Xanthomonas axonopodis. [Descriptions of Fungi and Bacteria].

Author(s):  
J. F. Bradbury

Abstract A description is provided for Xanthomonas axonopodis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Axonopus scoparius, A. micay, A. compressus and A. affinis. Also able to infect by inoculation Digitaria decumbens, Hypharrhenia rufa, Panicum sp. (Guinea grass) and Saccharum officinarum (54, 5464). DISEASE: Gummosis of Imperial and Micay grasses, important pasture grasses in tropical America. Diseased stems usually stand out from healthy ones in the same tuft by their elongated, partly bare appearance with a few pale, yellowish leaves at their ends, giving a characteristic flag-like appearance. Closer examination shows many diseased leaves with pale stripes running parallel to the main veins. After cutting diseased Imperial grass the new shoots are feeble and twisted, and often wither in a short time. Subsequent shoots behave in the same way. In severe attacks of whole tuft may shrivel and die. Such tufts are very easily pulled from the soil. When diseased stems are cut across, especially in the rainy season, minute droplets of yellowish bacterial ooze appear in a short time. In longitudinal cuts the vascular bundles are seen to be stained reddish or brownish, especially near the nodes. Masses of bacteria and mucilage are found in vessels when examined under the microscope. GEOGRAPHICAL DISTRIBUTION: Colombia. TRANSMISSION: Mainly by machete and other agricultural implements. Cattle can infect young shoots when grazing, evidently transmitting the bacteria in their saliva. Trampling by cattle and man and the passage of wheeled vehicles can also transmit the disease, and rain splash can carry infection from the exudate of recently cut stems. Insect transmission is not thought to be important and the bacteria do not survive free in the soil (46, 666). Seed transmission is also thought to occur (43, 2799c).

Author(s):  
J. F. Bradbury

Abstract A description is provided for Corynebacterium oortii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Tulipa gesneriana, the garden tulip. DISEASE: 'Geel-pok' (yellow pustule) of tulip bulbs and 'hels vuur' (hell-fire) of the leaves. Primary infection occurs on leaves, which show silver grey spots after a short time. These become up to about 5 mm diam. with brittle, easily cracked epidermis and disorganised-looking parenchyma within. Plants may also show leaves with areas in which the upper and lower epidermis is badly cracked, giving a characteristic rough look to the leaves. These plants show yellowish stem interiors that run down to the young growing bulbs. On bulbs the outermost white scale develops many tiny white spots which turn yellow and by the end of the storage period are yellow areas with raised tissue and ruptured outer skin. In section many vascular bundles are yellow. Less severely affected bulbs develop into stunted plants with leaves showing silvery streaks along veins. GEOGRAPHICAL DISTRIBUTION: Netherlands, England. TRANSMISSION: By planting out of infected bulbs, which may produce infected plants and in turn more infected bulbs; also from plant to plant in the field by leaf infection. The latter presumably in windy and wet conditions.


Author(s):  
J. L. Mulder

Abstract A description is provided for Ustilaginoidea virens. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Oryza sativa and Zea mays. DISEASE: False smut of rice appears as olive-green, velvety, globose masses, up to 1 cm diam. in some of the ears of the inflorescence. The spore ball, beneath the dark layer of mature spores, is orange-yellow, paling inwards until it is almost white, as it ages it becomes almost black. The glumes are closely applied to the lower part of the spore ball which is at first covered with a membrane. Infection, producing similar symptoms, has been reported on the male inflorescence of Zea mays (8: 716) and on wild species of Oryza. GEOGRAPHICAL DISTRIBUTION: Widespread in the tropics, in U.S.A. (California and S.E. states) and in Italy (CMI Map 347, ed. 2, 1968). Records not yet mapped are Australia (NT), Costa Rica, Dominican Republic and Laos. TRANSMISSION: There appears to be no evidence for seed transmission and the conidia are probably viable for a short time only. The air-borne conidia have a diurnal periodicity with peak at 22.00 hr, numbers being very low between 04.00 and 16.00 hr (46, 316). The ascospores of the reported perfect state may also be air-dispersed.


Author(s):  
G. Morgan-Jones

Abstract A description is provided for Leptosphaeria michotii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Saccharum officinarum and a variety of other monocotyledonous genera including Agropyron, Agrostis, Andropogon, Arundo, Brachypodium, Calamagrostis, Carex, Cladium, Dactylis, Deschampsia, Festuca, Holcus, Iris, Juncus, Melica, Molinia, Nardus, Oryza, Panicum, Phalaris, Phleum, Scirpus, Triticum, Typha, Zea. DISEASE: Leaf spot of sugarcane (Booth, 1960), leaf blast of sugarcane (Yen & Chi, 1954). GEOGRAPHICAL DISTRIBUTION: Africa (Kenya, Sierra Leone, Uganda); Asia (Japan, Nepal); Australasia and Oceania (Australia, Fiji, New Caledonia, New Guinea, New Hebrides, Samoa, Solomon Islands); Europe (Belgium, Denmark, France, Germany, Great Britain, Italy, Sweden, Switzerland); Caribbean (Jamaica); South America (British Guiana). TRANSMISSION: Persisting in stubble and leaf debris. Conidia disseminated by rain-splash.


Author(s):  
K. G. Mukerji

Abstract A description is provided for Sclerospora sacchari[Peronosclerospora sacchari]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Saccharum officinarum, Echinochloa colonum, Eleusine indica, Euchlaena luxurians, E. mexicana, Panicum barbinodes, Polypogon interruptus, Saccharum barberi, S. robustum, S. sinense, Setaria verticillata, Sorghum halepense, S. sudanense, S. vulgare and Zea mays (35, 125; 40, 626; 44, 648), and others cereals and grasses. DISEASE: Downy mildew of sugarcane and one of the downy mildews of maize, the others are caused by Sclerospora philippinensis[Peronosclerospora philippinensis] (CMI Descript. 454) and S. maydis (Racib.) Butler. Sclerospora sacchari has larger oogonia than S. philippinensis; these spores are unknown in S. maydis which has smaller conidia than those of S. philippinensis. The symptoms on sugarcane differ, depending on when infection occurs. When diseased setts are used the young plant may die or become generally stunted, discoloured and conspicuous. Infection at a later stage causes pale green to yellow longitudinal stripes which increase in length after each leaf unfolds. The stripes may become a chlorotic mottling, later necrotic with oospores lying interveinally. Later infections cause abnormal stem elongation (jump up canes); stems are weak, have more internodes and fewer shorter leaves which may not unfold. Shredding caused by the disintegration of leaf tissue occurs in sugarcane but not in maize. In the latter host infection at a very early growth stage causes stunting and death. Systemic infection causes chlorotic leaf streaks, small poorly filed ears (formed in abnormally large numbers), elongated ear shanks, imperfect tassels with grain and sterility (21, 347; 42, 47, 629; 48, 1166). GEOGRAPHICAL DISTRIBUTION: Australia (Qd.), Fiji, India. Japan, Philippines, Taiwan, Thailand (CMI Map 21. ed. 2. 1965). Recent records from Central America are considered doubtful (49, 3185, 3740). TRANSMISSION: In Taiwan conidial air dispersal was mostly at 0100-0300hr (50, 3701). There is evidence for seed transmission in maize (47, 2705). The role of the oospore in spread appears uncertain, most spread in sugarcane apparently occuring through the conidia, but infection of this host with the sexual spore was successful (41, 544). The fungus passes readily from one primary host to the other.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Pseudomonas andropogonis[Burkholderia andropogonis]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Sorghum vulgare[Sorghum bicolor] and its vars. sudanense, technicum, saccharatum, S. halepense and unspecified grain and grass varieties of Sorghum, Zea mays, Bougainvillea sp., Mucuna deeringiana, Trifolium repens, T. pratense, Euchlaena mexicana and Vicia saliva. The following have been infected artificially: Medicago sativa, Viciafaba, Trifolium subterraneum by spray inoculation, and Dolichos lablab, Lespedeza sp., Phaseolus vulgaris (Allen et al. ; 36, 408) and Saccharum officinarum (Elliott & Smith, 1929) after injury. DISEASE: Bacterial stripe of sorghum, bacterial leaf spot or blight of velvet bean, vetch and other legumes. usually a leaf spot disease. On species of Sorghum spots and stripes on leaves and sheaths vary in colour from reddish or purplish-brown to tan or brick red, depending on host reaction. On legumes the spots are usually small, angular, dark brown to dark reddish-brown or nearly black. Stem lesions are extensive in vetch, where they can result in death progressively from the base. GEOGRAPHICAL DISTRIBUTION: Argentina, Brazil, USA, Rhodesia, Uganda, Zambia, South Africa, Nigeria, Hungary, USSR, China, Australia (NSW), Japan, Taiwan (CMI Map 495, ed. 1, 1973). TRANSMISSION: In the field transmission is by wind and rain and can lead to very rapid development of the disease if conditions remain humid. Overwintering is thought to take place in plant debris, in soil and possibly in weed hosts (42, 194). There is some observational evidence for seed transmission in Sorghum (Elliott & Smith, 1929) and in Mucuna (Allen et al, 1970). This would explain the very scattered distribution. With Bougainvillea, when the new wet season starts, the young growth is infected by rain splash from old infected leaves that have lasted over from the previous wet season, either attached or on the ground.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Clavibacter michiganensis subsp. nebraskensis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Zea mays is the natural host. By inoculation Euchlaena mexicana, Saccharum officinarum, Sorghum bicolor, S. sudanense and Tripsacum dactyloides are infected (Schuster et al., 1973). DISEASE: Leaf freckles and wilt, or Goss's bacterial wilt and blight. The disease is characterized by the appearance of discrete, water-soaked spots, dark green to blackish at first, becoming brown and more freckle-like, then coalescing and inducing a leaf scorch. The spots may arise from direct infection or via systemic infection from roots and stems (Schuster et al., 1973). GEOGRAPHICAL DISTRIBUTION: USA (IA, IL, KS, NE). (IMI Distribution Map 549, ed. 1, 1982; 67, 4495). TRANSMISSION: The bacterium can overwinter in debris from diseased corn, particularly stubble and this is a source of primary inoculum in the new growing season. It is also present within the seed where it can remain viable for more than a year. However, experiments suggest that seed transmission is rare (Schuster et al., 1973).


Author(s):  
E. Punithalingam

Abstract A description is provided for Phoma insidiosa. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Sorghum spp., Oryza sativa, Saccharum officinarum, Setaria, Triticum aestivum and Zea mays. DISEASE: A minor leaf spot of Sorghum and Setaria spp. and other Gramineae. The macroscopic symptoms are variable and not particularly distinctive. Leaf lesions have an irregular outline, sometimes beginning at the tip or edge, and are brown to grey with narrow redish-purple margins. The scattered pycnidia occur sometimes in clusters or lines, interveinally. Spotting and pycnidia form on grain and glumes. GEOGRAPHICAL DISTRIBUTION: Argentina, Australia (W.), Brazil, Canada, China, Cuba, Ethiopa, Hawaii, India, Jamaica, Kenya, Laos, Malawi, Malaysia (W.), Nepal, Nigeria, Puerto Rico, Rhodesia, Senegal, Sierra Leone, South Africa, Sudan, Tanzania, Uganda, USA, USSR, Venezuela, Zaire Republic, Zambia. The fungus may be detected on introduced seed. TRANSMISSION: Probably carried on the seed; infection of the seed reduces both germination and subsequent growth. May remain viable on seed for 1 yr.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Xanthomonas campestris pv. phlei. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Phleumpratense. In inoculation tests Egli & Schmidt (1982) found that Phleum alpinum, P. arenarium, P. bertolonii (2 cvs.), P. phleoides and P. pratense (2 cvs.) were all highly susceptible. Lolium multiflorum showed mild symptoms in this test, but none in another. Other grasses, including Festuca pratensis, Arrhenatherum elatius and Poa trivalis showed little or, more often, no symptom development. DISEASE: Bacterial wilt of timothy grass. The symptoms are the same as those caused by X. campestris pv. graminis on other forage grasses. Young leaves curl and wither and shoots remain stunted or die. In some plants growth continues poorly and small, distorted inflorescences are produced. Chlorotic and necrotic zones form along the vascular bundles of older leaves, often extending to the sheaths. Bacterial streaming is often visible under the microscope from the cut edges of infected tissue. GEOGRAPHICAL DISTRIBUTION: Norway (Egli & Schmidt, 1982) and Belgium (61, 6162) are the only reports so far, but the disease is probably more widespread in Europe than this would suggest. TRANSMISSION: As for X. campestris pv. graminis transmission within the crop is thought to be mainly by mowing machinery. The possibility of seed transmission should not be overlooked, although this has not been proved.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Clavibacter XYLI subsp. XYLI. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Saccharum officinarum, where it is restricted to the xylem. It produces a characteristic wilting when inoculated into sorghum-Sudan grass hybrid NB280S (61, 5933); also able to multiply in the xylem of various grasses and cereals, including Brachiaria mutica, B. miliiformis, Chloris gayana, Cynodon dactylon, Echinochloa colonum, Imperata cylindrica, Panicum maximum, Pennisetum purpureum, Rhynchelytrum repens, Sorghum bicolor, S. halepense, S. sudanense, S. verticilliporum, Sporobolus capensis and Zea mays when artificially inoculated, but although it can be transmitted back to sugar cane to produce the disease, it does not produce symptoms in these plants (Gillespie & Teakle, 1989). DISEASE: Ratoon stunting disease (RSD) of sugar cane. The cane makes slower than normal growth and is generally unthrifty. Canes are thinner with shorter internodes than normal and ratoon or stubble crops are particularly affected. Internally, reddish vascular bundles may be seen, especially at the nodes, or in immature cane, the interior of the nodes may be generally a faint pink. Such symptoms are, however, not particularly reliable for diagnosis, as they can result from stress caused by other factors. To confirm the disease it is probably best to observe the bacterium in the vessels by light or electron microscopy, use a serological method or both. GEOGRAPHICAL DISTRIBUTION: Very widespread due to transmission in planting material. Records include: Burkina Faso, Cameroon, Congo, Egypt, Ethiopia, Kenya, Madagascar, Malawi, Mali, Mauritius, Mozambique, Nigeria, Reunion, South Africa (Natal), Sudan, Swaziland, Tanzania, Uganda, Zaire, Zimbabwe, Bangladesh, Burma, China, India (Madhya Pradesh, Karnataka, Punjab, Uttar Pradesh), Indonesia (Java), Japan, Malaysia (W.), Philippines, Sri Lanka, Taiwan, Thailand, Australia (NSW, Qd), Fiji, Hawaii, Spain, Mexico, USA (Florida, LA), Antigua, Barbados, Belize, Cuba, Dominican Republic, Jamaica, Nevis, Nicaragua, Panama, Puerto Rico, El Salvador, St. Kitts, Trinidad, Argentina, Brazil (Rio de Janeiro), Colombia, Guyana, Peru, Uruguay, Venezuela (IMI Distribution Map 318, ed. 4, 1982; 63, 2478; 64, 2151; 66, 2051; 69, 5165; ISSCT List 1983). TRANSMISSION: To new areas in vegetative planting material and within the crop by mechanical means such as cutting knives and mechanical harvesters. Rats may also spread the disease.


Author(s):  

Abstract A new distribution map is provided for Listronotus bonariensis (Kuschel) Coleoptera: Curculionidae Attacks Lolium spp. and other pasture grasses and cereals. Information is given on the geographical distribution in SOUTH AMERICA, Argentina, Bolivia, Brazil, Chile, Uruguay, OCEANIA, Australia, New South Wales, South Australia, Tasmania, Victoria, Western Australia, New Zealand.


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