Plant virus disease control

The use of antibiotics for the control of plant virus diseases( ) is of interest. Several antibiotics have been tested for inhibition of replication of viral nucleic acid and/or protein synthesis within the host cell. Chloramphenicol, cycloheximide, actinomycin D and others are the most used antibiotics and the disease caused by tobacco mosaic... 

The pest control situation in California and Florida is reviewed, with particular attention to mechanical developments and the introduction of new fungicides and insecticides, such as the insoluble coppers and parathion, and the outstanding unsolved problems such as control for nematodes which will not injure the plant and the need for a systemic material which will control virus diseases. Emphasis is on needed lines of investigation. Pest control problems in Central America, the Caribbean Islands, and South America are discussed, with special reference to lack of suitable equipment and material because of dollar exchange problems. 

The time-honored method of controlling insect-borne virus diseases is by breeding resistant varieties. This has been practical in annual crops, but is hopelessly slow in tree crops, where it may take 20 years or more to test a new variety. What is needed desperately is some sort of treatment which will control the virus, probably a systemic treatment, as the virus works within the plant cells. This is not a new idea and work has been done along this line by many workers. A sense of urgency is inevitable, however, when 500 to 600 acres of citrus can be wiped out completely in 3 to 5 years time, followed by an expensive replanting job and a wait of 5 to 6 years to get back into production. This is the outstanding problem at the present time and may need years to answer. 

Do everything you can to prevent disease, as it can spread rapidly. Virus diseases are very difficult to control and affected plants should be removed and composted as soon as you notice them. The risk of infection by some fungal diseases can be reduced by raising the pH of the soil with lime (seep.55). Crop rotation (see pp.230-233) also plays an important role in reducing the severity of other soilborne diseases and some pests. 

It is often said that when a suspected virus disease may be controlled by antibiotics(Table 3), the cause of the diseases must be mycoplasma and never a virus. This arbitrary statement segregating viruses from mycoplasma has many times been held valid, but there remain several other instances where application of antibiotics to the host plant has reduced the pathogenesis of viruses to a considerable degree(69-70). 

One of the most serious problems on plant disease control is the virulence of virus diseases. Trials to develop antiviral antibiotics have been enthusiastically conducted by many workers. Consequently, many antibiotics have been revealed to be effective on inhibiting the multiplication of several plant viruses by in vitro test and pot test. They are blasticidin S, laurusin, bihoromycin, miharamycin, citrinin and aabomycin A etc. However,... 

Virus diseases cannot be controlled. The highest priority must therefore be given to ensuring that the planting stock is clean. Even so, re-infection often cannot be ruled out in the case of many virus diseases, e.g. plum pox in plums and apricots. 

Leaves and flowers greenish yellow, distorted new growth spindly. Cause Viral diseases. Chrysanthemums are prone to several viruses, which are spread by sucking insects such as aphids and leafhoppers. Control such pests to limit virus problems. Remove and destroy infected plants do not compost them. Wash tools used around infected plants. Viruses overwinter in perennials and weeds such as daisies and plantains. 

Sometimes it is possible to avert viruses by controlling insects that spread the disease. But good control of the insect is necessary, and you must keep the insect from the plant or kill it before it has a chance to inject virus particles into the sap. You can protect your... 

Soil organic matter is not known to play any appreciable role in either the spread or control of air-borne virus diseases. This is an obvious statement since these viruses are obligate parasites on green plants and the vectors are insects. There is more likelihood that soil organic matter plays a role, even if a minor one, in soil-borne virus diseases since the vectors are nematodes, fungi and probably other forms of life that feed in part on decaying crop residues. 

Tobacco is an important economic crop and a model plant for research. Many reports reveal that CTS can induce tobacco s resistance to tobacco mosaic virus (TMV), tobacco necrosis virus (TNV), and Phytophthora parasitica nicotianae. For example. Falcon studied the effect of different sizes and deacetylation degrees of chitosan derivatives on tobacco protection against P. parasitica (Falcon et al. 2008). The result of their experiment showed that different chitosans have distinct effects on this disease control though less acetylated chitosan are better for inhibition of P. parasitica... 

Northern Ireland and the hill areas of England and Wales where substantial seed potato enterprises still continue. The main advantages of these areas ate that the low temperatiues and strong winds keep aphid populations in check. This means that the severe virus diseases (leaf roll and the mosaics) which are spread from diseased to healthy plants by aphids, are less likely to occur. However, recent advances in aphid control and concerns over the quality of seed from some traditional areas have seen successful seed production extended to some of the English arable areas as a profitable break in predominantly cereal and break crop rotations. As with other forms of seed production the certifying authority in England and Wales is FERA, for Scotland SASA (Science and Advice for Scottish Agriculture) and DARD in Northern Ireland. In all cases the same basic Seed Potato Classification Scheme (SPCS) obtains. 

Humans, plants, insects, and other animals are all susceptible to viral infection therefore, prevention and control of viral disease carry important health and economic implications. The common cold, acquired immune deficiency syndrome (AIDS), and some cancers are carried by viruses. Viral plant diseases are known to impact fruit trees, tobacco, and many vegetables [1]. Both insects and animals have the ability to transfer viral disease to humans and other animals. The health and economic consequences of viral disease carry enormous consequences, and significant advances have been made toward amelioration of antiviral threats. There is a critical need to identify novel drug classes and new chemical structures, which can be exploited for antiviral drug development. 

Leaves puckered and curled downward plant dwarfed. Cause Curly top virus. Remove and destroy infected plants. Prevent problems by controlling aphids that spread the disease and by planting resistant or tolerant cultivars such as Goldcrop , Great Northern , and Hystyle . 

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