white spots on bushes

White Spots on an Evergreen Bush

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White spots on evergreen shrubs indicate that something is wrong. Closer inspection can help you determine the exact cause, such as a fungal infection or insect infestation, but the three most common problems require mostly the same treatment. Investigating the problem can help you adjust your evergreens’ environment to ensure that they stay healthy in the future.

Powdery Mildew

White or gray powder spots on your evergreen bushes are evidence of powdery mildew. This typically manifests on leaves, but you can find it on other parts of shrubs, too. As a fungal disease, it needs immediate pruning before it spreads to other parts of the shrub or other garden plants. You can also apply fungicidal soap or spray with a mixture of one quart water and one teaspoon baking soda once a week. Preventive measures include keeping your evergreens pruned allows air movement and watering them in the morning gives them the entire day to dry.

Spider Mites

If the white spots on your evergreen occur as tiny dots on the leaves of broad-leafed evergreens, spider mites could be the culprits. These little creatures, the size of a period at the end of a sentence, suck fluids from plant cells, leaving the white spots as evidence. Eventually, leaves look freckled with these dots, until they turn yellow and drop from dehydration. The easiest way to get rid of mites is to dislodge them with a spray of water on the undersides of leaves, followed by application of horticultural oils to keep them away. Applying dormant oils in winter will kill overwintering eggs.

Scale Insects

Scale insects can infest even needled conifers, making them especially dangerous in a garden of prickly evergreens. Immature scales and adult female scales are round and wingless, making it difficult to identify them as insects. They suck fluids from bark and leaves, including needles, leaving pale spots. Leaves gradually turn yellow and wilt before dropping. Remove infested branches and spray horticultural oil to control the population. You can also introduce natural predators into the environment for biological control, such as lacewings, beetles or parasitic wasps.

Keeping Evergreens Healthy

To prevent white spots from appearing on your evergreens in the future, seasonally spray horticultural oils that will deter or kill insects and fungus. The safest time to do this is when temperatures are over 40 degrees Fahrenheit in winter, as oil can harm shrubs when they’re growing in spring or summer. Don’t spray junipers (Juniperus), Japanese holly (Ilex crenata) or spruce (Picea) with oils, as they are sensitive to them. Providing proper cultural care for your evergreens keeps them healthy and helps them withstand diseases and infestations.

White Spots on an Evergreen Bush. White spots on evergreen shrubs indicate that something is wrong. Closer inspection can help you determine the exact cause, such as a fungal infection or insect infestation, but the three most common problems require mostly the same treatment. Investigating the problem can help you …

White Leaf Spot Control – How To Treat White Spots On Plant Leaves

It’s late spring and the leaves of your trees are almost full sized. You take a walk under the shady canopy and look up to admire the foliage and what do you see? White spots on the plant leaves. If that tree you’re standing under is a nut tree, the chances are good that you’re looking at a case of downy leaf spot, also known as white leaf spot.

Control and elimination of this downy spot disease will probably be the next thing on your mind. You’ll want to know what to do for white spots on the leaves. Will it harm your tree? First, let’s take a closer look.

What is Downy Spot?

Early on, downy leaf spot presents itself as small (about 1/8 to 1/4 inch)(3 to 6 mm.), white, furry areas on the underside of the leaves, and pale green spots on the upper side. If some of those white spots on the plant leaves have fused together to become blotches, they should look like white powder. If the disease attacking your nut tree fits this description, you’ve got downy spot.

The proper name for your leaf destroyer is Microstroma juglandis. It is a fungus that commonly attacks host trees such as butternut, hickory, pecan and walnut trees. It’s found anywhere in the world where these nuts are grown.

Those white spots on the plant leaves are fungal structures and spores that thrive in the warming temperatures and rains of spring. As the downy spot progresses, the upper sides of the leaves become chorotic, that is, show yellowish spots that will eventually turn brown. Affected leaves will fall from the tree by early August.

As time passes, the ends of the branches may develop witch’s broom formations. The newly growing leaves will be stunted and malformed and will appear more yellowish than green. Many of the broom leaves will shrivel and die over the course of the summer, but before they do, these witch’s brooms can grow to be several feet (1 m.) in diameter.

White Leaf Spot Control – How to Treat White Spots on Plant Leaves

Unfortunately, the answer to what to do for white spots on the leaves of your nut tree is nothing. Commercial growers have the advantage of proper equipment to reach the full height of these trees and to spray the entire tree with commercial fungicides not available to the home owner with only one or two trees.

The good news is that the life of your tree won’t be threatened by white leaf spot. Control of future infections is largely a matter of good sanitation practices. All leaves, infected or healthy, and all shucks and nuts should be cleared and destroyed each winter or in the early spring before buds begin to swell. Infected leaves and nuts that are left to overwinter on the ground are major sources for new infections in the spring. Removing damaged twigs and limbs, including the unattractive witch’s broom, should also be practiced during the dormant season, if possible.

While downy leaf spot won’t kill your tree, any infection will weaken it and leave it vulnerable to more serious infections. Keep your trees well fertilized and watered, and they’ll stay strong enough to easily survive this fungal disease.

White spots on the plant leaves – what is it exactly? Read this article to learn more about downy leaf spot and what to do for these white spots on leaves. Click here for more information.