Dry lime-sulfur is made by adding a stabilizer such as cane sugar to liquid lime-sulfur and evaporating to dryncss. Self-boiled lime-sulfur is made by Insecticides utilizing the heat of hydration or slak- ing of quicklime, CaO, to carry on the From Plants reactions with sulfur. Ammonium polysulfide and sodium Louis Feinstein polysulfide are made by passing hydro- gen Sulfide gas, H.^S, into ammonium or sodium hydroxide containing excess More than 2,000 species of plants are sulfur. It is supposed that the chemical said to have some value as insect killers. reactions are similar to those taking They belong to 170-odd families. Com- place in the preparation of lime-sulfur. mercial insecticides of plant origin are Sulfur is used under some conditions found in five families : Nicotine in the for the control of potato leafhopper, Solanaceae family; pyrethrum in Com- the cotton fleahopper, tomato psyllid, positae; derris, cube, and timbo in mites, and plant bugs. Leguminosae; hellebore in Liliaceae; Organic sulfur compounds, includ- and anabasine in Chenopodiaceae. ing thiocyanates, xanthates, and thi- Anabasine is also found in Solanaceae. uram disulfides, have some insecti- Who first discovered the insecticidal cidal properties although they are used value of plants is not known. The Ro- largely as fungicides. mans divided poisons into three groups, Sulfur dioxide, SO2, made by burn- animal, plant, and mineral. They used ing sulfur, is sometimes used to kill in- two species of false hellebore in medi- sects in closed spaces. cines and in rat and mice powders and Thallium sulfate, Tl^SO^, sometimes insecticides. The Chinese discovered is used as the toxic agent in ant poisons. the insecticidal value of derris. Several zinc compounds are in Chemists in the Bureau of Entomol- limited use as insecticides. Zinc sulfate, ogy and Plant Quarantine since 1927 ZnS04, is sometimes used in place of have conducted research on the prin- copper sulfate in reactions with hy- cipal insecticides of plant origin, such drated lime to form a zinc bordeaux as nicotine, nornicotine, anabasine, ro- mixture that has special uses. Zinc tenone, deguelin and related rotenoids, chloride, ZnCl^, is used to protect quassin, and the pyrethrins. They also against termites. have worked on more than 450 plants in an effort to discover new sources of R. H. CARTER is a chemist in the these and other insecticides, as well as Bureau of Entomology and Plant attractants, repellents, and adjuvants. Quarantine, assigned to the division They have learned that many of the of insecticide investigations at the Agri- species in the 170 families do not war- cultural Research Center at Beltsville, rant further investigation and that bo- Md. After graduation from Morning- tanical classification is not a depend- side College and the State University able guide in the search for insecticidal of love a, he was employed in chemical plants. research in the Chemical Warfare Plant insecticides are only a small Service for 10 years. Since joining the fraction of the insecticidal material Department of Agriculture in ig2y, he used each year. Yet in the development has been engaged in research in the of new insecticides they deserve careful development of insecticides, investiga- consideration: Often they are highly tions of spray residue problems, and effective against many insect enemies toxicological investigations of the ef- that are not successfully controlled by fects of insecticide materials on farm inorganic insecticides. The plant insec- animals. ticides often are relatively nontoxic to 222 Insecticides From Plants 223 man and other plants. Poisonous spray of plants grown in Arizona is toxic to residues on fruits and vegetables may adult house flies. The crude alkaloid menace public health. The relative from this plant is effective against most safety of plant insecticides to man insects. It is as toxic as pyrethrum to helps to maintain their continued use. the squash bug. In this article I discuss the commer- Boraginaceae {Borage Family). He- cial plant insecticides and other plants liotropium peruvianum. The borage that appear promising as insecticides. family contains many well-known gar- Included here are plants only of the den plants and often is called the helio- higher orders (phanerogams). They trope family. The compound heliotro- arc listed alphabetically according to pine was one of the best chemicals plant family and genus. The plants are tested against the body louse, being sufficiently promising to warrant inten- apparently nontoxic to the skin and sive chemical and toxicological studies. lasting more than 168 hours when used The lower orders of plants (crypto- in cocoa butter. gams) include the algae, fungi, mosses, Tournefortia hirsutissima is used as ferns, and horsetails. A more complete a general insecticide in Haiti. study of them may also prove to be Cannaceae {Canna Family). Mem- worth while. bers of this family mostly have tuberous ^ Aesculaceae {HOT se chestnut Fam- rootstocks, stately, broad leaves, and ily). Aesculus californica is called the showy flowers. The leaves and stems of California buckeye. The horsechestnut canna plants contain an insecticide that is a highly prized street and lawn shrub gives results similar to tobacco in green- and tree. The common horsechestnut house fumigation. casts the densest shade of almost any Celastraceae {Staff-Tree Family). cultivated tree. George H. Vansell and Tripterygium wilfordii, the thunder- his coworkers in California found that god vine, is a common insecticidal bees feeding on buckeye blossoms be- plant in southern China. The poison in came paralyzed and died. Reports of it has been found in the root bark. Its other investigators, however, show that chemistry has been investigated by the insecticidal value of species of the M. Beroza, who reported that wilfor- horsechestnut family varies. dine is a mixture composed mainly of Annonaceae {Custard-Apple Fam- two similar alkaloids, a- and ^-wilfor- ily) . The genus Annona includes some dine. Both are insecticidally active ester 90 species of trees and shrubs, mainly alkaloids. Powdered fresh small roots in tropical America. S. H. Harper, G. are toxic to first-stage larvae of the Potter, and E. M. Gillham m England codling moth, the diamondback moth, extracted Annona reticulata and A. and the imported cabbageworm. Alco- squamosa seeds and roots with ether. holic extracts of the roots are more The petroleum ether solution of this ex* toxic. Small roots, powdered, are about tract at 0° C. precipitated out an in- half as toxic as pyrethrum to the Amer- secticidal material that was 50 to 100 ican cockroach. The large^and medium times more potent than the original roots are nontoxic. ether extract. Against some insects the Chenopodiaceae {Goosefoot Fam- concentrate had about the same toxic- ily). Anabasis aphyila contains the al- ity as rotenone. More work should be kaloid anabasine, closely related to done with the custard-apple. nicotine. It is the only commercial Apocynaceae {Dogbane Family). source for the alkaloid. It grows mainly Haplophyton cimicidum, the cock- in Russia and is not available in the roach plant, has been used to combat United States. Anabasis aphyila is re- cockroaches, flies, mosquitoes, fleas, lated to the American tumblewecd. In lice, and other insects in Mexico. The this country my coworkers and I ex- dried leaves are toxic to the Mexican tracted anabasine from Nicotiana fruit fly. The water extract of the stems nlauca. 224 Yearbook of Agriculture 1952 Clusiaceae {Balsam Tree Family). curhita pepo commonly is called pump- Mammea americana is known as kin. Freshly cut pumpkin leaves rubbed mamey, "mamey de Santo Domingo." on cattle and horses reputedly repel Harold K. Plank of the Federal Experi- flies. Acetone extracts of pumpkin ment Station at Mayaguez, P. R., be- seeds killed mosquito larvae in experi- lieves that this indigenous West Indian ments conducted by A. Hartzell and tree has greater insecticidal potential- F. Wilcoxon of Boyce Thompson In- ities than any other plant he examined. stitute. The active principle in the mature Euphorbiaceae {Spurge Family), seeds^ the most toxic part, is a type of Crotón tiglium contains crotón oil. substance some^what similar in compo- The plant is cultivated in China, where sition and efTect to pyrethrins. Plank the seeds are the source of a home- found that six of the nine parts of the made insecticide. The plant has insec- plant were appreciably or highly toxic ticidal value against aphids. J. R. Spies, to one or more insects. The bark has a chemist in the Department of Agri- little toxic material. culture, reported that an acetone ex- Cochlospermaceae. Cochlospermum tract of the seeds was more toxic to gossypium. Kutira gum increases the goldfish than der ris extract and that effectiveness of nicotine sulfate sprays. crotón resin was more toxic than ro- The kutira appears to be a synergist to tenone. nicotine sulfate in its action against the Ricinus communis, the castor-bean bean aphid. plant, is said to have some insecticidal Compositae {Thistle or Aster Fam- value. If that is true, the insecticidal ily), This large family of plants in- principle is present only imder certain cludes thousands of herbs, vines, trees, conditions with respect to variety, cul- and shrubs. The dahlia, chrysanthe- tural practice, and environment. A val- mum, coreopsis, mangold, aster, cos- uable synergist is prepared from isobu- mos, and many other garden flowers tylamine and undecylenic acid, which are composites. To the dried flowers of results from the chemical decomposi- Chrysanthemum einerariaefolium the tion by heat of castor oil. By the action name pyrethrum is applied. Pyre- of sulfuric acid on castor oil, we get a thrum, a safe and effective insecticide, useful emulsifier for insecticidal oils. is widely used in household sprays. Flacourtiaceae. Ryania speciosa. The Four compounds exist in pyrethrum— active principles of the plant are alka- pyrethrins I and II and cincrins I and loids and are effective in the control of II. Pyrethrins are practically nontoxic the European corn borer. The roots to warm-blooded animals and can be and stems contain the insecticide, safely used in the home. which is commercially prepared for Heliopsis scahra is called oxeye. use as dusts and sprays. M. Jacobson, at the Agricultural Re- Fagaceae {Beech Family). Castanea search Center, discovered that these dentata is called the American chest- plants contaio compounds toxic to the nut. F. W. Metzger and D. H. Grant house fly. Nearly all the toxic material found that a commercial dyeing and is extracted by petroleum ether. Jacob- tanning extract of the American chest- son purified the petroleum ether ex- nut was a good repellent against the tract and named one of the toxic mate- Japanese beetle. rials scabrin. W. A. Gersdorff and N. Labiatae {Mint Family). Ocimum Mitlin, entomologists in the Depart- basilicum is known as common basil or ment of Agriculture, reported that sweet basil. Its oil killed 95 percent of scabrin compares well with pyrethrum the mosquito larvae tested at a con- in killing value. centration of 50 parts per million, but Cucurbitaceae [GourdFamily). The an extract made from the whole plant cucumber family is often called the killed none. H. D. Hively obtained a gourd, melon, or squash family. Cw- patent in 1940 for the use of the plant Insecticides From Plants 225 as an insecticide. It is successful as a devils-shoestring were slightly more contact poison against flies, Colorado poisonous than pyrethrum, but less potato beetles, and many other insects. poisonous than dcrris. Against ñvc Salvia officinalis, or garden sage. species of insects the plants showed Salvias are grown for their flowers and promise as a contact spray. Technical for their leaves. The leaves of some Bulletin No. 595 of the Department of species are used for seasoning. Hartzell Agriculture outlines studies of the pos- and Wilcoxon found that acetone ex- sibilities of devils-shoestring as a com- tracts of the leaves killed 80 percent and mercial source of insecticides. extracts of the roots killed 95 percent Liliaceae {Lily Family). The foliage of the mosquito larvae they tested. and rootstock of most species contain Leguminosae {Pea Family). The a poisonous juice. Amianthium mus- pea family is one of the most important caetoxicum, crowpoison, shows prom- group of garden plants in the world. ise as an insecticide against the house Haematoxylon campechianum is called fly, cockroaches, grasshoppers, and logwood. Hematoxylon is from the bees. It is inefficient against tent cater- Greek for blood and wood, in allusion pillars and aphids. The powdered bulbs to the red wood. Metzger and Grant and leaves are used as dusts. Water reported that two commercial extracts extracts show a slow but considerable were good repellents against the Japa- insecticidal efí"ect against Colorado nese beetle. potato beetle larvae and cockroaches. Millettia pachycarpa, fish-poison Melanthium virginicum, bunch- climber, is worth further investigation. flower. L. H. Pammel in 1911 stated The ground seeds kill several species that the bunchflower had long been of insects. Alcoholic extracts of the used to poison flies. roots from China paralyze the bean Schoenocaulon officinale is com- aphid. The plant contains a large monly known as sabadilla. R. J. Dicke amount of saponin and rotenonc. The in a thesis submitted to the University plant acts as a contact and stomach of Wisconsin in 1943 reviewed 76 ref- poison when it is mixed with soap. erences on this plant, which has been Mundulea sericea, or M. suberosa^ used as an insecticide since the six- is a promising insecticidal plant. It was teenth century. The University of Wis- discovered in the 1930's. It is a rote- consin has patented a method for in- none-yielding species. The plants from creasing the toxicity of sabadilla: India are toxic, but those from various Heating the powdered seed in kerosene locations in Tanganyika and Zanzibar or other solvent to 150° C. for i hour. fall into two main divisions, those with Sabadilla is effective against squash smooth barks, which are toxic, and bugs, chinch bugs, harlequin bugs, and those with rough, corky barks, which lygus bugs. Scientists in the Depart- are nontoxic. ment of Agriculture in 1949 began a Pachyrhizus erosus, or the yam bean. chemical study of the constituents of In some tropical countries the seeds of sabadilla seed. the yam bean plant are used as an Veratrum. Three plants are popu- insecticide and fish poison. Tests in the larly called hellebore—Veratrum al- United States by R. Hansberry and bum, V. viride, and Helleborus niger. C. Lee gave promising results against The term hellebore is incorrect when the bean aphid and the Mexican bean it is applied to the first two plants. The beetle. last, which is the true hellebore, grows Tephrosia virginiana is known as in Europe and is not a commercial devils-shoestring. It is a pretty little product in the United States. V. viride native plant, which prefers dry^, open, is the American plant. Powdered roots somewhat sandy places. It has long of the first two plants prevent the emer- been known to possess insecticidal gence of house flies from horse manure. properties. The most toxic samples of Veratrum viride is often called 220 Yearhook of Agriculture 1952 American falsc-hcllcborc, swamp helle- dron amurense, the Amur corktree, is bore, Indian poke, and itchwced in the native to several Asiatic countries and United States. Its active principles are was introduced into the United States alkaloids, which are toxic to man. Its in 1856. The unsaponifiable portion value as an insecticide for the control of the oil of the fruit is toxic to house of chewing insects on ripening fruit is Hies in acetone solution but not in high- due to its rapid loss of toxicity on ex- boiling kerosene. The residue of the posure to light and air. fruit, the oil liaving been removed, is Meliaceae {Mahogany Family). toxic to mosquito larvae, house flies, Melia azedarach is called chinaberry. and larvae of codling moth. The ma- Water extracts of the berries affect terial is a fast-acting poison like pyre- cockroaches slightly but are more toxic thrum and nicotine. against honey bees. Leaves applied to Zanthoxylum clavahcr culis, the the soil greatly reduce attacks of ter- southern prickly-ash, contains as- mites. An alkaline extract of the fruits arinin, a compound structurally related is effective against aphids. Cultivated to sesamin and, like it, a good synergist plants sprayed with extracts of the for pyrethrum against house flies. The chinabcrry leaves are not touched by southern prickly-ash also contains her- locusts. The active principle is soluble culin, a pungent substance highly toxic in hot water, alcohol, chloroform, or to house flies. It is closely related to benzene but not in petroleum ether. several other isobutylamides previously Myrtaceae {Myrtle Family). Pi- isolated from plant materials. A trace menta racemosa is the bay-rum tree. of the active material, when placed on The oil of the leaves is toxic to mos- the tongue, jiroduces an intense burn- quito larvae. Bay rum has been used in ing, paralytic eflcct on the tongue and Venezuela to kill insects. A foreign on the mucous membranes of the lips ]3atent covers its use in a mixture of and mouth. Hcrculin has approxi- several substances. Applied to summer mately the same order of paralyzing garments, it protects the wearer against action and toxicity to house flies as the gnats. Effective as baits to attract Jap- pyrethrins. anese beetles are 90 parts of geraniol Sapindaceae {Soapberry Family). and 10 parts of the leaf oil of a Pimenta Sapindus marginatus. This tree, up to species, or 90 parts of anethole and 10 30 feet high, is native in Florida. It is parts of the oil. planted occasionally for interest or Pedaliaceae. Sesamum inducum, ses- ornament. The word sapindus comes ame. The seeds yield sesame oil, which from the Latin for soap, combined with contains sesamin, a powerful Synergist Indian, in allusion to the Indians' use for pyrethrum. In the Second World of the berries for soap; the ])ulp lathers War the Armed Forces used more than easily like soap. S. L. Hoover obtained 40 million aerosol bombs containing a patent for the use of the berries of pyrethrum, liquefied gas, and sesame the tree as an insecticide or insectifuge. oil. The later bombs used 8 percent of Three berries protected a bushel oí the oil in the formula. Sesame oil also wheat against infestation. In powdered acts as a Synergist for rotenone. or liquid form and mixed with dried Ranunculaceae {Crowfoot Family). foodstuff's, it repelk^d weevils and other Delphinium consolida is called field insects. larkspur. The oil from larkspur seed Simarubaceae {Allanthus or Quassia tested as a contact spray (2-percent Family). This tree stands smoke and emulsion) was efTcctive against spider city conditions well, but the male mites and aphids but had little value flowers have a strong odor, which is against some other insects. The alka- offensive to some persons. The bark loids of this plant were also effective and wood contain insecticidal princi- p.gainst insects in various degrees. ples, which are used on only a few Rutaceae {Rue Family). Phellodeji- crops. Insecticides From Plants 227 Solanaceae {Nightshade or Potato Hannan and I were granted patents Family), The potato family, often covering two methods useful in extract- called the tobacco or tomato family, in- ing the alkaloids from Nicotiana cludes vegetables of world-wide culti- species, including the alkaloid anaba- vation, narcotics, drugs, tobacco, and sine from Nicotiana glauca. Anabasine a large number of garden flowers. is a liquid alkaloid that closely re- Duboisia hopwoodii, called pituri, is an sembles nicotine in its physical, chemi- Australian species and often is men- cal, toxicological, and insecticidal tioned in discussions of nicotine. C. V. properties. It has been reported to be Bowen, a chemist in the Department of four or ñwt times as toxic as nicotine Agriculture, analyzed the dried leaves to certain aphids of economic impor- and larger stems and found the leaves tance. to contain 3.3 percent and the larger Nicotiana spp. Tobacco and its chief stems 0.5 percent of nornicotine. H. H. alkaloid, nicotine, have been used since Smith and C. R. Smith of the Depart- 1690 as insecticides. Nicotine forms ment studied 29 wild species of Nico- salts with acids and most of the nico- tiana. They found that 5 species con- tine used for insecticidal purposes in tained the alkaloid nornicotine only the United States is in the form of the and 18 a mixture of nornicotine and sulfate. More than 29 species of Nico- nicotine. Against some insects, nornic- tiana have been analyzed for their otine is superior to nicotine. Nornico- alkaloid content. Some American to- tine is more toxic to a nasturtium aphid baccos used in making cigars of low and the pea aphid ; about equally toxic nicotine content contain as much as to the cabbage aphid, the citrus red 0.7 percent of nornicotine. One-eighth mite, and other spider mites; but less of the total alkaloids in certain samples toxic to the celery leaf tier, the large of commercial nicotine sulfate solu- milkweed bug, and larvae of codling tions was nornicotine. Most species of moth. aphids may be controlled with concen- Nicandra physalodes is also known trations of I part nicotine to 1,000 as the Peruvian groundcherry or shoo- parts of water. Nicotine is recom- fly plant. It repels insects. In India it mended against only those insects that is used as an insecticide. Stories told have soft bodies and those that are mi- about it are many: The plant distrib- nute in size, such as aphids, whiteflies, uted around a room repels flies; in a leafhoppers, psyllids, thrips, spider greenhouse it causes the whitcfly to dis- mites, and some external parasites on appear; a few hundred planted near a animals. barn apparently keep the animals from Stemonaceae. Stemona tuberosa, or being bothered by flies. paipu, has long been known and used Physalis mollis is commonly known in China as an insecticide. Decoctions as smooth groundcherry. Thomas A. of the dried roots are said to be toxic Nuttall described it in 1834. It grows to crickets, weevils, and the caterpillars throughout Oklahoma. Before the de- of moths and butterflies. A 50-pcrcent velopment of prepared fly sprays, the alcoholic extract of the plant is efí*ec- fresh plant was used to control house tive against lice and fleas. flies. The bruised leaves and stems, Umbelliferae {Carrot Family), mixed with a little water and sugar, Carum carvi is called caraway and con- killed flies. L. E. Harris of Ohio State tains oil of caraway, which will help University isolated a glycoside in an cure scaly-leg of poultry. Hartzell and impure form; it was toxic to flies. He Wilcoxon found that acetone extracts also isolated an alkaloid, but it was not of the seed killed 90 percent of the mos- toxic to flies in the small dosage used. quito larvae they tested. Nicotiana glauca, tree tobacco, is a Conium maculatum, poison hem- wild, fast-growing plant in Texas, lock, contains an alkaloid, coniine, Arizona, and California. Patrick J. which is related to nicotine. 2.28 Yearbook of Agriculture 1952 Coriandum sativum, or coriander, new income to the farmer; the public contains an oil that repels screw- gets farm products that are clean and worms. Applied in a 2-percent oil free from insects and poisonous resi- emulsion spray, it kills spider mites and dues. Since 1947 Department research cotton aphids. Coriander oil repels on plant insecticides covering only six house flies, green bottle flies {Lucilia plants—tree tobacco, oxcye, sabadilla, sericata), and black blow flies. devils-shoestring, thunder-god vine, Pimpinella anisum is anise. Clothing and sesame—has led to the publication treated with a soapy emulsion of anise of more than 17 papers and the grant- oil protects wearers from the sting of ing of three public service patents. gnats. Anise oil repels black blow flies, house flies, and green bottle flies. LOUIS FEIN STEIN, a research chem- Vitaceae {Grape Family). Parthe- ist, joined the Department of Agricul- n o eis sus quinquejolia, or Virginia ture in igsg. He holds degrees from creeper. An old reference to it states Georgetown University and the Uni- that a bunch of leaves rubbed on an versity of Pennsylvania. Dr. Feinstein infested area of an apple tree and has published papers on vitamins and crushing all the woolly apple aphids, nicotine alkaloids and holds patents on made the tree entirely free of aphids a the extraction of alkaloids and other week later. Formerly the tree could not materials from plants. be kept free of aphids for any length of time. For further reference: G. T. Bottger and C. V. Bowen: Com- parative Toxicity Tests of Anabasinc, Nor- THE PLANT WORLD contains many nicotine, and Nicotine, Bureau of Entomol- Interesting and useful insecticides that ogy and Plant Quarantine publication E— have not been investigated yet. Only a yio. 1946. R. N. Chopra and R. L. Badhwar: Poi- few have been mentioned here. The sonous Plants in India, The Indian Journal entomologists and chemists have passed of Agricultural Science, volurne lo, pages by many thousands of plants in their 1-44. 1940. search for an insecticide that kills in- E. O. Eddy and C. M. Meadows: Karaya Gum in Nicotine Sprays, Journal of Eco- sects but is safe to people and animals. nomic Entomology, volume 30, pages 430- Once a scientist discovers a plant 432- 1937- useful as an insecticide, he must take W. A. Gersdorff and Norman Mitlin: In- the plant apart and discover the active secticidal Action of American Species of principles in it. The discovery is only Heliopsis, Journal of Economic Entomology, volume 43, pages 554-555- ^950. the first step tow^ard the commercial H. L. Haller, E. R, McGovran, L. D. usefulness of the plant. The next steps GoodhuCy and W. N. Sullivan: The Syner- take time and effort. gistic Action of Sesamin With Pyrcthrum That a plant is poisonous to other insecticides, The Journal of Organic Chem- istry, volume y, pages 183-184. 1942. animals or is a common weed rarely Roy Hansherry and Cecil Lee: The Yam attacked by insects is not a positive Bean, Pachyrrhizus erosus Urban, As a indication of insecticidal properties. Possible Insecticide, Journal of Economic The insecticidal principles may be pres- Entomology {scientific note)^ volume 36, pages 351-352, 1943. ent in one or more of the following S. H. Harper, C. Potter, and E, M. Gill- parts: Leaves and leaflets, flowers, ham: Annona Species as Insecticides, An- petioles, seeds and seed hulls, fruits, nals of Applied Biology, volume 34, pages twigs and stems, roots, bark, and wood. 104-112. 1947. L. E. Harris: Chemical Studies in Okla- Often the plant will be insecticidal homa Plants. VI. Physallis mollis Nuttall— when it is ground up, but the extract A Plant Insecticidcj Journal of the Ameri- of the material will not be poisonous. can Pharmaceutical Association, scientific The farmer and the general public edition, volume 37, pages 145—146. 1948. Albert Hartzeil and Fredericka Wilcoxon: share in the discovery and development A Survey of Plant Products for Insecticidal of new insecticides from plants. Grow- Properties, Contributions from Boy ce ing new plants for ins-ecticides micans Thompson Institute, volume 12, 1941. Ralph E. Heal, Edward F. Rogers, Robert T. Wallace, and Ordway Starnes: A Survey of Plants for Insccticidal Activity, Lloydia, volume IS, pages 8g-i62, 1950. . Martin Jacob son: Herculin, A Pungent Oil Sprays for Insccticidal Constituent of Southern Prickly Ash Bark, The Journal of the American Fruit Trees Chemical Society, volume yo, pages 4234- 4237, 194S. F. B. LaForge: Constituents of Pyre- p. J. Chapman, L. A. Rie hi thrum Flowers. XX. The Partial Synthesis G. W. Pearce of Pyrethrins and Cinerins and Their Rela- tive Toxicities, with W, F. Barthel, The Journal of Organic Chemistry, volume 12, Petroleum oils are used in several pages 199-202, 1947; The Presence of an ways to control pests. Some kill insects Insccticidal Principle in the Bark of South- and mites directly through their own ern Prickly Ash, with H. L. Haller and W. action. Some supplement the action of H. Sullivan, The Journal of the American Chemical Society, volume 64, page iSy. other insecticides as co-toxicants, sol- 194s- vents and carriers, stickers, or stabil- N. E. Mclndoo: The Castor-Bean Plant izers. as a Source of Insecticides ; A Review of the In the water-borne oil sprays com- Literature, Bureau of Entomology and Plant Quarantine publication E-666, 1945; Plants monly applied to fruit trees, the oil of Possible Insccticidal Value; A Review of usually is the sole or primary inscctici- the Literature up to 1941, E—661, 1945; dal agent. That is also true of oils used A Bibliography of Nicotine. Part II. The In- to rid bodies of water of mosquitoes. sccticidal Uses of Nicotine and Tobacco, with R. C. Roark and R. L. Busbey, E~392, Light petroleum fractions are widely ^93^i Plants Tested for or Reported to used as solvents and carriers for many Possess Insccticidal Properties, with A, F. insecticides. The original fly sprays are Sievers, U. S. D. A. Publication 1201. 1924. a good example. The introduction of H. K. Plank: Insccticidal Properties of Some Plants Growing in Puerto Rico, DDT and other organic insecticides Puerto Rico Federal Experiment Station has meant a great increase in the use (Mayaguez) Bulletin 49. 1950. of oil as the carrier for applying insec- R. C. Roark: Excerpts from Consular ticides, especially the chemicals used Correspondence Relating to Insccticidal to control household and building and Fish-Poison Plants, United States Bu- reau of Chemistry and Soils, 1931 ; A Third pests. These oil-insecticide mixtures Index of Patented Mothproofing Materials, usually are applied in the form of fine with R. L. Busbey, Bureau of Entomology mists. With heat and a suitable gen- and Plant Quarantine. 1936. erator they can be applied also as M. S. Schechter and H. L. Haller: The thermal fogs, which remind one of Insccticidal Principle in the Fruit of the Amur Corktree, The Journal of Organic military smoke screens. Chemistry, volume 8, pages 194-197, 1943. Often oils are added to insccticidal E. H. Siegler and C. V. Bowen: Toxicity and fungicidal spray, dust, and poison- of Nicotine, Nornicotine, and Anabasine to bait formulations as stickers, stabili- Codling Moth Larvae, Journal of Economic zers, and conditioning agents. Entomology, volume 39, pages 673-674. 1946. ^ In this chapter we discuss the water- United States Patents: 1,619,258, Insec- borne oil sprays as they are used to con- ticide, patented by Sidney L. Hoover, trol pests of citrus and deciduous fruit March i, 1927 {U. S. Patent Office Official trees. Gazette,^ volume 356, page 132) ; 2,223,367, Insecticide, patented by Howard D. Hively, Kerosene w^as apparently the first December 3, 1940 {volume 521, page 58) ; petroleum product used for the control 2>525f7^4y Process for Extracting Alkaloi- of plant pests in the United States. A. J. dals from Plants with Aqueous Aluminum Cook of Michigan State College in- Sulfate, and 2,525,785, Process for Extract- troduced in 1877 a kerosene-soap emul- ing Alkaloidals from Plants with Aqueous Ammonia-Ethylene Bichloride Mixture, sion which was widely employed to patented by Louis Feinstein and Patrick J. combat aphids and scale insects. Hannan, October 17, 1950 {volume 639, Entomologists sought something pages 719-720), more effective and turned to crude pe- 229