Marginal leaf necrosis

Xylella fastidiosa

140 host plants

Last updated April 21, 2026

Data Maturity Baseline

This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.

Leaf edges brown and die back progressively, often from water stress during dry periods or low potassium availability in the soil. Maintain consistent watering throughout the entire growing season and check soil fertility with a professional soil test. Ensure good drainage to prevent root stress and anaerobic conditions. Potassium fertilizer applications may help if deficiency is confirmed by testing.

Good sanitation is your most effective tool against marginal leaf necrosis. Remove and dispose of infected plant material, clean up fallen debris, and sterilize your pruning tools between plants. Reduce leaf wetness by watering at soil level and spacing plants for adequate air movement. These practices reduce the pathogen load in your garden over successive seasons.

Quick Reference

Causal Agent

Xylella fastidiosa

Host Plants

140

Favorable Conditions

Warm temperatures above 60°F required for bacterial multiplication. Vectored ...

Management

Vulnerability Window

Growing season when vector insects are active and temperatures support bacterial multiplication. Symptoms intensify during hot, dry conditions when water demand exceeds what blocked xylem can deliver." # Source: PNW Plant Disease Management Handbook

What Triggers Infection

Warm temperatures above 60°F required for bacterial multiplication. Vectored by xylem-feeding insects (sharpshooters, spittlebugs). Mild winters that stay above 25°F allow overwinter survival in host xylem." # Source: PNW Plant Disease Management Handbook

Cultural Controls

Diagnose cause before implementing management. Laboratory testing (PCR or culture) may be necessary to confirm or exclude Xylella fastidiosa." # Source: PNW Plant Disease Management Handbook
If bacterial (Xylella confirmed): remove infected plants to prevent spread. Monitor for xylem-feeding insect vectors (sharpshooters, spittlebugs) during the growing season." # Source: PNW Plant Disease Management Handbook
If abiotic: provide consistent deep watering during dry periods; avoid overwatering in poorly drained soils." # Source: PNW Plant Disease Management Handbook
If abiotic: avoid excess fertilizer, particularly high-nitrogen applications during hot weather." # Source: PNW Plant Disease Management Handbook
If abiotic: improve drainage with organic matter amendments or raised beds; apply 2-3 inches of organic mulch over the root zone." # Source: PNW Plant Disease Management Handbook
If abiotic: avoid herbicide applications near susceptible plants or when drift is likely." # Source: PNW Plant Disease Management Handbook

Regional Notes

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Host Plants (140)