ISHS Acta Horticulturae 36: III International Symposium on Virus Diseases of Ornamental Plants
TREATMENTS THAT IMPROVE MECHANICAL TRANSMISSION OF CHRYSANTHEMUM CHLOROTIC MOTTLE VIRUS |
| Authors: | R.K. Horst, C.M. Geissinger, M. Staszewicz |
| Abstract:
Chrysanthemum chlorotic mottle virus (ChCMV) disease was first observed in 1967 in Chrysanthemum morifolium (Dimock and Geissinger, 1969; Dimock et al., 1971) and is now known to occur in several chrysanthemum cultivars. The chief observable symptom is a marked inhibition of chlorophyll development resulting in severe chlorosis and dwarfing of reactive cultivars. Acute symptoms are expressed as a leaf mottle. The intensity of the yellowing in each phase of the syndrome can be controlled almost at will by: 1) choice of cultivar (Dimock et al., 1971); 2) control of light intensity and photoperiod (Horst et al., 1972); 3) control of temperature (Horst and Kryczynski, 1971). The disease is of economic importance because it produces dwarfing of the plants and flowers and delays flower development. Mechanical transmission of ChCMV is accomplished only with difficulty and results are not uniformly reproducible. Efficiency of transmission by rubbing with Carborundum is increased by grinding infected tissue in a chilled mortar in the presence of cold water containing 1% bentonite (1 ml diluent/g tissue) and by immediately inoculating test plants (Kryczynski et al., 1971). We have no evidence that difficulty in transmission is due to presence of inhibitors in chrysanthemum. The instability of ChCMV is quite apparent since in crude juice it survives only an hour or two at room temperature and no longer than 4 hr at near 0°C. Studies were initiated to examine the effect of additives on virus stability and to improve the reliability of mechanical inoculations by the conventional rubbing method. | |
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