Determining Disease or Attack
The initial reaction to seeing an unhealthy plant is to fertilize the plant then dump a lot of water on it. This is exactly what you shouldn’t do! Water and fertilizer will, very often, make matters worse.
All plants are susceptible to attack by diseases and pests. It is usually easier and more cost effective to maintain a healthy plant than to treat or replace weak one. There are also situations where it makes sense to remove a pest infested plant when the foliage has been damaged beyond repair. Learning the signs of plant problems will help you determine which course of action will bring the plant back to health.
Always determine what is wrong with the plant before taking any action. It will take a few minutes longer but the results will be a healthier plant and a happier client.
Diseases can be cause by fungi, mold, improper watering or fertilizing, or viruses. Pest attacks are caused by an insect, spider, or other living pest crawling, flying, or otherwise being transported to the plant. You must figure out whether the plant is suffering from a disease or a pest attack before taking action. By taking the wrong action, you may either kill the plant or cause an already weakened plant to fall victim to other predators or diseases.
Symptoms of Disease Attack:
1. Chlorosis (yellowing of leaves)- All leaves. This may be caused by a lack of nutrients, extremely bright light, or high temperatures.
- Youngest leaves only. A lack of iron or manganese, or insufficient light may cause yellowing of youngest leaves.
- Older leaves only. May mean soil lacks nitrogen or potassium, or that soil needs aeration.
- Leaf edges. Often the sign of deficiency in both magnesium and potassium.
Between leaf veins. May indicate a lack of iron or manganese or there may be sulfur dioxide in the air. - Round spots, all leaves.
- Irregular spots, all leaves. Cold water can cause this type of yellow spots on leaves.
- Small dots, all leaves.
- Mosaic patterns, all leaves. Cold water can cause this type of yellow spots on leaves.
- Leaf edges or tips. Could indicate a potassium deficiency, boron excess, fluoride excess, excessive heat or cold, or insufficient water.
- Spots or sections, all leaves. Cold water can cause this type of damage to leaves.
- Edge or inner sections, all leaves. This can be caused by too much light, cool temperatures, or cold water.
- Water-soaked or greasy appearance. Excessive heat or cold, cold water on the foliage, or overwatering may cause this effect.
3. Premature defoliation.
4. Wilting plant.
5. Abnormal plant growth.
6. Plant dies mysteriously or suddenly.
7. White mold on soil.
Symptoms of Pest Attack
Some of the most common symptoms of insect or pest attack include the following:
- Leaves chewed from the outside edge
- Holes chewed in the leaves
- Complete defoliation
- Wilting or discoloring of leaves
- Discolored speckles on the leaves
- Leaves curled
- Tiny “fruit flies” reported within days of watering
- Cottony egg sacs on leaves
- Honeydew on leaves
- Tiny red spots on leaves
- White dots on undersides of leaves