Presumed virus particles mostly occur in parenchyma cells of the lesion in affected orange leaves, fruits or stems. Particles are short, bacilliform, 120-130 nm long (occasionally up to 300 nm) and 50-55 nm wide. They occur within the lumen of the endoplasmic reticulum (Kitajima et al., 1974, Colariccio et al., 1995). There is a report of similar but unenveloped particles in the nucleoplasm (Kitajima et al., 1972).;In addition to the presence of the rhabdovirus-like particles within the endoplasmic reticulum of tissues from the lesion, dense viroplasm-like material is commonly found in the cytoplasm, near the particles. Small vesicle-containing fibrillar materials are frequently present in the vacuole, associated with the tonoplast, next to the dense material (Kitajima et al., 1972, Colariccio et al., 1995).;Chloroplasts are usually affected with a disorganized hypertrophied lamella system (Kitajima et al., 1972, Rodrigues, 1995). There is a report in which rod-like particles, considered to be naked rhabdovirus particles accumulate in the nucleoplasm associated with the nuclear envelope (Kitajima et al., 1972).
FACTSHEETS FOR FARMERS www.plantwise.org Created in Kenya , September 2011 Coffee wilt disease Recognize the problem Coffee wilt disease can kill coffee plants. At first, the leaves of affected plants become yellow, wilt, shrivel and fall off. The disease causes blue-black staining of the wood below the bark " ganda ". Finally, the tree loses all leaves and dies. Background Coffee wilt disease is caused by a fungus which spreads quickly within the tree. It will also spread from diseased trees to healthy trees in planting material, water, soil...
EENY-214 Mediterranean Fruit Fly, Ceratitis capitata (Wiedemann) (Insecta: Diptera: Tephritidae) 1 M. C. Thomas, J. B. Heppner, R. E. Woodruff, H. V. Weems, G. J. Steck, and T. R. Fasulo 2 1. This document is EENY-214 (originally published as DPI Entomology Circulars 4, 230 and 273, updated for this publication), one of a series of the Department of Entomology and Nematology Department, UF/IFAS Extension. Original publication date July 2001. Revised October 2007, June and September 2010, and October 2016. Visit the EDIS website at http://edis.ifas.ufl.edu . This document is also...
Photo 1. Adult coffee bean borer, Hypothenemus hamperi, about 1.5 mm long and covered with stiff hairs. Photo 2. Adult Hypothenemus hampei, about 1.5 mm long, showing its relative size to a coffee bean. Photo 3. The life cycle of the coffee bean borer, Hypothenemus hamperi, takes place in the coffee bean; this photo shows the frass that accumulates as the larvae and adults eat the beans. Photo 4. Coffee beans damaged by the coffee bean borer, Hypothenemus hamperi. Even a few bored beans lower quality, and if the consignment is not dried properly the beetles will continue to breed...
JULY, 1958] HELMINTHOLOGICA L SOCIET Y 13 3 On th e Morpholog y of th e Coffe e Root-Kno t Nematode, Meloidogyne exigua Goeldi, 1887* LUIZ GONZAG A E. LORDELL O AND ADIE L PAES IjEM E ZAMIT H Escola Superio r de Agricultur a "Luiz de Queiroz, " Universit y of S . Paulo , Piracicaba , Brazil The firs t recor d on nematode s attacking root s of coffe e trees in Brazi l was publishe d by Jober t in 1879 . Som e years later , Goeld i (1887) stated that the primar y cause of a diseas e affectin g coffee plantation s at th e so-calle...
W or ki ng P ap er Climate change impacts on African crop production Working Paper No. 119 CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) Julian Ramirez-Villegas Philip K Thornton 1 Climate change impacts on African crop production Working Paper No. 119 CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) Julian Ramirez-Villegas Philip K. Thornton 2 Correct citation: J Ramirez-Villegas, Thornton PK 2015. Climate change impacts on African crop production. CCAFS Working Paper no...
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Round to elliptical local lesions are seen on fruits, leaves and twigs. The severity of the lesions varies with the type of citrus and the region of origin. Leaf symptoms are usually round with a dark-brown central spot about 2-3 mm diameter, surrounded by a chlorotic halo, in which 1-3 brownish rings frequently appear surrounding the central spot, the overall lesion size varies from 10 to 30 mm, though larger lesions may form by the fusion of 2 or more adjacent lesions.;On fruits, lesions are necrotic spots 10-20 mm in diameter, with a necrotic centre. Gum exudation is occasionally observed on the lesion. On green fruits, the lesions are initially yellowish, becoming more brown or black, sometimes depressed, and reducing the market value of the fruits.;On stems, lesions may be protuberant, cortical, grey or brown. Lesions may coalesce when present in large numbers, leading to the death of the twig. In extreme cases observed in different places (JCV Rodrigues, personal communication), as described initially in 'lepra explosiva' in Argentina, severe defoliation and fruit fall may occur (Frezzi, 1940, Bitancourt, 1955, Rossetti et al., 1969).;Citrus leprosis lesions are usually very characteristic, but may sometimes be mistaken for lesions of citrus canker caused by the bacterium Xanthomonas axonopodis pv. axonopodis, or zonate chlorosis (Rossetti, 1980). Zonate chlorosis, which is associated with infestation by the same mites, does not become necrotic. Symptoms are essentially concentric green and chlorotic rings (Bitancourt, 1934).;Other viral diseases are vectored by Brevipalpus phoenicis in Brazil. Coffee ringspot virus in Coffea arabica (Chagas, 1978), Ligustrum ringspot virus in Ligustrum lucidum (Rodrigues et al., 1995), and green spot of passion fruit in Passiflora edulis (Kitajima et al., 1997). In addition, Brevipalpus californicus is a vector of Orchid fleck virus in orchids (Maeda et al., 1998). However, cross-transmission was not described among these viruses and leprosis.
S. verticillata is an annual, or more usually perennial. Stems straggling, to 100 cm or more, glabrous or nearly so, usually erect and simple or sparsely branched, often copiously branched from the base, usually 40 cm high or less, the stems tetragonous. Stipule sheath very short, the setae about 1.5 mm long;leaves glabrous, sessile or nearly so, linear or lanceo-linear, mostly 1.5-4 cm long and 1.5-6 mm broad, commonly 1-veined, often with fascicles of smaller leaves in the axils. Flowers white, very small in sessile clusters at the upper stem nodes or more usually terminal, then the heads subtended by 2 or 4 leaf-like bracts. Hypanthium pilose above, the 2 sepals narrowly triangular, 1.5 mm long or less. Corolla of 4 petals, 3 mm long, hispidulous outside at the apex, the lobes about equalling the tube;anthers exserted. Capsule 2.5 mm long;seeds reddish brown about 1 mm long (PIER, 2016).
S. verticillata is a scrambling annual or perennial native to the Americas. It has been introduced widely but sporadically across Asia and the Pacific and to tropical Australia. It can grow on a wide range of land types but often requires disturbance to establish. S. verticillata can form large clumps which can smother other vegetation. In its native range it has been recorded as a significant weed of agricultural crops, for example in the Caribbean it is a problem of sugarcane, vegetables and root crops (Fournet and Hammerton, 1991). In addition to this, on St Helena, it is among the exotic plants threatening the critically endangered fern, Pteris adscensionis.
In a number of countries S. verticillata has been shown to have a negative impact on agricultural crops such as Coffea arabica, Oryza sativa, Phaseolus vulgaris, Saccharum officinarum, Theobroma cacao, Vigna unguiculata Manihot esculenta and Zea mays (Fournet and Hammerton, 1991;Holm, 1997;Johnson, 1997;Marques et al., 2011;Cherigo et al., 2012).