Spotty leafed marrows
For the last two years I have had trouble growing marrows. The plants start okay and produce the first marrow. Then the leaves start getting white spots which slowly spread until the leaves are covered in white. No more flowers will set and the plants are then useless. Can you advise me what the problem is and suggest a solution?
If the white spots are powdery, this could be powdery mildew, which can attack marrows at this time of year. A standard fungicide for powdery mildew should cure it.
If it is not powdery mildew, it could be a soil borne disease. Try applying the new plant strengthener Grow Boost to the soil around the marrows. The natural fungi in Grow Boost can out-compete soil borne diseases preventing them starting. Normally it is better to treat the soil just before or just after planting. Grow Boost can be used for a variety of plants and crops. It is available from Harrod Horticultural.
I hope this is of some help.