What pests attack dahlia?

Black Bean Aphid (Blackfly), Broad mite, Leaf Miner

What diseases affect dahlia?

Fusarium wilt, Tomato spotted wilt virus, White mould (Sclerotinia), Verticillium wilt

Dahlia pests and diseases: how to recognise them

Q: Which dahlia problems need quick action?

Fusarium wilt: Wilting and yellowing that often starts on one side of the plant, a branch or even a leaf; lower leaves yellow first. Tomato spotted wilt virus: Young leaves with a bronze cast that later show small dark brown spots; leaves may cup or roll. White mould (Sclerotinia): A soft, wet rot on stems, often near soil level; plants suddenly turn yellow, wilt and collapse.

Dahlia × pinnata

The pests, diseases and disorders recorded for dahlia in our library, each with a photo and its first symptom. Every page has the full list of symptoms, organic and chemical treatment and prevention.

At a glance

Problems in total	7
Pests	3
Diseases	4
Need quick action	3

How to grow dahlia · All pests and diseases

Pests

Black Bean Aphid (Blackfly)Dense colonies of black aphids up to 2 mm long, sometimes with white flecks, on soft shoot tips, flower stems and the undersides of young leaves.Also called: blackfly, bean aphidPhoto: Sascha Kohlmann from Berlin, Deutschland, CC BY-SA 2.0, Wikimedia Commons
Broad miteNew leaves are twisted, hardened and distorted, with bronzed undersides; the mites are too small to see without magnification.Photo: David Riley, University of Georgia, Bugwood.org, CC BY 3.0, Wikimedia Commons
Leaf MinerSmall pale dots on the upper leaf surface where adult female flies have punctured the leaf to feed.Photo: Flowersabc, CC BY-SA 2.0, Wikimedia Commons

Diseases

Which dahlia problems need quick action?

These spread or do lasting harm fast; check the plants and start treatment the day you see them.

Fusarium wilt: At first the plant seems to recover overnight, but the wilt soon becomes permanent; growth is stunted and few fruits form.
Tomato spotted wilt virus: Dark brown streaks on stems and leaf stalks; tips die back, and plants are stunted or grow lopsided.
White mould (Sclerotinia): Masses of fluffy white, cotton-like mould on the affected parts, especially in cool, damp weather.

Plants with many of the same problems

Which plants each problem affects: sources

The links between these problems and the plant were checked against these pages.