| You can control the mosquito larvae in standing water by using Bacillius Thuringiensis (Bt.) In the States we have small donut shaped packets called DUNK that can be put into standing water for use by ordinary citizens. This same thing can be dissolved into water used for orchid watering and feeding. It is totally harmless to the plant (as well as fish in ponds.) You may have something similar there. I would suspect the health authorities would make this readily available since it is very inexpensive.
Nick |