This blog offers in-depth information on the two major guava diseases-fusarium wilt and anthracnose. This blog gives you a good idea about disease identification and management approaches.

The guava is a significant fruit in subtropical regions. It is a resilient crop that may flourish even on neglected soils. Due to the wide variety of climate variations, guava is vulnerable to several diseases. However, the two most destructive diseases that impede guava output are wilt and anthracnose. We will discuss the effects of two major diseases on guava production in this blog, along with every effective measure to control them.

Table of content

• Guava wilt
• Symptoms of guava wilt
• Favourable conditions of guava wilt
• Guava wilt management
• Anthracnose
• Symptoms of Anthracnose
• Favourable conditions of Anthracnose
• Anthracnose management

Diseases	Symptoms	Favourable conditions	Management
Fusarium wilt/Guava wilt	Leaves turn light yellow. Premature shedding of leaves. Fruit remains stony and hard.	High levels of rainfall. Temperature ranges of 23–32 °C.	Maintain orchard sanitation. Apply lime, oil cakes, manures etc.
Anthracnose	The plant decay from the top of a branch. Dark brown spots with a depressed, circular shape are observed.	Rainy weather. High moisture condition	Make use of disease-free planting material. Maintain the cleanliness of the orchard.

Guava wilt

Wilting of guava trees has been identified as a national issue in India. The importance of disease cannot be overstated because this crop is very profitable for farmers.

Symptoms

It is essential to identify the disease at the right time. The identification measures to recognise the disease are listed:

• The beginning of the monsoon season marks the onset of the first symptoms. Foliage (leaves) turns light yellow and loses its water retention capacity.
• Plant growth eventually stops. As a result, there is premature shedding and defoliation.
• Some branches eventually dry out after becoming bare and incapable of producing new leaves or flowers. All the damaged branches’ fruit remains stony, hard and undeveloped. The plant finally loses all of its leaves and dies.
• This disease also affects the bark and root of the tree. The bark can be easily peeled away from the base, and the roots also exhibit rotting at the base. Internal tissues of plants also exhibit a little brown discolouration.
• The disease affects young and elderly fruit-bearing trees, but older trees are more susceptible to it.

Favourable circumstances for the spread of the disease

• High levels of rainfall in August and September.
• Long-term water stagnation in the guava field.
• Maximum and minimum temperature ranges of 23–32 °C and 76% relative humidity are favourable.
• Proper control measures are not being applied on time.
• Through the movement of plants growing in unhealthy soil.
• Wilt disease is induced by root damage.

Management

The best ways to prevent the fusarium wilt/ guava wilt from affecting your orchards are mentioned below:

• Maintain orchard sanitation standards and practise clean cultivation
• Wilted trees should be cut down, burned, and have a hole dug around the trunk.
• Plant roots shouldn’t be harmed during transplanting.
• Preserve healthy tree vigour by providing timely, adequate manuring, inter-culture, and irrigation to make them resistant to disease.
• The pits may be formalin-treated and covered for approximately three days. Then transplantation should occur after two weeks.
• Apply lime, oil cakes, and organic manures.
• Use rootstocks resistant to guava wilt, such as a cross between Psidium molle and P. guajava.
• Use an environmentally friendly method of guava wilt treatment such as biological control (Trichoderma spp., Aspergillus niger AN27), soil amendment (lime, neem cakes, gypsum), and intercropping (marigold, turmeric).

Anthracnose

Anthracnose is the most frequent disease affecting guava pre- and postharvest management. This disease can harm young, growing flowers and fruit and can result in significant postharvest losses.

Symptoms

The disease can impact the guava fruits in various phases of growth. The identification measures to identify the disease are listed below:

Die-back phase

• The plant begins to decay backwards from the top of a branch during the die-back phase.
• Young shoots, leaves, and fruits can be connected easily while still delicate. The initial green colour of the growing tip changes to dark brown, resulting in black necrotic patches that expand backwards.
• The infected twigs give rise to the fungus, which spreads to the stem and immature leaves, which may drop or fall and leave the dried twigs without leaves.

The fruit and leaf infection phase:

• Crops grown during the rainy season typically exhibit fruit and leaf infection. Unripe fruits initially have pin-head dots, which then grow larger.
• Dark brown spots with a depressed, circular shape, tiny black pores at the lesion’s centre, and creamy spore masses that form in humid conditions.
• Numerous spots combine to produce larger lesions.
• Unripe fruit that has been infected becomes corky and hard, and in cases of severe infection, it frequently develops cracks.
• It also affects buds and flowers that haven’t opened, causing them to shed.
• The fungus produces necrotic lesions on leaves that are typically ashy grey and have fruiting bodies at the tip or margin.

Favourable conditions for the spread of the disease

• When trees are planted closely together without proper sunlight. This promotes the prevalence of the disease.
• Rain or dew promotes spore generation and distribution throughout the vegetation between 10 and 35 °C, with 24 to 28 °C being the ideal range.
• The infection grows on dead leaves, twigs, and mummified fruits in the orchard and is spread by wind-borne spores.
• Due to the high moisture conditions, the dense canopy is favourable for spore germination.

Management

The best ways to prevent anthracnose from affecting your orchards are mentioned below:

• Maintain sanitation in the orchard.
• Keep track of sickness and the use of micro irrigation techniques.
• Maintain a clean growing environment and strict hygiene in the orchard.
• Make use of disease-free planting material.
• To lower humidity, use effective weed management.
• Follow the advised plant density to lessen competition for nutrients, water, and sunlight.

Conclusion

The greatest potential for developing numerous new diseases in guavas is presented by intensive cultivation. The primary goal of plant protection is to increase yield by maintaining the health of the crops and reducing losses from pests and diseases. Implementing improved scientific agricultural technology is critical to the development and profitability of the guava fruit sector.

Fasal is an intelligent solution for your farm.

• Guava diseases may have a negative effect on fruit development, production, and quality.
• The production of guavas is no longer threatened by diseases like anthracnose and fusarium wilt with the help of Fasal’s technology.
• Fasal is an IoT-based intelligence platform for horticulture crops like guava. It collects current information on conditions from farm sensors to provide farmers with actionable advice tailored to their farms, crops, and crop stages.
• With the use of Fasal technology, diseases like anthracnose and fusarium wilt can be properly handled. The farmer will benefit by saving up to 50% on spray expenses.
• The Fasal system also aids in enhancing the quality of the output, preventing diseases, and controlling irrigation according to the crop and its stage.
• Today, with the introduction of Fasal fresh, it is easier for farmers to sell their produce directly from farms.

Co-authored: Himani Kamboj