Here comes a gardening superstar!

Donna Balzer, an award winning media personality, a blogger and an author of three books, visited the Canadian Cancer Society, Saskatchewan Division in May for a full day healthy gardening event. Donna's current book, "No Guff Vegetable Gardening" is a Canadian best seller. Here is Donna with Sanela Begic Le from the Canadian Cancer Society featuring the book.

All you need to know about our enemy, the powdery mildew!

Powdery mildew is a common disease on many types of plants. Although different species of fungi cause the disease on different plants (Erysiphe infects vegetable crops and flowers; Podosphaera species infects apples and stone fruits; Sphaerotheca species infects berries, roses, some vegetable crops, and stone fruits; and Uncinula necator infects grapes), the infections are all characterized by a powdery white to gray fungal growth on leaves, stems and heads.

Symptoms

Powdery mildew usually shows up on leaf and stem surfaces, looking as if baby powder was sprinkled over them. Woody species such as grapes, fruit trees, roses, crape myrtle, and sycamore can be seriously affected; new growth is often distorted. The young fruit of apples and grapes can also develop rough skin due to powdery mildew.

Life Cycle

All species of powdery mildew fungi require living plant tissue to grow. On perennials, they survive on buds and stem tissue. Certain weeds will also act as hosts through the winter. The optimum temperature for infection is between 68 to 77 degrees F and relative humidity between 40 to 100% is sufficient for the spores to germinate. Low, diffuse light also seems to favor powdery mildew development.

The mildew can spread rapidly, in as little as 72 hours. However, it commonly takes 7-10 days from the time of infection to the development of symptoms and secondary spore production.

Management
In most cases, good cultural practices will adequately control powdery mildew:

1.     Select powdery mildew resistant varieties. This is particularly true of roses. For lawns, shade tolerant grasses such as creeping red fescue can be planted.

2.     Plant in full sunlight in a well-drained area.

3.     Do not crowd plants. Air flow and ventilation will discourage mildew growth.

4.     Powdery mildew thrives where high rates of nitrogen have been used. High nitrogen promotes tender leaf formation, causing dense stands that are more susceptible to infections. Adequately fertilize but avoid stimulating succulent growth. Organic fertilizers or slow-release formulations of lawn fertilizers are good choices.

5.     Prune infected plants to get rid of infected parts and increase airflow. If the infestations are severe, remove and destroy the plants that are infected.

6.     Disinfect your pruning tool in a bleach solution of one part household bleach to four parts water after each cut.

7.     Watering plants in the morning gives the plants the rest of the day to dry off, discouraging establishment of diseases, including powdery mildew.

Organic Sprays

In 1999, a Brazilian scientist named Wagner Bettiol discovered a new alternative to controlling powdery mildew - weekly sprays of milk!. Not only was milk found to be effective at controlling the disease, it also acted as a foliar fertilizer, boosting the plant's immune system.

How does milk control powdery mildew?

Scientist aren't 100% sure how milk works to control this disease. It seems that milk is a natural germicide. In addition, it contains several naturally occurring salts and amino acids that are taken up by the plant. From previous experiments using sodium bicarbonate, potassium phosphate, and other salts, researchers have found that the disease is sensitive to these salts. It is possible then, that milk boosts the plant's immune system to prevent the disease.

What kind of milk should be used?

In Bettiol's original experiment, fresh milk was used, straight from the cow. However, this is obviously not feasible to most home gardeners. The research work in New Zealand actually found that using skim milk was just as effective. Not only was it cheaper, but the fact that the milk had no fat content meant that there was less chance of any odours.

Sulfur

Sulfur is also  highly effective against powdery mildew if used in a protectant program with a minimum of 7 to 14 days between applications. Apply a sulfur-based fungicide at first evidence of mildew and repeat applications as necessary. Proper timing is critical to successful control so make sure to begin at the first sign of the disease.

Baking Soda

However, sulfur can be damaging to some squash and melon varieties. Another option is to spray once a week with a solution of baking soda. Baking soda increases the surface pH of the leaf making it unsuitable for the growth of powdery mildew spores.

Be sure to spray the undersides of leaves as well as the upper surfaces when using any of these sprays.

Here's a recipe to make your own spray:

1 teaspoon baking soda
1 quart water
A few drops of liquid soap

Before treating your plants, test the spray on a few leaves to make sure they are not too sensitive.

Stay tuned for my new blog entry very soon!

There are a number of tools that a gardener can use to combat slugs. Handpicking, traps, barriers, baits, and predators are just a few techniques. So, rather than shrugging off slug damage as inevitable, choose from the slug control menu and you'll be surprised by the results.

Please register at http://www.pesticidefreeforlife.ca/ for our upcoming event with Donna Balzer! She's coming to Regina to talk about all the secrets and tips on healthy gardening. May 10th, we are offering a noon and an evening session.

SLUGS!

There are not many gardeners who can look at a slug without some degree of horror. Slugs can decimate a garden, especially one with newly planted seedlings. The slimy creatures do, however, have a purpose in the grand scheme of things – breaking down woody debris. They’re wonderful in the compost pile but gardeners certainly don’t need to encourage any more than are already around.

In fact, their rate of reproduction is such that slugs do often need some level of control. The best way to combat slugs is to understand their lifecycle. Know thy enemy! Slugs contain a high percentage of water and will begin feeding as soon as soil temperatures rise above 40 F (5 C), emerging from the soil or from protected areas. They prefer to forage at night or on dull days when temperatures drop and the garden is damp. Their gelatinous eggs, laid in clusters of 40-100, can be found in the soil, under rocks and even in outdoor pots. Learn to recognize them!

Slug Predators
Many natural predators will eat slugs. Providing a habitat for them will help build their populations so that you do less work in the long run. Slug predators include:

• Ground beetles - Like to live under wooden boards during the day.
• Frogs - They prefer damp sites and a quarter of their diet may comprises slugs.
• Birds - blackbirds and thrushes, robins, starlings, rooks and crows, jays, ducks, seagulls and owls will eat slugs.

Cultural Methods of Control
There are many simple things you can do in the garden to decrease slug damage. Because slugs are made up of so much water, they are very susceptible to drying out. In the early spring, cultivate your soil to expose their eggs to drying air & predators. Try to keep your garden as dry as you can without damaging your plants. This can be achieved by using drip irrigation or soaker hoses rather than overhead sprinklers. In addition, if you mulch your garden, pull the mulch back from the base of susceptible plants.

Handpicking
Handpicking is an extremely effective way of riding your garden of hundreds of slugs. For the squeamish, chopsticks or tongs can be used to catch the offending pests. Neighbourhood kids are perfect for this kind of work. A headlamp, pair of tongs, and a bucket of soapy water is all that’s necessary. The best time to hunt for slugs is 2 hours after sunset.

Baits
Slugs are attracted to chemicals given off by the fermentation process. The most popular bait has been beer. However, not all beers are created equal. In 1987, a study at Colorado State University Entomology Professor Whitney found that Kingsbury Malt Beverage, Michelob, and Budweiser attracted slugs far better than other brands.

The range of slug traps is only a few feet so you need to supply a few throughout your garden. Never, sink the containers with their rims flush with the soil level or you run the risk of drowning ground beetles, important slug controllers. The rims should be 1" above the soil's surface.

In the last couple of years, a new product has been released into the market that is receiving rave reviews from organic gardeners. Baits made from iron phosphate have been found to decrease slug populations without harming birds, small pets or humans. The baits are sold commercially under the name Ecosense ® or  Safer's Slug & Snail Bait ®.

Barriers
Aside from diverting slugs to where you want them, gardeners can also use certain barriers to keep slugs out of particular spots. A ring of abrasive material such as eggshells, sand, wood shavings, diatomaceous earth, hair or ash can be placed around susceptible plants. These materials do have to be kept dry, however, in order to work. After rains, top them up again. Cutting the tops and bottoms off of plastic containers and using them as a cylinder around young seedlings can construct a more permanent barrier.

One of the most effective barriers, however, seems to be copper tape, as it works wet or dry. When slugs and snails make contact with the copper, there is a toxic reaction, similar to an electric shock, which repels them. The minimum width for the copper barriers needs to be at least two inches; slug barriers sold in nurseries are often smaller and should be doubled or tripled when installed..

There are a number of tools that a gardener can use to combat slugs. Handpicking, traps, barriers, baits, and predators are just a few techniques. So, rather than shrugging off slug damage as inevitable, choose from the slug control menu and you'll be surprised by the results.