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Plant Leaf Problems - Pest, Disease, Nutrition or Soil Problems?


The leaves of a plant are usually the first indicators that there is a problem somewhere with the plant. Often, what you see on the leaf is not the real problem, but simply shows up as an indicator that all is not well somewhere in the plant.

In terms of water provision and nutrients, the leaf is usually at the furthest point away from the source - the roots. But many problems at the roots of the plant will tend to show up firstly in the foliage of the plant.

Leaves are invariable the lushest, tastiest and most nutritious part of the plant - easy to chew and digest - so apt to be on the food menu for a whole range of insect pests as well as for us humans. Leaf chewers, sap suckers, and all manner of vegetarians of the insect world find what they need to sustain themselves in the foliage of plants. 

As if the leaf does not have enough to cope with in itself, leaves are invariable the lush - tastiest - part of the plant, so apt to be on the food menu for a whole range of insect pests. Leaf chewers, Sap suckers, and all manner of vegetarians of the insect world find what they need to sustain themselves in the foliage of plants.  

General Leaf Problems - Symptoms

Leaf scorch from over feedingApple leaf rustVine Weevil Leaf damage
These leaves show three different type of problems - Cultural, disease and pest. The first being though a flash release of fertiliser in heavy rain, causing scorch; the second is a leaf disease, in this case Apple Leaf Rust, and the third being insect damage caused by the chewing of the Vine Weevil Beetle Adult. There is not one 'cure-all' remedy!It is in the leaf that most goodies are found for the foliage feeders. The leaves are a vital finishing post for the actual feeding mechanism of the plant, are invariably full of water. They also make and hold the biggest store of accessible nutrients as far are insect pests are concerned.

(Whilst we talk of 'insects' we are actually covering a wide range of pests which are not 'true' insects. Forgiveness please. I do realise that a slug is not an insect, nor are spider mites!)

Leaves often suffer if there is a pest or disease at work in some other part of the plant or maybe cultural problem with the soil. What we do as gardeners will also have an affect on the health and appearance of the foliage of plants. Mostly good one hopes, but sometimes not!

A few examples of indirect causes of leaf problems - other than the symptoms caused by leaf pests and diseases.

Browning of leaves can be caused by bacterial wilts within the plant, or by diseases such as fire blight.

Sagging of foliage can be attributed to over watering, or over feeding. Sagging or collapse of foliage can also be caused by root-eating pests such as vine weevil larvae, or chafer grubs, together with a host of root aphids.

Discoloration of the leaf can be caused by a poor feeding or fertiliser regime, showing up as many shades of pink, orange, or cerise. Together with this, silvered foliage can be an indication of silver leaf fungal attack on some plants.

Climatic variations can also cause leaf problems. Immediately by way of frosted leaves, or at some time in the future by way of leaf problems resulting from ultra cold conditions when the leaves were wrapped in their buds.

Leaves on the lawn also show the first symptoms of something being wrong elsewhere under the turf lawn. Yes! Lawns are made of grass plants that have leaves.

Leaf Yellowing

If there were a single cause for yellowing of a leaf, then my job would be a lot easier and this part of the web site would be smaller. Leaves turn yellow for a multitude of reasons. Sap sucking insects under the leaves, on the stems or at the roots are just a few causes. Add in the fact that food deficiencies will also invariably show up in the leaf. Nitrogen deficiency will show up as a pale yellow leaf - but so also will lime-induced chlorosis. Anyone who grows tomatoes will - or should - know about magnesium deficiency, but this shows up as a different type of yellowing!

Lawns also have a tendency to show up as yellow for all manner of complaints.

Well fed plants can have yellow leaves for reasons other than poor diet. Waterlogged Soil; Red Spider Mite; Leaf Rust; Draughts; Lack of Water - Too much Water; Root Problems; Stem Problems; Virus Diseases: Bacterial Diseases; Red Thread Blight etc. Oh how I love those emails that start off by saying "The leaves on my plant are turning yellow!" (But keep them coming please.)

Chewed Leaves

With leaves that have simply been 'chewed' it is much easier to pin down the cause. The same goes for leaves that have developed a black mould over the surface, or have turned sticky. Mildews and Rusts are also easier to pinpoint. Leaf spots various - Rose Blackspot in particular - are also relatively easy to determine. But, not always easy to cure.

Then we have Silver leaf disease, leaf Curl, Bumps in Leaves, and "something burrowing' in my leaves"!

Leaves also turn brown - around the edges, between the veins and across the whole leaf. This type of discoloration is normally as a result of nutrient deficiency, but can also be bought about my all manner of environmental conditions. Draughts, Hot sun, waterlogged root system, over-feeding or fertiliser flash release, to name few!

Hopefully this section will find for you, the actual problems which are causing your leaves to look a bit strange!

 

Leaf Curl - Peaches and other plants
Leaf spots
Leaf diseases
Leaf Pests
Wind Scorch
Frost Damage
Leaf insects
Leaf browning
Leaves shriveled
Leaves chewed away
Spots and leaves
Leaf Disease Symptoms.

Leaf Rust Spots |



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