Top Viruses in Plants
Viruses can live in different plants and they will also exhibit various symptoms. In this section, we will have a short discussion of some of the most common plant viruses and how they affect their hosts.
Tomato Mosaic Virus
A virus that affects tomatoes in all growth stages, this is one of the most common concerns amongst gardeners. It can live for at least 50 years in infected plant debris, which is also the common carrier of the virus. Despite the name, it also affects other plants, such as tobacco, squash, rose, cucumber, and peppers.
This virus does not come with any cure. Therefore, when the infection starts, there is nothing that you can do about it. Transmission can also be quick. With this, the measures are preventive in nature.
Among others, sanitation is one of the best ways to prevent tomato mosaic virus. Make sure that your hands are clean when touching plants as this can be a common method of transmission. If there are already infections in the field, avoid planting the same crop in the area. Cross contamination is also common. With this, be cautious about the tools that you are using and make sure that they are not infected with the virus.
Tomato Spotted Wilt Virus
This virus affects more than 35 plant families that are of economic importance. While tomato is the most obvious host, it can also be present in potato, pepper, tobacco, peanut, and a variety of ornamental crops. The main method of transmission happens through thrips, which are tiny insects that suck nutrients out of their host plants.
Tomato spotted wilt virus can affect different parts of the plant. In the case of fruits, there will be circular and brown spots. There will be distortions in its shape. There will also be dark streaks on the stems of the plant. In some cases, stunting will also be evident.
The best way to control this virus is through controlling thrips. Remove weeds in the garden and decaying vegetation as they can be common overwintering sites for the pest. Choose resistant varieties as well. In the case of tomatoes, some of the varieties that can resist this disease include Mountain Glory, Red Defender, and Bella Rosa.
Tomato Yellow Leaf Curl Virus
From its name, the most obvious host of this virus is a tomato. Other than the latter, however, its hosts also include capsicum, beans, blackberry nightshade, and other Solanaceae plants. Stunting is one of the most common symptoms of the disease, resulting to dwarfed plants. There will also be small and dry fruits. The leaves, meanwhile, will bend downwards and will also develop a leather-like surface.
The transmission of tomato yellow leaf curl virus happens through silverleaf whitefly. The virus can remain in the insect for ten to 12 days. Unlike other viruses, mechanical transmission and plants with infection do not contribute to the spread of the disease.
To prevent the spread of the disease, avoid moving plants that are already infected. Weed control will also help to make the ground less attractive for the insects that carry the disease. In terms of chemical control, on the other hand, you can consider the use of systemic insecticides.
Cucumber Mosaic Virus
Some of the most common plants that are affected by this virus include cucumber, lettuce, spinach, lilies, and celery. Once a plant is affected by this virus, some of the most common symptoms include wrinkles and mottles in the leaves. In the case of cucumbers, white pickle will appear or gray white areas. Stunting is also common, especially in pepper and tomato. For flowers, on the other hand, white streaks will appear.
There are several ways by which the virus can transfer to healthy plants, such as through mechanical tools or drafting. Aphids are also common culprits for the spread of the virus. Once an aphid bites an infected plant, transmission of the virus will happen within just a minute. The virus stays in the body of the aphid for an hour. At such a duration, it can already spread infection to hundreds of plants.
To control and prevent cucumber mosaic virus, one of the best things to do is to use only clean garden tools and to avoid aphid vectors. Keep the garden free from chickweed and groundsel weed as they are common sites for the virus. Also, pick plants that can resist the virus, which include Defender, Supremo, Badger Cross, and Bonica, among others.
Potato Virus Y
This is one of the most serious viral diseases that affect potato. It can result in a significant reduction in crop yield and the quality of the tubers. It can lead to dead spots not only on the tubers, but on the leaves of the plant as well. Aside from potatoes, the virus can also affect tomato, tobacco, and pepper, among others.
The transmission of the virus happens primarily through aphids. They feed on an infected plant and they transmit the virus by feeding on a healthy plant. The virus will remain on the body of the aphid for as long as 11 days.
To prevent the virus from affecting your plants, grow your crops in a spot that is free from aphid population. Netting will also help as an exclusion method to keep the aphids out. Good hygiene practices are also essential to prevent transmission through contaminated tools.
Cauliflower Mosaic Virus
This is another virus that is transmitted by aphids, affecting the leaves and the entire plant. Some of the most common symptoms of infestation include having abnormal patterns in the leaves and dwarfing of the plant. As a result of the presence of the virus, the plant is unable to receive the nutrients that are necessary for its survival, which is why it suffers from stunting.
Cauliflower mosaic virus affects plants from the Brassica family. Aside from cauliflower, it also affects cabbage, Brussels sprouts, turnip, garden cress, wild mustard, and collard, among others.
Make sure that the seeds and seedlings are not infected when planting them. Also, be sure to isolate the crops that are already infected by the virus. Space the plants properly so that it will not be easy for the virus to transfer to other plants. Insecticidal control can also be effective, especially those that will target aphids.
African Cassava Mosaic Virus
This is the most significant virus that affects that production of cassava in East Africa. The main method of transmission is the use of planting material with infection. Aside from cassava, this virus can also affect castor bean and wild poinsettia.
Some of the most common symptoms of this disease include stunting and leaf distortion. Leaves that are normally green may turn pale or yellow. Uniform mosaic patterns will also be evident on the leaves. The size of the leaflets can be significantly reduced in cases of severe infestation.
For short-term control of the virus, the use of synthetic pesticides can help. For long-term measures, on the other hand, habitat management and cultural practices will be the most effective. Sanitation of the planting area and keeping it free from infected plants will be a good solution. Crop spacing and rotation will also be essential in the management of the virus.
Plum Pox Virus
Also known as sharka, it is the most destructive virus amongst stone fruits. The transmission of the causal agent happens primarily through aphid infestation. Most of its hosts are woody plants, which include apricots, plums, and peaches.
One of the problems with the plum pox virus is that the symptoms of infection can be sporadic. In some cases, they will not emerge until three years after the infection. Most of the virus sources are silent, which is dangerous since you are not aware that it is already affecting your healthy plants. Once the symptoms become apparent, on the other hand, there will be yellow spots and blotches on leaves. The fruits will have external rings and discoloration.
The best control measure is the exclusion of the plant that is already suffering from an infection. The use of chemical insecticides for the control of aphid is also a common solution. However, the problem is that once the infection starts, there is no way to remove it from the host plant.
Brome Mosaic Virus
This virus was first discovered in the 1940s and is known as one of the smallest from all the viruses. It is present almost anywhere there is wheat. Aside from wheat, other common hosts of the virus include rye, barley, corn, and oats. The method of the transmission of the virus normally happens through mechanical inoculation.
One of the most common symptoms of brome mosaic virus is the appearance of white or yellow streaks on the leaves of the host plants. Slight stunting can also be evident, which is a result of the inability to receive the essential nutrients.
One of the best control measures is the eradication of weeds in the garden or plantation. There are also insecticide treatments for beetles, which are common carriers of the disease. The use of floating row covers and nets, when necessary, will also be helpful to keep the insects away.
Potato Virus X
Also known as potato interveinal mosaic, this virus affects not only potatoes, but a wide array of hosts as well, including turnip, chili, tobacco, bell pepper, and tomato, among others. The main method of transmission of the virus is through mechanical contact. There are also some reports that the mouthparts of grasshoppers can facilitate the spread of the virus.
On its own, potato virus X does not cause significant damages to its plants, apart from the appearance of minimal patterns. However, when potato virus Y is also present in the same crop or plant, this is where the damage becomes more apparent. Mosaic leaf mottling and the appearance of rings are some of its most common symptoms.
Choosing cultivars that can resist the virus is the best way to prevent infestation. When it comes to cultural practices, on the other hand, make sure to keep the area clean and to use only sanitized tools. If there are plants with obvious signs of infection, pull them out before the virus spreads.