News & Updates:

The greatest advance ever made in the control of garden pests came with the introduction of a new group of products known as organic phosphates. HETP was the first of these to be available; parathion and E605 came soon after it. Any difference in the chemical composition of parathion and E605 is of a minor nature and of only academic interest, having no practical importance. The two names may be regarded as freely interchangeable, if not synonymous, but, to avoid confusion, only one name, E6o5, has been used in the section of this chapter that deals with insects. HETP seems a little quicker in its killing action than E605. They were by far the best contact sprays we had ever had for aphis, thrips, red spider, and pea mite, and were the only preparations that will kill the last two of these pests as adults; two sprayings at an interval of ten days are advisable. More recently Chlorparacide has been introduced, and it deals effectively with the eggs and pupae of arachnids, without having the disadvantage of being poisonous to man-it is not a phosphoric preparation.

The latest developments of organic phosphate preparations take the form of systemic insecticides, so called because they are absorbed into the system of the plant and render the sap toxic to pests. They also kill all insects rapidly by contact at the time of application and have persistent action on the surface of the plant, similar to that of E605. After absorption they have no harmful effect on the natural enemies of plant pests, of course, because such predators do not suck sap. E605 is absorbed by the plant and acts in this same manner but in much lesser degree. Systematic sprays are absorbed through both leaves and roots and they reach all parts of a plant irrespective of whether the spray has or has not covered the foliage completely. Once absorbed, rain or watering cannot wash them away, thus allowing them to remain fully effective for three or four weeks. Systemic sprays, therefore, need to be used less often than E605, which more than off-sets their higher cost. It is possible to obtain good results merely by watering the soil with systemic sprays. This avoids the dangers encountered in spraying, but is rather wasteful.

These organic phosphate sprays seemed, at first, to be what all horticulturists had been hoping for for many years. We knew that they were extremely poisonous to human beings, but we did not anticipate the fatalities of which reports were received quite soon. Fortunately, it seems that none of these tragedies occurred in Australia before the introduction in some States of regulations governing the use of these sprays. It must be conceded that there is no great danger if organic phosphates are handled with care, and it is regrettable that it is necessary to protect people against their own lack of caution. The new regulations make it compulsory for any person using organic phosphate sprays to wear waterproof overalls, a waterproof hood, gloves and boots of rubber or other suitable protective material, and a full face-piece respirator with charcoal container and filter pad. All clothes and protective coverings must be washed thoroughly upon ceasing work each day, as well as any exposed parts such as the face, hands, and forearms. As yet, we have no spray or combination of sprays to equal the usefulness of organic phosphates. The nearest approach to them can be made by mixing Chlorparacide with Lindane and DDT as in Spraymate. This combination is inferior to E605 solely because it is slower in action and has no effect as a systemic poison. This is important only in spring when aphides reproduce so quickly.

As a further precaution, it is illegal to sell any organic phosphate spray in any quantity less than one pint; this amount is quite costly. The sum total of all these regulations is that the use of organic phosphates is practicable only for those who spray on a large scale. For them, the elaborate precautions and expense are more than compensated for by the results; actually, where large amounts of sprays are needed, organic phosphates are less costly than most other materials, particularly if one considers the saving in labour costs, as a result of spraying being required less frequently. This makes it worth while to give more detailed consideration to HETP, E6o5, and systemic sprays.