What is the cause of yellowing of the bottom leaves of tomato seedlings?

If the leaves have grown for a while, the yellow of the leaves is a phenomenon of life, and they can be cut off. After picking the tomatoes below, they should be cut off even if the leaves are not yellow.

The new shoots of the tomato are yellow and purple.

Tomato virus diseases are mainly there.

Mosaic type, mainly occurs in the upper leaves of the plant, the surface is the yellow-green or dark and light leaf color on the leaves, the leaf color is green, the leaf surface is slightly wrinkled, and the plant is dwarfed. The new leaves are small, shrunken, and bright-veined, and the leaf color is light.

Fern leaf type, the plant is generally obviously dwarfed, the upper leaf mesophyll tissue is degenerated, the leaves are slender and linear, and the internodes are shortened. The petals are elongated and thickened.

Streak type, can occur on stems, leaves, fruits, stem susceptibility initially produces dark green short stripe spots, and then brown stripe spots, different lengths of stripe spots, and gradually spread, in severe cases, cause part of the branch or the whole plant to die. Leaf infection forms brown spots or moire or streak spots. The fruit is infected, the fruit surface is unevenly colored, deformed, and the diseased fruit is easy to fall off.

Clumping type, the top and leaf axils grow out of the clump branches, the leaves are linear, light and deformed. Diseased plants do not bear fruit or bear little fruit, and the fruit is hard and conical.

Leaf curl type, yellowing between leaf veins, leaf curl and the whole plant shrinks, or clumps can not flower and bear fruit.

Yellow top type, the top leaves are greened or yellowed, the leaves become smaller, the leaf surface is shrunken, the middle of the diseased leaf is protruding, the edge is curled, the plant is dwarfed, and the branches are increased.

In the early stage of the disease: 500 times of 20% mololinoguanidine acetate copper wettable powder can be used

Haohan Hi-Tech 2% amino-oligosaccharide aqueous solution 300 times.

2% Ningnanmycin aqueous solution L50 250 times.

300-500 times of 5% bacterial poison water agent.

and other fungicidal pesticide sprays, spray 1 time every 5 7 days, spray 2 3 times continuously.

Insufficient oxygen in the soil. Root respiration is more active, such as peach trees planted in heavy or compacted soils.

When there is too much water in the early stage of growth, it can also cause difficulty in root breathing.

The soil is too salty. Yellowing of leaves often occurs in heavy saline soils.

Excessive application of nitrogen or phosphate fertilizers can also affect nutrient absorption, resulting in yellowing of leaves.

When spring tomatoes are planted, the seedlings are generally older, and they are generally no longer watered during the period from the time of slow seedling watering to the first ear of fruit sitting. The seedling age of summer and autumn tomato planting is small, after slowing the seedling, it is necessary to promote the rapid growth of seedlings, timely watering, and pay attention to cultivation after watering. Flowering period of water control squatting seedlings, flowering rarely watered, unless the drought is serious, this period is mainly to keep the soil loose, the surface dry, promote strong seedlings, to ensure that the root system expands downward, for the future plant vigorous growth, lay a good foundation. When the fruit water sits 2-3 in the first ear of fruit, it should be watered in time to promote the fruit, pay attention to the watering time, the water is early, it will often make the plant grow vigorously, the vegetative growth is too vigorous, it is not easy to set fruit or the fruit setting period is delayed, you can use Ribery Yanwo water-soluble fertilizer, the water is watered, the growth of the plant is hindered, although there are many fruit sets, but the leaves become smaller, the growth is slow, and the yield is reduced.

The yellowing of tomato leaves is due to poor nutrient absorption by the roots of the plant, or low utilization of nutrients, and this situation is also related to improper fertilization of successive crops.

Possible causes of yellowing of leaves during tomato cultivation include:

1. When planting tomatoes, if it is dry weather, it may cause the yellow leaves of tomatoes, especially the lower leaves of tomatoes, to be dehydrated for a long time, resulting in green aging of the leaves.

2. Watering in a high temperature environment, if the watering amount is too large, it may also cause tomato yellow leaves. Excessive watering will affect the growth of the root system, resulting in insufficient nutrient absorption and supply, and some leaves will show yellowing.

3. Yellow leaves caused by diseases, when tomatoes encounter diseases, the growth is weak, and some leaves will appear yellow leaves.

4. Lack of relevant nutrients and elements, resulting in yellowing of leaves, if the nitrogen is insufficient during planting, the leaves will show yellowing, the lower leaves will be yellow first, and gradually the whole plant will lose its green, and the lower part will be more yellow; Or during the critical period of vegetative growth, there is not enough nutrients in the soil, resulting in yellowing of the leaves.

5. Unreasonable fertilizer use leads to yellowing of leaves. When planting tomatoes, too much fertilizer is sprinkled, and the fertilizer is transpired to produce gas and burn leaves at high temperatures, causing yellow leaves!

6. Yellow leaves caused by pesticide damage, when spraying, unreasonable mixing, or excessive pesticide type and concentration, will also cause leaf burning.

7. The planting density of tomatoes in the field is large, and the lower leaves show yellowing. This condition is mostly caused by insufficient light and poor air tightness.

There are many kinds of causes, how many cases there are, top-down or bottom-up, individual plants that occur in patches, and whether there are insects in the ground.

Hello The yellowing of the leaf tip of the top leaf of the eggplant is due to the yellowing of tomatoes and the disease of curly leaves, so it is necessary to do a good job of pastoral cleaning in time, rotate crops, irrigate the shed for more than 15 days, and appropriately postpone the sowing date. Seedling stage: the heart leaves are shrivelled, the leaf color is slightly yellow, and the plant is short.

Flowering period: The plant is significantly dwarfed and grows slowly. Fruiting period:

The disease is aggravated, the leaf edge is seriously rolled, the leaf quality becomes hard and the edge is small, and the fruit is not commercial. Late growth: the leaves are curly yellow and shrivelled, but do not affect the yield.

1. Symptoms of yellowing of the top leaves of tomatoes 1, seedling stage (1) The yellowing of the top leaves of tomatoes can appear 25-30 days after sowing, and the specific manifestations are that the heart leaves are shrunken, the leaf color is slightly yellow, and the plant will be shorter than the normal seedlings. (2) The symptoms at the seedling stage in the high temperature season were relatively obvious and easy to identify, and the symptoms at the seedling stage in the low temperature season were slightly reduced. What's the deal with yellow leaves on the top of tomatoes?

How to prevent 2. Flowering period (1) Generally, obvious symptoms begin to appear 40 days to 50 days after tomato planting, and the flowering period is generally the peak period of yellowing of the leaves on the top of tomatoes. (2) The main manifestations are obvious dwarfing, slow growth, yellowing, shrinkage and smallening of new leaves at the top, and thickening of leaf veins on the back of leaves. (3) The edge of the blade is rolled up, and some of the blades become thicker, but the leaves remain green.

If the plant is severely infected, it will be severely dwarfed and unable to set fruit normally. After the crop harvest before planting tomatoes, it is necessary to completely remove the residual branches, fallen leaves and weeds in the field to reduce the number of whiteflies. 2. Crop rotation and stubble planting tomatoes should advocate water-dry rotation, rice-vegetable rotation, and can also be changed to vegetables that whiteflies do not like to eat, such as celery, lettuce, leeks or onions and garlic.

What's the deal with yellow leaves on the top of tomatoes? How to prevent 3, irrigation stuffy shed 7 August high temperature season is the season of high incidence of pests and diseases, during this time to level the greenhouse field land in time, around the ridge, with the old film paved, the whole shed filled with water stuffy for more than 15 days, in order to eliminate whitefly and reduce the occurrence of soil-borne diseases. 4. Appropriately postpone the sowing period If the whitefly is not easy to control, it can be postponed to mid to late September, which can reduce the occurrence of tomato yellowing leaf curl virus disease.

The causes of yellowing of tomato seedlings are: overwatering, soil clumping, and malnutrition.

1. Overwatering.

In the process of tomato growth, if the watering is too frequent, or the amount of watering is too large, resulting in serious water accumulation in the soil, and the roots will rot as a result, it will cause the leaves to turn yellow.

2. Soil agglomeration.

When the soil for planting tomatoes is compacted, it will affect the smooth breathing of the roots, resulting in yellowing of the leaves.

3. Malnutrition.

During the maintenance period of tomatoes, if they are often watered with tap water, or if the plants are not fertilized for a long time, the leaves will turn yellow due to soil alkalinity or insufficient nutrients, and iron can be added to the tomato to alleviate it.

Conservation and management of tomatoes

1. Apply basal fertilizer.

Tomatoes are suitable for growing in soft and breathable soil with rich organic matter, when cultivating tomatoes, it is necessary to plough 30-40 cm of land to make it more soft and breathable, and then apply rotten organic fertilizer or cake fertilizer to the soil to improve soil fertility and promote the vigorous growth of tomatoes.

2. Top dressing fertilizer.

Tomato needs sufficient nutrients in the growth process, when breeding tomatoes, it is necessary to apply 1-2 times of phosphate fertilizer and potassium fertilizer in the peak season of plant growth, so that the growth rate of the plant is accelerated, and during the tomato bud pregnancy, it is necessary to spray potassium dihydrogen phosphate or urea to improve the fruit setting rate of the plant.

3. Pruning.

When cultivating tomatoes, it is necessary to cut off the withered yellow leaves and long branches of the plant in time, so as not to lose the nutrients of excess jujube, and promote its growth of strong new branches.

Summary. Pro, the causes of yellowing of tomato seedlings cotyledons:

1. Too much nitrogen fertilizer.

Too much nitrogen fertilizer is applied in the process of breeding tomatoes, which will lead to malnutrition of the plant, so that the leaves are yellow, and more nitrogen and phosphorus fertilizers should be applied during the growth period of tomatoes, phosphorus and potassium fertilizers should be applied during the flowering period, and foliar fertilizers should be applied during the fruiting period.

2. Soil alkalization.

The salt content in the soil is too high, which will affect the normal growth of tomatoes, and the leaves are prone to yellowing.

3. Watering too much.

Tomato seedlings yellowing may be the cause of too much watering, plant roots grow in moist soil for a long time, will not breathe well, so that the leaves are yellow, in the cultivation of tomato seedlings to follow the principle of not drying and not watering, the seedling period must control the amount of watering.

4. Sufficient light.

Tomatoes like sunlight, under good light conditions, the branches and leaves grow vigorously, the fruit is more red and bright, the cultivation process should provide soft light for it, and at noon in summer need to pull a layer of shade net, and strengthen ventilation, so as not to wilt tomatoes.

What is the cause of yellowing of tomato seedlings.

Pro, the reasons for the yellowing of tomato seedling cotyledons: 1. Too much nitrogen fertilizer is applied in the process of breeding tomatoes, which will lead to malnutrition of the plant, so that the leaves are yellow, and more nitrogen-containing and phosphorus-containing fertilizers should be applied during the growth of tomatoes, phosphorus and potassium fertilizers should be applied during the flowering period, and foliar fertilizers should be applied during the fruiting period. 2. The salt content of the soil alkalized soil is too high, which will affect the normal growth of tomatoes, and the leaves are prone to yellowing.

3, watering too much tomato seedlings yellowing may be due to too much watering, plant roots grow in the moist soil for a long time, will not breathe well, so that the leaves yellow, in the breeding of tomato seedlings to follow the principle of not dry and not watering, the seedling period must be in the middle of the skin to control the amount of watering. 4. Tomatoes like sunlight with sufficient light, the branches and leaves grow vigorously under good light conditions, and the fruits are more red and bright, and the cultivation process should provide soft light for them, and a layer of shade net needs to be pulled at noon in summer, and ventilation should be strengthened to avoid tomatoes wilting and wilting.

5.Disease cause: When leaf spot disease occurs, it will also cause yellowing of eggplant seedlings.

The leaves will gradually turn yellow, and then spread to the petioles and stems, and the initial leaf surface will have yellow to yellowish brown lesions, and the edges will not be too obvious. It can be sprayed with 300 times of ammonia copper solution during the yellowing period for prevention and control, and the solution can be sprayed every seven days.

The above is all my reply, I hope to help your relatives, I wish you a happy life.