Pest & Disease Late blight

Late blight

Phytophthora infestans

What is Late blight (Phytophthora infestans)?

Late blight, also known as potato blight, is a devastating plant disease caused by Phytophthora infestans. The disease is responsible for the Irish potato famine. Symptoms include lesions on leaves, petioles, and stems, with a whitish growth of spore-producing structures on the underleaf surfaces. Potato tubers develop rot. The rot can penetrate up to 15 mm (0.6 inches) deep, causing significant losses during storage, transit, and marketing.

How does Late blight (Phytophthora infestans) occur?

P. infestans reproduce through both sexual and asexual means. Sporangia, which are asexual spores, and sexual oospores are dispersed by wind and can infect nearby plants within hours. Below 15 °C (59 °F), sporangia germinate by producing zoospores with flagella. Above that temperature, most sporangia produce a germ tube directly. Foliage blighting and new sporangia are produced within four to six days after infection. The cycle continues in cool, moist weather. The oospores, with their thickened walls, can persist in the soil for several seasons, making eradication challenging.

Symptoms

1 - Effects on Plants

• Phytophthora infestans cause rapid rotting, and lesions on leaves, stems, and tubers, leading to significant crop damage and yield loss. • The disease, responsible for the Irish potato famine, results in spore-producing structures on leaves and deep rot in potato tubers, causing losses during storage and transportation.

2 - Effects on Soil

Late blight can introduce pathogens into the soil ecosystem through infected plant debris, potentially impacting soil health and crop rotation practices.

Solutions

1 - Cultural Practices

• Avoid planting crops in the same location year after year to reduce the buildup of the pathogen in the soil. • Start with healthy seedlings or certified disease-free seeds to minimize the risk of introducing the pathogen. • Provide adequate plant spacing to ensure good air circulation and reduce humidity, creating an unfavorable environment for the disease. • Immediately remove and destroy any plants showing symptoms of late blight to prevent the spread of the disease.

2 - Resistance Cultivars

• Some known examples include the potato varieties 'Kennebec', 'Agria', and 'Sarpo Mira', which exhibit strong resistance to late blight. In tomatoes, varieties like 'Mountain Magic', 'Iron Lady', and 'Defiant' are known for their resistance to late blight. • However, it is important to note that no variety is completely immune, and proper management practices should still be followed.

3 - Chemical control

• Systemic fungicides like dimethomorph, cymoxanil, fluopicolide, and propamacarb have been approved and registered for controlling late blight. • It is recommended for growers to rotate the use of different fungicides to prevent the development of resistance in the pathogen, following the instructions provided by the manufacturer and local agricultural authorities.

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.