| Table 1: Diagnostic Guide for Landscape Plants Exhibiting Nonspecific Symptoms. | |
|---|---|
| Symptoms | Possible Causes |
| 1. Brown or scorched leaves; progressive dieback of branches. | a. Poor root health from poor drainage, excessive soil dryness, excessive fertilizer, compaction and poor water penetration into soils, or girdling roots. b. Mechanical injury (construction damage, trenching, adding or removing soil, lawn mower, or string trimmer damage). c. Specific nutrient toxicities or imbalances. d. Excessive heat or light reflected onto leaves from driveways or buildings. e. Pesticide or mechanical injury. f. Air pollution. g. Winter drying. h. Vascular fungal or bacterial infection. i. Root rots or crown rots caused by fungi. |
| 2. Leaf spots, blotches, blemishes, blisters or scabby spots, or malformed leaves. | a. Excessive soil dryness coupled with high temperatures. b. Frost injury. c. Chemical spray injury. d. Fungal or bacterial infections. e. Herbicide injury. f. Insect damage |
| 3. Foliage yellow-green. | a. Insufficient fertilizer or nutrient imbalance. b. Poor root health due to compacted soil, poor drainage, girdling roots, or planted too deep. c. Winter drying. d. Root or crown injury. e. Root rots or crown rots caused by fungi. f. Air pollution. g. Soil pH (acidity) lower than 5.0 or higher than 8.0. (Nutrient imbalance.) h. Herbicide injury. i. Mites or sucking insects, root-feeding nematodes |
| 4. Foliage of one branch dying. | a. Fungal canker. b. Mechanical injury (construction damage, trenching, adding or removing soil, lawn mower or string trimmer damage). c. Insect damage. d. Winter damage. e. Chemical spray injury. |
| 5. Early leaf drop. | a. Poor root health from poor drainage, excessive dryness, excessive fertilizer, compacted soil, or girdling roots. b. Mechanical injury (construction damage, trenching, adding or removing soil, lawn mower, or string trimmer damage). c. Heat and drought stress. d. Insect infestation. e. Herbicide injury. f. Fungal or bacterial leaf spots. g. Improper pesticide application. |
| 6. Wilting or drooping of foliage. | a. Poor root health from poor drainage, excessive dryness, excessive fertilizer or other soluble salts in the soil, compacted soil, overwatering, or planting too deep. b. Mechanical injury (construction damage, trenching, adding or removing soil, lawn mower, or string trimmer damage). c. Toxic chemical poured into soil. d. Fungal or bacterial infection of vascular system. e. Fungal cankers. f. Root rots or crown rots caused by fungi or root-feeding nematodes. g. Insect infestation. |
| 7. Leaves with tiny yellow speckling or yellow banding of needles. | a. Mite infestation. b. Air pollution. c. Insect infestation. d. Fungal or bacterial infection. |
| 8. Deformed or misshapen leaves | a. Herbicide injury. b. Late frost or freeze. c. Insect infestation. d. Anthracnose. e. Virus infection. f. Spray injury. |