What the economic entomologist wants to achieve is a method or methods of maintaining insect population below the level where they do material damage. If the natural environmental resistance provides this, nothing more is necessary but if it fails to do so, then I am expected to devise methods of bringing about this desired end. You must decide sooner or later, whether you can completely ignore the role of environmental resistance and particularly biological control, or whether you should use chemical control only as a supplementary measure.
As far as fungus diseases are concerned, there is one which gives particular trouble to apple and pear growers known as scab. I have found little difficulty at the present time in controlling this disease by using an 'organic' fungicide known as Fuclasin or Captan. It is quite a good plan to use one of these washes-first of all when the blossoms have fallen, that is to say just as the little apples or pears are starting to form. It can then be applied again some three weeks later and possibly once more three weeks after that.
I want to say that I believe the proper approach to the orchard insect control problem, or any control problem, whether plant or animal, is through a complete ecological study of the problems involved. If insecticides are necessary to keep injurious species below the economic level, we must take the trouble to determine the overall long-range effect of the chemicals on all the factors in the environment.
Derris is an organic wash, coming as it does from the powdered root of the Derris elliptica bush. The alternative would be to use pyrethrum, which is another of nature's own insecticides.
One can only approach the whole question of insect pests and fungus disease control in the experience of the past. It is, however, impossible to lay down hard and fast rules for every county or even for every orchard, and at the present time the aim must be to adopt such methods as will ensure clean fruit being grown which can be put on the market or can be eaten by the householder without fear of poisoning or of damage to health.
Most fruit growers agree that trees and bushes should be sprayed with a tar-oil wash in December for it is almost impossible to control aphids in the spring and summer unless this is done. Some omit the tar-oil application every fourth or fifth year in order not to overemphasize the insecticidal control. They then watch carefully that spring and spray with liquid derris or if necessary. - 15266
As far as fungus diseases are concerned, there is one which gives particular trouble to apple and pear growers known as scab. I have found little difficulty at the present time in controlling this disease by using an 'organic' fungicide known as Fuclasin or Captan. It is quite a good plan to use one of these washes-first of all when the blossoms have fallen, that is to say just as the little apples or pears are starting to form. It can then be applied again some three weeks later and possibly once more three weeks after that.
I want to say that I believe the proper approach to the orchard insect control problem, or any control problem, whether plant or animal, is through a complete ecological study of the problems involved. If insecticides are necessary to keep injurious species below the economic level, we must take the trouble to determine the overall long-range effect of the chemicals on all the factors in the environment.
Derris is an organic wash, coming as it does from the powdered root of the Derris elliptica bush. The alternative would be to use pyrethrum, which is another of nature's own insecticides.
One can only approach the whole question of insect pests and fungus disease control in the experience of the past. It is, however, impossible to lay down hard and fast rules for every county or even for every orchard, and at the present time the aim must be to adopt such methods as will ensure clean fruit being grown which can be put on the market or can be eaten by the householder without fear of poisoning or of damage to health.
Most fruit growers agree that trees and bushes should be sprayed with a tar-oil wash in December for it is almost impossible to control aphids in the spring and summer unless this is done. Some omit the tar-oil application every fourth or fifth year in order not to overemphasize the insecticidal control. They then watch carefully that spring and spray with liquid derris or if necessary. - 15266
About the Author:
To plant a fruit tree in your garden, dig a hole larger than the spread out roots and fill it about one third full with 2 parts topsoil and 1 part peat moss.
