The Importance Of Winter Wash Spraying Plants

Growing fruit in residential areas can be an interesting, fun and rewarding hobby. Many novices dream of plucking perfect fruit of trees or plants in their gardens. However, high quality harvests do not happen without knowledge and a great deal of work. Controlling pests (insects and diseases) is an integral part of the care necessary to achieve good results. 

This blog provides guidelines for pest management in home fruit plantings, but good pest control is not possible if spraying is the only action taken. Success starts with selection of disease resistant cultivars and sites that are open and full sun. Cultural practices such as pruning and sanitation are also necessary for good pest control. 

The Importance Of Plant Protection In Winter and Schedule of Spraying

Most fungicide (disease control product) and some insecticide (insect control product) applications are effective only if applied preventatively because it is not possible to control the pest satisfactorily after infection or infestation. 

In very rainy seasons, sprays may need to be applied more frequently than the usual practice. Wet weather favours development of the disease-causing organisms; thus, more chemical protection is needed. Also, rains can wash off the pesticides (fungicides and insecticides). When rain occurs before a spray has dried or if rainfall totals more than 1 inch within 24 hours, the spray should be re-applied. However, do not delay fungicide application if rain is forecast because fungicides provide more benefit when applied before a rain than after. Protection from infection by disease-causing organisms is needed when plant surfaces are wet. 

Thorough coverage of all aboveground plant parts is needed for good pest control. One of the biggest mistakes home fruit growers make is allowing plants and trees to grow too tall. If dwarf and semi-dwarf trees are selected and then maintained at a manageable height, it is easier to spray them properly as well as to harvest the fruit. Proper pruning practices also reduce the amount of spray needed and permits better coverage. 

The type of sprayer used depends on the size of the fruit planting. For most plantings of small fruits or for a few small fruit trees, hand-pump sprayers are adequate. Trombone-type sprayers are helpful for taller trees. For the increased spray volumes required by larger home orchards, power sprayers are recommended. 

Mixing a commercial spreader-sticker with the spray solution provides better coverage of slick surfaces, such as apple fruit or blackberry stems. See the pesticide label to find a suitable spreader-sticker. 

The product labels give the rates, and those rates must be followed. The label rates are expressed as amount per gallon of water. The following table can be used to determine the amount of spray mixture needed. 

Multipurpose Fruit Spray 

Multipurpose fruit tree spray products are mixtures containing a fungicide and insecticides. Insecticides should not be applied during bloom because they will kill bees. It may be more convenient to purchase the fungicide separate from the insecticide. Multipurpose sprays are effective against some, but not all, pests. 

Protect Pollinating Insects 

Honey bees and other pollinating insects must be protected from insecticides, which will kill them. Do not spray fruit plants with insecticides while the plants are in bloom. The literature is mixed on the safety of copper products (copper sulphate + lime [Bordeaux Mixture], copper hydroxide) for bees, and some literature suggests other fungicides may negatively impact pollinator health. To reduce risk to bees, when applying fungicides during bloom (especially copper products), only apply products during late evening, night, or early morning when bees are not foraging. 

To protect people and the environment, pesticides should be used safely. This is
everyone’s responsibility, especially the user. Read and follow label directions carefully before you buy, mix, apply, store or dispose of a pesticide. According to laws regulating pesticides, they must be used only as directed by the label.

Pesticide Safety 

Most of the pesticides suggested for use in this publication are low-toxicity materials; however, some precautions are still needed. 

• Keep pesticides in the original, labelled container. 
• Keep pesticides in a locked storage cabinet, away from children or pets. 
• Read the label each time before you use the product. 
• Wear rubber gloves, goggles, a long-sleeved shirt, long pants and a hat when mixing and applying pesticides. 
• Handle the pesticide carefully when mixing. Avoid breathing dust or vapours. Wash any chemicals on the skin immediately with plenty of water. 
• Never apply insecticides or fungicides with a sprayer that has been used for weed killers. 
• Do not spray if it is windy. 
• Mix only as much as you need. Do not store diluted spray mixtures from one application to the next. They will lose effectiveness and are unsafe. 
• Observe the waiting period in days between the final spray and harvest (pre-harvest intervals) and re-entry requirements given in the following table and on the product label. 

How Do Winter Sprays Work?

Just like the trees are sleeping and recovering during the winter, so are a lot of insects and diseases in their own way. They’re going through a dormant period of their own and many of these insects and diseases will do their winter rest on the tree itself. Some examples might be mites, scales, or woolly apple aphids.

Some diseases, particularly bacterial diseases like fire blight, will be residing on the tree itself. And so we want to be aware of that. And in order to reduce the pest pressure or the disease inoculum when the season starts, there are some treatments that we can apply that we need to think about that will help to reduce the population say of overwintering mite eggs or overwintering scale. And by getting a jump on the season, it reduces the potential for those pests and diseases to be bigger problems in season than they would be if we didn’t do anything.

One of the most classic applications is horticultural oil. And the horticultural oil would be applied in a dilute spray. And by dilute, I mean maybe 1% to 2% oil in water, and that would be applied to the entire surface of the tree. What the oil does is it essentially smothers the mite eggs or the scale or the woolly apple aphids.

Some other sprays can be applied, copper being one of them, lime sulphur would be another, and also neem oil and Karanja oil which are seed oils from trees in India have also become very popular. They act differently than horticultural petroleum oils and they actually have some added benefits for the health of the tree, but in the dormant season, those are the basic options that we’re dealing with to help with these overwintering insects and disease pressures.

When it comes to oils or copper and lime sulphur, if those products are applied when there’s foliage on the tree, you can get what’s called phytotoxicity. So these products can damage or burn off the leaves. And if it’s even later than that, they could potentially burn the flowers or lead to roughened fruit.

And so, if it is known there is a mite problem or a scale problem, these products need to be applied earlier in the dormant season. Maybe in late January, mid to late March or so. At that time, you can apply them at a higher rate and have a greater impact on those pest species populations.

The sooner we get to that bud swell, bud break, and what we call green tip, which is when you start to see the very, very first hints of green tissue emerge, we need to reduce the rates so that we don’t cause any phytotoxicity problems in the tree itself.

And so, by reducing the rates once the buds start to break, we’re obviously going to have less efficacy against some of those insects and disease pests. But as well, those pests are starting to wake up and they become more susceptible. So, there’s a little bit of a sweet spot.

We don’t like to recommend applying anything too early in the dormant season. We also don’t want to apply it too late because then we have to reduce the rates too much. So somewhere right around what we call delayed dormant. So just as the buds start to swell, but before there’s that green tissue, that’s really the sweet spot of when you want to apply these for the most efficacy.

Spraying Different Plants 

Proper identification of insect pests and diseases is an important step before attempting to control the pest. Not all plant problems are caused by pests; some are caused by cultural, nutritional or environmental conditions. 

If you are unsure, feel free to contact our experts who provide a host of garden maintenance services. 

BZ Gardens – Garden Maintenance Services 

Winter wash spraying your plants and shrubbery is a great way to improve their longevity and health going into spring and summer. Our experts at BZ Gardens offer a range of important garden maintenance services to improve your garden’s appearance and health, whether you need a general tidy-up or some trimming we’d be happy to offer our assistance. For more information take a look at our services here, alternatively get in touch with us here.