Why are sunflower leaves yellowing and how to fix it

If the sunflower lacks nutrients, it will cause a lack of fertilizer yellow, the leaves are dark yellow, and the sunflower is too much fertilizer or too concentrated, which will lead to root burning, the leaves are dull, uneven, and the old leaves fall off. If the sunflower lacks fertilizer, you can pay attention to the thin fertilizer applied frequently, if the sunflower fertilizer is too much, stop fertilizing immediately, and water and rinse appropriately.

Sunflower Planting Management:

First, timely top dressing.

Sunflower is a plant that needs more fertilizer, partial application of a certain fertilizer or only a certain kind can not meet the needs of sunflower flowering, timely top dressing is very necessary, generally before sunflower buds. Top dressing is used to green water-soluble fertilizer, which can be applied in furrows or holes, generally applied at 10 cm to 15 cm at the root, but nitrogen fertilizer should not be applied in the later stage of sunflower growth, because it may cause a reduction in yield.

2. Scientific watering.

Sunflowers not only need a large amount of fertilizer, but also a large amount of water, growers should replenish water in time according to the weather, soil and the growth of sunflower plants, but do not carry out large watering, after watering, they should also be cultivated in time to loosen the soil, so as to avoid soil compaction and water evaporation.

3. Prune and prune in time.

Sunflowers will grow excess branches during the flowering period, in order not to consume too much nutrients, farmers should remove the branches in time, usually the earlier the better. Between budding and flowering, it is generally done two or three times in a row.

4. Artificially assisted pollination.

Sunflowers are typical cross-pollinating crops that rely mainly on bees and insects for pollination. In the case of insufficient bee sources and insects, artificial assisted pollination should be used to improve the pollination and seed setting rate of sunflowers. Artificially assisted pollination should be selected at about 9 a.m. after the dew subsides to before 12 o'clock when the pollen grains are more and the vitality is vigorous, generally 2-3 times in a row, the first time in the flower disc when half of the flowers are open, the first.

2. The third time is when the flowers of the flower plate ** are open. This can greatly reduce the empty shell rate, increase the fullness of seeds, and increase the yield of sunflowers.

There are two methods of artificially assisted pollination: one is the pollen beat pollination method, that is, the cardboard is cut into a disc as large as the flower plate, the cotton wool is paddled to make the ** part slightly convex, wrapped with flannel or gauze, and a handle is tied on the back to make a pollination puff, when pollinating, hold the pollination puff with pollen in one hand, hold the flower plate with one hand, press the flower plate with the pollination puff and gently pat it a few times, so that the pollen can fall on the stigma; The second is the flower disc contact method: that is, in the full flowering period of the sunflower, the two adjacent flower discs "face to face" are gently rubbed a few times to achieve the purpose of mutual pollination.

Sunflowers have a very high demand for sunlight.

If there is enough light, the leaves still turn yellow, then it must be the accumulation of a large number of metabolites in the cells after a certain period of physiological activities, such as minerals, causing the decline of physiological functions and death (chlorophyll destruction).

It is recommended that you buy a bottle of chlorophyll supplement nutrient solution on **, which is very cheap.

The little aphid-like insects you are talking about will not make the leaves yellow1 3 so much ......Watering flowers to see dry and wet, watering thoroughly, and then waiting for dry watering, each spray a little, the surface is wet, the root may be very serious, and the pot is too small, not suitable for planting sunflowers, even if it is ornamental sunflowers, the root system is also very developed.

You need a larger pot, and if the leaves are yellow, spray carbendazim 1000 times solution, whether it is a lot of water or exposure to the sun or the yellowing of the leaves caused by bacterial infection.

There are many reasons for the yellowing of sunflower leaves, and the cause should be found and then addressed symptomatically:

1.Improper watering.

Lack of water often causes sunflower leaves to turn yellow and wilt, and prolonged lack of water can cause sunflower plants to die.

Solution: Watering the sunflower in moderation, place the sunflower in a cool place, its leaves will fall naturally, and when the sunflower grows new leaves, it can receive light. When the weather is hot, water twice a week and the sunflowers will slowly come back to life.

2.Lack of lighting.

Sunflower is a light-loving plant, and it is easy to get yellow and wilt the leaves when it is placed in a cool place for a long time during the growth period.

Solution: Because the sunflower has less sunshine time in the early stage, do not expose it directly to the sun. Gradually increase the amount of light to avoid burning the shoots. When the sunflowers return to normal, they can bask in the sun every day.

3.Improper fertilization.

Sunflower is a fertilizer-loving plant, if the amount of fertilizer is too large or the concentration is too much, it will cause sunflower to be unable to get sufficient nutrients, resulting in yellowing and wilting of leaves.

Solution: Stop fertilization, and in severe cases, you need to rinse the foliar surface with a large amount of water, loosen the soil, and place it in a ventilated place for maintenance.

4.White rot.

White rot is a common disease of sunflowers, which causes the leaves to turn yellow and fall off until they are all gone.

Solution: The state of the sunflower should be observed in time, and when white rot is found, scientific medicine should be carried out immediately. When the condition is severe, it should be unplugged and destroyed immediately to prevent spread.

Summary. 1. Insufficient light: Sunflowers like light, if they lack light, if they are placed in a shady environment for a long time, insufficient light will lead to yellow leaves.

2. Improper watering: Sunflowers need to be watered appropriately, once the watering is insufficient or too much watering, it will lead to yellow leaves. 3. Improper fertilization:

Long-term insufficient fertilization or fertilizer damage can also lead to poor growth and yellow leaves. 4. Pests and diseases: After sunflowers are infected with pests and diseases, they will also cause yellow leaves.

1. Insufficient light: Sunflowers like light, if they lack light, if they are placed in a shady environment for a long time, the light is not good enough to cause yellow leaves. 2. Improper watering:

Sunflowers need to be watered in moderation, once the watering is insufficient or the big lead is too much watering, it will lead to yellow leaves. 3. Improper fertilization: long-term insufficient fertilization or fertilizer damage will also lead to poor growth and yellow leaves.

4. Pests and diseases: After sunflowers are infected with pests and diseases, they will also cause yellow leaves.

What's going on?

Sunflower black spot disease is a disease caused by Alternaria sunflower and occurs in the epithelial manuscript of sunflowers. The lesions on Ye Biyan are round, 5-20 mm in diameter, dark brown, slightly concentric rings, and black mold on them, that is, conidia of pathogenic bacteria. The stems are fusiform, dark brown, quite large, and often connected with each other.

The lesions on the receptacle are also round and slightly concave.

Is this a melanoma? So what should I do?

Remove the diseased leaves when the black spots of sunflower leaves first appear, spray Bordeaux liquid and benomefen if necessary, 1 time in 10 15 days, 1 2 times for control.

Want to cut off the leaves? Then what if some of the leaves are a little bit old.

It is best to cut off the leaves to prevent infection of other leaves.

It is also possible to use carbendazim.

Is it a whole piece to cut out, or is it to cut out the infected area.

Cut off the infected ones.

Then spray the fungicide. Good.

Sunflower leaves have macula for the following reasons:

1. Light. Sunflower it is important during its growth period with full sun. If it is placed in the shade for a long time, the leaves will not see the light, and the whole leaves will turn yellow and fall off.

2. Moisture. Watering can also have yellow spots on the leaves. The new leaves of the sunflower plant are dark yellow and dull, the branches are small yellow-green, the growth is slow, but the old leaves have no obvious changes, and the wheat is too watered, so the watering should be controlled, the plant is depotted, and it is replanted after drying in a cool place.

Planting management: Since sunflowers like the sun, pay attention to light and watering, at least three times a day, it is best to apply sea and Weihai water-soluble fertilizer, so that sunflowers can grow fast.

Sunflower is a water-loving plant, which requires a large amount of dry water resources. In the summer, when the weather is hotter, we must maintain sufficient water resources for sunflowers. It is best to water twice a day, once in the morning and once in the evening.

Otherwise, the lack of water will easily cause sunflowers to shrink.

The causes of yellowing of sunflower leaves and the solutions are as follows:

1) Water yellow: the young leaves are pale yellow, and the old leaves are also gradually darkened yellow. The reason is that the water has been wet for a long time, the soil is hypoxic, and some fibrous roots are rotten. Watering should be controlled and fertilization stopped.

2) Fat yellow: the new leaves are thick and shiny, but the leaf surface is uneven, and the old leaves are yellowing and falling off. This is due to over-fertilization. The fertilizer should be stopped immediately, watered more appropriately, sprinkled some radish or cabbage seeds into the pot, and removed a few days after the emergence of seedlings to consume the excess fertilizer in the pot.

3) Dry yellow: the top center and new leaves are normal, and the lower part of the plant and the inner part of the leaves are dry and yellow first. The reason is that the potted flowers are dehydrated due to long-term lack of watering.

It should be watered in moderation to keep the potting soil moist up and down. The small seedlings in the hungry yellow pot are large, the fertilizer and water are insufficient, the fibrous roots in the pot are dense, the soil is very little, and the flowers and leaves turn yellow.

4) Shade yellow: Because potted flowers are placed in the shade for a long time, the light is insufficient. Sunflowers need strong light, and if the light is too weak or they do not see light for a long time, they will fall and the leaves will turn yellow.

Sunflowers can be planted in all seasons, mainly in summer and winter. The flowering period can be more than two weeks. The growth of sunflowers is proportionate and agile, and the flowering period can be more than two weeks, and the growth of sunflowers is closely related to factors such as temperature, moisture, light, and soil.

1) Temperature. Sunflowers are native to the tropics, but they are more adaptable to temperature and are temperature-loving and cold-tolerant crops. Its seeds are very resistant to low temperatures, and the local temperature is stable, and the seeds begin to germinate above 2; 4 5 times, the seed can sprout and take root; When the ground temperature reaches 8 10, it can meet the needs of seed germination. The optimal temperature for germination is 31 37 and the maximum temperature is 38 44.

Sunflowers can grow normally as long as the temperature is not lower than 10 during the whole growth process. In the appropriate temperature range, the higher the temperature, the faster the development.

2. Moisture. Sunflowers are tall plants with many and dense leaves, making them water-intensive crops. It absorbs twice as much water as corn. However, because its growth and development are mostly synchronized with local rain and heat, the contradiction between water supply and demand is not prominent.

The water requirements of sunflowers vary greatly among different growth stages. From sowing to budding, it is relatively drought resistant and does not require much water, only the total water requirement. Proper drought is conducive to root growth and enhances drought resistance.

From budding to flowering, it is the peak water demand, which accounts for about 43% of the total water demand. The lack of water during this period has a great impact on production. This stage coincides with a lot of rainfall, which can basically meet the water needs of sunflower growth and development.

If it is too dry, it needs to be replenished with irrigation. It also requires more water from flowering to maturity, accounting for about 38% of the total water volume. If the moisture is insufficient, it will not only affect the yield, but also reduce the oil content.

3) Lighting. Sunflowers are short-day crops. But it is not very sensitive to sunlight. For example, under the sunshine conditions of Tianjin, it can bloom and mature normally without special treatment.

Sunflowers prefer full sunlight and have strong phototropism in their seedlings, leaves, and flower discs. Sufficient sunshine and strong seedlings can prevent growth; Sufficient sunshine in the middle stage of growth can promote the vigorous growth of stems and leaves, normal flowering and pollination, and improve the seed setting rate. In the later stage of growth, the sunshine is sufficient, and the seeds are full and full.

1. Lack of light: Sunflowers like light and should provide all-weather sunshine during growth. 2. Improper watering:

Overwatering or drying up the soil can cause yellow leaves. 3. Excessive fertilization: Applying thick fertilizer to sunflowers will burn the leaves.

4. Insect pests: After suffering from scale insects or aphids, the leaves will grow yellow spots, and gradually wither and wither.

Why do sunflower leaves turn yellow.

1. Lack of light

Sunflower is a very light-loving plant, the plant has a strong phototropism, during the growth period to provide sufficient light, if the breeding environment is more chaotic and dark, the leaves can not photosynthesize, it is difficult to synthesize nutrients, which will cause the leaves to yellow and fall off.

2. Improper watering:

Sunflowers are drought tolerant, but too little watering during the growing season will cause yellow leaf problems, and sunflowers are not resistant to water and moisture, once watered through the chain to call more, the roots are waterlogged, and the new leaves will be dark yellow and have no luster, so when breeding sunflowers, it is necessary to water according to the dryness and wetness of the soil.

3. Excessive fertilization

Too much sunflower fertilization or excessive fertilizer concentration will lead to root burning, so that the leaves are yellow and convex, at this time to stop fertilization immediately, appropriate amount of watering to flush the root system, to avoid sunflower root rot, later fertilization should be diluted with water.

4. Infected with insect pests

Sunflowers are susceptible to aphids and scale insects in the growth process, and the leaves gradually wither yellow from the outside to the inside when the disease occurs, and need to be sprayed with carbendazim solution, and when breeding sunflowers, they should be pruned frequently, and the yellow leaves, dead leaves, and diseased leaves should be cut off in time.

Through our introduction, I believe you have a deeper understanding of the reasons why sunflower leaves turn yellow.

There are several main reasons why sunflower leaves turn yellow:

1. Water yellow: the new leaves of sunflower plants are dark yellow and have no luster, the branches are small and yellow-green, and the growth is slow, but there is no obvious change in the old leaves, indicating excessive watering.

At this time, the watering should be controlled, the plant should be depotted, and it should be placed in a cool place to dry and replanted.

2. Dry yellow: If the plant turns yellow due to lack of water, the leaf tips and the bottom of the leaves are the first to dry up and dry, and the plant turns yellow from bottom to top, but the new leaves grow normally.

At this time, pay attention to timely watering, but not too much, ensure that the water is thorough, and the soil is moist.

3. Lack of light yellow: If the sunflower is placed in a shaded environment for a long time, the leaves will not see light, and the whole leaf will turn yellow and fall off.

The plants can be placed in the sun to increase sun exposure, and when there is a lack of light, they can be appropriately supplemented with fluorescent lamps.

4. Lack of fertilizer yellow: Lack of fertilizer is manifested as a large pot of small seedlings, dense fibrous roots in the pot, and dark yellow flowers and leaves.

At this time, it is necessary to change a large pot, cut off the old leaves of the plant, and change the soil in time if there is a phenomenon of dry knots.