When growing and caring for plants, we often come across the appearance of various diseases and damage, but we are not always sure what the cause is. In some plants, this can be noticed by the fact that the leaves start to turn yellow. Sometimes it can mean that we don’t water the plants enough or we water them too much, and sometimes that they lack something to grow luxuriantly. Diseases and pests are different and each of them attacks a certain part of the plant, but by the color of the leaves we can find out what is happening to the plants and discover ways and solutions for a certain problem.
Don’t worry, if the leaves have started to turn yellow or simply droop, there are still ways to save them from decay with proper care and procedures that you can read below.
Caring for plants
Too much water (overwatering)
Probably one of the most common problems we face when growing plants is an excessive amount of water, or watering, which can be recognized by wilted and yellow leaves. This can also be caused by poor soil drainage, which results in water retention. In this process, the root will eventually start to rot, fungi will grow more easily, while the leaves will soon begin to wither.
A good solution to this problem would be to add sand to the soil or transplant the plant into a jar with an opening at the bottom, where excess water can then escape.
Lack of water (too little watering)
As for the signs of dehydration, they are easy to recognize. The leaves are crisp and dry to the touch. Therefore, it is not wrong to think that the reason for the yellow color on the leaves of your plants could be too little water, that is, a smaller amount than what it needs.
In the case of too little watering, the plant will first start to discard the leaves that are the oldest and smallest, and those that are closest to the base of the stem, because ultimately they did not receive enough light and water for growth. When the plant is not watered enough, its source for the growth and development of the least important leaves is reduced.
When such a plant is properly watered it can recover, but some damage has already been done, given that some plants react to a change in watering more slowly than others.
In some cases, it can happen that the plant will still have yellow leaves even after receiving enough water, which can be quite confusing because by all other characteristics it looks healthy.
Plants need regular watering, and it’s best to do it early in the morning or in the evening when it’s not too hot. Before watering, be sure to check in professional literature or in a nearby garden center what suits your plant best, because some of them do not like too much water and watering.
You can recognize the signs of too little watering if the yellow leaves can be easily removed from the plant or if they have already fallen off, depending on which plant it is. But if the leaves take on a mosaic yellow color or light green with dark veins, and are firmly attached to the stem, then it is probably a different problem.
Lack of sun
This problem can be identified if the leaves of the plant are faded and look lifeless. When this problem occurs, the jar with the plant needs to be moved and ensure that it gets enough sunlight. At the same time, you should make sure that it does not face south and spend some time in the shade.
Changing the plant’s environment
This is common for plants that we have just bought because in garden centers or other stores they grow in ideal conditions. From the moment we buy the plant and place it in our home, these conditions change because they often do not have enough light and air flow, which can cause the leaves to fall off. This process will probably stop after the plant gets used to the new space and conditions in it.
Lack of minerals in plants
The deficiency and lack of minerals in plants manifests itself in different ways, and some of them are the yellowing of the leaves.
Potassium deficiency in plants
When the edges of the leaves of the plant start to turn brown or yellow, it is a sign that the plant lacks potassium.
A high-quality solution to this problem would be to bury the peel of a citrus fruit, such as a lemon, grapefruit or orange, in the ground, preferably unsprayed, and add compost that is rich in vegetable and fruit waste to feed the plant.
Nitrogen deficiency in plants
The lack of nitrogen in plants can be recognized by the leaves, when the central vein and the edges of the leaf begin to turn yellow.
Nitrogen deficiency can be solved by adding organic compost such as manure or coffee grounds to the soil.
Iron deficiency in plants
Signs of iron deficiency in plants can be recognized when the leaves completely turn yellow, and their veins are small and green. Lack of iron causes chlorosis, the symptoms of which are precisely the appearance of such leaves. Another way to recognize chlorosis is when you notice new growth on a plant that is a washed out green color.
This problem is best solved by determining the pH of the soil and reducing it below seven, after which you need to reduce the amount of phosphorus in the soil.
Below we present the symptoms of the lack of some other minerals in plants.
Calcium deficiency in plants
With calcium deficiency, the leaves lose their natural shape and get black spots. With this problem, you should determine whether your soil is alkaline or acidic. If the soil is alkaline, you should add gypsum, and if it is acidic, you should add lime.
Zinc deficiency in plants
Signs of zinc deficiency can be recognized by discoloration, i.e. darker and lighter areas on the leaves, especially between the large and main veins. This problem can be solved by spraying the plant with seaweed extract.
Magnesium deficiency in plants
If your plant lacks magnesium, you will recognize it most easily by the appearance of white lines next to the green ones on the leaf veins. With this problem, it would be good to add magnesium-rich compost to the soil, such as salt or lime.
Diseases and pests of plants
Determining the cause of yellowing leaves can be very difficult due to all the possibilities. Very small insects that are not visible to the naked eye may be present. Each of them has different symptoms that are visible on the plant as yellow leaves. Often the leaves get wrinkled at the edges and fall off. Insects can be aphids and aphids, midges, or red spiders that can be recognized by the webs that appear on the plant.
If you notice holes on the leaves of the plants, and especially if there are some insects on them, this is a sign that they have attacked them and that they can dry out because of them. When plants are attacked by insects, it would be best to spray the plant with neem oil or an insecticide to prevent further decay.
Aphids
Diseases and pests can attack both fruit and vegetable crops, and in the garden aphids that appear on carrots and other sardines are common. Carrots can be attacked by several types of aphids, the most dangerous being Cavariella aegopodi, which often overwinters on willow, and a species called Semiaphis dauci. They are small and delicate insects with a round body, and their colonies are found on the youngest leaves of the plant. They most often attack celery, parsley, parsnips and carrots.
Colonies can be found on the underside of young leaves and their stalks in the crown. The attack of these insects can be recognized by leaves that look deformed, torn and are yellow or reddish in color. The leaves of infected plants often turn yellow, curl and lag behind in growth, and may even die. Both types of insects secrete a large amount of honeydew, which then completely covers the leaves.
Infection from these insects can appear as early as May, but the largest number of lice appear at the end of June. Although there is a possibility of their occurrence in July and September. What favors their infection is the sudden rise in temperatures after a long rainy period.
If an aphid infection occurs on a young carrot plant, the yield may be destroyed.
Carrot seed aphid infections can be very dangerous because they are carriers of the plant’s leaf spot virus complex, so the seeds of plants affected by the virus are not recommended and usable for sowing. Much less damage occurs on older plantations.
These pests are controlled exclusively curatively with the help of insecticides called aphicids, the most famous of which are: Pirimor 50WG, Aztec EC, as well as broad-spectrum insecticides such as Actara 25 WG, KARATE 2.5, Calypso 480 SC and Methomex 20Sl.
In the same way, infection can be reduced if you place yellow sticky boards on the edge of plantations, and on smaller areas, infections can be prevented by installing a net.
Powdery mildew
Powdery mildew is a disease that recently appeared on tomatoes, and every year it becomes an increasing problem for gardeners. In the year 2000, large infestations were found on Adelaide and Raisa varieties in the vicinity of Županja, and after that on tomatoes that are on outdoor surfaces in the vicinity of Zadar and Zagreb.
Powdery mildew can be recognized by spots on the face of the leaf that are yellowish in color, and the middle of the leaf is necrotic. A dirty white scale-like coating appears on the underside of the leaves, and the infected leaves curl, dry and turn yellow. The dried leaves remain hanging on the plant, and it often appears on the eggplant, where it causes very similar changes on the leaves. Given that there are differences in the sensitivity of varieties, it would be good to choose and grow those that are less sensitive when planting.
Sulfur-based fungicides do not provide special protection, because unlike other fungi that cause powdery mildew that develop on the surface of tissues, L. taurica is an endoparasite. As soon as you notice the first signs of the disease, it is necessary to start with chemical protection.
Systemic fungicides are much more effective than sulfur fungicides. The most famous are: Saprol, Anvil, Rubigan and Bayelton Special, which are used in Mediterranean countries. In Croatia, the use of Quadris, which can also be used against powdery mildew, is allowed to control downy mildew and concentric spotting on tomatoes. It is recommended that it is not used more than twice in the growing season and that it is applied in a concentration of 0.1% with a withdrawal period for tomatoes of three days.
Zlatica
It is characteristic that plants lose their leaves when the yellowworm appears, because the adult yellowworms and their larvae eat the outer bark from the stem as well as the leaves. Because of this damage, the stems of the plants dry up and take on a yellowish brown color.
It is possible to recognize potato blight by leaves that have holes drilled in them or that have been completely eaten. The aphid, about 1 centimeter long, lays its eggs on the underside of the leaves. It is noticeable due to its black and yellow color, and the larvae are recognized by their pink color with black stripes. Adult goldfinches can be recognized by their black color with six yellow spots on the wings of their mantle.
Both larvae and adult insects can cause enormous damage, and these pests must be destroyed immediately. In the absence of a timely response, yellow blight can destroy the entire crop.
If you notice something like this on your plant, you should immediately spray the soil with a suitable insecticide and repeat the process.
Nematodes and fleas
An example of a nematode can be small white cysts on the main roots, such as potato nematode cysts, or large brown or yellow swellings, such as root knot nematodes. Leaves that are located lower veins and yellow. The plants are usually destroyed before the end of summer, which causes very small tubers. They occur on tomatoes, potatoes and onions.
With this problem, it is necessary to pull out and burn the infected tubers and plants. It is also good to plant French or African corduroy near sensitive crops, which will help repel intruders.
It is not recommended to plant potatoes, onions or tomatoes in infected soil for at least six years. After that, it is recommended to plant resistant types of potatoes.
Another phenomenon can be flea beetles that appear on radishes, cabbage and beetroot seedlings, and they drill holes in the leaves that turn yellow.
It is known that each type of plant has its own laws about planting and sowing, the amount of sun, and watering. It is important to react in a timely manner in order to protect the plant and restore its health, and if we do not know or cannot discover the cause, it would be good to consult a nearby garden center on how to solve a certain problem, because we can discover a lot in time by the color of the leaves to react.
Photo: jcesar2015/Pixabay