Reddish Blotches on Jasmine in Desert Climate

Investigating Leaf Spots on Las Vegas Jasmine

A jasmine plant in Las Vegas shows reddish circular blotches on some leaves this spring. Otherwise healthy. The owner seeks a diagnosis.

Challenges of Remote Diagnosis

Leaf spots have many causes: fungal (Cercospora, Alternaria), bacterial, nutrient deficiency, sunburn, chemical phytotoxicity, or even spider mite stippling. Without seeing the spots—size, pattern, margin, presence of spores—accurate ID is guesswork.

Practical Steps

• Send a close-up photo to an expert or Extension service.
• Bring 5–6 affected leaves to your county Extension office (Clark County, NV) for microscopic exam.
• If only a few leaves: Remove and discard them. Monitor for spread.
• Check cultural factors: Overhead watering? Recent fertilizer spray? Herbicide drift? Sudden heat spike?

Desert climates with intense sun and low humidity favor physiological disorders (sunscald, salt burn) as much as pathogens. A local diagnosis is best.