« PreviousContinue »
INTRODUCTION OF BENEFICIAL INSECTS.
The most important work in connection with the introduction of beneficial Insects has been the importing from Europe of the parasites and predaceous enemies of the gipsy and brown-tail moths, in cooperation with the officials of the State of Massachusetts.
PARASITES OF THE GIPSY MOTH AND BROWN-TAIL MOTH.
It has been shown that it is an easy matter to bring the European parasites of these injurious insects to this country, simply by collecting numbers of the larvae and chrysalides in different parts of Europe and sending them direct to Boston. A certain percentage of these insects on arrival in New England have given out the European parasites, which have either been cultivated in wiregauze inclosures, with plenty of food, or have been liberated in the open, there being chosen for this purpose patches of woods not subject to forest fires or to remedial work against the insects. It has been ascertained further—and this is a fact hitherto unknown even to European entomologists—that the young larve of the brown-tail moth in their overwintering nests in Europe are extensively parasitized. Therefore, during the winter of 1905-6 over 117,000 nests of the brown-tail moth were collected in 33 different localities in Europe, ranging between North Germany, South Hungary, and West Brittany, and comprising a large range of varying elevations and climatic conditions. More than 70,000 parasites were reared from these nests on American soil. About 8 per cent of these were hyperparasites—that is, parasites upon parasites.
By means of specially constructed cages the hyperparasites were separated and destroyed. The primary parasites were placed in out-of-door cages or liberated in the open. The largest colonies included 10,000, 15,000, and 25,000 parasites, respectively. Owing to the very wet season a fungous disease prevailed among the caterpillars, vitiating to some extent the results of the experiments, but nevertheless three species of parasites were seen to lay their eggs in American-born caterpillars, and there is positive proof of the derelopment on American soil of at least one complete generation of two of the European species. It has been shown that they may breed successfully through the season.
Egg parasites of the brown-tail moth have also been imported during the summer, and have been seen to lay their eggs in the eggs of North American injurious insects. Two important European predatory ground beetles have been successfully imported, and have bred through an entire generation upon American soil. Large numbers of Tachina flies have been reared from European specimens of the larvæ of both the gipsy moth and the brown-tail moth, and are breeding in the vicinity of Boston.
The greatest care has been taken to prevent the introduction of hyperparasites and other injurious insects, and there seems every reason to suppose that sooner or later the complete natural environment of both the gipsy moth and the brown-tail moth will be established in New England, placing them on a par with European conditions, thus greatly reducing their present importance.
NEW LADYBIRDS FROM EUROPE,
During the late winter months and spring of 1906 several species of European ladybirds, well known as destroyers of plant lice, scale insects, and softbodied insects of other groups, have been imported from Germany, France, and Austria. All of these have been liberated in the vicinity of the parasite laboratory at Nortlı Saugus, Mass., the country about being orchards and forests, with an occasional vegetable garden, promising plenty of food for the beneficial species.
THE KELEP OR GUATEMALAN ANT.
Efforts to successfully overwinter in Texas the kelep or Guatemalan ant, enemy of the cotton-boll weevil, have failed and a posible useful role for this insect in Texas is seemingly very slight. It is possible that this species may have some economic value in some of our tropical or subtropical possessions, where the climate will be more suitable than in Texas.
THE SENDING OF USEFUL INSECTS ABROAD.
It is possible, in many instances, to secure the sending of beneficial insects by the official entomologists of other countries without expense to the Department, as was done notably in the case of the introduction of an important enemy of the black scale from the government of Cape Colony, South Africa. In return for such services and as an earnest for possible future courtesy of the same sort exportations of parasitic and predatory insects have been made, under the auspices of the Bureau of Entomology, to foreign countries. A notable instance has taken place during the fiscal year. A scale insect which occurs abundantly upon various fruit trees in portions of the United States is a serious enemy to the mulberry tree in Italy, and therefore large sendings of parasitized scales of this species have been shipped to Professor Berlese, director of the Royal Station for Agriculture and Entomology, at Florence. After arrival two species of parasites were bred in some numbers, and efforts are now being made to colonize them in Lombardy. It is hoped that they will prove effective aids in the eradication of the mulberry scale.
INSECTS DAMAGING FORESTS.
Investigations of insects damaging forests have progressed in a satisfactory manner in cooperation with the Forest Service of the Department. Numerous problems have been studied and a large store of general information upon forest insects has been accumulated.
Field work has been conducted from stations in West Virginia, North Carolina, South Dakota, Idaho, Washington, and California, the locations of the stations being determined by the advantages offered at the points selected for the study of some special problem or problems.
A special investigation was carried on in regard to the Black Hills beetle, which has extensively ravaged the forests in Colorado, and the results prove to be in the highest degree satisfactory and have been published in Bulletin 50 of the Bureau. The recommendations are now being actively followed by private persons with excellent chances of checking what might otherwise prove a most serious invasion.
The conditions in the Black Hills are not so encouraging, owing, doubtless, to the failure of the parties interested to realize the importance of the recommendations of the Bureau. These difficulties, however, have now been partially overcome, and all concerned seem alive to the seriousness of the situation.
Investigations in the South of the destructive pine-bark beetle and of a number of important insects injurious to forest products have been carried on, and studies have been made in regard to the insect enemies of forest reproduction. Special studies and recommendations have been made concerning the western pine-bark beetle in the region north of Boise, Idaho, and a study of the forest insects of the Pacific slope has been carried on.
INSECTS DAMAGING DECIDUOUS FRUIT TREES.
For the investigation of insect enemies of deciduous fruit trees field stations at Youngstown, N. Y., and Fort Valley, Ga., were carried on to the close of the growing season of 1905, and in the spring of 1906 others were started at Myrtle, Ga., and North East, Pa. Later another one was established at Nebraska City, Nebr. In the course of this work some studies have been made of the parasites of the San Jose scale, and experiments have been made with a number of insecticide mixtures. The chemical study of the lime-sulphur and other washes has been undertaken in cooperation with the Bureau of Chemistry. New studies have been made of the plum curculio. The peach borer has also been studied throughout its geographic range, and extensive demonstration work has been done in Nebraska on remedies for the codling moth, in cooperation with the Bureau of Plant Industry, which at the same time was dealing with the apple scab, combination treatments for both being carried on cooperatively. Cooperation in this work is also under way with the several other experiment stations and the Georgia State entomologist.
The most important work in connection with field-crop insects has been upon the Hessian fly and jointworms, especial investigations having been made of the Hessian fly in the spring-wheat regions. It was predicted that this insect would (Witness: Howard.)
not damage wheat in regions where the spring crop is exclusively grown. This has proved to be a fallacy, and by reason of remarkable changes in the life history of the insect it has adapted itself to the conditions existing in the far northwestern country. This means a radical modification in remedial work, and the studies have indicated that it will not be difficult to bring about conditions of comparatively small insect damage. Important results have also been reached in the study of parasites of the Hessian fly, which will probably have a marked effect upon the multiplication of the fly. In the same way the jointworm investigations have resulted in the acquisition of important knowledge, both regarding possible remedial work and the handling of parasites. Studies have also been made of clover seed and clover insects, and also of other field-crop pests.
The saving value of the work on insects injurious to the great field and forage crops is estimated annually at about $9,500,000.
INSECTS AFFECTING VEGETABLE CROPS AND STORED PRODUCTS. Work on insects affecting vegetable crops and stored products has been continued along the same lines as conducted in previous years. Insects affecting the sugar beet have been studied with care, and a special investigation has been made of a leaf hopper affecting this crop in Utah, Idaho, and Colorado. Many other insects of this group have been under careful observation, and results of value have been obtained. The saving effected annually by the use of measures based upon the work of the Bureau of Entomology against insects affecting vegetable crops and stored products is estimated at $3,000,000,
INSECTS WHICH CARRY DISEASE TO MAN AND DOMESTIC ANIMALS.
The work of the Bureau on the subject of mosquitoes has been continued. A further study of the yellow-fever mosquito was made in the autumn of 1905, and experiments were made with remedies and methods of destruction against both larva and adults. Records have been brought together of the life histories and geographic distribution of the majority of the mosquitoes inhabiting North and Central America and the West Indies.
In the spring of 1906 a publication was issued upon the subject of the house fly, calling attention to its agency in the spread of typhoid fever, pointing out proper methods for its control, and urging the adoption of these methods by individuals and communities.
It was shown by observations made by the Bureau of Entomology upon a series of stables in two different sections of the city of Washington that it is a comparatively easy matter greatly to reduce the numbers of the house fly in any given community at a comparatively slight expenditure of funds and effort.
The investigation of the life history of the Texas cattle tick, mentioned in the last annual report, has been continued in cooperation with the entomologists of the States of Louisiana, Arkansas, Alabama, Tennessee, and South Carolina. This work has considerably increased our knowledge of the development of tha tick, and in connection with this work the life history and habits of a number of other common ticks, frequently confused with the fever-transmitting species, bave been investigated.
SCALE INSECTS AND EXPERIMENTAL WORK WITH INSECTICIDES.
This work, in special charge of the Assistant Chief of the Bureau of Entomology, has been continued. An immense amount of material in this group is sent in to the Bureau for identification and advice and the work grows in importance and value.
A thorough inspection was made of all new plants which the Department of Agriculture is importing from different parts of the world to detect and destroy any new insect enemies, principally scale insects, which might be brought in with them.
The work with insecticides has covered tests with standard insecticides, fumigation of mills, granaries, and dwellings against insect rests, and many new insecticide ideas or mixtures, which come to the Bureau for attention almost daily, have been examined and reported on.
Tests carried on upon a large scale and in a very thorough manner with sulphurous-acid gas have fully demonstrated its usefulness.
(Witnesses: Howard, Zappone.)
The work on bee culture has greatly increased. A large number of queen bees of different varieties were reared and distributed from the Department apiary, as well as from the substation at Chico, Cal. Investigations of the giant bees of India and the Philippines were continued through the year.
The various methods of queen rearing have been tested in rearing queens for distribution, and studies in bee diseases and in the important subject of honey. producing plants have been carried on.
There has been no change in the method and scope of the work on silk culture during the year. The correspondence was increased; a supply of eggs has been brought from Europe and distributed to correspondents in the United States; mulberry stock has been distributed, and cocoons have been purchased from correspondents and reeled.
Work on insects injurious to strawberry, raspberry, blackberry, and other bush fruits has been continued, and studies have been made of insects injurious to flower gardens and in greenhouses. An especial study of the insect enemies of roses is under way. The study of insects affecting shade and ornamental trees has also been continued, and an investigation has been made into the habits of the gadflies.
Routine work in the laboratory has greatly increased, and biological studies have been made of nearly 500 species not hitherto studied. Increase has also been noted in the work of determining specimens for the entomologists of experiment stations and other workers. Many thousands of specimens have been received for is purpose.
The CHAIRMAN (continuing). I notice under your cotton boll weevil investigations on page 249 that you have two items, one of “Advance to George P. Goll, temporary special disbursing agent," of $2,602.39, and another item, "Advance to W. D. Hunter, temporary disbursing agent,” of $12,106.23. What sort of an advance is that? How does that $12,000, for instance, happen to be advanced to Mr. Hunter?
Doctor HOWARD. He acted as what is called a temporary field disbursing officer. We tried it simply as an experiment during that year; we have since stopped it. When large parties of men are in the field their accounts come in monthly and we pay them by individual checks from the disbursing office. By this method of appointing a temporary disbursing officer that officer could pay the men's salaries and accounts from his central laboratory in central Texas. It is an arrangement common in the Government service. These accounts would be paid by Mr. Hunter at once, and he could be reimbursed later. Mr. Zappone can explain that much better than
The CHAIRMAN. Did Mr. Hunter advance the money to the Government or did the Government advance the money to Mr. Hunter, for this purpose ?
Mr. ZAPPONE. The Government advanced it to Mr. Hunter, who paid it out, just as any disbursing officer would in Washington. Under a general statute the head of a Department can appoint special fiscal agents in cases of emergency, such as travel abroad, necessitating the expenditure of money in connection with the Government work. It would be unfair to compel these men to pay such expenses from their private funds.
(Witnesses: Howard, Zappone.) The CHAIRMAN. Who is it that audits these expenditures?
Mr. ZAPPONE. The accounts come direct to the Department and are given an examination both in the bureau and in the disbursing office. They are then transmitted to the Treasury Department and audited in the same manner as my accounts as disbursing clerk are audited.
Doctor HOWARD. As to the case of Mr. Goll, that was a foreign case. He was sent to Central America to investigate in regard to a parasite.
(At 4.45 o'clock p. m. the committee adjourned.)