Management of plant virus and viroid diseases is a matter of vital importance and concern to the farmer, horticulturist, forester and gardener. It is well established that the virus and viroid diseases in different crops cause enormous losses in terms of quantity and quality of products (see Chapter-3 of Volume-I) (Sastry 2013b). Because of the serious losses they cause to agriculture and horticulture, virus/viroid diseases have acquired great importance in the realm of plant pathology and call for effective management measures against them. These diseases are not amenable to control by direct methods. Unlike fungicides and bactericides, no commercial viricides have yet been developed. However a number of indirect control measures for different crop plant-virus/viroid pathosystems suitable to varied agro ecosystems have been developed with an aim to avoid the pathogen or to minimize their impact on crop yields (Thresh 2003, 2006). As these diseases routinely cause systemic infections and have very effective methods of transmission, preventing their spread has become a complicated problem. Some diseases like Tobacco mosaic virus (TMV), Potato virus X (PVX), Cucumber green mottle virus (CGMMV), Citrus exocortis viroid (CEVd) and Potato spindle tuber viroid (PSTVd) are highly contagious and affect large number of hosts belonging to several families.

background

Occurrence of pea seedborne mosaic virus and new virus-immune germplasm in the plant introduction collection of Pisum sativum.

Management of Virus and Viroid Diseases of Crops in the Tropics

Some 44 viruses have been reported from naturally infected plants of pea (28), lentil (9), faba bean (32), and chickpea (9). These viruses differ ecologically and thus their control requires a variety of preventive measures. Several infect other crops, notably widespread clover species, which frequently constitute natural reservoirs of virus inoculum and from which insect vectors transmit them to crop plants. A number of viruses perennate in seeds or in wild-plant species and may be disseminated long distances in infected seeds. Localized spread from weeds or seed-infected crop plants is usually accomplished by vectors. Crops may suffer substantial yield losses from virus infections. The extent of crop damage, however, is generally dependent on plant genetic susceptibility to viruses (and virus complexes) or on plant sensitivity to virus infection. Precise methods for detecting, identifying, and characterizing viruses are an essential prerequisite to disease-control measures. Effective virus-disease control generally requires combinations of measures. For example, hygienic measures, including use of virus-tested, certified seed, spatial separation from recognized virus inoculum sources, and control of vector populations should be combined with development of virus resistance or disease tolerance, through selection and breeding. Crop impovement to meet current world food legume needs is increasingly dependent upon international, interdisciplinary approaches to research.

Viruses and virus diseases of pea, lentil, faba bean and chickpea

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Pea seed-borne mosaic virus : a review Ravinder Kumar Khetarpal, Yves Maury

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Pea seed-borne mosaic virus : a review

The Plant Viruses

Two potyvirus isolates from endive, originating from southern France (Ls252) and from the Netherlands (Ls265), that were highly and poorly pathogenic on lettuce, respectively, were compared with a common isolate (Ls1) of lettuce mosaic virus (LMV) and with two highly deviant Greek isolates fromHelminthia (Picris) echioides (Gr4) and endive (Gr5), earlier recognized as LMV. The isolates could not be distinguished by particle morphology and serology, and were all identified as LMV. Leaf curling, plant stunting and necrosis were more characteristic of the virus than mosaic. The isolates studied varied considerably on differential host species and a range of lettce cultivars including pathotype differentials of Pink et al. [1992b]. Ls1 and Ls265 reacte largely as pathotype II, including the ‘common strain’ of the virus, but Ls265 was least pathogenic on lettuce. Ls252 fitted pathotype IV and was very similar to LMV-E (the ‘Spanish strain’). The Greek isolates were very similar to each other in causing very severe symptoms on some non-lettuce hosts and a number of lettuce cultuvars. In lettuce variectal reaction Gr4 resembled pathotype I, but Gr5 severely affected ‘Salinas 88’, resistant to pathotypes I, II and III, and it appears to be a novel pathotype. Genetic interaction between lettuce and LMV is not following a simple yes-or-no pattern, and it is not a mere matter of resistance versus susceptibility. Adoption of a more realistic resistance terminology is proposed. None of the lettuce cultivars tested was resistant to the most pathogenic isolate Ls252, but resistance to it was found in 2 out of 12 wildLactuca species tested (Lactuca perennis andL. tatarica) while the symptomless plants ofL. perennis clearly reacted in ELISA.

Occurrence of pea seedborne mosaic virus and new virus-immune germplasm in the plant introduction collection of Pisum sativum.

Citations

Management of Virus and Viroid Diseases of Crops in the Tropics

Viruses and virus diseases of pea, lentil, faba bean and chickpea

Pea seed-borne mosaic virus : a review

The Plant Viruses

Further observations on variation of lettuce mosaic virus in relation to lettuce (Lactuca sativa), and a discussion of resistance terminology.

Related Papers (2)

A Seed-Borne Mosaic Virus of Pea

Inheritance of resistance to the pea seed-borne mosaic virus.