The Mango Red Rust Disease is an epiphytic algal disease caused by the algae Cephaleuros virescens. It is a foliar disease most often found in humid climates and is particularly prevalent in tropical areas. The algae are spread by wind-blown spores, and the disease can spread quickly among trees in the same area. Management of this disease is important to prevent yield losses and includes cultural practices such as pruning, irrigation, and crop rotation.
Algaecides may also be used to control the disease, but they should be used cautiously and in combination with other management practices. To effectively manage this disease, it is important to understand its disease cycle, the mode of disease spread, and the best methods for controlling it. This article will provide an overview and discussion of the Mango Red Rust Disease in Mango crops, including its symptoms, identification techniques, and control.
Mango Red Rust Disease Management
The Causal Organism of Mango Red Rust Disease
- Cephaleuros virescens is a hemibiotrophic, saprophytic pathogen that belongs to the Family Trentepohliaceae of Order Trentepohliales of the Phylum Chlorophyta.
- The pathogen is found in the mango tree’s vegetative and reproductive stages.
- The sporangia produced on the thallus are thick-walled and sessile with orange-colored pigments.
- After ripening, the sporangia produce zoospores and disseminate them through a pore in the wall. The zoospores actively swim with the help of cilia, and they are ovoid and orange in color.
The Disease Cycle of Mango Red Rust Disease
The disease cycle of the Mango Red Rust Disease, Cephaleuros virescens, in Mango Crops begins when the algal spores are dispersed by wind and rain and settle on the leaves of the mango tree. Once the spores settle, they germinate and form a new alga, producing red-brown rust on the leaf surface. This rust comprises small, round, reddish-brown spots, which may eventually cover the entire leaf. As the disease progresses, the rust spots will become more numerous and darker, and the leaves may become brittle, yellow, and fall off.
In severe cases, the branches may die, and the tree may be killed. The algal spores may remain on the dead leaf surface, and once they come in contact with other mango trees, they can cause an outbreak. The algal spores can also be spread from one tree to another through infected pruning tools or infected soil particles carried by wind or water. Additionally, the spores may be spread through contaminated irrigation water. Once the spores are spread, the disease cycle can begin again.
Occurrence of Mango Red Rust Disease in Mango Crop
- Location of Mango Red Rust disease: This disease occurs in mango crops in India, Africa, Bangladesh, Sri Lanka, Vietnam, Thailand, Malaysia, Indonesia, the Philippines, the United States, Mexico, Brazil, and Australia.
- Host range: The most common crops affected by Cephaleuros virescens are mango, watermelons, cantaloupes, squash, cucumbers, tomatoes, and peppers.
Favorable Conditions for Mango Red Rust Disease Spread in the Field
- Warm and humid conditions, high relative humidity, and temperatures between 24–32°C are ideal for spreading the disease through wind-borne spores.
- As the pathogen needs a moist environment to survive, the wetness of leaves contributes to the spread of the disease.
- The presence of dust particles or other suspended particles on the leaves can also promote the spread of the disea