Fruit Rot Disease is a major concern for guava growers as it can cause significant yield losses and reduce the quality of the fruit. The disease is caused by several fungal pathogens and can spread rapidly in favorable environmental conditions. Growers can employ chemical, biological, and cultural control strategies to manage the disease.
Fruit Rot Disease Management in Guava
The Causal Organism of Fruit Rot Disease
The causal organism of Fruit Rot Disease in guava is a group of soil-borne fungi belonging to the genus Phytophthora. Specifically, Phytophthora parasitica and Phytophthora nicotianae var. parasitica are responsible for causing the disease, with Phytophthora parasitica being homothallic and capable of producing oospores in a single culture.
The Disease Cycle of Fruit Rot Disease
- Inoculation: The disease cycle begins with introducing the pathogen, which can occur through the spores produced on the surface of diseased tissues. These spores are most commonly produced when the temperature is around 25°C.
- Infection: Once the pathogen has been introduced to the fruit, it infects the plant tissue and grows. This results in the development of the white cottony growth characteristic of the disease.
- Sporulation: As the pathogen grows and develops, it produces many sporangia and spores on the surface of the diseased tissues. These spores serve as an important source of inoculum for developing epidemics.
- Spread: Rain splashes from infected plant material or soil can spread the pathogen’s spores. This is particularly likely during rainy weather or when there is a strong wind.
- Secondary infection: As the spores are dispersed, they can land on other fruits or plants, leading to secondary infections and the further spread of the disease.
- Re-inoculation: As the disease progresses, more and more spores are produced, leading to a greater likelihood of re-inoculation and the continued spread of the disease.
Causes/Conditions Favorable for Fruit Rot Disease Spread in the Field.
- Cool, wet environmental conditions: Fruit Rot Disease thrives in cool, wet environments with high soil moisture. These conditions provide an ideal environment for the growth and spread of the pathogen.
- High humidity: High humidity is favorable for developing Fruit Rot Disease, as it creates an ideal environment for the pathogen to grow and reproduce.
- High temperature: Temperature between 28-32°C (25°C) is favorable for initiating Fruit Rot Disease. This temperature range provides optimal conditions for the pathogen to infect and spread throughout the fruit.
- Close plantation: Close plantation can increase the humidity and reduce air circulation, creating an environment favorable for spreading Fruit Rot Disease.
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Symptoms of Fruit Rot Disease
- White cottony growth: The affected fruit area is covered wit