Precautions for Supplementing Water to Edible Fungi and Methods for Preventing and Controlling Orchid Viral Diseases

For the foreseeable future, viral diseases will remain a stubborn and difficult problem for orchid cultivation. The difficulty lies first in the preciousness of orchids. Whether in batches or as individual plants, ornamental orchids may well be the most expensive artificially cultivated plants. Potted flowering ornamental orchids retail at about 5 to over 100 US dollars per pot. Some strains of Cymbidium ensifolium, Paphiopedilum and Vanda are worth more than several thousand US dollars. In addition, some orchids are rare varieties and are especially precious; such orchids are generally not traded commercially. Even if such orchids become infected with viruses, they will be kept in orchid nurseries, and no orchid grower would be willing to discard them. Second, many orchid growers do not much approve of the strict quarantine measures imposed on imported and exported orchids, believing that these measures hinder international exchange of orchid resources. Third, monopodial orchids such as Af8lldl and Vanda are the most important varieties for cut-flower production of orchids in Southeast Asia, and they are difficult to propagate in vitro, which limits the application of tissue culture for producing large numbers of virus-free plantlets.

For less showy orchids such as Vanilla and endangered varieties kept in germplasm nurseries, eradicating their viral diseases may be even more difficult. In fact, although more attention has recently been given to the conservation of germplasm of wild orchids and other orchids, growers still make little or no due effort to protect them from viral infection during cultivation.

The prevention and control of orchid viral diseases mainly relies on prevention. Orchid growers should purchase guaranteed, virus-tested orchid plantlets, and at the same time use various detection techniques to inspect orchids plant by plant, and take various necessary measures to prevent healthy plants from being infected by viruses. If the above measures can be implemented, even if viral diseases cannot be completely eliminated, the vast majority of orchid growers can successfully prevent viral diseases from infecting their orchid nurseries.