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As to other topical applications intended to destroy the beetles, whether directly or by poison taken with the food, the experience with the arsenites is that they are of little avail, and the experience with other materials, like hellebore and pyrethrum, has been so conflicting that we can not consider either of them reliable or satisfactory. Pyrethrum would seem to have given on the whole the most satisfactory results.
The trouble with all these remedies is that the beetles during their brief season continue to issue from the ground and to congregate upon their preferred plants in such numbers, under favorable circumstances, that however fatal an application may be it has to be continued, and the most persistent may justly become discouraged in a fight with these beetles when they are abnormally abundant and swarm to the extent we have known them.
With this insect as with many others success will only follow diligence in the combined application of the insecticides that have been found effective, and the persistent shaking on to sheets or stretchers saturated with coal oil. A few choice plants may be
protected by covering with netting; Another protective measure is to dust the plants with air-slacked lime or gypsum, or to spray with lime water, from one half to one peck of lime to a barrel of water.
ADDED EXPERIENCE DURING THE SUMMER OF 1890.
Since the publication of the article in INSECT LIFE we have had some interesting correspondence on the subject of the Rose Chafer.
Mr. J. S. Strayer, of Port Republic, Virginia, wrote, under date of July 2, emphasizing the fact that the insect breeds in sandy land and that it has never been known to attack vegetation upon clay lands. This statement is exaggerated, as the beetle is a strong flyer and when sufficient food is not found in its breeding places it will fly to the nearest point where food is abundant and will attack it whether upon clay or sandy land. An interesting point which shows the certainty with which the breeding in sandy soil is known, is brought out by Mr. Strayer in a statement to the effect that it has even been recommended by gentlemen in his neighborhood to place clay around the roots of grapevines as protection. This recommendation is of little or no value under the circumstances.
Mr. John K. Hoyt, of Luther, North Carolina, wrote us July 21 that jarring the vines and catching and destroying the beetles made no perceptible diminution in their numbers. He thought his entire grape crop was doomed, but after spraying a row of one hundred vines with London purple, at the rate of 1 pound of the poison to 150 gallons of water, the beetles entirely deserted them within two days. The spraying was done on May 29, so that the disappearance was entirely produced by the remedy.
June 19 we received a letter from Mr. E. H. Wynkoop, of Catskill, New York, reporting upon some experiments with pyrethrum (4 ounces to 5 gallons of water) and with hellebore without effect. Shaking upon a stretcher saturated with crude petroleum he found quite effective. A neighbor told him that he had driven the beetles from his vineyard by burning pieces of old rubber between the rows.
Mr. S. Justus, of Mentor, Ohio, wrote, June 22, and again November 27, concerning his use of a mixture of unslacked lime and carbolic acid in water in the proportion of i bushel of unslacked lime to 1 quart of acid and 50 gallons of water. He applied the dose freely and his vines looked white when he finished. He sprayed at the rate of 5 acres per day and lost no grapes afterwards. The mixture had no injurious effect on the vines and the experiment was satisfactory for the reason that a large untreated check patch was left, on which the crop was entirely destroyed.
In none of the localities mentioned, however, was the rose chafer as abundant as it seems to have been in parts of New Jersey and Delaware. The numbers in which they occurred in the two latter States, as described by Professor Smith, Mr. Beckwith, and others, would seem almost incredible to one who has not seen one of the great incursions of this species. The result was that neither of the gentlemen mentioned were able to find any remedy which would effectually protect vegetation. Myriads of beetles were destroyed but their places were filled by others, and by sheer force of numbers the effect of all remedial work was vitiated. Professor Smith found that there was scarcely a plant which they did not eat, although flowers and some fruits are always preferred. He experimented with pyrethrum, tobacco, London purple, powdered naphthaline, pure and mixed with carbonate of lime, hellebore, foxglove infusion, digitaline, quassia and copper compounds, iron solution, kerosene emulsion, corrosive sublimate, sludge-oil soap, and a mechanical apparatus consisting of an umbrella with a sack attached. In his opinion the only way to save the crops is to plant spiræa, roses, or blackberries between some rows of the vineyard. These plants are preferred by the Chafers, and by persistent collecting they can be kept from the grapes.
The experience of the past season was discussed at the meeting of the Association of Economic Entomologists at Champaign, Illinois, early in November, and the report of this meeting will be found in INSECT LIFE, Vol. III, No. 5. "An article by Professor Smith, reprinted from Garden and Forest, will be found in INSECT LIFE, Vol. III, No. 3.
THE WORK OF FIELD AGENTS.
A BRIEF STATEMENT OF THE WORK OF THE FIELD AGENTS OF THE
Mr. D. W. Coquillett, the agent stationed at Los Angeles, California, has devoted most of his time during the past year to the further improvement of the apparatus and methods used in fumigating orange trees as a remedy for the red scale (Aonidia aurantii Maskell). This process, which is the outgrowth of the experiments which we began at Los Angeles in 1887, and which was described in full in our annual report for that year, was, by the work of the season of 1889, much simplified and the cost of its use was reduced about one third. The expensive machinery figured upon Plates IV, V, and VI of the 1887 report has been greatly simplified, with a corresponding reduction in cost. During the present season still simpler apparatus has been devised and the arrangements have been so perfected that it is now possible for the planter to fumigate his orchard at the rate of thirty to forty trees a night. Most large orchardists, however, use as many as six tents at once, and in one case four men, using six tents, fumigated two hundred and forty trees in one night. During the past season over twenty thousand trees have been fumigated in Orange County alone, and the red scale is being rapidly reduced in numbers. Mr. Coquillett is convinced that better results are obtained than by the use of any kind of spray, and many instances have occurred where upon large trees treated with the gas he was unable to find a single living red scale, a result which it would be hardly possible to obtain by spraying. An interesting point which has been brought out is that the trees are less liable to injury when fumigated at night than they are when operated upon in the daytime, while the gas is just as fatal to the insects at night. This is accounted for by the fact that in the daytime the light decomposes the gas into other gases, which, while being more hurtful to the trees, are not so fatal to the insects. Moreover the trees are more or less in a state of rest at night. Mr. Coquillett reports in full upon apparatus, methods, and preparations.
During the winter he carried on a series of experiments with washes against another very injurious scale insect, víz, the San José or pernicious scale (Aspidiotus perniciosus Comstock), using several substances heretofore not experimented with upon scale-insects, such as salt and water, salt and slacked lime, sulphur, corrosive sublimate, glue and aloes. The high price of the latter would debar its general use, but the results were exceptionally good. Of the substances experimented with the resin wash first introduced in Mr. Koebele's experiments for the Division was found to be one of the most efficacious as well as the cheapest.
Mr. Lawrence Bruner, the agent of the Division stationed at Lincoln, Nebraska, has investigated an outbreak of a local grasshopperCamnula pellucida—which has for the past two or three years been appearing in numbers in parts of Idaho and Utah, but the greater part of his work has been connected with the collection and study of the insects injurious to the sugar beet, as the State of Nebraska has recently taken up the cultivation of this crop to a considerable extent. Mr. Bruner has found that no less than sixty-four different insects prey upon this crop at the present time, and the major part of his report is taken up with the enumeration of these species and comments upon them. The beet crop is an easy one to which to apply remedies, for, like the potato, the tops are valueless after a certain stage of growth and solutions so strong as to seriously injure them do not affect the root. Therefore, by a thorough use of arsenical solutions and strong kerosene emulsion the crop can be kept free from insects.
The report of our Indiana agent, Mr. F. M. Webster, on insects affecting cereal grains, relates largely to experiments and observations extending over a period of more than six years, to determine the number and development of broods of the Hessian fly. His observations and experiments have been made chiefly in the State of Indiana. He has found that the double-brooded habit of this insect, long ago pointed out by Dr. Fitch, holds true for ordinary seasons throughout Indiana. The fall brood in the southern portion of the State he finds to appear some weeks later than in th north and between the spring and fall broods retarded individuals of the one and accelerated individuals of the other brood appear, rendering the strict limitation of the other broods in some cases difficult, or giving the appearance of an intermediate third brood. The additional thira brood, if it ever occurs, is certainly abnormal and unimportant, as shown by experiments carried out in the field and not subject to the vitiating influences of the breeding cage.
The usual time of appearance of the fall brood in southern Indiana
is from the last of September to the first of October, so that to escape the attacks of the fly wheat in this region should be sown soon after the first of October.
In the northern half of Indiana the flies appear from two to three weeks earlier, and experience has practically indicated that in this part of the State wheat sown between the 15th and 25th of September is the most likely to escape the attacks of the Hessian fly.
The later appearance southward of the fall brood has been noted by all observers. Mr. Webster's experiments give more accurate information as to dates of appearance of the flies and, therefore, of the best time for seeding in the region under study and will be of great practical value to the Indiana farmer. His conclusions will also apply to a large part of our wheat belt.
The report on this insect also includes some interesting observations on the effect of the larva on the plants, particularly in the matter of color, of the effect of the weather on the development of the fall brood, and concludes with a review of the preventive and remedial measures.
The report further contains a brief account of the European grain Toxoptera (T. graminum), which during the last few years has been very abundant in certain sections in the West and Southwest, and which we instructed Mr. Webster early in the year to carefully investigate. Our knowledge of this recently imported grain pest is still far from complete, although the season's observations have added considerably thereto.
A short report on the grain aphis (Siphonophora arence), supplementary to our article in the Annual Report of the Secretary of Agriculture for last year, is given, and also brief accounts of the apple plant-louse (Aphis mali) on small grains, a new species of Diplosis and the twelve-spotted Diabrotica, of which latter unmistakable larvæ were found eating into the stems of young wheat.
The principal work reported upon by Mr. Albert Koebele, the agent at Alameda, California, is a series of experiments which he has carried on chiefly during the month of September in the Sonoma Valley to ascertain the effect upon the grape Phylloxera of certain of the resin washes which proved so valuable when used against the fluted scale. The results have been quite as good as we anticipated and the experiments have shown that in the use of these washes we have a most valuable addition to the remedies for this great pest. The formula which gave most satisfaction is as follows: Caustic soda (77 per cent).
.pounds.. 5 Resin....
do 40 Water to make 50 gallons. The soda should be dissolved over a fire in 4 gallons of water, then the resin should be added and dissolved. After this the required water can be added slowly while boiling to make the 50 gallons of the compound. To this water may be added at the rate of 9 gallons for 1, making 500 gallons of the dilute compound, sufficient for one hundred large vines, at a cost of only 84 cents, or less than a cent a vine.
In addition to this work Mr. Koebele has studied the tent caterpillars of the genus Clisiocampa of the Pacific coast and has done some extensive collecting and breeding of fruit tree and garden pests in that section of the country. He has also done some excellent work in the study of parasites of the codling moth and of other injurious insects.
Miss Mary E. Murtfeldt divides her report into three sections: (1) general observations, (2) a few more injurious Microlepidoptera on apple, and (3) experiments with insecticides. Under the first head she gives a general account of the injurious insects of the season in Missouri, calling attention to the comparative immunity from thə chinch bug, the canker worm, and cut-worms. The stalk borer (Gortyna nitela) and the corn ear-worm (Heliothis armigera) were particularly abundant, while the slug caterpillars or stinging caterpillars (family Cochliopodide) were noticed in unusual numbers. All through Missouri and adjoining States there was a notable outbreak of the walnut, hickory, and oak caterpillars (Datana ministra and D. angusii). One of the most interesting observations made by this agent was to the effect that the fall web-worm (Hyphantria cunea) was extensively preyed upon in Missouri this summer by the larvæ of a Carabid beetle, Plochionus timidus.
In the second section of her report she considers four new apple enemies: Penthina chionosema, Proteopteryx spoliana, Steganoptycha sp., and Geiechia intermediella. Under the head of experiments with insecticides are given accounts of experiments with X. 0. dust, buhach, arsenites of ammonia, and petroleum sludge. It was found that dry X. O. dust blown from a bellows during the middle of the day is a thoroughly satisfactory remedy for plant-lice of all kinds. The arsenites of ammonia when used according to the manufacturer's directions, one tablespoonful to a gallon of water, proved to be an efficient insecticide, but badly scorched the leaves of peach and cherry, and damaged slightly the foliage of plum, apple, rose, and squash. The petroleum sludge arrived too late for satisfactory trial, but Miss Murtfeldt thinks that its intolerable and persistent odor is a serious obstacle to its general use, especially in small gardens.
The Iowa agent, Professor Osborn, has continued his work on the parasites of domestic animals and has submitted for publication in bulletin form that portion which relates to the Mallophaga. He has continued his observations on insects injurious to pasturage, a subject which received treatment in his report for 1889 (published in Bulletin No. 22 of the Division), and reports upon additional species of importance in this direction. He has also reported upon the insects of the season in Iowa, mentioning among others two pests new to the State, viz: Abbott's white pine worm (Lophyrus abbottii) and the potato stalk-borer (Trichobaris trinotatus). Some remedial experiments were also reported. He has found that in Iowa the arsenites of ammonia in the customary dilution do not injure the foliage of squash, cucumber, potato, plum, cherry, box elder, willow, eleagnus, elm, mountain ash, birch, apple, raspberry, bean, grass, and clover, while his experiments seem to show that it is as effectual as an insecticide as the more generally used Paris green and London purple.