4 Properly cf «& L'r.ilid ; Covernmer. i I aited States k-prinmnn Si .\"ju \U OP KNTOMOLO : and Chic! ol i)«**ui I III ( URN LEA I \ PHIS VM» ( dI:n ROO Bj I M '■' Tli>» coin leaf -aphis (^ dis Fitch) and the corn root-aphis (Aphis orbcs) are together made the subjects of tlii- circular because l>otli attack growing corn, because it has yel to !».■ clearly shown thai there is no direct kindred connection between them, though it is possible that they are distinct s] ind because thi> question of their identity or relationship presents itself to almost every ol»ser\ ing farmer. The leaf-aphis does the farmer little direct injury. The root-aphis, on the other band, sucks the sap from the roots of his corn', then causing the plants t" become dwarfed, and in serious cases the leaves turn brown and die. In an infested field the corn will !»<■ "spotted,' 1 as farmers term it thai is, while "the plants on certain areas in the field may make a normal growth and mu\ ear well later on, those on other areas will make little growth, but tassel out after they have become n foot or a foot and ;i half high, producing the almost worth- less ears known as "i or none ;it all. Thus the dun the crop in Bome fields at times reaches 50 per rent or more, and the annual loss throughout the corn belt must amount to well on toward a million dollars. This root-aphis is really becoming the most serious the many insect peats ot the cornfield, especiallj where a atricl system of crop rotation is not carried out. THE CORN LEAF-APHIS The corn leaf-aphis (figs. 1,2) was descril»ed by l>r. Asa Fitch in L856 from eastern New York, but it is now known to occur from New England to North Dakota and Texas, as well as on the Pa< ific coast. Besides, it was found by the writer in great abundance '»\ sorghum on the grounds of the Agricultural College of South Australia, at Roseworthy, February '•'. 1889. !' L »wrie, at that time prin- cipal of the college, assured the writer that it sometimes becam essivelj abundant as to render the plants obnoxious as foddei for stock. The insect is known also from Japan. In our own country, while not usually a serious pest, it is said to damage corn, sorghum, and barley in Texas, while Doctor Forbes has noted a reddish dis- coloration due. he thinks, toa bacterial effect following its occurrence on broom corn. APPEARANCE AM) HABITS. The corn leaf-aphis is bluish green in color. It appears on corn throughout the Middle West early in July — about the time that the root-aphis begins to decrease in numbers on the roots — sometimes literally swarming on the leaves, husks, and tassels. Here it gives birth to its young, and disappears from the plants only as these ripen and become dry, some individuals even remaining among the husks of belated ears until freezing weather kills them outright. AYhence these insects come, in July, when the first few winged females appear on the leaves of the corn, is a mystery, equaled only Fig. 1. — Tin' com leaf-aphis ( Aphis maidis : Winged female. Much enlarged original). by the problem as to the destination of the winged individual- that leave the same plants in autumn. While on the plants they are attended by the little brown ant, the same one that cares for the root- aphis. Thus it will be seen that we have but a fragment of the life cycle of this insect; for, if it is a distinct species, it must occur else- where than on corn long before July, and it is equally clear that if distinct it must migrate in the fall to some plant that will afford food for the young the following spring, there to deposit its eggs. We judge this to be the case, as it is known that with most species of aphides there occurs in fall a generation of winged females that fly to the spring food-plant, there to produce a generation of both males and females, the latter laying eggs that do not hatch until spring. From spring until fall there are no males and no eggs; all young [Cir. 86J 3 are born alive, aftei the manner of mammals, and :ill are fertile females. Ii will therefore be verj clear thai with no knowledge of the males and with onl) ilii- fragment <»t" tin' life cycle of the females it i- impossible to saj whether the leaf aphis i- an alxn e ground form of the root-aphis or whether it i- distinct from and wholly inde pendent of that insect. : hi i> i \ i 'KM mi \ i -. In < ).-tc »ber, 1885, the writer transferred some volunteer plants of corn from the ii«'M of fall wheat, where thej were growing, to some breeding cages. The plant- were thicklj populated with winged females of the leaf-aphis, and these were careful lj Becured with the plant-, both being subjected to the same conditions \n 1 1 i < • 1 1 would have influenced them had tln\ remained in the field, except that the ants in attendance were excluded. < )n Ma\ 8, 188(5, corn was planted in these cages and ipvu therein till after the L5thof June when it was thrown out without a single individual of either root or aerial form of the root-aphis being on or about t li«' plants. Dr. S. A. Forbes, State entomologist of Illinois, under whose direction most of tin' investigations of these insects have been carried out, in summing up the results of a long series of careful I3 conducted experi ments of bis own. comments as follow-: Wingless female. Much enlarged (original). Tin' foregoing data confirm our ignorance more than they increase our knowledge, showing, as they do, the Failure "t' all attempts to find "r produce a bisexual generation or an alternative food plant of i u> Irani how and where it normally sea the winter. Its willingness to feed "ii winter wheal and ability to breed v .hi that plant, its indisposition toward grass or the foliage of the apple, and the natural frequency of successive generations, are the principal other facte evident from these ■ ibsen ations.* 1 Winged females of the root-aphis occur in summer on the leaves of corn together with those of the leaf-aphis, but never in such immense numbers. The two forms of winged females seem to be distinguish- able, t>ut tin- sexes have never yet been observed to interbreed indeed without males above ground they could not do so; heme it is yet too much to say whether there are two distinct species, with the male- of but one yet discovered, or whether these are two form- ,<\ a single species, with as yet undiscovered relationships obscured by long-continued influences of ants. A- it i- with the root-aphis that the farmer has most to do, that species will be chiefly considered here. 'Twenty-third Report. - of Illinois, p. 133, 1905. THE CORN ROOT-APHIS. Although the corn root-aphis (figs. 3,4) was no! definitely described until L891, its presence in the cornfields <>i' Ulinois was noticed by Mr. 1). 1). Walsh in L862, near Ruck Island, and these two corn aphides were made the subject of a paper contributed by him to the Transactions of the Illinois State Agricultural Society." Mr. Walsh, who was afterwards the firsl State entomologist of Illinois, stated thai his attention was called to the "' lice" on the roots of corn in this field in the latter part of May. L862,and about a fortnight later he visited the field in person. He illustrates a section of corn root "as I saw il with my own eyes, swarming with these tiny pests." Further, he state- that from wingless specimens, secured at the time of his visit, lie afterwards reared 15 winged female-. From the fact thai the description of the leaf-aphis by Doctor Fitch "agrees Fig. 3. — Thecorn root-aphis i, male. Much enlarged (original . tolerably well" with that of the species that he found attacking the roots in dune, he suspected that the two were identical. An illustra- tion of the winged female reared from the roots does not. however, tend to convince oneof the correctness of his opinion, as it best repre- sents the winged root-aphis and rather sustains the fact that the root- aphides were present on the roots of corn at that time, in tin' vicinity of Rock Island, and that from some of these he succeeded in rearing winged adults in June. While this is not in the least surprising it is nevertheless interesting as being a record of the original discovery of the root-aphis and of the discovery and rearing of the winged female. The statement made that the root-aphis was attended by little brown ants is still further evidence of the validity of these observations, however incoi red Walsh's conclusions therefrom may have been. As a matter of fact, up to about that time spring wheat culture had dorni- [Cir.86] a Vol. 5, pp. 491-497, 1861-64. nated over the prairie itrj eaal of the M »pi River and north of the ohi.. River, *o thai conditions were not >le for the rool aphis. Bui ahoul thai time conditions chan| I corn culture became dominant, n th< • ontinui d i ultivation of to this latter -ruin for i r or less number of g this | ' nto continually inert prominent Walsh's observations were ma I the time of what was tabh ill" begin ni of destructivem ~. ft] r iii in. For nil practical purposes the rool aphis may be sufficiently • barac terized as follows: I lor is bluish preen, slightly whitened h mun bloom, l'lf '■■• h i oval, and on the anterior pari of the b :lll . two short, slender, rather conspicuous cornicles or tubes, either standing ereel or projecting slightly backwa (fig. i). The \\ inged femah black head and brownish-black thorax, the abdomen b in.'- nale preen, w ith about three marginal Mack spots and numerous small dark sp< r the surface. The antennae are dark, with paler tinge at articulations, and the legs are mostly black. The only form of male known is wingless, like the female found on the roots. mi ri .1 n v i ■ 1 1 1 -- \np i in' i .1 1 i ii BR< >W n \n i . Much Before proceeding further it is necessary to describe a most important and astonishing mestic condition involving the brown ant (I 1,., var. • Enierj i and the other- wise helpless A The | of ants burrow about young com plants in the field has frequently attracted the attention of farmers, and damages to the cro ery frequently attributed to them. The species under consideration is oi f our mosl abundanl and widely distributed ants, occurring in colonies from fifty to several hundred in burrows in the fields. ^ bile it is ol itself harmless, it is in realty responsible for all of the by the root-aphis, whose lit'-' history and habits it appears to h entirely revolutionized, as will now be explained. i iii HISTOB1 VST) HABITS OF nil' BOO! \rni-. The normal life history of aphides in general is as follows: The win- ter i- passed in the egg state upon or near the plant upon which tin- young must first subsist in spring. From these eggs there hatch young aphides thai are all females and these in a short time begin to give birth to living young which are likewise all females. Thus the life cycle goes on, and though there is usually a radical change of food plant, there are neither c<^^s nor males until autumn, when there i- ;i genera- tion consisting of both males and females, the latter depositing eggs that winter over. This egg-laying female and the male are the un- known forms of the leaf-aphis. Now. taking up the life history of the root-aphis, we find (':- in the fall, it is true, but only in the burrows of and attended by these ants. If there are eggs, egg-laying females, or males elsewhere they have yet to be discovered. The ants care for these eggs throughout the winter, shifting them about, according to Forbes, as they do their own young, to accommodate them to changes of weather and moisture. In spring, the young, as soon as they hatch from these eggs, are trans- ferred by the ants to the roots of young foxtail grass, smartweed, and even ragweed. The young are carried out to pasture, as it were, dur- ing fair weather, but in bad weather, or on cold nights, they are taken back to the burrows of the ants. The plants just mentioned are the ones that push up early in spring in last year's corn lands, and espe- cially in fields that have been plowed and allowed to stand untouched for a week or so. Usually the farmer plows his ground in spring and pays little attention to this early growth of weeds and grass, as he can generally dispose of it as soon as he begins to cultivate the corn, although this is not until the rows of young plants can be followed by the eye across an ordinary held. As >oon. however, as the corn plants begin to show above ground the ants not only transfer the young root-aphides from the burrows to the roots of corn, but they will also remove them from the roots of grass and weeds and recolonize them on the roots of young corn. Now these young aphides are all females and within a few days they begin to give birth to young, also all females; these, too, are cared for by the ants, which place them on the freshest and most tender rootlets. This procedure goes on about the roots of corn throughout the spring and summer. Forbes has found that under the most favorable artificial conditions there may be as many as sixteen generations between April 8 and October 10, ten of which may coexist at the same time. It is hardly probable, however, that so many generations can exist under ordinary field conditions; nevertheless it may be rightly inferred from this that the multiplication of the species is enormous. These ants not only transfer the root-aphides from one root to another of the same plant, but will carry them from one plant to another a considerable distance away. In the spring of 1887 the writer placed a number of flowerpots containing young, growing, uninfested corn plants between rows of infested hills of corn in the [Clr.86 field. The corn in the infested hills wu then pulled up, exposing the roots on which the aphides were clustered. The little brown ants at once began i" earn the aphides t" new quarters, and the oex! daj the latter, some of them lull grown, were abundanl on the roots of the corn in i lif pots, although there were none on them when the pots were I hi i in place. Ants were observed over a yard awaj from the plants thai I khI I n uprooted, w ii Ii root aphides in their mouths, in nil uppearam es searching for :i suitable place in which to establish their charges on the roots of corn. Thus it i- that from the la\ ing of the eggs in fall to the last or egg- laying generation of the following year this aphis is wholly dependent on the little brown ant I'm- it- existence in the culti vated fields, ami i In' farmer can justly charge up bis losses through the attacks of the root aphisto the influences of thisant. Bui the matter does n"t terminate here, as will be seen by what follows. WINGED FEMALES OF THE ia>< n \riu-. So long as the roots upon which the root aphides are colonized afford an abundance of nourishment for them, all will be wingless, but as soon as tin 1 roots become tough ami woody or drj out there \\ ill be a generation of both winged and wingless individuals, the former escaping from the burrows about the roots to il\ to other plants, and in all probability to other Gelds, where tiny may In- found on the leaves. The ant- usually transfer tin' wingless individuals to more succulent root-. I nit seem to pay little or no attention t«> the winged individuals, letting these make their way out ami away. But in May, L887, the writer was able to watch some of these winged nomadic individuals in a cornfield to which they had migrated ami to note the results of their wanderings. A field of corn hail been planted on May 1^. Fivedays later there came a heavy rainstorm that flattened the surface of tin' ground, which was soon incrusted by the action of wind ami sun. Four day- afterwards there were fre-hl\ thrown up inouml- of earth about some of the corn plants, and ants were busily engaged in and about these ami running up ami down over the young corn. On examining these mounds ami burrows the writer was surprised to find winged root-aphides giving birth to young on the roots, attended by ant-. All of these young were very -mall, at most hut a few day- oh I. Other winged individuals were found on the leaves ami even on the Btems of corn, and when any one of these was placed where the ant- could find it. it was promptly captured by an ant ami transported to the rout-, of the corn. Observation showed that a- soon a- the ant- running about over the young corn plant- found a w inged aphis they made a burrow about the base of a plant, ami soon domiciled the wanderer on the root under their guardianship. Then when the aphis began to give birth to young these were promptly removed to another part of the same 8 root or to another root close by, and there watched over by the patient and industrious ants. The same thing was observed going onabout a young plant of fox-tail grass in this same cornfield. [NFLUENCES LIKELY TO PRODUCE FEMALES. While the production of winged individuals seems to be brought about largely by insufficient foodsupply, Forbes is of the opinion that the production of egg-laying females is fully as much — it' not indeed much more — influenced by the temperature, a low temperature caus- ing them to be produced at any time, regardless of generation: and he himself has secured them from as many as five different generations. In two cases recorded by him the first young produced developed to adults that gave birth to their young, whereas the last developed to adults that laid eggs. These cases, although seeming rather out of the ordinary, illustrate the fact that the insect may adapt itself to widely different autumn conditions: that is to say, an early frost, which pre- supposes a low temperature, kills the corn but does : ,ot annihilate the insect, for an egg-laving generation is thus precipitated and the ants promptly secure the eggs. This egg-laying generation is probably produced in September or October, as these females are found in the burrows of ants at that time. Possibly it is produced earlier to the South. Mr. C. N. Ainslie, of this Bureau, one of the writer's assist- ants, found the egg laying females quite numerous in such situations on September 22, at Annapolis Junction. Md. The chief item of interest to the farmer is the fact that these eggs are taken charge of by the ants and kept through the winter. THE ANT'S CARE FOR EGGS AM) TOUNG OF THE ROOT-APHIS. There is no indication that the ants hunt the fields for egg-laying females; on the contrary, they secure their supply of c ggs from females kept for precisely that purpose in their burrows about the roots of corn. This affords ample explanation of the increasing abundance of root-aphides in fields that are cultivated to corn year after year in succession, and it also points to a preventive measure. The object of all of this care on the part of the ants is to obtain from the root-aphis a sweet fluid known as ""honey dew." Owing to this peculiar rela- tion, this and some other aphides are commonly termed "•ants' cows." Thus the economic importance of this insect and its association with ants is for practical purposes fully accounted for and an explanation furnished a- to why farmers are misled into believing that it is the ants that actually destroy the corn. Not only this, hut a condition of affairs is revealed which shows why this young growth of grass and weeds that springs up soon after the ground is plowed in spring, pre- 9 parator) to putting ou( the young crop, and which usually causes the farmer little concern, is n all\ of vital importance. The farnx ure in the knowledge thai b< -il.\ kill this growth of we< and grass later. This is true; l>m he does m<>i do so until bis corn ■_: i . >w ii thai will permit cultivation, and by this time the ants have transferred the root aphis i" the corn. The aphii longer depondenl on the roots of tin ind weeds, so thai destruction of the latter ;ii this time does not seriously affi domestic arrangements of the ants and aphid \ \ I t I: \i ENKMIKS OF nil ROOl kPHIS. While the leaf-aphis is attacked by a 1 1< »—t of parasites, the root- aphis does in >i appear to suffer in the least from inroads of either para- sitic or predaceous insect enemies. This is, perhaps, owinj I to the protection offered by the ants. All natural checks must ill be meteorological influences, and, as pro iously show n, these also are to a marked degree overcome by the watchful care of attendant :mN. PR] \ i nii \ i an i> i : i . m i : i >i \i. mi - Preventive measures deal with the pest prior to it- becoming estab- lished "ii the roots of corn in the fields; remedial measures, with di-- posing of it afterwards. From the fact that in the midst of tin- corn belt, and where the root-aphis is known t<> prove destructive under certain conditions, almost complete immunity is secured where a system of crop rotation has been carried oul for many years, involving l>ut our coin crop in the cycle «>t' rotation, it is self-evident thai this measure offers the greatest protection from the ravages of this pest Indeed, it is only where such a system <>t* crop rotation is not practicable that the root- aphis need be considered in farm practice. To the eastwai'd, where there is more general rotation of crop-, this pesl i\<»'< but little injury. Unfortunately, local conditions, often extending over large sections of country, will not permit of crop rotation being generally adopted, and some other plan more feasible must be put into practice. Two other methods ma} be followed. One of t In -<• is practicable through- out the corn-growing section of the country in - ' not more than normal precipitation limine- the time intervening between the first plowing of the ground and the first cultivation of the young corn. The other i- perhaps best adapted to the southern portion of tin- coun- try on account of the milder winters. [Cfcr.1 10 STIRRING THE SOIL AFTER PLOWING AND BEFORE CULTIVATING THE ('Hoi'. The action of the ants in colonizing the 3*011110- root-aphides on the roots of young grass and weeds that spring up in the fields almost immediately after plowing in spring has already been explained. Indeed, this is the only pasturage for 3 T oung root-aphides that is avail- able at that particular period, and if this can be destroyed the pest can not survive until corn roots are available. If. then, the ground is frequently stirred from the time it is plowed until the first cultivation takes place, not only will this pasturage for the pest be destroyed, but the homes of the ants will be continually broken up and a greater or less number of their own young, as well as the young root-aphides, will be killed, while many unhatched eggs of the pest will be destroyed or lost to the ants. This measure involves additional labor, it is true. but in the writer's experience it has proved effective, and. beside-. every up-to-date farmer knows that the more the soil is stirred, pul- verized, and compacted prior to the first cultivation, the more thriftily will his crop grow when it is fairly started and the more grain will it produce. So, then, the extra labor involved in this practice is not with- out ample return, aside from the fact that it demoralizes the ants and destroys the root-aphis. The only sections of the country where this is not strictly true are some portions of the South, where the planter must endeavor to curtail the growth of stalk in order to secure larger and more perfect ears. But here, again, corn is not the major crop, it is not grown for several consecutive years on the same ground, and the root-aphis is not so excessively abundant. LATE FALL OR WINTER PLOWING. It is in the southern section of the country that the second prevent- ive measure, i. e.. late fall or winter plowing, can be best applied. In the corn belt of the more northern section of the Middle West, not only is winter plowing, as a rule, utterly impracticable on account of the more severe weather, but the fodder, instead of being .-eeured as in the East and South, is pastured off after the corn has been husked. To practice late fall plowing, or indeed to fall-plow at all. would mean, therefore, in this northern section, the sacrifice of this important item in farm economy. As far north at least as the latitude of Washing- ton, however, winter plowing is frequently entirely practicable, and there is little doubt that it will prove entirely effective against the root-aphis. During the winter of 1906 Mr. John Bowie, of Annapolis Junction, Md.. winter-plowed the major portion of a 60-acre field in preparation for corn the following season. The plowed portions occupied each of two sides of the field and a narrow headland at one end ; thus the un- plowed area was left in the middle of the field and this was plowed in [Cir. B6] II the spring. < >n July 28 the writer went over this field of corn care i'iiIU and found thai over the spring plowed portion nearly ever) hill of corn was infested l>\ the root aphis. The crop was an almosl coin plete Failure. Much of the corn bad been killed oul previous to the time of the writer's v i-ii and the remaining pari was dwarfed in growth, bore i'\\ ears, and Buch :i- it bad were very small and almosl worthless. All over ili<' winter plowed portion, however, there was everj pros pe< i of a heavj j ield of both stalk and ears, even to the narrow head- land previously mentioned. A.n assistant, Mr. Unslie, visited the field in late September and was able, without information from anj person, to locate, to a row, the dividing line between the two plowings. This was clearly visible on account of the difference in appearance in the stubble— the com having by this time been cul and shocked and also on account of the number, size, and appearance of the shocks. There \\ a- a difference of fullj two-thirds in favor of the winter-plowed por- tions of tlii— field. A- the yield of the winter-plowed portion was ap- proximately 75 bushels per acre, the spring-plowed would nol exceed 85, showing a probable loss of about 50 bushels per acre. At the markel price, 75 cents per bushel, the loss would amount to $37.50 per acre, to which musl be added the loss in fodder. These figures show quite conclusively the amount of damage this rool aphis is capable of doing, as well as w hal can be accomplished in t he way of pn\ ention by thoroughly practical methods. TIIK DBI OF BAHNTABD M ANt'RK. It seems to be a fact, borne out by field observations, thai where ground has been fertilized with barnyard manure the root-aphis does not becom destructive. A.s far hack as l sv '>. on the experiment farm of Purdue University, at Lafayette, End., the writer made some observations which led to the conclusion thai proper fertilizers applied to the soil are a general preventive of damage. This was clearly pro* ed by the appearance of the crop on a series of eighteen plats on the uni- versity farm. These plats were located side by side and numbered ] to Is. All had produced corn for the previous six crops, those plats of even numbers not ha vine- been fertilized during thai time. 1'lat- L, 7. and L3 had. three and again two years previous, received appli- cations of gas-lime; plats 3, 9, and L5 had received application- of superphosphate- during the same year-, while plats •">. 1 1. and 17 had received similar treatment with barnyard manure. The result, up to July, L886, was that the corn on all plat- except those fertilized by barnyard manure was small and uneven in growth, while o"h plats 5, LI. and l~ the plants were fully a third larger, more thrifty, and far less uneven in height. In fact, these plats could he distinguished from any of the others at a distance from the tield. It was unfortunate [Ctl - 12 • thai the carrying on of the experiments forbade any examinations of the roots in order to estimate the relative number of aphides inhabit- ing each series of plats. EXPERIMENTS IN" DRIVING THE ANTS FROM THE ROOTS OF CORN IX THE FIELD. During June, L886, a number of experiments were made to test the immediate effect of fertilizers, including salt, upon the aphides, and also to learn it' the ants could be induced thereby to abandon or remove their favorites to oilier plants. The substances used were two commercial fertilizers (Bunner hone dust and hone guano), barnyard manure, and common salt. A double experiment was made with each. The first two substances were applied (1) by scattering a tablespoonful on the surface of the ground about the plant and sprinkling with water sufficient to wash it at once into the soil, and (2) by drawing the earth away from the root-, scattering the same amount of fertilizer about the roots, then replacing the earth, and sprinkling the surface less thoroughly than with the first. The barnyard manure was well-rotted and a quantity sufficient to till a pint measure was used in the same way. The salt was used in the same way as the manufactured fertilizers. The result, a week after, was that the '"lice"' were still about the roots in every case, and. except where salt was used, they were found in the midst of the substances applied. The salt only drove them from one portion of the roots to another. Sand dampened with kerosene was then applied in the same way. hut the surface application had no effect, and that made directly to the roots only drove the aphides from one part of the roots to another, as did the salt. TREATING THE SEED BEFORE PLANTING. During the last two years Doctor Forbes, in Illinois, has been test- ing a great number of substances with a view to treating the seed with some repellent that would render it so obnoxious to the ants that they would not place the aphides on the roots of the young plant-. It has indeed seemed possible to take advantage of the well-known fastidiousness of these ants and find something that, applied to the seed, would not injure its vitality, hut would give off an odor >o dis- agreeable to the ants that they would shun the vicinity of its applica- tion. The writer tried something of this sort in 1887— except that in his experiments substances supposed to be offensive to the ants were placed in the soil about the roots of the corn — but the result- were not satisfactory. In treating the seed, however, Doctor Forbes seems to have had very encouraging success and he has permitted the writer to use here the results of his experiments, which are quoted in brief as follow-: [Cii -i 13 found mi tmenl of seed corn I icture itl of lemon and « I alcohol T" I gallo »hol add I pint "i "il "i lemon, nnd uprinkle and tin *>n- thia mixture into • thai the Huid II) 'ii-tiii share. \ I i ■ ture ia all I in. I, w liuli w ill ! ii -nficld ant, and tl long thei -. the hill I i both more ti'. I for liable .IriiL'-i-i-, the '>il of lemon especially 1* ion. If tl w hen shaken up tl Doctor Forbes h led by this means in reducing the number of rool aphides 8U per eenl and the number of ant* T'.» per rent, which i-> certainlj a ver) creditable showing for tlii- mixture. The mixture of wood alcohol and oil <>t* lemon is so easily made and the application so inexpensive and simple thai ii is t" be hoped thai farmers who have suffered from the ravages of this pesl will give the prepara tion a thorough trial in their fields. While local conditions m:i\ p vent the putting into practice of any or all of the other measures of relief here adi ised, it is difficult to conceive of a situation thai would prevent a farmer from treating his seed corn before planting, as recommended. Appro' .1 Wll - \\ II S< i\. s | | Washington, I >. C\, April '. ' O MCUMEM MARSTON SCIENCE LIBRARY Date Due Due Returned Due Returned &**» n*& - II IftMNnVOI 'LDM.OA I I I 3 1262 05252 3379 W'~M .