Control

Once the contamination has occurred , there is no way of getting rid of the virus ,short of destroying the infected plant. So extreme care should be taken in order to keep away infection . But only healthy looking plants; if there is any suspicion of infection , immediately test on susceptible hosts .

If the disease has already been spotted in the orchid house, immediate steps should be taken to avoid further spread of the diseae . The plant should be isolated as infection may spread through sap-sucking insects. Cutting knives are also an effective agent for spreading the disease . The knife should be sterilised after using it on a suspected plant . Heating is a foolproof form of disinfecting the knife, since virus is a protein and is immediately precipitated upon heating . Chemical disinfectants are also known . Lawson (1967) has reported that 5.25 % solution of sodium hypochlorite and mixture of 2 % formaldehyde and 2% sodium hydroxide can instantly inactivate virus particles . Heavy metal salts , tannins and some forms of radiations are also effective in this fields (Terwillinger , 1968). According to Thonberry (1967) trisodium phosphate dissolved in water can break up virus particles into a harmless product .

As a rule , virus particles do not penetrate into extreme meristamatic regions. Morel made use of this fact when he raised virus free Cymbidiums from those already infected . Today, meristemming is the only way of getting rid of the virus in Cymbidium and many other orchids. In Cattleyas this is not always reliable , since meristems used in this genus are large and might carry virus particles . CyMV is easier to get rid of than TMV -O .