Clavibacter XYLI subsp. XYLI. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
Geographical Distribution ◽  
Sugar Cane ◽  
Normal Growth ◽  
Saccharum Officinarum ◽  
Imperata Cylindrica ◽  
Pennisetum Purpureum ◽  
Panicum Maximum ◽  
Vascular Bundles ◽  
Serological Method ◽  
Planting Material

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.

Xanthomonas albilineans. [Descriptions of Fungi and Bacteria].

2000 ◽  
Author(s):  
G. S. Saddler
Keyword(s):  
Geographical Distribution ◽  
Chronic Phase ◽  
French Polynesia ◽  
Imperata Cylindrica ◽  
Disease Spread ◽  
Pennisetum Purpureum ◽  
Panicum Maximum ◽  
White Line ◽  
Bambusa Vulgaris ◽  
Xanthomonas Albilineans

Abstract A description is provided for Xanthomonas albilineans. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Bambusa vulgaris, Coix lacryma-jobi, Cymbopogon citratus, Saccharum officinarum, S. spontaneum, Sorghum halepense, Zea mays (Poaceae). Wild hosts: Brachiaria piligera, Imperata cylindrica, Panicum maximum, Paspalum conjugatum, P. dilatatum, Pennisetum purpureum, Rottboellia cochinchinensis (Poaceae). DISEASE: Leaf scald of sugarcane, considered to be one of the major diseases of this host. Two disease phases have been recorded: chronic and acute. In the chronic phase a typical white line (1-2 mm wide) runs parallel to the leaf veins almost the entire length of the leaf. Latterly, lines may become diffuse and redden, particularly in the middle of the stripe. Partial or total chlorosis of leaves occurs (scalding) and is accompanied by an inward curling. In the acute phase of the disease, sudden plant death occurs with few or no symptoms. The disease can remain dormant until environmental conditions are favourable for symptom expression. GEOGRAPHICAL DISTRIBUTION: AFRICA: Benin, Burkina Faso, Cameroon, Chad, Congo Democratic Republic, Congo, Ghana, Ivory Coast, Kenya, Madagascar, Malawi, Mauritius, Morocco, Mozambique, Nigeria, Réunion, South Africa, Swaziland, Tanzania, Zimbabwe. NORTH AMERICA: USA (Florida, Hawaii, Louisiana, Texas). CENTRAL AMERICA: Barbados, Belize, Cuba, Dominica, Dominican Republic, Grenada, Guadeloupe, Guatemala, Jamaica, Martinique, Mexico (Vera Cruz), Panama, Puerto Rico, St Kitts & Nevis, St Lucia, St Vincent & Grenadines, Trinidad & Tobago. SOUTH AMERICA: Argentina, Brazil (Säo Paulo, Sergipe), Colombia, Ecuador, French Guiana, Guyana, Suriname, Uruguay, Venezuela. ASIA: Cambodia, China, Taiwan, India (Andhra Pradesh, Uttar Pradesh), Indonesia (Java, Sulawesi), Japan, Malaysia, Myanmar, Pakistan, Philippines, Sri Lanka, Thailand, Vietnam. AUSTRALASIA: Australia (New South Wales, Queensland), Fiji, French Polynesia, Papua New Guinea. TRANSMISSION: Primarily on infected cuttings and fluffs (mature flowers). The use of contaminated tools and harvesters aids local spread. Airborne infection has occurred and wet and stormy conditions are highly conducive to disease spread. Root to root infections have also been recorded (KLETT & ROTT, 1994).

Xanthomonas axonopodis. [Descriptions of Fungi and Bacteria].

1977 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
Geographical Distribution ◽  
Seed Transmission ◽  
Saccharum Officinarum ◽  
Vascular Bundles ◽  
Xanthomonas Axonopodis ◽  
Digitaria Decumbens ◽  
Pasture Grasses ◽  
Tropical America ◽  
Rain Splash ◽  
Short Time

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).

scholarly journals Actual and potential photosynthetic rates of tropical crop species

2001 ◽  
Vol 13 (1) ◽  
pp. 24-32 ◽  
Author(s):  
FÁBIO M. DA MATTA ◽  
RODOLFO A. LOOS ◽  
RODRIGO RODRIGUES ◽  
RAIMUNDO S. BARROS
Keyword(s):  
Average Rate ◽  
Photosynthetic Apparatus ◽  
Saccharum Officinarum ◽  
Oxygen Electrode ◽  
Pennisetum Purpureum ◽  
Panicum Maximum ◽  
Crop Species ◽  
Photosynthetic Rates ◽  
Tropical Crop ◽  
Group A

The actual (A) and potential (Apot) photosynthetic rates of C3 and C4 tropical crop species grown under greenhouse conditions was compared. The following species were investigated: Oryza sativa, Phaseolus vulgaris, Glycine max, Helianthus annuus, Gossypium hirsutum, Manihot esculenta, Theobroma cacao, Coffea arabica, Hevea brasiliensis, and Eucalyptus urophylla × E. grandis, all from the C3 group, and Amaranthus sp., Panicum maximum, Pennisetum purpureum, Zea mays and Saccharum officinarum, from the C4 group. A, determined under non-limiting light at ambient temperature and CO2, was measured with an infrared gas analyser, whilst Apot, determined under saturating light and CO2 at an optimal temperature (35 ºC for all species), was gauged with a gas-phase oxygen electrode. On an area basis, A varied from 5.0 up to 26.3 mumol CO2 m-2 s-1, whilst Apot was very similar in 14 of the 15 species, with an average rate of 35.0 ± 2.4 mumol O2 m-2 s-1. The value of Apot in T. cacao was approximately half the mean of the remaining species. On a mass basis, variations in A were much larger, and differences in Apot, although not large, emerged. The overall mean Apot per unit mass in the four tree species was 28.0 ± 2.2 mumol O2 g-1 min-1 against 44.6 ± 5.8 mumol O2 g-1 min-1 in the remaining species. As a whole, the results evidenced a conservative behaviour of the photosynthetic apparatus to fix CO2 amongst the species investigated, despite the large differences in A among them.

Drechslera sacchari. [Descriptions of Fungi and Bacteria].

1971 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Geographical Distribution ◽  
French Guiana ◽  
Toxin Production ◽  
Saccharum Officinarum ◽  
Pennisetum Purpureum ◽  
Leaf Spots ◽  
Lemon Grass ◽  
Axis Parallel ◽  
Young Leaves ◽  
The Tropics

Abstract A description is provided for Drechslera sacchari[Bipolaris sacchari]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Saccharum officinarum and also reported causing diseases in Pennisetum purpureum (Napier or elephant grass) and Cymbopogon citratus[Cymbopogon nardus] (lemon grass). DISEASE: Eye spot and seedling blight of sugarcane. Small reddish spots, surrounded by a straw-coloured halo, develop on the leaves; conspicuous on young leaves, becoming 5-12 × 3-6 mm, longer axis parallel to the main veins, coalescing. These spots may develop long chlorotic streaks running towards the leaf tip, 60-90 cm long and possibly due to toxin production. Germinating seed may be killed 12-14 days from sowing and severely attacked young plants show a top rot. On lemon grass the leaf spots have pale centres with a dark purple border, 4-10 × 1.5-2 mm (20: 229). Older leaves of Napier grass are attacked most, severe outbreaks causing death (17: 753; 21: 258). GEOGRAPHICAL DISTRIBUTION: Widespread in the tropics and subtropics (CMI Map 349, 2nd ed. 1968). Additional records not yet mapped: Cambodia, French Guiana, Panama, Salvador and Senegal. TRANSMISSION: Presumably through air-dispersed conidia; seed-borne infection also occurs (36: 350).

Xanthomonas vasculorum. [Descriptions of Fungi and Bacteria].

1973 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
Geographical Distribution ◽  
Vascular Tissue ◽  
Cocos Nucifera ◽  
New Guinea ◽  
Pathogen Transmission ◽  
Pennisetum Purpureum ◽  
Panicum Maximum ◽  
Resistant Varieties ◽  
Terminal Bud ◽  
Bambusa Vulgaris

Abstract A description is provided for Xanthomonas vasculorum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Saccharum officinarum. Also found naturally infecting Zea mays, Dictyosperma album, Thysanolaena maxima, Roystonea regia and Areca catechu. In addition to these, infection has beer; obtained after artificial inoculation on Bambusa vulgaris, Brachiaria mutica, Cocos nucifera, Coix lachyrma-jobi, Panicum maximum, Pennisetum purpureum, Sorghum halepense, S. verticilliflorum, 20: 381, S. vulgare, S. vulgare var. sudanense, Sorghum spp. (18, 710; 20, 381; 43, 218). DISEASE: Gumming disease or gummosis of sugarcane. On leaves, yellowish chlorotic stripes occur. These may be the only symptoms on the more resistant varieties. On other varieties they may become spotted with brownish spots that become necrotic with age. The necrosis may involve large areas of leaf. The vascular tissue of the stem becomes darkened and contains bacterial slime. In very susceptible varieties the yellow slime may also form below the terminal bud and sometimes interferes with the development of the top of the plant. The tops often die and the terminal bud decays. GEOGRAPHICAL DISTRIBUTION: Recently reported in the following countries: Africa: Ghana, Madeira, Malagasy Republic, Malawi, Mauritius, Mozambique, Reunion, Rhodesia, South Africa; North America: Mexico; Central & South America: Puerto Rico, Argentina, Brazil, Colombia, French Guiana, Far East: New Guinea; Hughes (34, 487) considers that the pathogen may not be present in New Guinea (CMI Map 3, ed. 5, 1971). The disease has been observed in the past in 25 or more countries where sugarcane is grown (48, 3137k; 50, 915y). In some it is claimed to have been eradicated and in others it has not been seen for many years. It may be that the local conditions and use of resistant varieties have combined to eradicate the pathogen. TRANSMISSION: Introduction into new areas and countries is by planting diseased setts or cuttings. Healthy setts may be infected from diseased ones during planting by means of the cutting knife. Agricultural tools, workers, vehicles, animals and even insects may carry inoculum from field to field. The most rapid and important local spread, however, is from plant to plant by wind-driven rain. Fresh wounds are needed for entry of the pathogen, but these are available, especially in windy weather, as a result of leaves rubbing together. The saw-tooth edges of the leaves cause many tiny abrasions (North, 1935; Hughes, 1961).

Eudarluca caricis. [Descriptions of Fungi and Bacteria].

2001 ◽  
Author(s):  
M. Rodríguez Hernández
Keyword(s):  
Puerto Rico ◽  
North America ◽  
South America ◽  
Central America ◽  
Geographical Distribution ◽  
New Caledonia ◽  
Biological Control Agent ◽  
Pennisetum Purpureum ◽  
Panicum Maximum ◽  
North Borneo

Abstract A description is provided for Eudarluca caricis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Hyperparasitic on rust pustules. This species has been discussed as a potential biological control agent by various authors (PELHATE, 1961, and SEBESTA, 1963, according to ERIKSSON, 1966; GONZÁLEZ & CASTELLANOS, 1978). HOSTS: On many rust species (including Kuehneola malvicola, Phakopsora gossypii, Peridermium peckii, Puccinia cynodontis, P. fimbristylidis, P. gouaniae, P. huberi, P. levis, P. liberta, P. melampodii, P. melanocephala, P. polysora, P. purpurea, P. raunkaerii, P. sorghi, P. thaliae, Puccinia sp., Uredinales fam. indet., Uredo aeschynomensis, U. kyllingiae, U. commelinae, U. costaricensis, U. phaseoli, U. setariae-italicae, U. tenuicutis) associated with the following plants: Allium ampeloprasum, A. schoenoprasum (Alliaceae), Canna coccinea, C. glauca (Cannaceae), Commelina elegans (Commelinaceae), Centaurea scabiosa, Synedrella nodiflora, Wedelia rugosa (Compositae), Carex sp., Cyperus odoratus, Cyperus sp., Eleocharis interstincta, Eleocharis sp., Fimbristylis diphylla, Kyllinga sp., Rhynchospora micrantha (Cyperaceae), Andropogon sp., Arachis hypogaea, Cynodon dactylon, Digitaria decumbens, Eriochloa polystachys, Lasiacis divaricata, Panicum maximum, P. purpurascens, P. trichoides, Paspalum plicatulum, Pennisetum purpureum, Phragmites communis, Rhynchelytrum roseum, Sorghum bicolor, S. halepense, S. vulgare, Sporobolus indicus, Tripsacum laxum, Zea mays (Gramineae), Aeschynomene americana, Inga vera, Phaseolus vulgaris (Leguminosae), Althaea rosea, Gossypium barbadense, Hibiscus syriacus (Malvaceae), Rivina humilis (Phytolaccaceae), Gouania lupuloides (Rhamnaceae), Persica vulgaris, Potentilla canadensis, P. verna (Rosaceae), Salix fragilis, S. purpurea (Salicaceae). GEOGRAPHICAL DISTRIBUTION: Ubiquitous. Records of the anamorph are as follows. AFRICA: Algeria. NORTH AMERICA: Canada, USA (NAG RAJ, 1993). CENTRAL AMERICA: American Virgin Islands (SEAVER, 1924, 1925), Cuba (COOK, 1906), Puerto Rico. SOUTH AMERICA: Argentina, Brazil. Ecuador. Venezuela (CHARDÓN & TORO, 1934). AUSTRALASIA: New Zealand. EUROPE: Austria, former Czechoslovakia, France, Germany. Records of the teleomorph are as follows. AFRICA: Ghana, Guinea, Kenya, Libya, Malawi, Nigeria, Sierra Leone, South Africa, Sudan, Tanzania, Togo, Uganda. NORTH AMERICA: USA. CENTRAL AMERICA: Costa Rica, Dominican Republic, Jamaica, Puerto Rico. SOUTH AMERICA: Argentina, Brazil, Guyana [as British Guiana], Ecuador, Venezuela (ERIKSSON, 1966). ASIA: China, India, Japan, Malaysia (including North Borneo), former USSR. AUSTRALASIA: New Caledonia, Papua New Guinea. EUROPE: Austria, Belgium, Finland, France, Germany, Sweden, Switzerland. TRANSMISSION: By air-borne conidia.

Ustilago scitaminea. [Descriptions of Fungi and Bacteria].

1965 ◽  
Author(s):  
G. C. Ainsworth
Keyword(s):  
Zea Mays ◽  
Geographical Distribution ◽  
Saccharum Officinarum ◽  
Imperata Cylindrica ◽  
Comprehensive Account ◽  
Ustilago Scitaminea

Abstract A description is provided for Ustilago scitaminea. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Saccharum officinarum (sugarcane), S. barberi, S. spontaneum (Kens grass) and (fide McMartin, 24: 290) in S. Africa the wild grasses Imperata arundinacea[Imperata cylindrica] and Erianthus saccharoides. Zea mays (maize) has been experimentally infected by Hirschhorn (44: 686). DISEASE: Sugarcane smut. See Antoine (1961) for a comprehensive account. GEOGRAPHICAL DISTRIBUTION: Africa (Egypt, E. and S. Africa, Madagascar), Asia (widespread), S. America, and elsewhere; absent from N. America and Australia; see CMI Map, 79, Ed. 2, 1960. TRANSMISSION: Infection is by air borne spores. The spores germinate easily and under moist conditions soil borne infection is not considered to be a hazard.

Gloeocercospora sorghi. [Descriptions of Fungi and Bacteria].

1971 ◽  
Author(s):  
J. L. Mulder
Keyword(s):  
Sorghum Bicolor ◽  
Geographical Distribution ◽  
Cynodon Dactylon ◽  
Pennisetum Glaucum ◽  
Saccharum Officinarum ◽  
Pennisetum Purpureum ◽  
Agrostis Palustris ◽  
Vetiveria Zizanioides ◽  
Sorghum Vulgare ◽  
Agrostis Canina

Abstract A description is provided for Gloeocercospora sorghi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Sorghum vulgare[Sorghum bicolor]; besides the main host it has been reported from Agrostis canina (bent grass), Agrostis palustris, Agrostis tenuis, Cynodon dactylon, Pennisetum glaucum, Pennisetum purpureum, Pennisetum typhoides, Saccharum officinarum, Sorghum halapensis, Sorghum sudanense, Vetiveria zizanioides, Zea mays. DISEASE: Zonate leaf spot was first reported from Sorghum vulgare[Sorghum bicolor] in 1943 from Louisiana; on turf grasses it is known as copper spot. On sorghum the initial lesions are red-brown, water-soaked and sometimes with a narrow, pale green halo. The lesions enlarge, become dark-red (on some vars. dark brown) and elongate parallel to the veins. Possibly by coalescence, semi-circular, irregular lesions (several cm diam.) are formed. Smaller spots have a light brown centre surrounded by a reddish border, but larger ones may have alternate light and dark zones, and the whole leaf can be covered. Often younger, red lesions are so numerous as to form red blotches. The pinkish, gelatinous, conidial fructifications (over the stomata) are easily visible. Spherical sclerotia (0.1-0.2 mm diam.) form within the tissue, in a somewhat linear fashion. On bent grass small, irregular, copper tinted spots become coalescent. GEOGRAPHICAL DISTRIBUTION: Widespread in tropical Africa, also in south west USA, parts of C. & S. America, India, Japan and N.E. Australia, (CMI Map 339, ed. 2, 1969). TRANSMISSION: Probably soil-borne in crop residue and also seed-borne (29: 556). Infected seed may have caused an outbreak in Venezuela (29: 97).

The Lepidopterous Stalk Borers associated with Gramineae in Uganda

1958 ◽  
Vol 49 (2) ◽  
pp. 367-383 ◽  
Author(s):  
W. E. Ingram
Keyword(s):  
Sugar Cane ◽  
Host Plants ◽  
Finger Millet ◽  
Crop Residues ◽  
Dry Season ◽  
The Other ◽  
Pennisetum Purpureum ◽  
Cereal Crops ◽  
Panicum Maximum ◽  
The North

SummaryThe Lepidopterous stalk borers that occur in Uganda in association with the Gramineae were studied there during 1954–1956 by collecting on all likely host-plants at two centres and by a country-wide survey in which stalk-borer damage in cereal crops was qualitatively assessed at five-mile intervals along the routes followed, and the species of borer present in such crops and, where possible, in nearby wild host-plants were determined. The commonest Noctuids were Busseola fusca (Fuller), B. segeta Bowden, Sesamia calamistis Hmps. and S. poephaga Tanas & Bowden. All these attacked sorghum, maize, sugar-cane and (except the last) finger millet (Eleusine coracana.); so also did S. botanephaga Tarns & Bowden, but only near swamps, in which it infested sedges (Cyperus spp.) and reeds (Typha australis), from which the other species were virtually absent. Only S. calamistis and S. botanephaga attacked rice. All attacked Pennisetum purpureum, Sorghum vertictlliflorum, Vossia cuspidata, and (except S. botanephaga) Panicum maximum, and also other wild grasses.B. fusca is widely distributed but most abundant in areas of intensive cultivation, where crop residues abound in which the resting larvae can survive the dry season. B. segeta is the most frequent species in Pennisetum purpureum and Panicum maximum, which are extremely common over most of the country, but is rare in cereal crops. S. calamistis (to which earlier records of S. cretica (Led.) and S. vuteria (Stoll) must be attributed) is not numerous but occurs in every district except Karamoja, where it cannot survive the dry season; and S. poephaga is known only from northern and eastern districts and is unimportant.Chilo zonellus (Swinh.), which may be a recent introduction, occurs in all the cultivated host-plants and most of the wild ones except Cyperus and Typha; it has not been found at altitudes above 4,000 ft. in the west or 5,000 ft. in the north and east, but elsewhere it is the prevalent borer and can cause severe damage in dry years and on out-of-season crops. It was the only species besides B. fusca found on bulrush millet (Pennisetum typhoides), the tough stem of which resists attack. On the western border, Eldana saccharina Wlk. attacks sorghum, maize and sugar-cane at high altitudes, and Maliarpha separatella Rag. attacks rice. A fourth Pyralid, Pectinigeria sp., occurs on maize.When small plots of host-plants were grown in a matrix of sorghum, and also in a swamp, and the whole sampled at harvest for borer infestation, all the cultivated hosts and many of the wild ones suffered some attack, the percentage of stems bored varying from 10 (finger millet) to 89 (sorghum) amongst the former, and reaching 34 (Panicum maximum), 40 (Sorghum verticilliflorum) and 50 (Pennisetum purpureum) amongst the latter. Immature stages of C. zonellus and B. fusca greatly outnumbered those of Sesamia, especially in the more heavily infested host-plants.Notes are given on the life-histories of the commoner species of borer and on their habits in the field. In the laboratory, the lengths of the life-cycles, in days, were 68–75 (B. fusca), 65–78 (B. segeta), 46–58 (S. calamistis) and 46–53 (C. zonellus). In the dry season, the larvae of B. fusca entered a resting stage, which prolonged the life-cycle to 200 days; such larvae were found only in living or dry stems of crop plants. C. zonellus and Sesamia spp. bred continuously, in the dry season the former being found chiefly in trash, stubble and volunteer tillers of sorghum, the latter in these and living stems of grasses.Of the principal cereal crops in Uganda, sorghum is the most widespread. The main crop, sown after the longer of the two dry seasons, suffers little borer attack; second crops are more severely affected, but plants with thick stems or numerous tillers nevertheless yield heavily. Finger millet is the staple food crop in the north and west; borer damage is negligible and restricted to small patches of “dead-hearts” caused by larvae from single egg-masses of S. calamistis. Maize is grown on a large scale in the districts bordering Lake Victoria and in the highlands; borer attack is usually very late and, where rainfall is adequate, appears not to afiect yields.Apanteles sesamiae Cam. and another, unidentified, Braconid probably control S. calamistis, but on the other stalk borers the incidence of parasites, which are listed, is low. Destruction of all crop residues and wild species of Sorghum around cultivated areas would considerably reduce borer attack at the beginning of the growing season, but chemical control was only partly effective and did not increase the yield.

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