Pest & Disease Common smut

Common smut

Ustilago maydis

What is Common smut (Ustilago maydis)?

Ustilago maydis, commonly known as corn smut, is a fungal pathogen that can infect two different hosts: maize and teosinte. This unique fungus, belonging to the phylum Basidiomycota, holds significance both as an agricultural concern and a culinary delicacy in specific regions. Ustilago maydis causes blackish galls (tumour-like growth) filled with spores on corn plants that vary in size from less than 1 cm to more than 30 cm in diameter, appearing on ears, leaves, stalks, or tassels. Galls start with white to silvery tissue and mature into dark spore-filled masses. However, in central Mexico, the galls on corn ears are cherished as the edible delicacy cuitlacoche (huitlacoche), adding cultural significance to the fungus's practical impact.

How does Common smut (Ustilago maydis) occur?

It overwinters in crop debris or soil and can remain viable for several years. Ustilago maydis, or corn smut, reproduces through a complex life cycle involving sexual and asexual reproduction. The fungus reproduces asexually through sporidia, secondary spores released from the mycelium. Sporidia contribute to the rapid spread of the fungus. while sexual reproduction is through basidiospores, which are released and dispersed by the wind. Basidiospores infect healthy corn plants, initiating the infection process. This reproductive cycle enables Ustilago maydis to disseminate and infect new corn plants.

Symptoms

1 - Impact on Corn Crop

• Ustilago maydis causes galls on corn, reducing yield and quality, and leading to economic losses for farmers. • Infected plants may experience stunted growth, reduced vigor, and overall decreased productivity. • The galls can interfere with nutrient uptake and photosynthesis, negatively impacting the plant's development.

2 - Impact on Soil and Environment

The fungus can overwinter in soil and crop debris, serving as a potential source of infection. • Despite its negative impact on crops, corn smut contributes to ecosystem nutrient recycling and decomposition processes.

Solutions

1 - Cultural Practices

1. Implementing a crop rotation plan can help reduce the risk of infection. Avoid planting corn and teosinte in the same area year after year. 2. Choose crop hybrids that have shown resistance or tolerance to corn smut. 3. Remove and destroy infected plant material, including galls and crop debris, to reduce the presence of inoculum in the field. 4. Maintain proper plant nutrition and irrigation practices to promote plant health and vigor, reducing the susceptibility to infection. 5. Regularly inspect corn and other plants for signs of galls and promptly identify any infected individuals.

2 - Biological Control

Some beneficial microorganisms can help suppress Ustilago maydis such as Bacillus subtilis, Trichoderma spp., Gliocladium spp., Streptomyces spp., and Pseudomonas fluorescens are used to kill fungi.

3 - Chemical Control

1. In severe cases or when economic thresholds are reached, fungicides can be used to control corn smut such as Azoxystrobin, Flutriafol, Propiconazole, Mancozeb, Thiophanate-methyl and Triadimefon. 2. Consult with agricultural experts or extension services to determine the appropriate fungicides and application timing.

FAQ

Do shade growing plants need any Sunlight?

Shade growing plants do need sunlight, although they require less than other plants. They need some direct sunlight each morning to help them photosynthesize and grow properly. Also, indirect sunlight throughout the day helps them stay healthy. Shade growing plants will benefit from the sunshine, but if they get too much or too little, then they can suffer the consequences. It's important to pay attention to the needs of your plants so that you can provide them with the proper light for optimal growth.

How often should you water indoor plants?

Indoor plants should be watered when the soil feels dry to a depth of about two inches, usually about once a week. A helpful technique to determine your plants' watering needs is to feel the soil before and after watering to get a sense of how long it takes to dry out. An important note to remember is that some plants require less water than others, and it's best to research the specific needs of your individual plants. Likewise, if your home is very dry, you might need to water more often as the lack of moisture can stress the plants and lead to problems like brown leaves and wilted stems.

Can my monstera plant get root rot?

Yes, a plant can get root rot. Root rot is a fungal disease that can be caused by over-watering, poor soil drainage, or high humidity levels in the air. Signs of root rot include yellowing leaves, wilting and stunted growth, and damaged or browning root systems. Sometimes it is difficult to detect root rot until the plant is removed from the soil, as the problems are mainly below the soil surface. Treating root rot usually involves removing the affected parts of the plant and replanting the unaffected ones.

Can I put my Monstera outside in summer?

No, you should not put your Monstera outside in summer. Monstera plants need warm, humid air to thrive, and direct sunlight can scorch their leaves. Instead, put your Monstera in a bright, sunny spot with indirect light, making sure the sun never directly hits the leaves. During the summer, keep your Monstera's soil damp and mist it occasionally to keep the leaves hydrated. At nighttime, keep the temperature around 16 - 21°C (60 - 70°F). You can definitely take your Monstera outdoors for short periods of time, just make sure to bring it back in if it starts to get too hot.

What happens if my monstera plant gets too cold?

If your monstera plant gets too cold, it will become vulnerable to pests, disease, or other damage. Cold temperatures can damage the leaves of the plant, causing them to become spotted or limp. The roots of monstera plants may also suffer in cold temperatures, leading to root rot or other diseases. Belonging to the tropical family, monsteras are used to warm environments and do not do well in cold temperatures, so it is important to ensure your plant is kept in conditions that suit their needs.

Is it possible to grow a vegetable garden in a small space?

Yes, it is possible to grow a vegetable garden in a small space. Gardening in a small space can be as simple as growing a few containerized plants in pots and raised beds, or as elaborate as vertically stacking planters, hanging pouches, and hanging baskets on a wall, railing, or fence. Regardless of the size of the space you are working with, some simple techniques such as companion planting, organic fertilizers, and water conservation can help you get the most out of your small vegetable garden.

Is peppermint herb green good for digestion?

Peppermint herb is indeed beneficial for digestion. The flavonoids in the herb support digestion by reducing inflammation in the digestive track, aiding in digestion and relieving indigestion, heartburn, and even the symptoms of irritable bowel syndrome. Additionally, peppermint is naturally rich in menthol, which helps to relax the muscles of the stomach, aiding in the digestion of food. Peppermint herb can be consumed in a variety of forms, such as teas, tinctures and capsules, as well as by adding the herb to food or directly to water or tea.

Should peppermint herb green be consumed daily?

No, peppermint herb green should not be consumed daily. This is because it contains high levels of menthol, which can be toxic if taken in large doses. Additionally, consuming large amounts of peppermint herb green could interfere with the absorption of essential minerals and vitamins, potentially causing vitamin deficiencies. For these reasons, it is best to consult with a doctor before incorporating peppermint herb green into your daily diet.