Best ways of treating and controlling powdery mildew

Powdery mildew

As name suggests it is a fungus (mildew) caused plant disease in which plant parts like leaves, stems, flowers and buds are covered with a powder like substance. The powdery substance is nothing but numerous spores of fungus produced in high humidity and moderate temperature environment.

Powdery mildew is common problem of plants like rose, zinnia, and lilacs. It also affects some vegetables – sweet peas, gourds, melon, and onion and grapes plant.

Symptoms

Powdery mildew attacks lower plant parts (bottom leaves) first which are just above the ground, then it move upwards affecting upper leaves, stem, buds and flowers. White spots start developing on affected leaves which keep enlarging with time. Leaves become colorless and fall off ultimately.

However, plant doesn’t die on attack of powdery mildew but it weakens and produces less number of blooms and fruits. In ornamental plants, it could affect look of the plant by destroying foliage. 

Reasons of infection

On favorable conditions of high humidity and moderate temperature fungus reproduces quickly and generates large number of spores.  Spores spread with wind and affect nearby plants. 

Control and Treatment

Powdery mildew can’t be cured but it can be prevented and treated in following ways.

- Take out infected leaves or plant in case of small level infection and put them separately in a plastic bag. It would help in stopping infection to nearby growing plants and vegetables. Compost bag material if you want.

- Make sure that plants are having proper aeration and getting enough direct sun light as it inhibits spore germination.

- Spray milk diluted with water (1: 10) on susceptible plants. Repeat the application to eliminate the disease.

Mix 1 tablespoon baking soda with normal water and spray on affected parts. Add few drops of liquid soap in it.

- Garlic extract is a good and cost effective way of controlling powdery mildew. It can be made by blending two garlic in 1 liter water with few drops of liquid soaps. Strain the mixture through a cloth to remove the solid part and spray the liquid on the plant.  

- Spray plant with neem oil made by seeds. Neem oil has fungicidal properties. It disrupts fungus metabolism, forms a barrier between the plant and the fungus and inhibit spore germination. On application it is absorbed by the leaf and circulated around to maximize area of coverage. Neem oil mixed in water, absorbed by the roots and circulated all over the plant.

- Use sulfur sprays available in market to control powdery mildew as sulfur creates low pH environment which is detrimental for the fungus.

Read ways of controlling mealy bugs and aphid attack on the plants.

Best Tips For Growing Vegetables At Home - Part 8 ( Onion )

Onions are a cold season crop, easy to grow because of their hardiness. We recommend using onion sets, which can be planted without worry of frost damage and have a higher success rate than direct seed or transplants. Onions are a basic and essential ingredient in many meals.

Propagation

Onions can be grown from seed or sets (small bulbs). Sets are more costly but they are quick, reliable and a good choice for beginners.

Dig small holes, put sets into it exposing tips on the ground. You can lay a piece of string on the soil as a guide to make sure you dig the row in a straight line. Gently firm down the soil around the tips with your fingers. The sets should be planted with the tips pointing upwards and positioned about 10 cm apart. Each row should be 20-30 cm apart.

Onion seeds are short-lived. If planting seeds indoors, start with fresh seeds each year. Start seeds indoors about 6 weeks before transplanting. Move transplants into the garden as soon as the ground can be worked.

Soil

Avoid heavier soils such as clay and silt loams unless modified with organic matter to improve aeration and drainage. Onions are sensitive to highly acid soils and grow best when the pH is between 6.2 and 6.8. 

Sun / Temperature

Onions grow best in full sun, so be careful not to plant the them in a location which will be shaded by taller vegetable plants. The onion is adapted to a wide range of temperatures and is frost-tolerant. For best production  cool temperatures (55 F to 75 degrees F) prevailed over an extended period of time is required, permitting considerable foliage and root development before bulbing starts. A constant supply of adequate moisture is necessary for best results. 

Watering

Generally, onions do not need consistent watering if mulch is used. If you want sweeter onions, water more.Onions will look healthy even if they are bone dry, be sure to water during drought condition.

Fertilizer

Fertilizers of a 1-2-2 ratio (5-10-10, for example) are good for onion production. As the onion plant's root system is very limited, high soil fertility is essential for good production.

Harvesting

Harvest green onions when the green stems reach about 6-8 in height. Scratch away the mounded soil around the stem base, grasp stem near the base and pull the green onion straight up. Lay the onions on top of the garden soil for a couple of days to dry out, then gather them up for storage preparation.