Major diseases of Guava are given below:-
- Symptoms of this disease are observed on mature fruits on the tree.
- The characteristic symptoms consist of sunken, dark coloured, necrotic lesions. Under humid conditions, the necrotic lesions become covered with pinkish spore masses.
- As the disease progresses, the small sunken lesions coalesce to form large necrotic patches affecting the flesh of the fruit
- Spray Mancozeb 0.25%.
2.Guava rust: Puccinia psidii Symptom
- The pathogen can affect foliage, young shoots, inflorescences and fruit of guava.
- Typical symptoms associated with this disease include distortion, defoliation, reduced growth and if severe, mortality.
- On fully expanded leaves, dark bordered, roughly circular brown lesions with yellow halos develop
- Control of guava rust is based on the use of fungicides.
- Scouting fields for the onset of disease or during the times of year when environmental conditions are favourable for pathogen infection are recommended so that proper and timely fungicide applications can be made.
- In addition, proper cultural tactics such as proper fertilization, irrigation, pruning and sanitation aide in achieving a healthy, vigorously growing tree less vulnerable to disease pressures.
3.Algal leaf spot: Cephaleuros virescens
- Disease symptoms are exhibited on both abaxial and adaxial leaf surfaces as orange, rust-colored, dense silky tufts ranging from 5 to 8 mm in diameter.
- Upon scraping away these spots, a thin, greyish white to dark-colored, necrotic crust remains on the leaf.
- These spots usually come together to form large irregular patches on a leaf. As the spots mature they take on a dull, greyish green colour.
- Twigs and branches are also affected causing the bark to crack due to the growth and expansion of the pathogens filaments into the cortical tissues of the host.
- Algal leaf spot can be reduced by maintaining tree vigour with cultural techniques such as proper fertilization and irrigation, proper pruning to enhance air circulation within the canopy and sunlight penetration, managing weeds and wider tree spacing.
- Managing insect, mite and other foliar diseases increases tree vigour and lessens susceptibility to this disease.
- Spray Copper oxychloride 0.25%.
- TamilNadu Agritech Portal