Pest & Disease Powdery mildew

Powdery mildew

Erysiphe lagerstroemiae

What is Powdery mildew (Erysiphe lagerstroemiae)?

The Erysiphaceae family or powdery mildews, are Ascomycetes fungi that are obligate parasites, relying on living plant tissues. E. lagerstroemiae can be severe on woody species like roses, crape myrtles, and sycamores. It affects new growth, causing dwarfing, distortion, and a white powdery coating. Infected leaves die and drop prematurely. They infect above-ground parts like leaves, stems, flowers, and fruits.

How does Powdery mildew (Erysiphe lagerstroemiae) occur?

The Erysiphaceae family reproduces through asexual conidia, which are dispersed to initiate new infections. On perennial hosts like roses, they survive as vegetative strands in buds or as chasmothecia, fruiting bodies, on branches and stems. They form thin mycelium layers on plant surfaces, producing visible spores that contribute to the powdery appearance on leaves, flowers, fruits or stems.

Symptoms

1 - Plant Health

• Powdery mildew inhibits photosynthesis, reduces vigor, and causes premature leaf drop stunted growth, reduced fruit production, and an overall decline in plant health may occur. • Yield losses and diminished crop quality can result from powdery mildew infections. Infected fruits/vegetables may become unmarketable or have reduced shelf life.

2 - Soil Health

• Powdery mildew's direct impact on soil health is minimal. Severe infections leading to plant stress or death can indirectly affect soil health by reducing organic matter inputs and altering nutrient cycling.

3 - Environmental Impact

• Powdery mildew does not cause significant environmental contamination or long-term soil pollution due to the misuse of fungicides. • Powdery mildew infections can disrupt natural ecosystems by affecting native plant species and reducing food resources for beneficial insects and other organisms.

Solutions

1 - Cultural control

• Locate plants in sunny areas with good air circulation to reduce humidity and create an unfavorable environment for powdery mildew growth. • Water plants at the base in the morning to allow foliage to dry quickly, minimizing fungal infection opportunities. • Overfertilization can promote succulent growth, making plants more susceptible to powdery mildew. Use slow-release fertilizers or follow recommended application rates. • While not a prevention method, overhead sprinkling can help wash off powdery mildew spores from plant surfaces, reducing their spread.

2 - Least-Toxic Fungicides

• Myclobutanil (Immunox) can function as an eradicant and protectant. • Horticultural oils such as JMS Stylet Oil and Saf-T-Side Spray Oil, along with natural oils like Neem Oil (e.g., Powdery Mildew Killer) and Jojoba Oil (e.g., E-rase), are effective options for controlling powdery mildew. It's important to read and follow the instructions provided by the manufacturer when using any fungicides.

3 - Biological Control

• Biological fungicides, like Serenade, contain beneficial microorganisms that destroy fungal pathogens. It has an active ingredient, Bacillus subtilis, which helps prevent powdery mildew infection. It's important to read and follow the instructions provided by the manufacturer when using any fungicides.

4 - Chemical Control

Here are some chemical fungicides commonly used to control powdery mildew: Propiconazole (e.g., Banner Maxx, Funginex), Myclobutanil (e.g., Immunox, Eagle), Thiophanate-methyl (e.g., Cleary's 3336, Domain), Azoxystrobin (e.g., Heritage, Quadris), Trifloxystrobin (e.g., Compass, Flint), and Tebuconazole (e.g., Folicur, Orius). It's important to read and follow the instructions provided by the manufacturer when using chemical fungicides.

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.