A lot of different native and ornamental trees and shrubs get leaf spot diseases. Many leaf spot diseases have similar biology and therefore very similar management options.
Here is information about some of these diseases, along with advice on how to treat all leaf spot diseases in shade trees and shrubs. Marssonina leaf spot.
Finding tiny red moving dots on your houseplant leaves can be alarming. Upon closer inspection you may identify them as spider mites – one of the most destructive pests for indoor plants.
Spider mites are part of the Tetranychidae family and live and breed on the undersides of plant leaves. They use their piercing mouthparts to suck moisture and nutrients from the plant causing stippling, discoloration and even leaf loss.
Left unchecked, spider mites can decimate both outdoor and indoor plants But with some diligence and patience, you can get rid of them and recover your plants
In this comprehensive guide, we’ll cover:
- What spider mites look like
- The signs of spider mite damage
- How to identify spider mite infestations
- Effective ways to get rid of spider mites
- Tips to prevent future infestations
What Do Spider Mites Look Like?
Spider mites are tiny pests measuring only up to 0.4 mm long. They have oval bodies and eight legs like spiders. Under a magnifying glass, you can see tiny hairs on their legs and body.
Their color ranges from red, yellow, brown, to green. The young larvae are paler, nearly transparent. The red species is most common indoors.
Spider mites thrive in hot, dry conditions. A single female can lay up to 20 eggs per day and live for 2-4 weeks. This allows them to multiply rapidly into large infestations.
Signs of Spider Mite Damage on Plants
Spider mites are sneaky pests that can go undetected until major damage is done. Signs of an infestation include:
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Fine webbing on leaves and stems – spider mites spin protective silk webs on plants. Look for tiny cobweb-like threads.
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Speckling or stippling on leaves – Early spider mite feeding causes light dots on leaves.
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Yellowing or browning leaves
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Drooping or wilting leaves
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Leaf loss
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Slowed growth
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Silk strands dangling from plant
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Clusters of eggs on the undersides of leaves
How to Identify Spider Mites on Plants
To confirm spider mites, you’ll need to inspect leaves closely with a magnifying glass or microscope. Look for:
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Tiny crawling dots that are red, yellow, brown, or green
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Oval-shaped bodies with 8 legs
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Webbing and silky strands on and under leaves
You can also hold a white sheet of paper under the leaves, shake them, and look for specks falling onto the paper.
Check leaf undersides and the joints where leaves attach to stems. This is where spider mites like to hide and lay eggs.
How to Get Rid of Spider Mites on Houseplants
If you catch an infestation early, you may be able to control it with regular pruning and spraying:
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Prune off heavily infested leaves and stems. Discard them – don’t compost.
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Use a forceful stream of water to blast away mites.
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Apply insecticidal soap or neem oil sprays. Coat all leaf surfaces to suffocate mites. Repeat every 5-7 days for 2-3 weeks.
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Release predatory mites which will feed on spider mites.
For severe infestations, you may need to use miticides containing chemicals like abamectin, bifenazate, or acequinocyl. Always follow package directions carefully.
Completely removing mites takes persistence. Don’t give up too soon or they may develop resistance!
Preventing Spider Mites on Houseplants
Prevention is critical to avoid spider mite issues:
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Check new plants closely before bringing home
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Quarantine new plants for 2-4 weeks before introducing to others
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Keep plants out of direct sun
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Provide adequate humidity – spider mites thrive in hot, dry conditions
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Hose plants down or place in shower periodically
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Keep leaves dust-free by wiping periodically
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Avoid over-fertilizing plants
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Release predatory mites or insects preventatively
With diligence, you can keep spider mites at bay and maintain happy, healthy houseplants. Be on the lookout for signs of infestations and address issues promptly. A little effort goes a long way against these destructive pests!
Causes of leaf spots Tar spot on maple
- Fumes cause most leaf spot diseases, but bacteria and other pathogens can also cause some diseases.
- A lot of pathogens are host-specific, which means they will only hurt trees in the same family.
- One or more leaf spot diseases can hurt almost all trees and shrubs.
Managing leaf spot diseases
Even though leaf spot diseases don’t do much damage to plants, there are things you can do that, when done together, will make the disease less likely to spread to trees in the years to come.
- Rake up and destroy fallen leaves before the first snowfall. Diseases can live in leaf piles for a long time and infect the plant again the next growing season.
- Do not overcrowd plants. Space plants according to the size they will grow to.
- Cut back trees and bushes to let more light in and improve air flow throughout the canopy.
- Diseases grow in damp places, so water trees from the bottom up and be careful not to splash water on the leaves. A drip or soaker hose works best for this. Avoid sprinklers.
- To keep your tree from getting stressed, water it enough so that the top 6 to 8 inches of soil are always wet, especially in the summer when it’s dry. Allow soil to dry before watering again. Keep a layer of mulch three to four inches deep around your tree. Do not mound the mulch around the tree trunk. Spread the mulch out flat, leaving at least 2 inches of space between each stem to let air flow. Annually reapply mulch and inspect to ensure levels are maintained.
- Do not feed trees and shrubs that have leaf spot diseases unless a soil test says that they need it to make up for a lack of nutrients.
- If a tree hasn’t lost all of its leaves for several years in a row, it doesn’t need fungicides.
- Fungicides protect plants and need to be used before symptoms show up on the leaves. When to use fungicides correctly can change depending on how the disease works. To completely cover the canopy of big trees, you need high-pressure spraying gear. An arborist should be hired to treat leaf spot diseases in big trees.
What are these RED SPOTS on my Fiddle Leaf Fig??
FAQ
What are the little red dots on my plant leaves?
How do you treat red leaf spot?
What are the red balls on plant leaves?
What causes red spots on Rose leaves?
Roses are predominantly affected. Cercospora Leaf Spot, caused by the fungus Cercospora spp., is characterized by small, circular to angular dark brown or reddish-brown spots on leaves. These spots may coalesce, causing premature leaf drop. It affects a wide range of plants, impacting their overall vigor and aesthetics.
Which plants get leaf spots?
Almost any plant can get leaf spots, and most can get leaf spot disease. The following plants are especially susceptible to leaf spot disease. Roses, petunias, rhododendrons, geraniums, lettuce, beetroot, and peppers. How Do I Prevent Leaf Spots?
How do I know if I have leaf spots?
One good way to determine the likely cause of leaf spots is by color. Black leaf spots: Most likely to be leaf spot disease (fungal or bacterial). Red leaf spots: Most likely to be fungal leaf spot disease or a nutrient deficiency. Grey leaf spots: Most likely to be fungal leaf spot disease.
What causes a leaf spot on a tree?
Fungal spores, the most common causes of leaf spot, overwinter in fallen leaves and other plant debris. Remove and dispose of leaves and other plant material in fall, especially around affected trees and shrubs. Leaf spot diseases rarely get so bad that they need chemical treatment.
What are the most common leaf spots?
Black leaf spots: Most likely to be leaf spot disease (fungal or bacterial). Red leaf spots: Most likely to be fungal leaf spot disease or a nutrient deficiency. Grey leaf spots: Most likely to be fungal leaf spot disease. White leaf spots: Most likely to be fungal leaf spot disease, too much sunlight, or an insect infestation.
What are leaf spot diseases?
Leaf spot diseases are a collective term for a variety of fungal and bacterial infections that cause discolored lesions or spots on the leaves of affected plants. These spots can range in size, color, and shape and can compromise the plant’s health if severe. Almost every region around the world is susceptible to some form of leaf spot disease.