TREE MEDICATION.
Reading edition
The experiments in tree medication, in charge of Dr. Caroline Rumbold, have been for some time conducted in a large chestnut orchard located near Martic Forge, Lancaster County. The following is a brief statement of recent work:
PLOTS UNDER EXPERIMENT.
In 1912 three plots were selected for experiment. Each contained about fifty trees varying in age from seedlings to eighteen years old. This year two new plots were added to the three of 1912. Some tree surgery work was done, and the trees sprayed with lime-sulphur.
OBSERVATIONS OF THE WORK OF 1912.
Last year fifty-four trees were injected; 15 with salts of the heavier metals; 5 with formaldehyde; 12 with stains; 22 with alkalies, and the remainder with water. An attempt was made to inject two trees with canker extract, but the solution would not go into the trees.
On June 7, 1913, results of observations on these trees injected last year were made as follows:
To date, the injections of the salts of the heavier metals, (copper, zinc, barium), appear not to have killed the trees, although they mutilated them. Those injected with the copper salts suffered the most. Inoculations made on these trees after they were injected have taken, and the cankers forming are larger than those on the check trees. Of the five trees injected with the formaldehyde, two are alive, but mutilated. Inoculations on these trees have formed cankers larger than those on the check trees. Most of the trees injected with stains have been cut down, for observation. None were killed, however, by the injection. The trees injected with water are in good condition with the exception of one tree infected with a canker, which is now girdled. The only unusual sign about the tree is the large amount of suckers at its base.
FAVORABLE EFFECTS OF ALKALIES.
The trees injected with alkalies are all in good condition at present. An encouraging feature of the experiment with alkalies is that a number of inoculations on these trees did not take, and on those which have taken cankers have formed smaller than those on the check trees. These trees were cut into in April in order to count the number of inoculations that took, and in a number of cases these cuts have formed callus.
INJECTIONS IN 1913.
The past spring, 69 trees have been treated—21 with colloids, 18 with alkalies, 18 with acids, 17 with benzenes, one with methyl alcohol, and two with methylene blue, while five are water checks. The method of injection used this year is the same as in 1912.
EFFECTS OF THIS YEAR’S INJECTIONS.
The trees have not reacted to the injections this year as quickly as last summer. The slowness of reaction may be due to the season of the year, the cool weather, and the large amount of rain since injections began. As was to be expected, the trees have reacted to the injections differently. Potassium chromate and bi-chromate caused the fastest and most severe reactions. Reactions of the trees to the chemicals are generally shown by discoloring, drying, or falling leaves. Sometimes the trunk shows the path the solution followed by sunken areas, or long cracks in the bark, extending up the tree. So far no results can be given as to the effect of this year’s injections, either on the trees themselves or on the canker growth. The full effect of the present injections probably cannot be seen until next year.