Plant Response to Chemicals

Plants respond to chemicals about the same as animals and humans do. Scientists have developed proof of this during the past which promises to be of great value to truck gardeners, orchardists, and farmers in general. John W. Mitchell discusses the subject on page 256.

Cuttings can be stimulated to grow roots faster by moistening and then dipping the basal ends in a plant-growth regulating chemicalcontaining 0.05 to 0.2 percent indole butyric acid. The same results can be obtained by soaking the bottom ends of the cuttings from 1 to 3 hours in about an inch of water containing 0.005 percent of the acid. After this treatment, the cuttings are set in moist sand for rooting.

NEMATODES—hundreds of different kinds of them—are known to reduce seriously the yields of many important tree, truck, and field crops. Efforts to find ways of controlling them have been successful as shown by the pictures on this page. Above is a small section of a plot used to test a soil fumigant called D—D (not DDT or 2,4—D) on squash. The soil at the left was treated, at right untreated. Picture was taken 4 weeks after the squash was planted.

At left, Dr. Darrow displays some hybrid blueberry fruits, the result of crosses with the lowbush blueberry of Maine and other Northern States. The plants are most vigorous and produce large berries of high flavor.

An important goal of the peach breeder is to develop varieties for specific purposes such as seasonal ripening, high yields and quality, attractive appearance, and resistance to diseases. A first step in "reaching" for a new variety is to transfer the pollen from one parent variety to the flower stigma of another (above, left). The offspring from this process is planted and grown to about 18 inches in the greenhouse during early spring. When danger of frost is past, the young trees are planted in the field . The first fruit is usually borne the third summer, when selections are made and only the most promising trees are kept for further testing.