Cucumbers - culture which is grown up practically by all gardeners. Plant this not especially whimsical: it needs only watering and fertilizing, processing of stalks and leaves antiparasitic and antifungal medicines as required.
In most cases white spots on cucumbers appear because of defeat of plants fungal disease which is called ""mealy dew"". Leaves look so as if they are sprinkled with flour. The disease extends quickly enough and if in time not to take any measures, then leaves one by one dry that leads to death of the whole plant.
""Mealy dew"" strikes generally the cucumbers which are in the greenhouse. In the greenhouse the most favorable conditions for emergence of fungus: high humidity. If at the same time temperature in the greenhouse does not rise higher than 20 degrees (very often occurs at the beginning and the end of summer), then defeat by fungus appears in 99% of cases.
To secure cucumbers against ""mealy dew"", it is necessary to air surely in the afternoon the greenhouse, to water saplings moderately, and at night to close construction that temperature did not fall too low. If the disease has already affected some leaves of cucumbers, spray them with either horsetail broth, or mullein infusion. In that case if ""mealy dew"" has struck half and more leaves, for spraying use special chemical medicines.
It should be noted that leaves can turn white also for other reasons. For example, if on leaves white slime, at the same time edges of leaves dry, then in this case plants were struck by white decay. Become covered light spots leaves of cucumbers can also because of the shortage of nutrients. In this case timely fertilizing will help to cope with them. The lack of application of fertilizers can reduce many times harvest and even deprive of it.
To protect landings from the above diseases, surely before planting of seedling replace soil in the greenhouse, disinfect the earth, disinfect hotbed, feed up plants, in due time water, as necessary air the greenhouse.