Chrysanthemum is the most popular loose flower as well as cut flower crop of India. This flower crop is attacked by a very serious fungal disease known as White rust (Puccinia horiana) which makes the plant weakened and affects the quality and yield of flowers. This is the most destructive disease for chrysanthemum and its related species under severe conditions it may result in yield losses up to 80%.
Hence farmers should be very careful during the commercial cultivation of Chrysanthemum to manage White rust effectively to avoid economic yield losses.
- It will be more prominent during late summer and autumn season
- Symptoms generally appear more during cooler and wet weather conditions however infected plants may not always show symptoms specially during hot and dry conditions.
- The infection will be more severe with high relative humidity and low temperature
- Symptoms develop in 5-14 days after infection and there after fungus will reproduce on the infected plant itself and spreads further.
- The disease transmits from infected plants to healthy plants mainly through water splash from rain or irrigation and also through wind
- The disease may also spread through contaminated soil, litters, dead leaves, equipment’s, etc. The spores can survive on the contaminated parts and objects for up to 8 weeks.
- Infected plants show symptoms on younger leaves and flower bracts, but symptoms can also occur on older leaves and petals.
- The initial symptoms include sunken yellow colour spots on upper surface of leaves, later notable pustules subsequently develop on lower surface of leaves also.
- Pustules will be pinkish in the beginning later turn to waxy white colour
- During propagation take cuttings only from healthy mother plants/blocks
- Chrysanthemum white rust has got the ability to spread rapidly, hence early detection is important and required to control the further disease development
- Hot and dry weather can itself control the disease by avoiding the significant disease symptoms development because of unavailability of congenial environment
- Remove all the infected plant parts and burn or burry them to avoid further spreading
5. Avoid overhead irrigation
6. Ensure proper ventilation especially in greenhouses to reduce the relative humidity
7. Keep the field free from weeds and maintain hygiene
8. Remove excessive basal shoots to ensure better aeration to the plants and avoid the development of microclimatic conditions which is congenial for disease.
9. Early detection and spraying with suitable fungicides (such as Tebuconazole and/ Trifloxystrobin/Azoxystrobin are proven fungicides to control white rust in chrysanthemum) can help to avoid the disease load
10. As a prophylactic measure, application of bio agents such as Pseudomonas sps, Bacillus sp and Trichoderma sp will give resistance against white rust as well as other problems in chrysanthemum
11. During the congenial environmental conditions, the prophylactic spray with suitable fungicides may also help to keep the disease load at minimum level
- Spray with the combination of fungicides (containing Tebuconazole and/ Trifloxystrobin/Azoxystrobin) + Insecticide (Acetamyprid/ Profenofos) + Nutrient mixture/growth booster (to resist disease and continue Profuse Plant growth)
The below different combinations can be sprayed twice or thrice @ 5-7 days interval based on the severity of disease
- In chrysanthemum, usually Thrips attack will be more common and serious problem, hence one insecticide is mixed with above combination as a prophylactic measure.
- Once the disease comes under control go for application of bioagents such as Pseudomonas sps, Bacillus sp and Trichoderma sp which develop resistant in plants against various problems including white rust disease
Products containing Trichoderma sps
Products containing Pseudomonas fluorescence
Products containing Bacillus sps
Dr. Asha, K.M.,
For more information kindly call on 8050797979 or give missed call on 180030002434 during office hours 10 AM to 5 PM
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