Lilies 'Dimension' Care (Watering, Fertilize, Pruning, Propagation) - PictureThis (2024)

Yellow spot is a common condition that affects all types of plants -- flowering ornamentals, trees, shrubs, herbs, and vegetable plants -- worldwide. Yellow spots may appear because of dozens of potential causes and occur in various environmental and climatic conditions, but fortunately, most are easy to address. The most common causes of yellow spots include diseases, nutrient deficiency, watering problems, and pests.

In most cases, yellow spots can be treated without permanent damage to the plant. However, in some fungal disease cases, nothing can be done to treat the disease after infection, and the plant will ultimately perish from the disease.

Due to this, the most critical aspect of addressing yellow spots on plants is correctly determining the cause.

Symptoms occur on varying parts of the plant, depending upon the cause. Smaller spots tend to be indicative of younger infections or newly developing problems.

• Small yellow spots appear on leaves
• Spots can occur on the lower or upper leaf surfaces, or both
• Raised, rounded, or sunken spots with fringed or smooth edges
• Spots may grow together, causing leaves to become totally discolored
• Stunted growth
• Premature leaf drop

The vast majority of yellow spot diseases are caused by fungal pathogens. However, there are some situations in which bacteria, environmental conditions, or other issues may be blamed.

Diseases are typically host-specific, so they may only affect plants within the same family. That said, just about every single species of plant is vulnerable to at least one disease that causes yellow spot. The most common problems are leaf blight, leaf septoria, powdery mildew, and downy mildew, to name a few.

All plants need specific nutrients from the soil to survive. When these nutrients become depleted or unavailable for plant uptake due to particular conditions, deficiencies occur, and yellow spots are seen.

• Nitrogen is an integral component of chlorophyll.
• Iron is needed in the enzymes that make chlorophyll.

Yellow spots may also appear because of incorrect watering, mainly underwatering, or infestations of sap-sucking pests such as aphids.

• Too little water inhibits photosynthesis. Too much water pushes oxygen out of the soil and the roots cannot take in nutrients or even water from the soil.
• Insect problems can cause yellow spots directly by damaging leaf tissue when feeding, or they may introduce pathogens.