Gourd cucumber comes from India. Therefore, it is heat-, light- and moisture-loving. In the process of growing, many gardeners, despite careful care, are puzzled by the problem of yellowing of the leaves. There can be many reasons for this.
Leaves turn yellow on cucumbers when affected by the most formidable disease -
downy mildew. It develops rapidly if the air humidity is increased, mainly in cold weather. Yellowish oil spots appear on the upper side of the adult leaves near the veins, and a white-purple coating is observed on the lower side. Over time, such leaves, starting from spots, dry up. The swiftness of the development of the process can be such that in a week it seems that it is deep autumn. We can’t talk about fruiting anymore.
As soon as the signs of the disease are detected, it is necessary to stop watering, ventilate the greenhouse well, cover the soil under the cucumbers with something drying, for example, chalk or ash, remove and burn leaves with spots. Healthy leaves should be sprayed with a bright pink solution of potassium permanganate to stop the development of pathogens.
Bacteriosis (cucumber disease) spreads more often in greenhouses . The leaves turn yellow at first with angular spots, which later dry up. On the bottom side
such leaves are visible pink droplets of liquid. Similar cloudy drops are detected on the ulcers of the fruit. The disease progresses dramatically in wet weather. It is known that cucumbers do not like drafts, but greenhouses must be constantly ventilated, because they suffer from bacteriosis and stem rot even more.
As soon as the leaves turn yellow on the cucumbers, they need to be sprayed with garlic infusion (200 g of chopped leaves and arrows, filled with 5 liters of water and infused for 4 hours). Reduce watering in the greenhouse to a minimum, feed with infusion of various weeds or manure (fresh), give additional potash top dressing. You can treat diseased plants with Bordeaux liquid, but after that it will be unsafe to eat the fruits for 20 days.
The leaves of cucumbers become yellowish spots, acquiring a yellow-green color, with a lack of trace elements. This is the lesser of all evils. They must be fed with special fertilizer, diluted according to the instructions. It is advisable to do this in the evening, after watering.
If damaged by a
spider mite, it first brightens, then the leaves on the cucumbers turn yellow, and later die off. These insects are very small, visible only under a magnifying glass. You can get rid of them through treatment with garlic infusion, provided that it will fall on the underside of the leaves. The use of chemistry is undesirable, since cucumbers will become dangerous for ingestion for almost 3 weeks.
Leaves turn yellow on cucumbers and when attacked by a black gourd aphid. This usually occurs in August. Against it, it is better to use garlic, needles, green soap and other home remedies. The body of the aphid is very tender and even water heated to 50 0 C will destroy it, but it will not harm the plant.
As you can see, there are many reasons why the leaves turn yellow on cucumbers, and there are even more ways to deal with this phenomenon. The measures taken in time will help to cope with any misfortunes, without which not a single summer season passes. Be attentive to your plantings, and they will thank you with a plentiful harvest.