Guava wilt

Nalanthamala psidii and Fusarium species Nalanthamala psidii (Sanwal) Schroers & M.J. Wingf., 2005; Fusarium oxysporum f. sp. psidii and F. solani are implicated in South Asia · formerly or also: Myxosporium psidii, Gliocladium psidii

अमरूद का उकठा (amrud ka ukatha) · Hindi, South Asia
marchitez de la guayaba · Spanish, Latin America
番石榴枯萎病 (fānshíliú kūwěi bìng) · Chinese, East Asia

Guava wilt is a destructive disease in which guava trees suddenly lose their leaves and die, branch by branch or all at once, often within weeks of the first symptoms. It has wiped out orchards in South Asia, Taiwan and southern Africa. The cause has been debated: Nalanthamala psidii is the proven pathogen in several regions, while Fusarium species, often together with root-knot nematodes, are blamed in South Asia. There is no cure; management is preventive.

Type: Fungal disease · Fungus (soil-borne ascomycetes causing wilt)
Classification: Fungi › Sordariomycetes › Hypocreales › Nectriaceae
Main crops: Guava
Found in: South Asia, East and Southeast Asia, Southern Africa, Latin America
Last reviewed: 2026-10-20

What causes guava wilt?

Guava wilt is caused by Nalanthamala psidii and Fusarium species Nalanthamala psidii (Sanwal) Schroers & M.J. Wingf., 2005; Fusarium oxysporum f. sp. psidii and F. solani are implicated in South Asia, a fungus (soil-borne ascomycetes causing wilt) (order Hypocreales, family Nectriaceae).

Older or alternative scientific names: Myxosporium psidii, Gliocladium psidii.

Where it occurs

Reported from South Asia (where it is a major problem), Taiwan, Malaysia, southern China, Bangladesh, South Africa and parts of Latin America. Nalanthamala psidii has been confirmed in Taiwan, South Africa, Malaysia, China and Bangladesh.

Region	Status
South Asia	Widespread in guava orchards; Fusarium and nematodes implicated
East and Southeast Asia	Nalanthamala wilt in Taiwan, southern China and Malaysia
Southern Africa	Severe Nalanthamala wilt in South Africa
Latin America	Reported in some countries

Symptoms and identification of guava wilt

The organism

Nalanthamala psidii produces slimy, salmon-coloured spore masses on the bark and in the wood of dying trees; Fusarium species are isolated from discoloured roots and wood. Laboratory isolation is needed to confirm the cause; a semi-selective medium has been developed to detect Nalanthamala in soil and plants.

Signs in the crop, stage by stage

Crop stage	What you see
Early	Leaves on one or more branches turn yellow with reddish tinge at the margins, then droop; often after the rainy season.
Advanced	Rapid leaf drop and dieback of branches; small, hard, unripe fruits stay on bare twigs; roots and lower trunk show brown to grey discoloration of the wood.
Final	Death of the whole tree, sometimes within a few weeks of first symptoms; neighbouring trees follow.

Disease cycle of guava wilt

Life cycle of Guava wilt — diagram drawn by Laisha from the stages below. Durations depend on temperature.

The pathogens survive in soil and infected roots and debris and enter through roots, especially wounded ones; Nalanthamala also infects through wounds on the trunk and roots. Spread occurs through infested soil, irrigation water, tools and nursery plants. Root-knot nematodes (especially Meloidogyne enterolobii) damage roots and are associated with more severe wilt.

Stage	Duration	Notes
Survival in soil and roots	Long-term	Chlamydospores (Fusarium); spores in wood (Nalanthamala).
Root or wound infection	Weeks to months	Favoured by root damage and waterlogging.
Vascular and wood colonisation	Months	Symptoms appear suddenly.
Tree death and spread	Weeks after symptoms	Spores spread to neighbours.

Temperature

Disease is most often reported after the rainy season in warm climates, with high soil moisture and temperatures of about 25-30 °C.

Generations

Continuous; trees die progressively through an orchard.

Conditions that favour it

Waterlogged or poorly drained soils, alkaline or sodic soils, root damage from cultivation and nematodes, poor nutrition, flood irrigation, and planting nursery stock from infested sources.

Economic threshold level (ETL)

There is no economic threshold: wilted trees cannot be saved, and removing them quickly protects their neighbours.

Damage and yield loss from guava wilt

Orchard losses of 5-30% of trees per year are reported in affected areas, and whole orchards have been abandoned in parts of South Asia, Taiwan and South Africa.

Monitoring

Inspect trees regularly, particularly after the rains, for yellowing and dropping leaves on single branches.
Send roots and wood from newly wilting trees to a laboratory to identify the cause, and test soil for root-knot nematodes.
Map dead and dying trees each season; clusters that spread along irrigation lines suggest water-borne spread.

How to control guava wilt (integrated management)

Control works best as a sequence: prevent, monitor, then act only when a threshold or a risk forecast says so, using the least disruptive option that works.

Cultural control

Remove and burn wilted trees including roots, and treat or leave the planting hole fallow before replanting.
Improve drainage and avoid flood irrigation that waterlogs the root zone; correct soil pH and nutrition (including adequate calcium and organic matter).
Avoid wounding roots and the trunk base during cultivation.
Plant healthy nursery stock from wilt-free sources, raised in clean media.

Biological control

Soil application of Trichoderma and Aspergillus niger strains with organic manure has reduced wilt in South Asian studies.

Host resistance

Rootstocks such as some Psidium species (for example P. molle hybrids) and resistant guava selections are being developed and tested; their resistance to nematodes and Fusarium varies.

Chemical control of guava wilt — by mode-of-action group only

Laisha names chemical options only by their resistance-committee mode-of-action group (IRAC for insects, mites and nematodes, FRAC for fungi, oomycetes and bacteria, HRAC for weeds), never by active ingredient or product. What is registered differs by country and changes over time; the label and your local plant-protection authority decide what may be used, on which crop, at what rate and with what pre-harvest interval.

No fungicide cures wilted trees; drenches around neighbouring trees have been tested with limited success. What is registered differs by country and changes over time; follow the label and your local plant-protection authority.

Resistance management

Not applicable to fungicides; rely on sanitation, drainage, clean planting material and tolerant rootstocks.

Look-alikes and how to tell them apart

Root-knot nematode decline (Meloidogyne enterolobii) — Gradual decline with heavily galled roots; often occurs together with wilt and increases it.
Waterlogging injury — Leaf yellowing and drop across low-lying parts of an orchard after flooding, with recovery when soil drains.
Anthracnose and dieback — Dieback from twig tips with dark lesions on shoots and fruit, rather than sudden collapse from the roots.
Stem borer and bark-eating caterpillar damage — Holes and frass or webbed bark on the trunk and branches, with dieback above the damaged point only.

Host range

Guava (Psidium guajava) is the only important host recorded.

What is still uncertain

The primary cause in South Asia (Fusarium species alone, Nalanthamala, or a complex with nematodes) is still debated.
Reliable resistant rootstocks are not yet widely available.

Grow guides for its host crops

How to grow the crop well is the first line of defence. Laisha's free grow guides cover each crop from sowing to harvest:

How to grow Guava

Not sure this is what you are seeing?Ask Laisha: describe the symptoms or send a photo, and get a reasoned first read with what to check next — for your crop, your stage and your region.Ask Laisha

Sources

Development of a semiselective medium for detection of Nalanthamala psidii, causal agent of wilt of guava — Plant Disease (APS). https://doi.org/10.1094/PDIS-12-12-1193-RE
Classification of the guava wilt fungus Myxosporium psidii as Nalanthamala psidii — Mycologia (Taylor & Francis). https://doi.org/10.1080/15572536.2006.11832814
First report of Nalanthamala psidii causing wilt disease of guava in Bangladesh — Plant Disease (APS). https://doi.org/10.1094/PDIS-08-18-1328-PDN
Integrated management of wilt disease in guava caused by Fusarium oxysporum f. sp. psidii — Annals of Plant Protection Sciences. https://doi.org/10.5958/0974-0163.2019.00017.x

Written by Laisha from the sources above, in its own words. This page is general reference, not a prescription: confirm identification locally and follow the label and your plant-protection authority.