almond leaf scorch

Symptoms

Marginal leaf scorch progressing inward, premature leaf drop on individual branches, reduced nut size and oil content, gradual canopy decline over 3–5 years.

Plants affected

• almond
• White oak
• Northern red oak
• American sycamore
• American elm
• American sweetgum

Easily confused with

• European brown rot / blossom blight

  How to tell them apart: Xylella fastidiosa subsp. multiplex causes almond leaf scorch: leaves show necrotic margins and tips with a distinctive chlorotic yellow band separating the dead brown edge from the still-green inner leaf; scorching is uniform across many leaves on a branch, develops slowly through summer, and progresses to whole-branch dieback and chronic decline with no gum or blossom involvement. Monilinia laxa (brown rot / blossom blight) instead kills blossoms and spur clusters first, producing sudden brown collapse of flowers, twig cankers oozing amber gum, and shepherd's-crook dieback of shoot tips with leaves that wilt and stay attached; look for tan-grey fungal tufts (sporodochia) on blighted blossoms and mummified fruit. Key tell: a yellow halo-banded leaf scorch with no gum points to Xylella; gummy cankers, blighted flowers and grey spore tufts point to Monilinia.

Common questions

How do I recognise almond leaf scorch on almond?

Marginal leaf scorch progressing inward, premature leaf drop on individual branches, reduced nut size and oil content, gradual canopy decline over 3–5 years.

Do I have to report almond leaf scorch?

Yes. almond leaf scorch is a regulated quarantine organism in the EU. A suspected finding must be reported to your national plant protection organisation — they will confirm it and tell you what to do next.

How is almond leaf scorch treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.