From Australia’s far north to its deep south and across to the Indian Ocean, deciduous fruit trees are resting. This is the perfect time to treat them with protective sprays and washes.
Ever since the late 19th century, when Professor Pierre-Marie-Alexis Millardet discovered that copper can be used to destroy fungal spores on plants, gardeners have been using it in their gardens in winter. Lime, too, controls pests and diseases and is used to treat garden plants.
When the trees are bare and leaflessin winter, copper and lime-based sprays can’t burn foliage or damage blooms, but they can destroy spores that are lying in wait for warmer conditions. As the weather warms, spores begin to infest trees and shrubs with diseases such as brown rot and peach leaf curl. The discovery of the copper-based fungicide, known as Bordeaux spray, by Professor Millardet of Bordeaux, saved the French wine industry at the time from the devastating effects of downy mildew.
Some of the most widely used agricultural fungicides contain copper, including copper oxychloride and copper hydroxide. While these remain effective pesticides, copper oxychloride is now considered unsuitable for organic gardens. Follow in the Professor’s steps and make your own organic Bordeaux spray, or buy a copper-based fungicide at the nursery.
Annual clean up
Before applying copper or lime, the first step in protecting fruit crops from both pests and diseases is to clean up.
Old leaves and fruit may harbour hidden overwintering eggs or spores from pests or diseases. By collecting spoiled fruit and raking up fallen leaves from around productive plants, you are removing spores. Don’t use the fruit and leaves for mulching, as they remain a source of reinfection and reinfestation, although they can be ‘hot’ composted.
If you haven’t time to make a hot compost heap, where it will warm up to the 60C necessary to kill spores and eggs, simply bury the lot in the garden. Bury the fruit half a metre deep in the soil, and place leaves in the bottom of a trench one spade deep where they can rot without spreading problems.
Shaping the future
When deciduous plants are leafless in winter, weak, dead, fractured or rubbing branches are readily seen and pruned off. This not only improves the look of the plant, but removes areas that are easy targets for fungi and bacteria, and provide niches for pests to lay eggs. Make sure your pruning equipment is sharp, so wounds are clean and not ragged. To prevent the spread of any bacterial and viral disease around a garden or orchard, sterilise pruning equipment in between pruning each tree or shrub. To do this, dip the blades in disinfectant for 30 seconds. Use tea-tree oil, which is expensive but effective, or Clensel, a commercial disinfectant.
Alternatively, you can make up your own disinfectant with a mixture of one part household bleach to 99 parts water. Never paint pruning wounds. Wound preparations have been proven to cause more problems than they are alleged to cure. Pruning wounds will naturally heal and seal far better if left alone.
A good wash
Many common pests and diseases are resting now, hiding unseen as eggs and spores lodged in bark and bark fissures. Reset the balance using a process known as ‘winter washing’, on all deciduous fruit trees and shrubs, from apples and figs to peaches and pomegranate. This treatment is also applied to ornamental plants such as roses and frangipani that suffer fungal problems later in the year.
Bordeaux spray and lime sulfur are commonly used winter washes. Both are very effective at controlling fungal spores along with the eggs of most pest insects and mites. Yates Fungus Fighter is an organic-approved fungicidal spray based on cupric hydroxide, but isn’t currently registered to control pest eggs.
Citrus winter care
Although citrus are evergreen in winter, they also benefit from care at this time of the year. Established trees that have become infected with melanose disease or brown rot disease need special care.
First, remove old mulch and fallen fruit. Either hot-compost or bury this waste as it will be contaminated with disease. Apply fresh mulch around trees, making sure it doesn’t touch the trunk. Apart from cooling the soil, controlling weeds and retaining moisture, a layer of clean mulch 5cm thick helps to break the cycle of infection. Fresh mulch reduces the risk of fungal spores in infected soil being splashed by rain (or irrigation) up onto healthy citrus leaves.
Any infected citrus trees with melanose disease or brown rot disease should then be winter washed with cupric hydroxide. Make sure all parts of the citrus trees are thoroughly soaked, especially leaf undersides, bark and bark fissures.
If you have experienced trouble with stink bugs, such as bronze orange bugs or spined citrus bugs, winter is also the time to control these pests. Spray trees twice in mid-winter using horticultural oil. The oil-based spray is particularly good at smothering the nymphal stages of the bugs, dramatically reducing the number that reach adulthood.
In warm, dry regions, water citrus regularly, especially in windy weather, but don’t feed them until after they finish flowering. Too much nitrogen encourages citrus to abort embryonic fruit, and the lush, leafy growth will only attract virus-transmitting aphids.
Step-by-step Bordeaux spray
If you have a lot of plants to treat, making your own Bordeaux spray is economical. Here’s how to do it.
Step-by-step
1. Mix lime and water
Mix ¾ cup of builders’ lime with 2.25L of water in a plastic bucket. Do not use metal buckets as the mix reacts with metal. Stir well with a wooden or plastic spoon.
2. Mix copper sulfate and water
Take a separate plastic bucket, add ½ cup of copper sulfate, available from hardware stores or chemists, then add 2.25L of water. Thoroughly stir, then pour this mixture into the lime water, while stirring continuously. The Bordeaux sprayis ready to use immediately.
3. Spray
Pour the mix into a sprayer. Wet all plant surfaces thoroughly, especially bark fissures. Bordeaux spray (and lime sulfur) settles, so shake the sprayer every now and then.
4. Wash
Wash off any spray that splashes onto turf, or other foliage, using fresh water. Thoroughly clean out sprayers with warm soapy water, paying particular attention to nozzles.
Caution
Bordeaux spray and lime sulfur burn leaves, which is why they must be applied during winter dormancy before flower buds or leaves open.
2013 Bedding Advertisements: If you want to decor your bedroom in 2013 brand new spring style or if you are seeking for some bedding sets for you and your family, Bedding Stores UK here offers brand new bedding sets uk to meet all your needs. Various styles and patterns are available for you.
No comments:
Post a Comment