'-=» -l&l Xs\ U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— CIRCULAR No. 121. L. O. HOWARD, Knlomologist and Chief of Bureau. THE OYSTER-SHELL SCALE AND Till] SCURFY SCALE. A. L. Quaintance, in GJiarge of Deciduous Fruit Insect Investigations, AM) E. K. Sasscer, S< n ntific Assistant. 36826 Cir. 121—10 1 WASHINGTON : GOVERNMENT PHINTING OFFICE : 1910 B UREA U OF ENTOMOLOGY. L. O. Howard, Entomologist and Chief of Bureau . C. L. Marlatt, Assistant Entomologist and Acting Chief in Absence of Chief. R. S. Clifton, Executive Assistant. ('has. J. Gilliss, Chief Clerk. F. H. Chittenden, in charge of truck crop and stored product insect investigations. A. D. Hopkins, in charge of forest insect investigations. W. D. Hunter, in charge of southern field cm p insect investigations. F. M. Webster, in charge of cereal and forage insect investigations. A. L. Quaintance, in charge of deciduous fruit insect investigations. E. F. Phillips, in charge of bee cultun . D. M. Rogers, in charge of preventing spread of moths, field work. Rolla P. Currik, in charge of editorial work. Mabel Colcord, librarian. Deciduous Fruit Insect Investigations. A. L. Quaintance, in charge. Fred. Johnson, S. W. Foster, E. L. Jenne, P. R. Jones, A. G. Hammar, R. W. I'raucher, C. W. Hooker, J. R. Horton, E. J. Hoddy, W. Postiff, agents and experts. E. \Y. Scott, C. II Gable, J. F. Zimmer, entomological assistants. [Cir. 121] (") Circular No. 121. Issued April 30, 1910. United States Department of Agriculture, BUREAU OF ENTOMOLOGY. L. O. HOWARD, Entomologist and Chief of Bureau. THE OYSTER-SHELL SCALE AND THE SCURFY SCALE. idosaphes ulmi L. and Ckionaspis/ur/ura Fitch.) By A L. Qi iiNTANi i , In i ha ■ ■ ous Fruit Insect 1 sligations, and E. R Sassceh - i lant. INTRODUCTION. The oyster-shel] scale (Lepidosaphes ulmi L.) and the scurfy scale (Chionaspis furfura Fitch) are, with the exception of the San Jose or Chinese scale (Aspidiotus pernidosus Comst.), more frequently the subject of inquiry by orchardists than all other species of scale insects combined. These two scale pests are now very generally distributed throughout the country, and from their relatively conspicuous appear- ance are often detected by observant fruit growers who frequently believe them to he the more serious San dose scale. The ovst er-shell and scurfy scales, while not dangerous in the sense of generally causing the death of infested trees, are, however, of considerable economic importance. The complete killing of individual branches of apple trees by either species is a matter of frequent observation, and trees so badly infested are frequently greatly stunted and retarded in their growth, resulting perhaps in extreme cases in the death of t he trees. Of the two species considered, the oyster-shell scale has been and is at the present time the more important. Its injuries to certain shade trees, especially poplar and maple, have been the cause of much complain t during recent years. Such shade trees are ordinarily not 3prayed for scale insects, and the increase of these pests from year to year is thus checked only l>\ their natural enemies. The writers bave frequently seen maple and poplar trees literally incrusted from top t" bottom witli the oyster-shel] scale, manj "I' the limbs killed, and in rarer instances the trees quite dead — -without doubt owing to the at t ack of i his scale insect. [Clr. 121] (1) THE OYSTER-SHELL SCALE. (Lepidosaphes ulmi L.) ORIGIN AND DISTRIBUTION. The origin of the oyster-shell scale is a matter of some uncertainty. It has a world-wide distribution, and was introduced into the New England colonies at an early date. The first American account of this pest was written by Enoch Perley in 1794, in which he stated that it was doing considerable damage to the apple in Cumberland County, Maine. In the early sixties it had reached the Mississippi River, and at the present writing (April, 1910) occurs in every State of the Union with the possible exception of South Dakota, Oklahoma, and Texas. Its occurrence in these States is practically certain, but there appear to be no records in literature to this effect, and it has not been received from these States by the Bureau of Entomology. The insect is very t mublesome in the Northern States and is especially common in the New England States and those bordering the Great Lakes. DESCRIPTION AND LIFE HISTORY. This insect has received the common name "oyster-shell scale," owing to the resemblance of its scale or covering to a long, narrow oyster shell, as may be seen by reference to figure 1. The adult female scales are about one-eighth of an inch in length, usually brown to dark brown in color, though occasionally they have a grayish appearance which is due to bleaching over winter. If present in large numbers, for want of room they assume various more or less curved shapes. The scale of the male in shape and color resembles that of the female, but is smaller and possesses at the posterior extremity a small hinge or flap which permits the exit of the adult male. If during winter or early spring one of the female scales be removed, numerous small, oval, white eggs varying in number from 40 to 100 will be revealed, and at the anterior portion can be seen the dead and shriveled body of the female. In Canada and the Northern States there is thought to be but one full brood annually, whereas in the Middle and Southern States the species is double brooded. The following records from literature and from the Bureau of Ento- mology will indicate the time in the spring of hatching of the eggs of this insect, in various localities. This time will, of course, vary with the season, but, in general, as long ago stated by Doctor Mygatt, in Illinois, will for any locality be shortly after the time of the falling of the blossoms of the apple. [Clr. 121] Ontario: I batch aboul firsl week of June (Jarvie ) l hatch latter part of Maj to early June (Fell . Hampshirt I batch in late May to early June (Sandei Vermont: Eggs hatch in late June (Ste^ batch aboul middle of June or later, depending upon the (Hitchings). I pi imena received June l v . 1909, from Stittsville, Mich., nearly all bad batched (Sasscer i. Fig. 1.— Theoyster shell -rale (Lepidosapka ulmi). All enlarged. (Original.) In specimens received May 24, 1909, from Lamoille, Minn., eggs were hatching in numbers when received (S Indiana: [n specimens received from Elwood, May It. L909, eggs were hatching in numbers when received 3 batch in laic May to early June i < iossard). Second-bro were found under many scales Augusl 22, and a few young crawl- ing at < !le\ eland (Quainl in i I In specimens received A]>ril 30, L908, from Parkersburg, W. Va., iwling in numbers - fClr. 121 1 Missouri (Wrighl County): Eggs hatch early in May. Insect double brooded according to a Mr. Wright (Riley). Olden, Mo., eggs hatched March 29, 1907; apple trees bloomed March 24 (Girault). Ozark region, Missouri, eggs hatch about April 25 to middle of May (Taylor). Illinois (Cook County): Eggs hatch about June 6, females reach full growth by August 1, and oviposit August 12-28 (Riley). District of Columbia: Eggs hatch May 5-14 (Quaintance). July 4, eggs already deposited by most females and young crawling (Quaintance). Maryland: Eggs hatch early in May (Symons). Eggs of first brood hatch in May; eggs of second brood hatch last week of July to first week of August (Johnson). College Park, many recently settled scales in evidence May 21 (S. W. Foster). Delaware: Eggs usually hatch in early May (Houghton). New Jersey: Eggs hatch during early June (Smith). Tennessee: In eastern Tennessee eggs hatch during first two weeks of April (Cham- bliss). Eggs begin to hatch in April and those of the second brood along in July and August (Bentley). This information as to the period of hatching of eggs in various parts of the country is of importance as bearing on the time to spray for the destruction of the young larvae. The female molts twice in the course of her growth, and in the adult condition is entirely without legs or eyes, being nothing more than a reproductive sack with her sucking mouth parts, through which the food is taken, inserted in the tissues of the plant. The adult male differs radically from the female in that it is provided with antennae and one pair of wings, the second pair being present in the form of club-shaped organs known as balancers or halteres. During the process of metamorphosis the mouth parts entirely dis- appear, and a second pair of rudimentary eyes assumes their place. Being without any means of taking in food the male is naturally very short lived, its only mission appearing to be the fertilization of the female. MEANS OF DISTRIBUTION. Transportation by nursery stock, scions, or by grafting or budding material is perhaps the only way this insect is carried from one section of the country to another, and this in a large measure accounts for its wide distribution. Locally it can bo transferred from plant to plant only while in the young or crawling stage. The young are often seen crawling on other insects, such as beetles, or upon the feet of birds, and may in this way be carried some distance. Man and domestic animals may also assist in their dissemination, and it is possible that the winds blow them from plant to plant. FOOD PLANTS. The oyster-shell scale has a wide range of food plants, but is com- monly found on apple, maple, horse-chestnut , poplar, willow, and [CIr. ii'i J lilac. The following is a lisl of the plants on which it is known to occur: Alder (Alnus rugosa Spn Almond i Prunus Bp.), ' Ihina. Americaxi aspen (Populus tremuloides Michx American bladdernul (Staphylea • I. inn Amorpha sp., exotic. Apple I Pyrus malus Linn. I. Apple. crab i Pyrus sp . Apricot Prunus ar ■ nicu a I. inn. . Arrow -w 1 I l 1 ! 1 Ash i !''■■'■ nui am* ricana Linn . F. ex a Isior Linn. i, I Fraxinua Bpp - Balm of Gilead \ I'uiinlus balsami/era Linn Basswood Tilia americana I. inn.), (T. angu.sti jol in, from Germany). Beech ea Sudw.). Bilberrj i VacciniummyrtillusIAan..). Birch, white (Betula populi/olia Ait.). Birch, river (Betula nigra Linn.). Bittersweel I ( < lastrus Bp Blackthorn (Prunus spinosa Linn.). Box (Bush* semperviri ns Linn.). Boxelder (Acer negundo Linn.). Broom i ' ytisus scoparius Link, i, Gurnsey. (C. nubigt nus Link, i, from Gurnsej i " Buckeye (JEsculus glabra Wild. i. Buckthorn • 9 cathartica Linn Butternut (Juglans cinerea Linn.). ' alhn, 11 Bp., Sweden. ' 'mm lUa Bp. Camphor tree (Camphora officinalis Steud.). ( 'assia Bp., in greenb Cherry 1 Prunus Bp < beetnul ( 'astanea americana Rai < !• mutts paniculata Thunb. t 'ocoa palm from Barbad Bp. Cranberrj 1 Vaccinium sp Currant; black Ribes nigrum Linn Currant, red ' Ribi 1 ruhru,: I 1 D "1 Cornusalba Linn. ,(C.albava.r. sibirim Lodd ?C. alterna Mars) ■ \ Mej ' sanguinca Linn.). Elm, English Ulmus campestris Smith). Elm, purple-leaved (I7Zmus scabra, var. purpurea Koch >horbia palustris Linn.. Germany. [Clr. lL'tl False bittersweet (Celastrus scandens Linn arii ■ Linn.). Filbert 1 ( 'orylus sp.). folium Linn.'). 1 -el., n . aosbati Linn. , Goatsbeard 1 4t*uticus Sylvester Kost. 1. Grape 1 l tfis mni/era Linn Backberrj (Celtis occidental^ Linn Bawthorn Crataegus crus-galli Linn oxyacantha Linn. 1. Helianthemum chamxeistus Mill., Eng- land. Ileniii ;/,,-,,,, ^|,. . England and Sweden. Beather 1 ( 'alluna Bp. 1. Holly i //< 1 in nata Thunb. 1. Bone} 3uckle 1 / onicera sp.). Bop tree (Pfc /, 1; trifoliata Linn. . Boree-chestnut 1 JSsculus hippocastanum Linn.). 5or< na duleis Thunb. June-berrj 1 .!///< lanchii r spp. 1. Leather leaf (Chamxdaphne calyculata Moench 1. Lilac (Syringa persica Linn . S vulgaris Linn Lime (Citrus Bp.). Linden. 1 n, , Basswood. Locust, cultivated < Robinia pseuda Linn.). Locust, water (Gleditsia aquatica Marsh). .Maple. Btllped I'.lr.T pi n tis,/l < u met/ in Linn Maple, sugar I leer surrlmrinuiu Linn.). Maple, mountain (Acer spicatum Lam.). Mespilus cuneata Miq., Japan. Mo alustris Lit Mountain ash (Sorbus americana Marsh). Mountain ash, European (Sorbus aucu- paria Linn. 1. Myrtle ( Myrtus sp. 1, Egypt. Nectarine 1 /'rnk (Querciis pedunculata Ehrh. . (Quer- elas Bpp. 1, < lermany. Orchid. isandra terminalis Sieb. iV Zu 1 Prunus persica Sieb. >v Zucc). i commun ■ 1 I ,inn. 1. Pear. Siekle. Peony (Pxonia sp.). Peppergrass (Lepidium suffruticosum Linn., Cav.), France. Planer a keakei C. Koch. Plum (Primus domestica Linn.). Poplar, Lombardy (Populus nigra var. italica Du Roi). Poplar, white (Populus alba Linn.). Quince (Cydonia vulgaris Pers.). Raspberry (Rubus idxus Linn.). Rose (Rosa rugosa Thunb.). Sassafras (Sassafras sassafras Karst.). Silverberry (Elxagnus argentea Pursh.). Spirxa spp. Spruce (Abies firma Sieb. & Zucc). Sycamore (Platanus sp.). Tallow tree (Sapium sebiferum Roxb.). Tamarisk (Tamarix afrirana Poir.). Tree of Heaven (Ailanthus glandulosa Desf.). Tulip-tree (Liriodendron tulipifera Linn.). Umbrella tree (Magnolia tripetala Linn.;. Viburnum sp. Virginia creeper (Ampelopsis quinquffolia Michx.). Willow, goat (Salix caprea Linn.). Willow, Napoleon (Salix babylonica Linn.). Willow, osier (Salix viminalis Linn.). Willow, (Salix xgyptiaca Forsk.). Willow, (Salix pedicellata Desf.). Walnut, English (Juglans regia Linn.). Walnut (Juglans sp.). Yucca ( Yucca sp. i. Algeria. PARASITIC AND PREDACEOUS ENEMIES. Minute parasitic Ilymenoptera are often efficient enemies of this scale, and in some localities they apparently hold the insect in check. If these little friends are present, small round holes can be seen on the dorsal part of the scale showing where the adult escaped. Those more commonly found are Aphelinus mytilaspidis Le B., A. abnormis How., A. fuscipennis How., A. diaspidis How., Aspidiotij^agus cilrinus How., Anaphes gracilis How., and Cheiloneurus diaspidinanim How. The larvoR of coccinellids, or ladybeetles, are sometimes found feed- ing on these insects, and certain species of mites assist in their de- struction. Birds are also credited with doing service, the most elli- cienl being the titmice and tree creepers. THE SCURFY SCALE. ( 'hionaspis furfura Fitch, i The scurfy scale, while infesting a considerable number of plants, is a less general feeder than is the preceding species. It occurs prin- cipally upon rosaceous plants, such as the apple, peach, pear, plum, cherry, etc., and also on currant and gooseberry among cultivated plants, hut seldom becomes so abundant as to cause particular in- jni\ or to require spec die treatment. The insect may be recognized from the accompanying illustration (fig. 2), much enlarged. The scale of the female is dirty gray in color, irregularly pear-shaped, as shown in the picture. The male scales are much smaller, elongate, snow\ white, with three distinct keels extending longitudinally along the back. Unlike the former species, the scurfy scale is a native North American insect, and appears to be less adaptable to [Clr. iui I the various conditions throughout the country.and has thus a more restricted distribution. LIFE IIISTOKY AND IIAIU'IS. The scurfy scale, like the oyster-shell scale, winters in the egg condition under the scales. The number which may be deposited Fio. 2.— The scurfy scale (Chionaspis furfura). Male at right, female at left. Ml enlarged. Original.) by a given female, as may be easily verified by examination, varies considerably. The following records show the number of eggs from each of twenty individuals: Number of eggs deposited by the scurfy scale, | Material collected on applt sprouts from bas< of applt si, imp MarchSl, 1905, at Arlington Farm, Virginia.) Scale Eggs. No No No Eggs. 1 61 6 71 11 54 10 2 18 7 78 12 111 17 Zi 3 78 B 7il 13 1- Is 83 l 18 9 19 14 • 19 21 ■ i in •11 15 7» 20 33 \v til'.- niiinl>er of eggs per scale, 57.5. 36826— (ir. Ul— 10 2 The following records from literature and from the Bureau of Entomology will indicate the times of hatching of the eggs of this insect in the spring for several localities: Ontario: Eggs hatch about June 1 (Jarvis). Connecticut: Eggs hatch usually between May 20 and June 1 (Britton). New York: Eggs hatch at about same time as those of oyster-shell scale. Ohio: Eggs hatch, and young arc crawling, during latter part of May or in early June (Houser). Illinois: Eggs hatch from June 5 to 12 (Walsh). Missouri: Eggs hatch soon after the formation of the young apples, the date depend- ing upon locality and upon forwardness of the spring (Taylor). District of Columbia: Eggs hatch from May 15 to June 1 (Howard). Delaware: Eggs hatch about same time as those of oyster-shell scale, which is usually early in May (Houghton). Tennessee: Eggs hatch in April, and there are two broods annually (Bentley). Georgia: In 1906 eggs hatched March 11 to 22. Eggs for second brood hatched beginning about June 2. In the more northern States there is but one brood each year, but in the South, as in Tennessee and in Georgia, there are evidently two full broods, and in the latter State there is a strong probability of a third. Thus, at Myrtle, Ga., in 1906, the eggs were hatching March 11, and hatching had probably ceased by March 22. Males of the new brood appeared May 15, and eggs had been deposited by the female May 28, the hatching beginning June 2. DISTRIBUTION. The following records of distribution have been compiled from various publications and from data collected by the Bureau of Entomology : California, Colorado, Connecticut, Delaware, District of Columbia, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska. New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, South Dakota, Ten- nessee, Utah, Virginia, Washington, Wesl Virginia, and Wisconsin. In Canada it is recorded from New Brunswick, Nova Scotia, Ontario, and Prince Edward Island. FOOD PLANTS. The following list includes all plants upon which this species has been found, so far as it has been possible to determine from records in literature and from those in the Bureau of Entomolpgy: [Cir. 121 J Apple (Pyrus mains Linn.). Apple, Chinese flowering (Pyrus specta Lit.). Apple, crab i Pyrus sp.). \-l* European mountain (Sorbus pwria Linn Ash, mountain (Sorbus americana Ail Ash, prickly (Xanthoxylon americanum Mill Ash, while i Fraxinus americana Linn.). Aspen, largetooth (Populus grandia Michx.). Buckthorn (Rhamnus cathartica Linn. Cherry, choke (Prunus virginiana Linn.). Cherry, wild black [Prunus serotina Ehrh Cherry, wild red is pennsylvanica Linn.). Chokeberrj (Pyrus Jloribunda Lindl.). Elm ( Ulmus sp.). Goo i ben \ i Ribes sp Hawthorn (( ratxgus oxyacantha Linn.). Hickory, big bud i Hieoria alba Britl Hoi e chestnul (JSsculus hippo Linn i. Peach il'niniiH persica Sieb. *V Zucc Pea] ■ a in, lis Linn i, (P. ft< / t i ^ , as a resull of tests of sprays upon the oyster- shell scale on shade trees in 1906, concludes: That maple tiers infested with the oyster-shell scale can be treated both in the fall and early Bpring with the line-sulphur and salt wash with satisfactory result regards controlling the pest, and without injury to the trees. That where one application is made these tests showed the fall treatment to be preferable. It is the writer's belief, however, thai when the wash is applied thoroughly in early spring equally good or even better results can 1 btained. The Duke of Bedford and Spencer V. Pickering 6 report results of detailed experiments with various washes in the destruction of the eggs of this insect, and found thai a •'! per cent caustic soda wash gave 100 per cent efficiency in killing the eggs. A 2.5 per cenl caustic soda wash with soap also gave excellenl results, but diffi- culty was experienced in handling the wash on accounl of its becom- ing semisolid. Results of tests of other washes are presented, as caustic soda and potash, paraffin emulsion, emulsion soda washes, emulsions with lime, lime-sulphur soda washes, etc. Concerning the scurf} scale, Mr. J. S. Houser' state-. That the lime-sulphur wash applied during the winter is effecth e, as are also c in- tact sprays applied at hatching time. The same ant I tor (1 c), in speaking of the oyster-shell scale, states: The lime-sulphur wash is undoubtedly the control method to be used against this scale, but in the author'- experience, it has proven somewhat of a disappointment. From observations made upon hundreds of trees and shrubs, sprayed with a mixture made b) experienced men and applied thoroughly, it is apparent that only when con- ditions are the most favorable are the results following its use satisfactory. A slight dampness, such as i at the time of application, a somewhat weakened spraying mixture, an extra case of infestation, where several scales are piled upon one another, a temperature below ;: i of these unfavorable conditions is sufficient to gh e | Prof. K. A. Coolev ' presents results of extensive tests of sprays for the destruction of the ovster-shell scale: (1 1 As againsl th inr- << Bul. Ill, Md. Agr. Exp. Sta., >■ 8th Rep. Woburn Exp. Fruit Farm, p. 33, 1908. Bul. 194, Ohio Agr. Exp. Sta . 1908. dJoura I m. I'.nt., vol, 3, p. 57, MHO. [Clr. 121] 12 ing dormant period of trees; (2) early during hatching period of eggs, and (3) late during hatching period of eggs. The results were not entirely consistent, and further experiments are promised. The two following points, however, are emphasized: (A) Eggs of the oyster-shell scale are unaffected by the application of lime-sulphur solutions made previous to the opening of the buds. On trees so sprayed the young were killed very soon after hatching. The intervention of rain storms before the hatch- ing of the eggs may more or less affect the value of the treatment. (B) It is indicated that emulsions of linseed oil and cottonseed oil may be useful for the treatment of this insect while in the egg stage and during the hatching period. On the whole, therefore, it would appear preferable, where the de- struction of these insects alone, is to be considered , to spray as the young insects are hatching in the spring. The table of dates of hatching given under the remarks on life history for each species will indicate approximately when the young insects may be expected to appear, but this time may be accurately determined by frequent examina- tions of the infested trees. The very small, yellow insects will be seen in numbers crawling over the limbs and branches in their efforts to find a suitable place for settling. The data on the dates of hatching of the two species, considered in connection with blooming dates of fruit trees, indicate that for any locality the young of both species will have hatched and settled, and may be effectively treated during the period of from one to three weeks following the blooming period of the apple; and from two to four weeks after the period of blooming of the peach. It will be preferable, however, positively to determine the time of crawling of the young for the particular locality and food plant, by actual observations. In spraying for the young insects when the trees are in foliage, the presence of the leaves will render thorough work more difficult, and especial care will be necessary to reach all limbs and branches, treat- ing every portion of the tree from top to bottom, as only those insects actually hit are destroyed. A weaker wash must also be employed than during the dormant season, as will be indicated later under the head of formulas, or else injury to the foliage and fruit may result. TREATMENT OF SHADE TREES. The oyster-shell scale will often require treatment on maples, Lombard y and Carolina poplars, ash, and willow. As these trees will be rarely sprayed during the dormant period for other scale pests, it will be advisable to give the treatment just after the hatching of the young, as already explained. Effective spraying of shade trees, when these are of some, size, will require painstaking work. In many cases it will he necessary for the man handling the nozzle to climb [Cir. 121] into the trees to reach the higher liml>s and branches and a long exten- sion or bamboo rod is indispensable. The Length of hose must be adapted to the height of the trees to be treated, and a coarse nozzle, such as the Bordeaux, will he preferable, as enabling the operator to throvi the spray some distance to inaccessible branches. A high- pressure pump, from 1"><> to 200 pounds, is especially desirable, though the writers have seen L r "od work accomplished with an ordi- nary barrel out lit. Spraying during the dormant season, however, may be practiced, if the work may he more conveniently accomplished during this time, using one of t he winter sprays later mentioned . as lime sulphur wash, kerosene or crude petroleum emulsion i_'ii to 25 per cent strength), or some of the miscible oils. TREATMENT OF CURRANTS, GOOSEBERRIES, ORNAMENTAL SHRUBS, WlHiniKi: LOW-GROWING PLANTS. After proper pruning, shrubs and hushes infested with these two scale pests should he thoroughly sprayed, preferably as the young are hatching in the spring, using the summer-strength kerosene or crude-petroleum emulsion or whale-oil soap wash. A knapsack or bucket pump will he suitable for treating a few plants in yards, and in view of the small amount of labor involved, a supplementary application is advisable in a week or ten days to destroy any belated larvae which escaped the first application. Where infested yard plants are growing close t,> the wall of a building, this may he pro- tected during the operation of spraying by a piece of tarpaulin or other heavy cloth, or even refuse paper. SPRAY FORMULAS. Kerosem emulsion (stock solution, 66 />< r cent <>il). — Kerosene emulsion is made after the following formula: Cer -1 oil, lamp oil) gallons. . 2 Whale-oil or laundry soap (or I quart soft soap) pound.. ^ Water gallon. . 1 The snap should first be dissolved in boiling water; then remove vessel from the lire. Immediately add the kerosene, and thoroughly agitate the mixture until a creanrj solution results. The stock emulsion max be more conveniently made by pouring the mixture into the tank of a spray pump, and pumping the liquid through the nozzle hack into the tank fur some minutes. The stock solution, if well made, will keep for SOme months, and is to he diluted hei'me using. In order to make a lu per cent spraj 'the strength (<n^ of water, for 20 and _'■"> p< r cent emulsions (for use on dor- [Clr. 121] 14 infant trees and plants) use respectively about 2\ and 1§ gallons of water for each 1 gallon of stock emulsion. Agitate the mixture in all cases, after adding the water. The preparation of the emul- sion will be simplified by the use of a naphtha soap. No heat will be required, as the kerosene will combine readily with the naphtha soap, in water, when thoroughly agitated. Double the quantity of naphtha soap given in the above formula, however, will be required, and soft or rain water should be used in making the emulsion. In regions where the water is "hard," this should first be broken with a little caustic potash or soda, as common lye, before use for dilution, to prevent the soap from combining with the lime or magnesia present, thus liberating some of the kerosene, or rain water may be employed. Crude petroleum emulsion. — Crude petroleum emulsion may be prepared in identically the same way as described for kerosene emulsion, substituting crude petroleum for kerosene. The grade of crude petroleum employed in the East is that known as "insecticide oil," having a specific gravity of 43° to 45° Baume. The same dilutions for winter and summer spraying should be observed as stated for kerosene emulsion, but it should be noted that for summer treatments of trees in foliage the kerosene emulsion is preferable, as it is less likely to cause injury. Whale-oil soap wash. — There are several brands of whale-oil soap on the market. Potash soap is preferable, and it should not contain over 30 per cent of water. For spraying dormant trees the soap is dissolved in hot water at the rate of 2 pounds to each 1 gallon, and spraying should be done before the wash cools, otherwise it is forced through the nozzle with difficulty. For spraying trees in foliage use the soap at the rate of 1 pound to 3 or 4 gallons of water, or even weaker. Lime-sulphur wash. — Lime-sulphur has become the main reliance in spraying orchards infested with the San Jose scale, and is effective in controlling numerous other insects and is valuable for certain fungous troubles. The following formula is used only on dormant t rees : Stone lime pounds. . 20 Sulphur ( flour or flowers) do 15 Water id make gallons. . 50 Heat in a cooking barrel or vessel about one-third of the total quantity of water required. When the water is hot add all the lime and at once add all the sulphur, which previously should have been made into a thick paste with water. After the lime has slaked, about another third of the water should be added, preferably hot, and the cooking should be continued for an hour, when the final dilution may be made, using either hot or cold water, as is most con- [Cir, 123 I venient. The boiling due to the slaking of the lime thoroughly mixes the ingredients at the start, but subsequent stirring is acces- sary if the wash is cooked In direcl heal in kettles, [f cooked \>\ steam no stirring will be uecessary. After the wash has been pre- pared it must be well strained as it is being run into the spray pump or tank. The wash may be cooked in large kettles or preferably l>\ steam in barrels or tanks. Miscibh oils. — Under the head of miscible oils are designated several commercial insecticides coming into considerable use as spraj s for scale insects during the dormant period of the trees, and their use will often be advantageous, especially where but a few tree- are to be treated. Miscible oils should be used on dormant tree- at the strength recommended by the manufacturers. Commercial limesulpkw washes. There are on the market several brands of concentrated lime-sulphur solutions, designed to replace the homemade lime-sulphur wash, mentioned above. These washes in general have proved to be satisfactory for the control of the San Jose scale, and will doubtless be about as effective against the oyster- shell and scurfj scales as the homemade wash, the preparation of which may thus be avoided if desired. These may be used on dor- mant trees, or, much more dilute, on trees in foliage. Approved: J IMES Wn SON, Si cri tary oj . igriculiurt . Washington, D. ('.. March 30, Wlu. [Cir. 121] o UNIVERSITY OF FLORIDA llllllilllj 3 1262 09216 5553