Why is Lasi in Xinjiang no longer rampant?

In the spring of 2001, I introduced someJianlan (Cymbidium ensifolium)from the south. Since I had just startedgrowing orchids, I did not know how serious Lasi disease was, nor did I expect it to spread so widely. I always felt it was unlikely that I would run into it. When planting, I was not strict about disinfecting the scissors, and during the subsequent care and management, I often saw withered leaves and scorched tips, so I casually used the scissors to cut them off. After a few months of this, I noticed that on some newly sprouted orchid leaves, along the direction of the leaf veins, there appeared chlorotic strip-shaped spots about 1 mm wide and of varying lengths, and I also noticed that the new shoots did not grow tall. I still did not know that this was Lasi. In 2002, more and moreorchidsbecame infected. I asked orchid friends in the interior, and they confirmed it was Lasi. Only then did I suddenly realize. At that time, almost all of the few pots oforchidsat home had become infected, and under such circumstances there was no need to discard or isolate them. Moreover, both I and other orchid friends felt that in Xinjiang, Lasi's harm toorchidsdid not seem as severe as described in orchid books. For example, orchid books say that after orchids are infected with Lasi, the orchid leaves will ulcerate, fluid will appear inside, and when the orchid leaves are broken, the fluid can be drawn into threads. But neither my nor other orchid friends' infected orchids showed this phenomenon. Therefore I decided to continue growing these orchids in order to observe the various manifestations of infected orchidplantsand seek treatment methods. After learning that the orchids were infected with Lasi, in the early period I also tried soaking human-use amoxicillin and ribavirin in water to spray and irrigate the orchids, spraying about once or twice a week, but I did not persist for long, probably only about a dozen times. Since then, from about the end of 2002 to now, I have not sprayed any more medicine. By the late summer and early autumn of 2003, two pots of orchids bloomed, and the results of Lasi's influence were clearly visible: the flower stalks were not tall, and on the petals, from the base to the tip, there were black strip-shaped spots about 1 mm wide and about 1 cm long. In 2004, new leaf buds grew again in the orchid pots. After the orchid leaves grew out, they were tender green and glossy, and no Lasi lesions could be seen. This was the case for several pots. What I introduced wasJianlan (Cymbidium ensifolium), which has strong vitality and wide adaptability, so my care and management were relatively extensive. Also, because my living space is small and conditions are limited, in summer I often placed them on a closed balcony where the temperature was over 40 degrees, and possibly even close to 50°C, and in winter I placed them directly on the indoor windowsill, enduring the baking from the hot air flow of the radiator below. With such harsh conditions, sometimes I even forgot to water them in time, causing the orchids to undergo even more severe tests. I am located in the great northwest, northern Xinjiang, where precipitation is scarce and the air is dry, with annual precipitation of only more than 200 mm. Summer sunlight is abundant and temperatures can reach above 40°C, while winter is cold, but the indoor temperature can be maintained at around 20°C because of heating. At present, no lesions can be seen with the naked eye on the surface of newly grown orchid leaves, and the height of newly grown orchid plants is also normal. Because of poor care, no flowers have been seen this year. If Lasi is truly unsuited to the dry, high-temperature, high-light climate of the northwest, could an orchid garden be established in the northwest, and could one try artificial inoculation with the Lasi virus so that orchids, with the help of the climate, overcome Lasi, and further mutate and evolve genes capable of resisting the Lasi virus, and then use methods such as artificial pollination and gene transfer to enable more orchids to acquire antiviral ability? I do not know whether this idea is feasible. I tell my discoveries to the seniors, experts and the broad community of orchid friends in the orchid world, for everyone's reference. If it can play some role in overcoming Lasi, I will be overjoyed. (Xinjiang Wang Zhiyu)