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RMPG4EC8–. Diseases of economic plants . Plant diseases. 394 DISEASES OF ECONOMIC PLANTS the Southern States from North CaroHna to Florida, and west to Texas, and is yearly noted in new localities. Owing to the all-important position the cowpea occupies in southern agriculture as a nitrogen crop, where the best rotation demands its frequent recurrence upon the same soil, the disease is of pecuhar moment. No remedy is known except the use of the iron cowpea, the re- sistance of which was noted by Mr. T. S. Williams of South Car- olina in 1900, and fur- ther tested by W. A. Orton of the United States Dep
RMRDEX78–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CROPS 77 ing. One county alone is estimated to have suffered a loss of $950,000. Owing to its superficial similarity to the scab, it has perhaps been confounded with it in some instances. The first publica- tion concerning the disease appeared in 1902,' and the first detailed description in 1907.- Upon the fruit the blotches are from 5-10 mm. in diam- eter, dark in color, with an advancing margin of very peculiar, irregular, jagged, or fringed appearance. By co- alescence large spots may form, and owing to tension, cracks appe
RMMCKAWB–. Fig. 111. — Young onion plants showing effect of smut; at left smutted plants, at right healthy plants same age. After Hinman. likely to result, even if the bulb be surrounded by thor- oughly infested soil.
RMPG4EPF–. Diseases of economic plants . Plant diseases. 206 DISEASES OF ECONOMIC PLANTS is destructive upon the lima bean, producing upon pods and leaves large, brown patches, mth the pyenidia ar- ranged in concentric circles. When the disease is very prevalent, the pods fail to mature their seeds. Spraying with Bordeaux mixture is recommended. Powdery mildew {Ery- siphe polygoni DC). — The characters of the powdery mildews as described for the grape apply here suffi- ciently to serve for recog- nition purposes. This dis- ease is not usually serious, and is amenable to treat- ment with flowers of sul-
RMRDEXB0–. Diseases of economic plants . Plant diseases. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
RMMCKB3C–. FiG. 42.—Pear blight ; healthy and diseased twigs. Original. ticular varieties, freezing of the roots, too high culture, insects, fungi, and absence of needed food. One of the
RMPG4EH1–. Diseases of economic plants . Plant diseases. VEGETABLE AND FIELD CROPS 313 weather damp. Often it is still better to begin spraying in the seed bed. Southern blight (Sclerotium Rolfsii Sacc. in litt.).— This is the same disease discussed under pepper. Upon the tomato it is often completely destructive in the south- ernmost states. The first sign is wilting of the terminal portion of the plant, distinguishing this trouble from the fungous wilt, which commences with the lower leaves. For discussion and treatment see pepper. Anthracnose [Colletotri- chum phomoides (Sacc.) Chest.).—-This is chi
RMRDE336–. Diseases of economic plants . Plant diseases. 272 DISEASES OF ECONOMIC PLANTS above ground, are conspicuous in this disease. Other characters are rotting of the stem, the rosette development of the tops, and a scabby growth upon the tubers. Infected potatoes in storage may give way to a wet rot. In Florida in 1904 scarcely a lot of seed pota- toes free of this disease could be found, and the hibernating con- dition of the fun- gus was evident in 60 per cent of the seed tubers in some instances.* Such infected tubers are largely responsible for the contamination of new soil. Diseased seed tub
RMMCKB29–. Fig. 56. — Peach scab. Original. it as an integral part of the peach, may consist of isolated, sooty, black specks, or of black specks so numerous as to coalesce into large blotches. These sometimes cover as much as one third or one half of the peach. The side which is attacked is dwarfed, often cracked, and the flesh adjacent to the diseased part is bitter and green, even after the normal portions are ripe. The disease develops in most serious form during rainy seasons, and is worse upon some varieties than upon others. It is especially bad upon Hill's Chili. It is reported from Missouri to
RMPG4EH8–. Diseases of economic plants . Plant diseases. 308 DISEASES OF ECONOMIC PLANTS The wilting of the fohage and the blackening of the bun- dles are distinctively characteristic' A soil bearing diseased plants one season is subject to the malady in succeechng years and must be abandoned for tomato culture. The disease is spread from plant to plant largely by the potato bug (Colorado beetle) and other. Fig. 134. — Tomato field showing effect of wilt (bacillose). Original. insects. For this reason all leaf-infecting insects should be given special attention. Otherwise this disease in symp- toms, ca
RMRDE3AP–. Diseases of economic plants . Plant diseases. 192 DISEASES OF ECONOMIC PLANTS areas. The entire fruit at length becomes rotten, wrinkled, and shrunken. LOQUAT Scab (Fusidadium dendriticum (Wallr.) Fckl., var Eriobo- trym Scalia.). — This disease is reported as very serious. Fig. 84.—Guava affected with ripe rot. After Rumsey. upon both fruit and leaves in the western part of California, Anthracnose, blossom blight. See citrus fruits. MANGO Anthracnose. See citrus fruits. OLIVE Elnot (Pseudomonas Savastanoi E. F. Smith). — Tu- bercles or galls upon the leaves and branches, and even. Please no
RMMCKB3N–. Fig. 35. — Black-spot of the quince, natural size. After Bailey. in color. While this spot does not materially injure the fruit for use, it does retard its full development, and, be- cause of impaired beauty, decreases its selling price. It also, as in the case of apple scab, gives entrance to the pink-rot fungus. The means of prevention consists in application of lime-
RMPG4EFG–. Diseases of economic plants . Plant diseases. CEREALS 355 with a dark green powder. Sometimes a yellow color pre- vails instead of the green. In section the interior is seen to be filled with a compact white mass, bordered by a brown- ish yellow zone, then by the green coating. Though the disease has been known in Louisiana for ten or more years, and is there present to some extent in most fields, it is not considered serious, since rarely more than 0.25 per cent of the heads, and only a few grains per head, are affected. Black smut {Tilletia horrida Tak.). — A smut upon rice received by And
RMRDEG73–. Diseases of economic plants . Plant diseases. OBNAMENTAL PLANTS 463 Ascochytose, ray blight (Ascochyta chrysanthemi Stevens). — In this disease, described by Stevens' as doing consider- able damage in North Caro- lina, the ray flowers are blighted, resulting in im- perfect opening of the buds. Thorough spraying with Bordeaux mixture from the beginning of the season un- til blossoming, accompanied by destruction of infected refuse, has proved a satis- factory treatment. Powdery mildew (Oidium chrysanthemi Rbh. of Ery- siphe cichoracearum DC). — This mildew occurs as white, flour-like spots up
RMMCKA27–. Fig. 112. — Onion plant illustrating manner of death of leaves affected with downy mildew. After Whetzel.
RMPG4E9D–. Diseases of economic plants . Plant diseases. 428 DISEASES OF ECONOMIC PLANTS change, a word is due to it on account of its vast impor- tance, involving, as it does, all structural wood. The fact that the railroads use more than 110,000,000 ties annually, and that the number of posts in use is approximately. Fig. 186. — Dry rot fungus (Meruliu8 lacrymana) ; on the right the mycelium is visible as white strings. After Freeman. 4,000,000,000, necessitating an annual replacement of some 500,000,000 in the United States, indicates the enor- mous money values involved. This kind of decay is broug
RMRDE2YN–. Diseases of economic plants . Plant diseases. CEREALS 341 plants, and it has been proved experimentally that such seed carries the disease to the offspring.^ As a preventive meas- ure resistant varieties should be selected for planting, and all seed from plants which are at all diseased should be avoided. The disease may be carried from one locaUty to another by any of the means sug- gested under soil dis- eases, and especially by manure infected with stalks of diseased plants. Rust {Puccinia Sorghi Schw.). — Corn rust seems to have taken its place in hterature in 1815. It is of compara- tiv
RMPG4FC6–. Diseases of economic plants . Plant diseases. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
RMRDEX6J–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CROPS 79 than a pinhole, while upon the lower surface of the dis- eased spot appear some weeks later the fringe-toothed cluster cups. This spot is sometimes so abundant that its presence upon orchards may be recog- nized at great distances by the characteristic hue imparted to the foliage mass as a whole. It robs the tree of nourishment and renders normal fruit- age impossible. A peculiar relation ex- ists, in that the causal fungus spends part of its life on one plant, the apple, and the remainder upon a totally different pla
RMMCKAJB–. Fin. 19H.^ Maple tar spot. Aftor HeaUI. value of the tree for ornament or shade. The silver maples are especially susceptil^Ie, and their sale has thereby been reduced. The leaf spot was first noted in 1874 and is dis- tributed throughout the United States. The blackish, subcircular spots as they enlarge change to brown and later
RMPG4E72–. Diseases of economic plants . Plant diseases. 450 DISEASES OF ECONOMIC PLANTS upon the Pacific coast, where it often causes a loss of 50 per cent of the crop. It may be recognized as black cankered spots upon the young nuts, which fall prematurely, or by similar spots upon the young green shoots. In seasons favorable to bhght much of the terminal growth is killed and the succeeding crop is thereby reduced.. Fig. 100.—Dact3rial b:i;ht of walnvitj. .-^rter R. E. Smith. Two treatments with Bordeaux mixture, after thorough removal of diseased parts, have been known to prevent 50 per cent of the
![. Diseases of economic plants . Plant diseases. 132 DISEASES OF ECONOMIC PLANTS probable, therefore, that at least one cause of crown gall is the organism mentioned. Ail diseased stock should be avoided, as well as stock from nurseries where the disease is known to exist. Bacteriose (Bacterium pruni E. F. Smith^).—A " shot hole" disease of peach leaves, which causes prema- ture defoliation, is attributed 1>3' Smith and by Rorer ^ to Ijacteria. The disease has been found during several years in different states and is believed to constitute one of the most common of the " shot Stock Photo](https://c8.alamy.com/comp/RDE3G9/diseases-of-economic-plants-plant-diseases-132-diseases-of-economic-plants-probable-therefore-that-at-least-one-cause-of-crown-gall-is-the-organism-mentioned-ail-diseased-stock-should-be-avoided-as-well-as-stock-from-nurseries-where-the-disease-is-known-to-exist-bacteriose-bacterium-pruni-e-f-smitha-quot-shot-holequot-disease-of-peach-leaves-which-causes-prema-ture-defoliation-is-attributed-1gt3-smith-and-by-rorer-to-ijacteria-the-disease-has-been-found-during-several-years-in-different-states-and-is-believed-to-constitute-one-of-the-most-common-of-the-quot-shot-RDE3G9.jpg ". Diseases of economic plants . Plant diseases. 132 DISEASES OF ECONOMIC PLANTS probable, therefore, that at least one cause of crown gall is the organism mentioned. Ail diseased stock should be avoided, as well as stock from nurseries where the disease is known to exist. Bacteriose (Bacterium pruni E. F. Smith^).—A " shot hole" disease of peach leaves, which causes prema- ture defoliation, is attributed 1>3' Smith and by Rorer ^ to Ijacteria. The disease has been found during several years in different states and is believed to constitute one of the most common of the " shot Stock Photo")
RMRDE3G9–. Diseases of economic plants . Plant diseases. 132 DISEASES OF ECONOMIC PLANTS probable, therefore, that at least one cause of crown gall is the organism mentioned. Ail diseased stock should be avoided, as well as stock from nurseries where the disease is known to exist. Bacteriose (Bacterium pruni E. F. Smith^).—A " shot hole" disease of peach leaves, which causes prema- ture defoliation, is attributed 1>3' Smith and by Rorer ^ to Ijacteria. The disease has been found during several years in different states and is believed to constitute one of the most common of the " shot
RMMCKAWP–. Fig. 104. — Muskmelon 65 hours after inoculation with Giddings' germ. After Giddings. The cause is a bacillus whicli gains entrance through wounds, often through ruptures occasioned by excessively rapid growth.
![. Diseases of economic plants . Plant diseases. 09l "^^ ^a.^t,^€cn.^c^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan Stock Photo](https://c8.alamy.com/comp/PG4FCC/diseases-of-economic-plants-plant-diseases-09l-quot-atcnc-please-note-that-these-images-are-extracted-from-scanned-page-images-that-may-have-been-digitally-enhanced-for-readability-coloration-and-appearance-of-these-illustrations-may-not-perfectly-resemble-the-original-work-stevens-frank-lincoln-1871-1934-hall-john-galentine-1870-new-york-macmillan-PG4FCC.jpg ". Diseases of economic plants . Plant diseases. 09l "^^ ^a.^t,^€cn.^c^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan Stock Photo")
RMPG4FCC–. Diseases of economic plants . Plant diseases. 09l "^^ ^a.^t,^€cn.^c^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
RMRDEG5M–. Diseases of economic plants . Plant diseases. 484 DISEASES OF ECONOMIC PLANTS pores) and elaborated under the influence of sunlight and by the aid of the green substance (chlorophyll) into sugar or starch, , two of the fundamental substances upon which plant growth depends. Any injury or diminu- tion of the green plant part results at once in diminished carbon .as- similation (photosjmthe- sis) and as a consequence in lessened growth. Ab- straction of elaborated carbon or other useful substances by parasites is of course detrimental. The starch or sugar made in the green parts is needed in a
RMMCKAKJ–. Fig. 187. —Trees infested wi tlir SoIj.ioI (if Bdtanvdf tl; i:iiiver.sily of 'l Very numerous genera and species of fungi other than those mentioned above can also bring about similar changes.
RMPG4F15–. Diseases of economic plants . Plant diseases. 120 DISEASES OF ECONOMIC PLANTS which spreads the spores and furnishes moisture enough to allow them to germinate, followed by a dry spell, best favors the development of this disease. The use of the Bordeaux mixture has proved very satisfactory. Apply about every ten days during the early growing season; more frequently if necessary to replace any poison washed off by the rain. Wood rot (Schizophyllum commune Fr.). — Small white specks, the sporo- phores, appear upon the limbs and trunic in early summer.' In the au- tumn they are well developed
RMRDE2NR–. Diseases of economic plants . Plant diseases. FORAGE CROPS 395 The disease is very widespread, but even in the worst seasons does not do much injury. Angular leaf spot (Cer- cospora cruenta Sacc). — The angular leaf spots of this disease are a famil- iar sight in most cowpea fields. They are of vari- ous colors above, chiefly reddish, and are gray to purphsh or slate-colored below. The damage is rarely very great. In some in- stances the attack may proceed to the stems, where, especially at the base, it may cause crack- ing and result in such lowering of the vigor of the plant as to cause sh
![. Fig. 215. â Bacterial blight of walnuts. After R. E. Smith. favorable to blight much of the terminal growth is killed and the succeeding crop is thereby reduced. Spraying is of questionable value. Care should be taken to select resistant trees for propagation. Melaxuma ^-'^ (Dothiorella gregaria Sacc). â In this dis- ease, reported from California, black sunken cankers develop on the trunk and larger limbs, and the leaves on the smaller limbs suddenly wilt. The first indication of disease is often a black area like a blotch of tar on the gray ])ark. Excision and disinfection should l)e pract Stock Photo](https://c8.alamy.com/comp/MCKAGF/fig-215-bacterial-blight-of-walnuts-after-r-e-smith-favorable-to-blight-much-of-the-terminal-growth-is-killed-and-the-succeeding-crop-is-thereby-reduced-spraying-is-of-questionable-value-care-should-be-taken-to-select-resistant-trees-for-propagation-melaxuma-dothiorella-gregaria-sacc-in-this-dis-ease-reported-from-california-black-sunken-cankers-develop-on-the-trunk-and-larger-limbs-and-the-leaves-on-the-smaller-limbs-suddenly-wilt-the-first-indication-of-disease-is-often-a-black-area-like-a-blotch-of-tar-on-the-gray-ark-excision-and-disinfection-should-le-pract-MCKAGF.jpg ". Fig. 215. â Bacterial blight of walnuts. After R. E. Smith. favorable to blight much of the terminal growth is killed and the succeeding crop is thereby reduced. Spraying is of questionable value. Care should be taken to select resistant trees for propagation. Melaxuma ^-'^ (Dothiorella gregaria Sacc). â In this dis- ease, reported from California, black sunken cankers develop on the trunk and larger limbs, and the leaves on the smaller limbs suddenly wilt. The first indication of disease is often a black area like a blotch of tar on the gray ])ark. Excision and disinfection should l)e pract Stock Photo")
RMMCKAGF–. Fig. 215. â Bacterial blight of walnuts. After R. E. Smith. favorable to blight much of the terminal growth is killed and the succeeding crop is thereby reduced. Spraying is of questionable value. Care should be taken to select resistant trees for propagation. Melaxuma ^-'^ (Dothiorella gregaria Sacc). â In this dis- ease, reported from California, black sunken cankers develop on the trunk and larger limbs, and the leaves on the smaller limbs suddenly wilt. The first indication of disease is often a black area like a blotch of tar on the gray ])ark. Excision and disinfection should l)e pract
RMPG4EGF–. Diseases of economic plants . Plant diseases. 328 DISEASES OF ECONOMIC PLANTS and is present to some extent in most fields of this country, though often unnoticed on account of the early season of. Fig. 139. — Loose smut of barley in various stages of development. After Johnson. its development, and its absence at harvest time. Every spikelet of the smutted head is usually affected and entirely. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resembl
RMRDEX6B–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CHOPS 81 Buckingham, Mammoth Black Twig, White Winter Pear- main, Winesap, and Ben Davis are resistant, the last al- most entirely so. In general the crab varieties are more suscep- tible than others. Black rot, canker (Sphoerop- sis Malorum Peck). — In many respects this disease closely re- sembles the bitter rot, particu- larly in that it appears both as rot of the fruit and as cankers upon the limbs, each of which is almost indistinguishable from bitter rot upon the similar part. In some instances it also appears as a twig
RMPG4F4W–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CHOPS 93 apple losses and has been noted in several states, notably Missouri, Nebraska, West Virginia, and North Carolina, in abundance enough to call for printed mention. Brown rot produces complete decay of the affected apples, which turn brown, become soft and wrinkled, and soon show pustules of bushy myceliimi breaking through rifts and fissures in the skin over the diseased tissue. The diseased fruits may mummify upon the tree or more fre- quently fall to the ground and there shrivel to dry, hard, wrinkled masses, in whic
RMRDEG4A–. Diseases of economic plants . Plant diseases. 486 DISEASES OF ECONOMIC PLANTS FUNGI AND BACTERIA Fungi and bacteria are devoid of chlorophyll, therefore they cannot utilize the carbon of the air and are dependent, for their carbon supply, upon this element as elaborated by some other organism. When they take this food (often other nutrients as well) from living plants or animals, they become parasites, and if. Fig. 207. — Apple cells invaded by the mycelium of Volutella. OrigiDal. their thievery becomes considerable, a condition of disease is pro- duced. By growing in the plant body they may
RMPG4F2R–. Diseases of economic plants . Plant diseases. 110 DISEASES OF ECONOMIC PLANTS Texas root rot. See cotton. Black mold {Alternaria sp.). — In addition to the ravages of this disease as upon the apple, the leaves and shoots are also attacked and the fruit injury is not limited to. Fjg. 46. — Young quinces showing mat. After Bailey. the blossom end. The disease has been noted chiefly upon the KielTer. For treatment, see apple. QUINCE Rust (Gymnosporangium clavipes C. & P.). — The quince rust, spring stage, agrees with the apple rust in general characters. The causal fungus grows upon the fru
RMRDE3AH–. Diseases of economic plants . Plant diseases. TROPICAL FRUITS 193 upon the trunk of the tree, are the first signs of attack. Upon the leaves, the knots are always small, particularly if they are numerous. Upon the small twigs the knots attain the size of a garden pea, while upon the trunk they become 2-3 cm. or more in diam- eter and finally destroy the tree. The disease was noticed in Cah- fornia in 1893 and appears to be confined to a very small range. Peacock leaf spot (Cycloconium oleaginum Cast). — According to Bioletti this disease is very prev- alent in certain regions of Cali- fornia
RMMCKA53–. Fig. 89. Bean rust upon leaf and pods ; note the numerous sori upon both surfaces. After Beach. dew or rain is still upon them should be avoided. Seeds already bearing the fungus, i.e., spotted seeds, should never be planted, since they not only raise sick plants,
RMPG4EFD–. Diseases of economic plants . Plant diseases. 356 DISEASES OF ECONOMIC PLANTS The smut closely resembles the stinking smut of wheat. The affected ovaries or grains are transformed into stilm masses which remain within the glumes, and so resemble the normal grains as to often be mistaken for them. The fungous mycelium grows within the stem tissue of the diseased plant, and, as is the case with wheat bunt, infection prob- ably occurs in the seedling stage, and the fungus remains un-. FiG. 153.—Three rice spikeleta : A, normal : 5. smutted ; C, glumes partly torn away exposing the spore mass. A
RMRDE3A1–. Diseases of economic plants . Plant diseases. 200 DISEASES OF ECONOMIC PLANTS Since the spores arc spread only when they are wet, handling or disturbing the vines in any way while the. Fig. 89. — Boan rust upon leaf and pods ; note the numerous sori upon both surfaces. After Heach. dew or rain is still upon them should be avoided. Seeds already bearing the fungus, i.e., spotted seeds, should never be planted, since they not only raise sick plants,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appea
RMMCKAHK–. Fia. 210. — Russula rubra. Portion of the hymenium. sh, sub-hymenial layer; fc, basidia; s, sterigmata; .sp, spores; p, paraphyses; c, a cystid (x 540).
![. Diseases of economic plants . Plant diseases. TREES AND TIMBER 435 CEDAR, RED Rust {Gymnosporangium, various species).—The "cedar apples," familiar upon the red cedar, are usually of but small significance to the cedar tree itself unless exception- ally abundant. See apple rust.. Fig. 190.- - Longitudinal section of cedar showing effect of Polyponts juniperinus. After von Schrenk. White rot {Polyporus juniperinus v. Schrenk). — In this disease long holes appear in the heartwood, extend- ing longitudinally with a partition of sound wood be- tween. These cavities may eventually unite Stock Photo](https://c8.alamy.com/comp/PG4E8E/diseases-of-economic-plants-plant-diseases-trees-and-timber-435-cedar-red-rust-gymnosporangium-various-speciesthe-quotcedar-applesquot-familiar-upon-the-red-cedar-are-usually-of-but-small-significance-to-the-cedar-tree-itself-unless-exception-ally-abundant-see-apple-rust-fig-190-longitudinal-section-of-cedar-showing-effect-of-polyponts-juniperinus-after-von-schrenk-white-rot-polyporus-juniperinus-v-schrenk-in-this-disease-long-holes-appear-in-the-heartwood-extend-ing-longitudinally-with-a-partition-of-sound-wood-be-tween-these-cavities-may-eventually-unite-PG4E8E.jpg ". Diseases of economic plants . Plant diseases. TREES AND TIMBER 435 CEDAR, RED Rust {Gymnosporangium, various species).—The "cedar apples," familiar upon the red cedar, are usually of but small significance to the cedar tree itself unless exception- ally abundant. See apple rust.. Fig. 190.- - Longitudinal section of cedar showing effect of Polyponts juniperinus. After von Schrenk. White rot {Polyporus juniperinus v. Schrenk). — In this disease long holes appear in the heartwood, extend- ing longitudinally with a partition of sound wood be- tween. These cavities may eventually unite Stock Photo")
RMPG4E8E–. Diseases of economic plants . Plant diseases. TREES AND TIMBER 435 CEDAR, RED Rust {Gymnosporangium, various species).—The "cedar apples," familiar upon the red cedar, are usually of but small significance to the cedar tree itself unless exception- ally abundant. See apple rust.. Fig. 190.- - Longitudinal section of cedar showing effect of Polyponts juniperinus. After von Schrenk. White rot {Polyporus juniperinus v. Schrenk). — In this disease long holes appear in the heartwood, extend- ing longitudinally with a partition of sound wood be- tween. These cavities may eventually unite
RMRDE30C–. Diseases of economic plants . Plant diseases. 332 DISEASES OF ECONOMIC PLANTS brane eventually bursts, loosening a powdery, dry, black mass of spores through which fibrous veins of the com plant still pene- trate. It has been conclusively dem- onstrated that the causal fungus is not conveyed to the new crop in the seed, as is the case with so many other smuts, and that therefore no form of seed treatment is of value for its pre- vention. The sow- ing of seed covered with smut spores does not result in any more smut than does the use of un- infected seed. It has been clearly shown that infec-
RMMCKA19–. Fig. 123.—Potato black leg. Original. render it probable that this same disease is present in this country, but to just what extent is uncertain because of the
RMPG4F89–. Diseases of economic plants . Plant diseases. APPLE DISEASES OF SPECIAL CROPS PoMACEOus Fruits Bitter rot, ripe rot {Glomerella rufomaculans (Berk.) Spaul. & von Schrenk). Untrue to its. two common names, this malady does not always render apples bitter, though. Fig. 21.âApple bitter rot (glomerellose) in early stage showing pycnidia. After Scott. this is sometimes the case; nor is the disease always lim- ited to ripe fruit. Its effect is seen upon both the fruit and the twig. Upon the fruit it produces a soft, wet, or in later stages corky, more or â less dry, brown, tan-colored, or bla
RMRDEWY7–. Diseases of economic plants . Plant diseases. I'lHEANES OF SPECIAL CHOPS 111 adjacent cedar trees, and there produce swellings upon the branches and twigs during the fall and winter. In the spring, these give origin to long gelati- nous horns, which consist of masses of spores embedded in a matrix of jelly. These spores upon drying are conveyed to the quince tree by the winds, and there produce again the quince rust. The cedar is a necessary resting place for this fungus dur- ing the winter. The remedy there- fore is, if possible, to remove the cedar trees from the neigh- borhood of quince t
RMPG4F5R–. Diseases of economic plants . Plant diseases. DISEASES OF ECONOMIC PLANTS fungi have been isolated from these spots/ some of them may sustain a causal relation to the disease. Whatever the actual causal fungus may be, these spots are all, or nearly all, of fungous ori- gin and are amenable to preventive spraying with Bordeaux mixture. The first of three or four appUcations should be given with the opening of the leaf buds. Illosporiose, leaf spot (Illosporium malijolio- rum Shel.). — This is said by Sheldon- to be the cause of much of the defoliation of apple or- chards in West Virginia and
RMRDE399–. Diseases of economic plants . Plant diseases. 204 DISEASES OF ECONOMIC PLANTS Round Pod Wax, Refugee Wax, Burpee's White Wax, Grenell's Rust-proof Ciolden Wax, Wardwell's Kidney Wax, Dwarf German Blacli Wax, Early Valentine.' Stem rot, pod rot {Rhizodonia sp.). — This disease is manifest in three forms: ^ — 1. Damping off of seedlings. See damping off. 2. Dry rot of the stem. In this condition the tissue is dead, discolored, and dry-rotted at from 2-5 cm. above the -T '^t«*. Fig. 92. — Bacterial disease upon bean seeds. After Clinton. ground. The rot extends to the pith and usually encircles
RMMCKAAF–. Fig. 35. — Hypochnose, showing sclerotia on twig at left and rhizomorphic strands on twig at right. Original, gether with the sclerotia and extending along the twig longitudinally are also found silvery, glis- tening, thread-like, fun- gous growths. This fungus hibernates in the sclerotia on or near the terminal bud and thence invades the new twigs as they develop, reaching out upon each leaf, spreading over its under surface in almost invisible thinness, and causing it to droop, die, and eventually to fall away. Thus in early au- tumn such trees are nearly or quite defoliated. The fruit may
![. Diseases of economic plants . Plant diseases. TREES AND TIMBER 433 gray border. The spots, from 3-6 mm. in diameter, often coalesce to form large blotches which are fragile, sometimes dropping from the leaf. Young leaves develop poorly and are deformed, while severe infection may cause complete defoliation of the tree.. Fig. 188.- ' Cedar apple." gall of the rust fungus. Original. Macrosporiose (Macrosporium Catalpw Ell. & Mart.).— This spot is scarcely distinguishable from phyllostictose except through the absence of pycnidia and the presence of a scant quantity of Ijlack mold. Pow Stock Photo](https://c8.alamy.com/comp/PG4E8X/diseases-of-economic-plants-plant-diseases-trees-and-timber-433-gray-border-the-spots-from-3-6-mm-in-diameter-often-coalesce-to-form-large-blotches-which-are-fragile-sometimes-dropping-from-the-leaf-young-leaves-develop-poorly-and-are-deformed-while-severe-infection-may-cause-complete-defoliation-of-the-tree-fig-188-cedar-applequot-gall-of-the-rust-fungus-original-macrosporiose-macrosporium-catalpw-ell-amp-mart-this-spot-is-scarcely-distinguishable-from-phyllostictose-except-through-the-absence-of-pycnidia-and-the-presence-of-a-scant-quantity-of-ijlack-mold-pow-PG4E8X.jpg ". Diseases of economic plants . Plant diseases. TREES AND TIMBER 433 gray border. The spots, from 3-6 mm. in diameter, often coalesce to form large blotches which are fragile, sometimes dropping from the leaf. Young leaves develop poorly and are deformed, while severe infection may cause complete defoliation of the tree.. Fig. 188.- ' Cedar apple." gall of the rust fungus. Original. Macrosporiose (Macrosporium Catalpw Ell. & Mart.).— This spot is scarcely distinguishable from phyllostictose except through the absence of pycnidia and the presence of a scant quantity of Ijlack mold. Pow Stock Photo")
RMPG4E8X–. Diseases of economic plants . Plant diseases. TREES AND TIMBER 433 gray border. The spots, from 3-6 mm. in diameter, often coalesce to form large blotches which are fragile, sometimes dropping from the leaf. Young leaves develop poorly and are deformed, while severe infection may cause complete defoliation of the tree.. Fig. 188.- ' Cedar apple." gall of the rust fungus. Original. Macrosporiose (Macrosporium Catalpw Ell. & Mart.).— This spot is scarcely distinguishable from phyllostictose except through the absence of pycnidia and the presence of a scant quantity of Ijlack mold. Pow
RMRDE2RN–. Diseases of economic plants . Plant diseases. 388 DISEASES OF ECONOMIC PLANTS dies, and shrivels. The rust is conveyed from plant to plant throughout the summer by spores of this stage. The teleutospores may appear in the same sori with the uredospores or in separate sori, and in either event come. Fig. 166. — Clover leaf showing sori of mat. Original. later in the season. They are recognized by their darker brown color. The cluster-cup stage, which is less abun- dant and less injurious than the other stages, may often pass unnoticed. It appears first as pale swollen regions upon the leaf or
RMMCKAXD–. Fig. 97. — Spots of downy-mildew upon cucumber leaf. After Orton. The mildew was first described in 1868 from Cuba. In 1889 it attracted attention in the United States (New Jersey, Florida, and Texas) and in Japan. Since that time it has been destructive in many states. The loss in Wayne County, Ohio, alone was estimated at $45,000 in one season. It grows upon muskmelons and cucumbers in most de- structive form and is less injurious to squash, pumpkin,
RMPG4FB1–. Diseases of economic plants . Plant diseases. - Sori of rust of asparagus. Original.. Fig. 5, — Hyphae in a leaf spot much enlarged. Redrawn after Gannan.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
RMRDE2PX–. Diseases of economic plants . Plant diseases. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York : Macmillan
RMMCKB2R–. I'lG. 46. — Peach leaves inoculated with culture of Pseudoinottds pruni. Photograph taken 43 days after inoculation. After Eolfs. susceptible to black-spot, affecting chiefly the leaves, but occurring, also, on fruit and branch. It constitutes a really serious disease on peaches, being next in importance to
RMPG4F2J–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CROPS 113 has not yet been proved that this fungus causes cankers on the quince trees such as have been described for the. Fig. 48. — Black spot of the quince, natural size. After Bailey. apple. The grower should, however, watch carefully for the presence of canker, as the relation between the canker and the rot in apple indicates that the canker may possibly be found on the quince also.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
RMRDE303–. Diseases of economic plants . Plant diseases. CEREALS 337 borne spores, which come, in part, from diseased ears, but more largely from diseased stalks left in the field.. Fig. 143. — Dipiodia on old shanks. After Burrill & Barrett. Any method of reducing the amount of infective trash, particularly old stalks near or in the fields, aids in control z. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Stevens, Frank Lincol
RMMCKABA–. Fig. 25.—Apple scab. After Craig. ing. The irritation and retardation of growth caused by the presence of the fungus induces the leaves to curl and wrinkle in a characteristic manner. The injuries by this disease may be enumerated as follows: lessened leaf value, retarded twig and wood growth, premature fall of fruit, retardation of full develop-
RMPG4F6K–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CHOPS 81 Buckingham, Mammoth Black Twig, White Winter Pear- main, Winesap, and Ben Davis are resistant, the last al- most entirely so. In general the crab varieties are more suscep- tible than others. Black rot, canker (Sphoerop- sis Malorum Peck). — In many respects this disease closely re- sembles the bitter rot, particu- larly in that it appears both as rot of the fruit and as cankers upon the limbs, each of which is almost indistinguishable from bitter rot upon the similar part. In some instances it also appears as a twig
RMRDE31W–. Diseases of economic plants . Plant diseases. 304 DISEASES OF ECONOMIC PLANTS. Fig. 133.—Tobacco leaf showing leaf spot (cercosporose). After Conn. Exp. Sta. The disease was first described hy Sturgis' from specimens sent from South Carolina. It was then very destructive, practically ruining the crop. A damage of $1000 to one crop alone was noted. It has since con- tinued as a troublesome pest. The use of Bordeaux early in the season is per- missible and advanta- geous. White speck {Macro- sporium tabacinum Ell. & Ev.). — White speck con- sists of small, circular spots, rusty red or brow
![. Fig. 147. — Loose-smut of barley in various stages of develo]iinent. After Johnson. the plant developing from such an infected seedling the disease does not show externally mitil the smut ripens at the next blossoming season. The life history of this smut is thus similar to that of Stock Photo](https://c8.alamy.com/comp/MCKAP8/fig-147-loose-smut-of-barley-in-various-stages-of-develo-iinent-after-johnson-the-plant-developing-from-such-an-infected-seedling-the-disease-does-not-show-externally-mitil-the-smut-ripens-at-the-next-blossoming-season-the-life-history-of-this-smut-is-thus-similar-to-that-of-MCKAP8.jpg ". Fig. 147. — Loose-smut of barley in various stages of develo]iinent. After Johnson. the plant developing from such an infected seedling the disease does not show externally mitil the smut ripens at the next blossoming season. The life history of this smut is thus similar to that of Stock Photo")
RMMCKAP8–. Fig. 147. — Loose-smut of barley in various stages of develo]iinent. After Johnson. the plant developing from such an infected seedling the disease does not show externally mitil the smut ripens at the next blossoming season. The life history of this smut is thus similar to that of
RMPG4F1F–. Diseases of economic plants . Plant diseases. DRUPACEOUS FRUITS 117 $25,000. This disease is identical with that of the plum, but since the spraying mixture adheres to the fruit, it cannot be applied on to the plum without injury to the market value of the product. Spraying as for plum leaf spot with. Fig. 51. — Cherry tree from same orchard sprayed with self-boiled lime-sulphur to control leaf spot. After Scott. such modifications as are needed to avoid spotting the fruit is the only recourse. Recent experiments by Scott' showed that the self-boiled lime-sulphur wash (10-10-50), the factory
RMRDE2Y5–. Diseases of economic plants . Plant diseases. CEREALS 355 with a dark green powder. Sometimes a yellow color pre- vails instead of the green. In section the interior is seen to be filled with a compact white mass, bordered by a brown- ish yellow zone, then by the green coating. Though the disease has been known in Louisiana for ten or more years, and is there present to some extent in most fields, it is not considered serious, since rarely more than 0.25 per cent of the heads, and only a few grains per head, are affected. Black smut {Tilletia horrida Tak.). — A smut upon rice received by And
RMPG4EN7–. Diseases of economic plants . Plant diseases. VEGETABLE AND FIELD CROPS 221 Powdery mildew (Erysiphe polygoni DC.)- — This mildew of the cucumber and cantaloupe in general appearance resembles that described for the grape. It is more com- mon under glass than in the open, and here indicates too much moisture and too little ven- tilation. It is sel- dom injurious in the field. Flowers of sul- phur applied to the hot water or steam pipes in the form of a paste is useful. Leaf blight, cer- cosporose {Cercos- pora Cucurbitoe Ell. &Ev.). —The spots of this disease are much hke those of altern
RMRDEWYH–. Diseases of economic plants . Plant diseases. 110 DISEASES OF ECONOMIC PLANTS Texas root rot. See cotton. Black mold {Alternaria sp.). — In addition to the ravages of this disease as upon the apple, the leaves and shoots are also attacked and the fruit injury is not limited to. Fjg. 46. — Young quinces showing mat. After Bailey. the blossom end. The disease has been noted chiefly upon the KielTer. For treatment, see apple. QUINCE Rust (Gymnosporangium clavipes C. & P.). — The quince rust, spring stage, agrees with the apple rust in general characters. The causal fungus grows upon the fru
RMPG4ER9–. Diseases of economic plants . Plant diseases. VEGETABLE AXD FIELD CHOPS 195 neath. This, the summer stage, is chiefly responsible for the hibernation of rust in the east. Later in the season the sori become black instead of rusty col- ored, thus constituting the winter stage of the rust. In the spring still an- other stage, the spring stage, may occasionally be seen, though it is rare east of the Rocky Mountains. This con- sists of small, oval, pale spots upon the bra,nches or leaves. In the cen- ters of these spots small round pustules develop in concentric lines. Soon each pustule opens, c
RMRDE388–. Diseases of economic plants . Plant diseases. 2U DISEASES OF ECONOMIC PLANTS shown in the accompanying fig:ure. It cannot be con- founded with any other disease unless it be that caused by eel worms (nematodes), and from this it may be easily dis- tinguished by the greater magnitude of the club-root galls. These enlargments may be noted in the seed bed, though they are usually overlooked until they be- come larger in the field. The J- so diminish the vigor of the plant that it assumes a sickly appearance, ceases to develop, and fails to head. The affected parts usually succvnnb to offen- siv
RMMCKACT–. Fig. 16. — Potato field showing benefits of spraying. Portion at left received Bordeaux mixture and Paris green ; portion at right received Paris green only. Original. first year, since spraying protects the foliage, the func- tion of which is to accumulate nourishment for the crop of the following year. Spraying should be regarded as insurance. It pro- tects the crop against the devastation of disease, yet in most cases it differs from insurance in the fact that it
RMPG4F6B–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CROPS Pacific coast canker, black-spot canker' (Macrophoma curvispora Peck). — The Pacific coast canker is particu- larly destructive in the northwestern states west of the Cascade Moun- tains. It was first noted about 1893 when it developed in such destruc- tive form as to cause the Wash- ington State Board of Horti- culture to call upon the Federal Government for its investiga- tion. It has since been reported in Oregon, Idaho, Nebraska, and British Columbia. The bark or sap- wood of twigs and larger branches is the seat of
RMRDEX10–. Diseases of economic plants . Plant diseases. DISEASES OF SPECIAL CROPS 107 This disease of pears is particularly abundant upon sev- eral varieties of the Japanese strain. Bitter rot, ripe rot {Glonierella rufomaculans (Berk.) Spaul. & von Schrenk). — This disease is of much less frequent occurrence upon the pear than upon the apple. For description and treatment, see pp. 64 and 74.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the or
