Welcome to our comprehensive guide on managing common guava fruit diseases! Guava trees are a delight to have in your garden, but they can be susceptible to various diseases affecting their growth and productivity. This article will explore the symptoms, causes, and effective management strategies for these diseases, equipping you with the knowledge to keep your guava trees healthy and thriving. Whether you’re a seasoned gardener or a beginner, we’ve covered you with easy-to-understand information and practical tips.
How to Treat Common Guava Fruit Diseases
What Are Common Guava Diseases?
Some of the common diseases that can affect guava trees are Guava wilt, fruit rot, dieback, anthracnose (fruit rot), stem canker, and dry fruit rot caused by Physalopara psidii Stevens & Pierce and Diplodia netalensis Evans.
Another disease to watch out for is fruit canker, caused by Pestalotia psidii Pat. Guava trees may also suffer from algal leaf and fruit spots caused by Cephaleuros virescens Kuntze and styler end rot caused by Phomopsis psidii de Camara. Understanding these diseases and their symptoms is essential for effective management.
Major and Common Guava Diseases: Damage Symptoms, Causes, and Spread of Disease
| Disease | Damage Symptoms |
| Wilt | Light yellow leaves, Sagging of the plant, Premature fruit drop, Complete defoliation |
| Stylar end rot | Discolouration of the bloom end of the fruit, spreading discolouration turning the fruit brown to black, Fruit becomes soft |
| Anthracnose | Dramatic dieback of young shoots with attached fruit and leaves Small black dots on fruit and leaves that grow into dark brown, sunken lesions |
| Algal leaf spot | Rusty or brown spots on leaves during humid weather. Reduction in plant vigour affecting fruit development. Severe infections may cause black sunken spots on the fruit |
Guava Wilt
- Symptoms: Light yellow foliage, loss of turgidity, premature shedding, and defoliation, drying up of twigs, underdeveloped and hard fruits, root rotting.
- Causes: Movement of plants containing infected soil, waterborne spread, root injury.
- Favorable conditions: High rainfall, water stagnation, temperature range of 23-32°C with 76% RH.
Fruit Rot
- Symptoms: Whitish cotton-like growth on the calyx disc of the fruit, rapid development during humid weather, softening and discoloration of fruit, severe infection near the soil level, and fallen fruits.
- Causes: Spread by rain and wind, production of spores on diseased tissues, spores spread through rain splashes.
- Favorable conditions: Cool and wet environment, high humidity, poorly drained soils, injuries, close plantation.
Dieback and Anthracnose
- Symptoms (Dieback phase): The plant dies backward from the top of a branch, with dark brown to black necrotic areas and dried twigs without leaves.
- Symptoms (Fruit and leaf infection phase): Pin-head spots on unripe fruits, dark brown sunken lesions with black stromata, necrotic lesions on leaves.
- Causes: Spread by windborne spores, movement of infected plant material, transportation of fruits.
- Favorable conditions: Dense canopy, dew or rain, temperature between 10-35°C.
Stem Canker and Dry Fruit Rot
- Symptoms: Cracking of lesions on main branches and stems, wilted branches, dark brown to black mummified fruits.
- Causes: Pathogen survives beneath the bark and spreads through the air.
- Favorable conditions: Rainy season, closer planting without canopy management.
Fruit Canker
- Symptoms: Minute brown necrotic areas on green fruits, circular lesions, high margins, cankerous spots, and underdeveloped and mummified fruits.
- Causes: Wound parasite, avoidance of fruit injury.
- Favorable conditions: Germination at 30°C, avoidance of temperature extremes.