malunggay (Morinda oleracea)
2. Saluyot (Corchorus olitorius)
3. Wild ampalaya (Mamordica charantia)
4. Katuray (Sesbania grandiflora)
5. Batao (Dolichos lablab)
6. Patani (Phaseolus lunatus)
7. Sinkamas (Pachyrisus erosus)
8. Summer squash (Cucurbita maxima)
9. Native eggplant (round) - (Solanum melongena)
10. Native tomato (susong kalabaw) - (Lycopersicum esculentum)
11. Native sitao (short) – (Vigna sesquipedalis)
12.Seguidillas (Psophocarpus tetragonolobus)
13.Alugbati (Basella rubra)
14.Talinum (Talinum triangulare)
15.Native spinach (Amaranthus sp.)
16.Gulasiman (Portulaca oleracea)
17.Sweet potato (tops and root) (Ipomea batatas)
18. Kangkong (Ipomea reptans)
19. Pepper or Sili (labuyo) (Capsicum frutescens)
20. Ginger (Zingiber officinale)
21. Rimas or breadfruit (Artocarpus altilis)
22. Sayote (Sechium edule)
23. Taro or gabi (Colocasia esculenta)
24. Kamoteng kahoy or cassava (Manihot esculenta)
25. Ubi (Dioscorea alta)
26. Tugui’ (Dioscora esculenta)
27. Kadios (Cajanus cajan)
28. Banana (Saba) (Musa paradisiaca)
29. Sampaloc (Tamarindus indica)
30. Kamias (Averrhoa bilimbi)

Most of these vegetables are native to our soil and climate. Consequently, they have natural resistance to pests and diseases that would not spare other introduced varieties, especially those of foreign origin.

Tinkering with the genes of indigenous species erodes natural resistance. Our native rice varieties for example, although they are not top producers, are resistant to pest, drought, flood, can compete with weeds, and do not need much care. Genetically “improved” rice varieties became pampered with fertilizers, water, planting distance, thorough soil cultivation, and most specially, spraying with insecticides and fungicides. They are likened to our present breeds of animals. Our poultry today can no longer thrive in the open, whereas our native fowls are “self-supporting”.

This is true with many vegetables. That is why commercial vegetables throughout their life cycle are provided with a “chemical blanket” to protect them from the onslaught of pests and diseases, many of them became destructive as a result of induced mutation. Indiscriminate chemical spraying has been found to build biological specialization so that certain insects and pathogens, which survive, carry on their acquired resistance to the next generation.

To the farmer this means more frequent sprayings at higher dosages, with elevated toxicities. This is what is happening today with many vegetables bought in the markets. The sector least heard of regarding this dilemma is the pesticide industry because it greatly benefits from it.

Pesticides are believed to be the most common source of poison that causes liver and kidney ailments. They affect our nervous system and impair our senses. They have long been tagged as a major cause of cancer, diabetes, allergy and other physiologic disorders. Because most of the pesticides today are synthetic chemicals, our body cannot readily degrade and excrete them. Instead, they tend to accumulate until a threshold level is reached that leads to many health problems.

Let us look at the second category of vegetables: those which are grown successfully only with the aid of pesticides. Without pesticides, they cannot survive the attack of pests and diseases.

The most sprayed vegetables are the crucifers – cabbage, cauliflower, lettuce, mustard, celery, carrot, pechay, wonbok, and the like. The pesticides used on them are the most potent brands, leaving no chance to caterpillars ensconced in deep holes, mites in the roots, and aphids in leaf axils. The poison must be absorbed and distributed throughout the plant so that any insect that feeds on the sap is sure to get the poison and die. This is why such poisons are called systemic, which means that they are translocated in all parts of the plant from roots to tips of stems and leaves, to flowers and fruits. The sap carries them in the same way substances are carried and distributed by blood to all parts of our body.

Poisons of this kind are also used on cucurbits (melons, watermelons, cucumbers, upo, squash, patola and ampalaya). The principal enemy is the fruit fly (Dacus cucurbitae), which lays eggs on the young fruits. Mango growers also use systemic poison to protect the fruits from another species of fruit fly, Dacus dorsalis. Mango importing countries like Australia, Japan and the United States impose strict regulations against fruit flies, which also attack other fruits and vegetables, like oranges and bananas, endangering their local fruit industries.

There are vegetables that may have been sprayed long before they are harvested such as peanut (Arachis hypogea) and mungo (Phaseolus radiatus). Rice and corn are relatively safe from the pesticides sprayed on them during their growing period. It takes at least 20 days for the grains to set and mature, ready for harvesting. By this time, the sprayed chemical has leveled off safely. It is the protective spraying before and during the storage of the grains that must be strictly regulated as this can leave harmful residues.


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