White Pine Blister Rust Control in 1919.

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T the Fifth Annual International Blister Rust Conference, held at Albany, N. Y., an interesting report was presented on what has been done and learned during the past four years of experimental work. A summary is as follows:

1. Experiments conducted on an extensive scale since 1916 demonstrate that white pine blister rust can be controlled locally by destroying wild and cultivated currant and gooseberry bushes within a comparatively short radius of the pines. A distance of 200 to 300 yards is sufficient to prevent serious damage under average forest conditions. This is a reduction of 50 per cent. in the minimum width of the safety zone hitherto recommended.

2. Unskilled laborers can be quickly taught, under trained supervision, to find and destroy at least 95 per cent of the wild currant and gooseberry bushes in going over the ground once.

3. Wild currants and gooseberries do not reproduce rapidly in an area that has been worked by an efficient crew. Thorough checking on 2485 acres in eight separate tracts previously gone over by eradication crews, showed that on an average acre, 62 bushes (95.5 per cent.) were destroyed in the first working and three bushes in the second working. Bushes missed by the crews usually are small plants growing in underbrush. Such plants have less leaf surface than the average plant; therefore, the total percentage of protection to the pines is considerably greater than the total per cent. of currant and gooseberry bushes destroyed. Judging from data at hand, control areas usually should be gone over again five to ten years after the first working.

4. No new pine infections could be found in 1919 on four control areas on which currants and gooseberries were destroyed in 1916 and 1917. This demonstrates that eradication of currant and gooseberry bushes is successful in controlling the blister rust.

5. The cost of eradicating currrant and gooseberry bushes in the northeastern States in 1919 averaged 42 cents per acre for labor, or 54 cents including supervision. In 1918, the average cost, including supervision, was 66 cents per acre. In the New England States, the average labor cost was reduced from 44 cents per acre last year to 24 cents per acre this year. This low cost was obtained by employing scientific methods in locating wild currant and gooseberry bushes. Costs are expected to be still further reduced in areas

where wild bushes are very numerous, as a result of successful experiments in destroying such bushes by spraying them with chemicals.

6. Blister rust infection on pine in the northeastern States is increasing rapidly. A strip survey in one locality in New Hampshire indicates that one-fourth of the pines on an area of 72 square miles are already infected with the rust. The disease is widespread in Minnesota, Wisconsin, Ontario and Quebec.

7. Assistance to individual pine owners, towns, and associations in protecting pine areas from the blister rust is given by the New England States, New York, Wisconsin and Minnesota, in co-operation with the United States Department of Agriculture. In 1919, about $10,000 was subscribed for co-operative eradication of currants and gooseberries by individuals and associations in New York. In Massachusetts, local co-operators furnished $1,075. In New Hampshire, 53 towns voted appropriations totaling $8,514, and 34 individuals and firms subscribed $2,053 additional. The interest of the public in blister rust control is further evidenced by the fact that this State destroyed 21,171 bushes of cultivated currants and gooseberries, belonging to 1,023 owners, and only three owners insisted on compensation for their bushes. The others willingly gave their currants for the safety of the pines.

8. Owners of young white pine stands in infected regions should hasten to remove currant and gooseberry bushes (both wild and cultivated) within at least 200 yards of their pines, to prevent greater damage than has already occurred. The blister rust is an insidious disease. A tree usually is severely diseased before the infection becomes noticeable. Cultivated black currants are especially susceptible to the blister rust, but all kinds of currants and gooseberries will cause serious damage to white pines if the bushes are not destroyed before they are infected.

9. Cultivated currants and gooseberries should not be planted in localities where white pine is an important tree. The laws of some States prohibit the planting of such bushes without permission from State authorities, except in areas designated as "'currant growing districts." White pine plantings are a safe investment if currant and gooseberry bushes are first destroyed within 200 to 300 yards. The cost of protection may be reduced by selecting planting sites as far removed from cultivated currants and gooseberries as possible, and where the wild bushes are naturally few or absent. Cultivated black currants may cause loss if within a mile of the pines. 10. White pine blister rust has not been found

in the western half of the United States or western Canada. The abundance of wild currants and gooseberries in the sugar pine and western white pine forests would make control of the blister rust difficult, if not impossible, in most localities. The principal safeguard of these valuable western forests lies in the strict enforcement of the Federal quarantines prohibiting shipment of 5-leaved pines, and currants and gooseberries to points west of the Great Plains.

In Pennsylvania no white pine blister rust was found in 1919, and relative scarcity of host plants in Pennsylvania and New Jersey will aid materially in delaying the spread of the disease. southward.

The disease has been found in all the New England States, New York, in a few scattered localities in the other Middle States, and a widespread infection in Michigan and Wisconsin. None has been reported from the Rocky Mountain and Pacific Coast region.

Sixty-five species of Ribes are indigenous to western North America. Out of this large number can be found species adapted to nearly every site condition occurring in these regions. The constant occurrence of these Ribes would afford unbroken chains for the dissemination of white pine blister rust.

If the sugar pine and western white pine are to be kept free from this disease, five-leaved pines and currant and gooseberry plants from infected regions must be kept out of the West, as provided by quarantines in both the United States and Canada. Several violations of the Federal quarantine have been discovered in the Rocky Mountain States. A single diseased shipment of either pine or Ribes may result in enormous losses in the Far West, both to private and government holdings.

There was also presented at the Conference an estimate of the stand of 5-needled white pines in North America in 1919 as follows:

The reported value of white pine lumber cut in 1918 in North America is given as over $80,000,000.

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Less Maple Sugar and Syrup Produced. RODUCTION of maple sugar and syrup has declined this year, according to the Bureau of Crop Estimates, United States Department of Agriculture. The sugar production was 7,529,000 pounds, which compares with 10,169,000 pounds in 1919, 13,271,000 pounds in 1918, and 10,839,000 pounds in 1917.

Syrup production has not fallen off in the same degree, and yet the estimate of 3,606,000 gallons for 1920 is much below the 3,854,000 gallons of 1919, the 4,905,000 gallons of 1918, and the 4,286,000 gallons of 1917.

With syrup converted to terms of sugar, the maple sugar production of 1920 amounted to 36,373,000 pounds, and this compares with the estimate of 41,005,000 pounds in 1919, 52,513,000 pounds in 1918, and 45,127,000 pounds in 1917.

The productive season of 1920 was a short one and the average number of pounds of sugar per tree, with syrup expressed as sugar, was only 1.91, while in the preceding three years the averages ranged from 2.16 to 2.72 pounds per tree.

Pennsylvania's maple trees produced a crop of syrup and sugar valued at almost a million dollars, this year, according to figures prepared by the Bureau of Statistics, Pennsylvania Department of Agriculture. The amount of maple syrup obtained was only 83 per cent. of last year's, while only 80 per cent. as much maple sugar was turned out. The decreased production was brought about by unfavorable weather conditions. About 264,600 gallons of maple syrup were produced and sold at an average price of $2.75 per gallon, representing a total value of $727,670. There were 549,440 pounds of maple sugar produced and sold for 37 cents per pound, the total value being $203,292.

Western Canada

Eastern Canada

66 10.00 66 66

$5,000,000 600,000,000

I

Work Against Forest Insects.

MPORTANT results have been obtained in investigations of insects affecting forest resources, according to the recent annual report of the chief of the Bureau of Entomology, U. S. Department of Agriculture. An extract from the report follows:

"An especial investigation of the insect damage to crude spruce products for airplane stock in the States of Washington and Oregon showed that the greater part if not all of the damage could be prevented by proper methods of logging and production with little or no additional cost. "Exhaustive studies of insect investigation and control were continued in the Sequoia and Yosemite National Parks. Much new information has been gained, and the methods of gathering and compiling field data have been standardized.

"A special study was completed on the interrelation of forest fires and insects on an area of about 8,000 acres in southern Oregon. This area had been under observation since 1914, and fire had burned over about 800 acres in 1918. The records show that previous to the fire the insects had killed 485,000 board feet of timber. The fire killed 170,000 feet, and subsequently the slightly fire-injured as well as the uninjured trees in the burned area were killed by beetles, which were attracted from the surrounding areas. It was noticed that the infestation in the burned area increased more than 1,000 per cent., but it was found that the infestation in the surrounding areas decreased. It was also found that the broods of the beetles in the fire-scorched trees failed to develop to much beyond the original number that attacked the trees. So the fire did not contribute to an increase of the beetles in the general area or to the starting or extension of an epidemic of beetles. This result is of extreme interest and hardly to be expected.

"The most careful study ever made of the history of an epidemic infestation by tree-killing beetles was completed and a report submitted during the year. In the Rogue River area in about 48,000 acres near Ashland, Ore., the western pine beetle in 1914 caused the death of 346,000 board feet of pine timber. In 1915, 1,615,000 board feet were killed; 1,383,000 feet in 1916; and 608,000 in 1917. A count of the young and matured stages of the beetles that developed in an average foot of bark, and also of the number of exit holes through which the beetles emerged to attack other trees, showed that there was a notable decrease in numbers during the develop

ment of the broods each year in the infested trees on account of the increase of natural enemies and other disturbing factors. This helps explain why these beetle epidemics rise and fall within a limited period of years, and it explains how the western forests of yellow pine are naturally protected from total destruction. These facts are especially significant in connection with the application of the percentage principle of control, as by aiding the natural forces which work against the abnormal increase and spread of the beetles, complete control may be gained. The history of this epidemic shows the importance of prompt recognition and prompt treatment of a threatened outbreak in order to prevent the great loss of timber which would occur before natural control became operative.

"Another special study was made of the number of all stages of the western pine beetle in 330 square feet of infested bark selected from 67 trees, which represented an average infestation within an area of approximately 36 square miles. It was shown that there is a large percentage of mortality between the young matured stages in the developing broods, but that normally an average of about 150 beetles to the square foot of bark developed to the adult, or reproductive stage; which would be 50,000 beetles to the average infested tree, or say, 39,000 beetles to 1,000 board feet of timber. Since it requires an average of about 10 beetles to the square foot to attack and kill a vigorous, healthy tree, it will be seen that all the pine timber of the western forests would soon be destroyed were it not for natural and artificial control.

"Experiments to determine the time of year to cut and the methods of handling mesquite for fuel, posts, etc., to avoid destruction by woodboring insects, have been nearly completed, and the results show that serious loss in the Southwest can be prevented by cutting the trees in the late fall and early winter and piling the wood in loose piles until it is thoroughly dry. Damage to posts can be prevented by cutting them at any time and laying them on the ground where they will receive the full force of the sun, turning them occasionally so that the young stages of the borers will be killed by the heat.

"Studies of damage to lead telephone cables in California by a wood-boring beetle have been continued, and the results so far show that the beetle is able to penetrate alloyed substances that are considerably harder than lead. The problem is still unsolved, and it will be difficult to find a practical means of controlling this pest, which is able to put hundreds of telephones out