the use of large quantities of platinum, and in existing circumstances platinum is not only very costly but also difficult to obtain. The possibility of oxidizing ammonia commercially by means of electrolytic cells was therefore taken up and studied actively throughout the year. This work was also carried on in cooperation with the War Department, which assigned chemists to work with the chemists of the Bureau of Soils. The fact that ammonia could be oxidized in this way with the production of ammonium nitrate as an end product has been clearly demonstrated and the relative efficiency of the process is being investigated. As a result of the work already done. the indications are that this process operated in connection with the Haber process and thereby providing a market for the hydrogen liberated in the oxidation process can be operated commercially in competition with the Oswald method using platinum. Efforts were made during the year to encourage the largest cities of the United States to utilize their garbage for the production of grease and garbage tankage. The mayors of all the larger cities. not now possessing garbage-rendering apparatus were communicated with and their attention was called to the urgent need of both grease and fertilizer materials, with a request that they take steps at once to effect this conservation of waste materials. As a result of this work certain cities during the year have taken definite steps to install garbage-rendering plants. With regard to phosphoric acid the research work of the division has been restricted during the year to the investigation of the possibility of smelting phosphate rock by some other means than electric power. Furnaces of different types have been designed and constructed, with the result that it is now believed a furnace has been found in which the smelting of the rock is satisfactory, with the evolution of phosphorus fumes. This furnace is now being tested. If satisfactory results can be achieved in this direction it will be possible not only to produce double acid phosphate more cheaply than heretofore, but what is probably of even more importance, it will be possible also to use mine-run material from the phosphate mines and thus avoid the heavy waste of phosphoric acid involved in the present methods of washing and screening the rock. The regular annual survey of the phosphate industry was also made and published. The work of analyzing the raw materials and slags from the blast furnace industry, to determine if possible the amount of potash now volatilized and lost in that industry which might be collected for fertilizer, has been continued during the year. It is anticipated that this work, which involves a very large number of potash analyses, will be completed during the current fiscal year. It is evident from the work so far done that the amount of potash available from this source, if suitable collecting apparatus were installed at the blast furnaces, would be very large. Research work on several of the problems involved in the commercial collection of potash from cement kilns has been carried on in cooperation with several of the cement companies of the United States, and the results of this investigation have either been published or are now in press. The bureau's experimental plant for the study of the commercial utilization of kelp as a source of potash has been in partial operation during most of the fiscal year. Large amounts of kelp have been har vested, dried, and passed through the experimental retorts, where the kelp has been charred with the evolution of combustible gas, ammonia, and tar. Apparatus for the leaching of the char and the evaporation of the resulting brine was installed during the latter months of the fiscal year, but is not yet operating with entire satisfaction. It is believed that the evaporation of the brine will not involve serious difficulties, as evaporation of similar brines is being carried on satisfactorily at several commercial plants. The new apparatus for effecting a satisfactory leaching of the char is at present being installed at the plant. Large amounts of dried kelp and kelp char have been sold on their potash content at the market price, and $25,894 has been realized from this source. During the latter half of the year a chemist has been employed constantly on the examination of the tar and other distillates from the retorts in the effort to determine the best retorting conditions and the possible byproducts recoverable from this source. With the practical completion of the plant it is believed that during the current fiscal year very important progress will be made in demonstrating whether or not it is commercially feasible to extract potash from the Pacific coast kelps. It is gratifying to record that studies of the kelp plant during the year seem to show definitely that the kelp beds are actually improved by cutting off the mature growth. In southern California it has been demonstrated that beds which have been cut clean renew themselves and are ready for cutting again within three or four months. The disease which caused the total disappearance of certain beds in southern California waters a year ago has not appeared during the past summer in such degree as during the previous season, and operations have nowhere been seriously hampered by this cause. It is believed that prompt cutting of an infected bed has the effect of staying the progress of the disease. The usual large number of samples of supposed fertilizer materials have been received by the division during the year and examined, and a large volume of correspondence on fertilizer matters has also been handled. SOIL PHYSICS. The personnel of the soil physics laboratory has been utilized as much as possible on war problems, only sufficient force necessary for routine analyses being maintained on this work. The other members of the division have been engaged on work on the synthesis of ammonia and the oxidation of ammonia, carried on in cooperation with the Division of Fertilizer Resources of this bureau and the Nitrate Division of the Department of Ordnance, United States Army. The production of synthetic ammonia is of fundamental importance from both a munition and a fertilizer standpoint, and is an emergency problem to the Ordnance Department. The work done in the Arlington laboratory has advanced far toward the solving of this problem. REPORT OF THE ENTOMOLOGIST. UNITED STATES DEPARTMENT OF AGRICULTURE, SIR: I submit herewith a report of the work of the Bureau of Entomology for the fiscal year ended June 30, 1918. In accordance with your instructions, I have confined this report to concise statements of work performed during the year, with emphasis on the activities having a direct bearing on war problems. Hon. D. F. HOUSTON, L. O. HOWARD, Entomologist and Chief of Bureau. Secretary of Agriculture. DECIDUOUS-FRUIT INSECT INVESTIGATIONS. Investigations of deciduous-fruit insects have been carried out under the direction of Dr. A. L. Quaintance, as in preceding years. APPLE INSECT INVESTIGATIONS. CODLING MOTH.-Biological studies of the codling moth have been continued, and a large amount of experimental work has been done in orchards bearing upon various practical points in the control of this serious pest. Spraying experiments, carried on in cooperation with the Colorado Agricultural Experiment Station, in the Grand Valley of Colorado, have indicated that a schedule of six applications of arsenate of lead at the rate of 4 pounds of the powdered product to 200 gallons of water, with the addition of 4 pounds of fish-oil soap, will make a very effective treatment for the orchards in that valley. In the Rogue River Valley, Oreg., the codling moth is not only seriously injurious to apples, but causes a large loss by injury to pears. Therefore, in cooperation with the Oregon Agricultural Experiment Station, extensive studies were undertaken in the fall of 1917 with headquarters at Medford. This work was begun so recently that it is too early to report results. At the same time this bureau and the Bureau of Plant Industry established a joint laboratory at Bentonville, Ark., for the study of apple and other insects and diseases in that region. This work is meeting with the hearty cooperation of the orchardists. Other experiments are in progress in southwestern Missouri and in Arkansas, with Bentonville as headquarters. Orchard spraying work is also being carried on, in cooperation with the New Mexico Agricultural Experiment Station, in the Pecos Valley, N. Mex. Here the effort is directed toward determining the comparative merits of different numbers of spray applications 97335°-AGR 1918--16 233 and at different times under semiarid conditions. At four localities in the valley portions of orchards have been taken over by the department under cooperative arrangements with growers. At all of these stations experiments to determine the comparative merits of dusting and liquid sprays are in progress. This side of the work has been especially keen at Winchester, Va., where it has been shown that, with certain varieties such as the York Imperial, which is little subject to apple-scab, dusting will be an effective substitute for spraying. OTHER APPLE INSECTS.-Especial attention has been given during the year to the plant-lice occurring upon apple, and particularly to a certain group in which much confusion exists regarding the identity of species and the alternate host plants, this confusion standing in the way of remedial and preventive work. Valuable results have been reached. The work which has been carried out on the apple-tree borers and other fruit-tree borers has been continued and will be brought largely to a conclusion this year. Studies have also been made of the apple curculio, the giant root-borer, various leafhoppers, the imbricated snout-beetle, the apple maggot, and others. GRAPE INSECTS. GRAPE-BERRY MOTH.-In northern Ohio the grape-berry moth work has been continued and materially enlarged. During the year especial attention has been given to the perfecting of a spray schedule and to the making of improvements in methods of application of sprays. There is some ground for belief that a single timely and thorough spraying will be sufficient, and if so this will do away with the objectionable spray residue on the fruit at harvest time. "Dusting experiments also are being carried on in connection with this investigation, arsenate of lime being compared with arsenate of lead. OTHER GRAPE INSECTS.-The so-called grape mealybug has become troublesome in parts of California, where its life history has been studied to practical completion, and a large amount of experimental work with sprays and other remedial measures has been carried on. This is a difficult insect to handle, since it secretes itself under shreds of bark where sprays can not reach it readily. The work on the grape phylloxera has been continued on a reduced scale, the effort being to determine the best means of disinfection of rooted vines and cuttings tied in bundles according to the usual nursery practice. A thorough survey of Fresno County, Cal., which has been carried on in cooperation with the Bureau of Soils, to determine the relation of soil conditions to severity of phylloxera attack, has been practically completed. PECAN INSECTS. Additional information has been gained regarding the life histories of important insect enemies to pecan, and especial attention has been given to the use of insecticides in orchards or groves in southern Georgia and Florida. Growers have actively cooperated. Work of this kind has also been carried on in southern Mississippi and in the vicinity of Brownwood, Tex. INSECTICIDE INVESTIGATIONS. Work under this project has been continued as in former years in cooperation with the Bureaus of Plant Industry and Chemistry, and has included the testing of miscellaneous proprietary insecticides, and further testing of insecticides developed by the bureau or others for use alone and in combination with fungicides. Further attention has been given to the determination of the range of usefulness of calcium arsenate on pome and stone fruits and grapes. Testing work is under way in Connecticut, Michigan, Virginia, Arkansas, New Mexico, Colorado, and Oregon. Working under these varied climatic and other conditions, the results, when available, should settle the points under investigation. In view of the present high cost of arsenate of lead, orchardists and manufacturers have evidenced decided interest in arsenate of lime. Experiments thus far made indicate that it may be used in all situations where Paris green has been employed, and that for pome fruits it will be a satisfactory substitute for arsenate of lead when used with lime or fungicides containing lime. Progress has been made in the investigation of the insecticidal constituents of plants, especially the so-called derris. This insecticide of oriental origin acts both as a contact and as a stomach poison. As a stomach poison it is efficient against only a few insects, while as a contact insecticide it is efficient against a wide range of insects. A detailed report on the subject is planned at the close of the growing season 1918. Further tests have been made with nicotine as an agent for killing the eggs of insects, especially those of the codling moth. Results as a whole indicate an ovicidal action of nicotine, but not sufficient to give satisfactory control of the codling moth when used alone. Preparation of a report on the subject will be undertaken as soon as data for the present season's work are in hand. Studies of the relative toxicity and physical characteristics of various arsenicals, undertaken in cooperation with the Bureau of Chemistry, are being continued and progress made. An extended report on insecticides, spraying apparatus, etc., has been issued as Farmers' Bulletin 908. CRANBERRY INSECT INVESTIGATIONS. The work on cranberry insects in New Jersey has been completed, and a Farmers' Bulletin (No. 860) covering the principal insect pests of this crop in that State has been published. Special articles on the more important species have been published or are in the course of preparation, and practical control measures have been developed for the principal pests. An investigation of the insects affecting cranberry bogs in the State of Washington has been undertaken in cooperation with the agricultural experiment station of that State, beginning with the spring of 1918. Several of the important eastern cranberry-insect pests have been introduced into the Washington bogs with plants from the East with which the bogs were started, but it will be necessary not only to study these insects under their new far-western conditions but also to see whether native western insects will take to the |