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Citrus tristeza virus
Citrus tristeza virus · Viral
Photo: Arizona Department of Agriculture · Public domain
Citrus tristeza (‘tristeza’ means sadness in Portuguese and Spanish — named for the grief of watching whole groves die) is a virus of citrus — orange, lemon, lime, grapefruit and their relatives. It is carried tree to tree by aphids and passed on inside infected budwood when new trees are grafted. What it does depends on the tree's rootstock: on sour-orange rootstock severe strains kill the graft join and the tree declines and dies; on tolerant rootstocks some strains still pit the wood, stunting the tree and shrinking the fruit. There is no cure — the whole fight is won or lost at planting, with the right rootstock and clean, tested trees.
Arizona Department of Agriculture · Public domain
Why it matters
Tristeza is a virus — once a tree catches it there is no medicine and no cure, and no spray can save it. On the wrong rootstock the virus kills trees outright, so a bad outbreak can wipe out up to 100% of your grove — every last tree. Worse, it hides for months and rides from tree to tree on aphids, so by the time trees are visibly dying it has usually already spread through the block. That is why the whole fight is won before you plant — with the right rootstock and clean, tested trees.
When to act
Prevention threshold: never plant on sour-orange rootstock in tristeza areas and use only certified virus-tested trees; on established trees, decline symptoms confirm infection but there is no cure.
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
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The full citrus tristeza virus field guide
- Identify it
- Scout for it
- Control it
18 field-guide sections in the app
The full guide to citrus tristeza virus — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify citrus tristeza virus?
What you notice first is a tree that was healthy going backwards: the leaves lose their shine, turn dull and pale-yellow, wilt as if thirsty even when the ground is wet, and drop. New shoots are few and weak. A declining tree often throws one last heavy crop of small fruit and then dies back from the top down — sometimes slowly, sometimes in a sudden collapse (“quick decline”).
When should I take action against citrus tristeza virus?
Prevention threshold: never plant on sour-orange rootstock in tristeza areas and use only certified virus-tested trees; on established trees, decline symptoms confirm infection but there is no cure.
How do I control citrus tristeza virus?
Prevent it — the rootstock is everything (your single strongest measure). Never plant citrus on sour-orange rootstock in a tristeza area. Choose trees grown on a tolerant rootstock — the trifoliate-orange types and their hybrids — which don’t collapse from decline. You usually can’t tell the rootstock by looking at a finished tree, so ask the nursery in writing what it is grown on, and refuse sour orange.
Which crops does citrus tristeza virus affect?
Among the crops covered here: Grapefruit, Lemon, Lime.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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