As a farmer, various factors can come between you and high yield from your crops. Among these factors include diseases.
You may be wondering what the white substance on your plants is, and why it is becoming increasingly difficult for the crops to thrive. Well, the problem may not be insufficient inputs or bad weather, but instead, a powdery mildew fungal infection. The infection is not fatal but can significantly weaken the plant.
About the Mildew Fungal Infection
Various diseases can affect your plants, and powdery mildew is among the most common. But powdery mildew is not a single infection. Instead, there are several of them with each affecting a particular plant species.
Powdery mildew is quite unlike the other fungal diseases as it does not need moisture to attack. The spores germinate without the need for moisture. It thrives in warm conditions but can strike at any time.
When mildew fungus attacks a single plant, it produces numerous spores that spread to other plants through the wind. It can also spread through runoff and insects and so it is critical for you to manage it within the shortest time possible.
That means the fungal infection can affect an entire crop variety within the shortest period, making it weak in the process. In severe cases, the disease can kill the plant.
How do you know a Powdery Mildew Infection?
The first tell-tale sign of powdery mildew infection is the flour-like substance on the leaves. It looks as if someone has been dusting them with flour. The disease starts with white spots that may appear in every part of the plant including the fruits. It will cover most parts of the leaves over a period.
Typically, the infection will cover the leaves’ top part and usually start with the older bottom leaves. The affected leaves gradually turn yellow and eventually dry out. Some leaves may become twisted, distorted and fall off to the ground.
The fungus will also distort other parts of the plant including the growing tip and buds. In the majority of cases, the symptoms will appear during the last phases of the growing season.
Controlling the Powdery Mildew Infection
The simplest way to partially remove the infection from the plant is by rubbing the leaves together. You will also need to isolate the infected plants and burn them to avoid spreading the disease. Avoid the temptation of composting or mulching with the infected plants. They may still give other plants the infection.
Use fungicides to treat the infected plants. Some of the most effective fungicides include potassium bicarbonate, neem oil, sulfur and lime sulfur.
- Neem Oil: the oil comes from the seeds of the neem plant. The oil is quite potent as it kills the fungi within 24 hours. It is also effective against insects and stops further spread through them – using neem oil is like killing two birds with a single stone.
- Milk: interestingly, several studies find milk to be a more effective treatment than your typical chemical fungicides. One study found out that a mixture of six parts water and four parts milk had better results than other chemical fungicides.It is unclear why milk demonstrates such effectiveness, but scientists believe the interaction between milk and sun produces free radicals, fatal to the fungi.
- Vinegar: vinegar contains acetic acid, effective against the powdery mildew spores. Be careful when preparing the mixture. If it proves too strong, the mixture may scorch the plant. Use a mix of 1-gallon water and four tablespoons of 5% vinegar solution, and spray every three days.
- Potassium Bicarbonate: is among the most effective organic treatments you will find anywhere. Potassium bicarbonate is safe and exterminates the spores on contact.The good thing about potassium bicarbonate is that it raises the PH level around the plant, making it unfavourable for the spores. It is an excellent powdery mildew safeguard.Mix three tablespoons of potassium bicarbonate with a half tablespoon soap and three tablespoon oil in a gallon of water, and spray it on the plant.
- Baking Soda: baking soda has a high PH level which possibly kills the fungus. Unfortunately, there are numerous mixed reports on the effectiveness of the remedy. It is, therefore best, to use baking soda as a preventative method.In a gallon of water, mix a tablespoon of vinegar and half tablespoon liquid hand soap and spray it on the plant. To prevent sunburn, don’t spray during the daylight hours. Ideally, test the effect of the solution on one leaf before spraying the whole plant.
- Sulfur: the substance is one of the most effective in keeping the mildew spores at bay. You can get sulfur in liquid or powder form.Wear gloves, eye protection and eye mask before spraying it in the plants.
- Garlic: the spice has a decent level of sulfur and is quite effective against the fungi. However, it will prove more effective when added to organic oil blends.Add six crushed garlic cloves to one ounce of rubbing alcohol and organic oil. Strain and keep the crushed garlic, as well as, the resulting liquid. Soak the garlic in a cup of water for about a day, and strain it out, throwing away the crushed garlic.In a gallon of water, add the garlic water and the blend of alcohol and oil. Use the mixture to spray on the leaves generously.
- Copper Fungicides: copper is quite useful at eliminating fungi. However, you will need to follow directions to the letter as an excessive amount of copper can damage the plant.
Powdery Mildew Prevention Measures
Ideally, you should choose powdery mildew resistant varieties. Your local nursery expert may have ideas on where to get the resistant varieties.
Powdery mildew loves hot and humid weather. Therefore, minimise the actions that enhance humidity as much as possible. Typically, avoid overhead irrigation and prune the thick bushes for better air circulation.
The fungi spores are susceptible to direct sunlight. Therefore, avoid as much as possible growing the vulnerable varieties under shade. Shade and cool conditions will encourage mildew development.