This slide includes detailed information about the fungal disease called Guava Rust. It includes the Introduction, Symptoms, Life cycle, Effect and Management of the Guava Rust

1. By Sambat Ranabhat
Rust of Guava

3. Introduction
Causative agent: Puccnia psidii
Origin and Distribution:
It was recorded first from Brazil in 1884 and its distribution is limited to
the western hemisphere in central and south America.
About pathogen:
The pathogen attacks leaves, flower, shoots, fruit and causes 80-90 %
losses. Puccnia psidii has wide range and infects about 8 genera & 25
species of plant belonging to family Myrtaceae.

4. Symptoms:
• Lesions are produced on young actively growing leaves,
shoots, as well as on fruits and sepals.
• Leaves distorted; defoliation of tree: circular lesion on fully
expanded leaves with dark borders and yellow halos.
• These lesions may be surrounded by, or totally covered in,
masses of bright yellow to orange spores.
• Severe infection in young trees may kill shoot tips, causing a
loss of leaders and a bushy growth habit.
• Prolific branching and galling, or persistent localised lesions,
stem swellings or leaf distortions have been reported in
many species.

5. Symptoms:
In fruits In leaves

6. Life cycle and Epidemiology
Puccnia psidii has an autoecious, but incomplete lifecycle.
Urediniospore germination leads to appressorium formation and
haustorium development that may result in formation of either
uredinosori or teliosori.
The Urediniospore can survive for weeks and are readily wind
dispersed. The Urediniospore cycle can be as short as 10 days. High
humidity and moderate temperature favour spore germination.
Affected host: Bottle brush, Eucalyptus species, brazil cherry, rose
apple, and black plum

7. Epidemiology

8. • Spores developed during lifecycle of Puccnia psidii are:
Basidiospore Aeciospore
Teliospore Uredinospore

9. Management:
1. Resistant variety: Sweet varieties both red and white fleshed are
more susceptible to the rust than the sour varieties. Variety with
vigorous growth have high infection.
2. Chemical control:
• Spray of Bordeaux mixture @1% after winter when tree began
active growth. Spray at monthly interval.
• B03818 (a combination of Nicl2 and Zineb) @ 0.03%
• chlorothalonil containing fungicide.

10. Mgmt cont……
3. Biological control:
• Fusarium Decemcellularey ( Nectria rigidiusula) is found
hyperparasites on the uredospore of puccina psidii.

11. Reference:
• https://www.apsnet.org
• www.agriculture.gov.au
• https://en.m.wikipedia.org
• https://www.researchgate.net
• www.slideshare.com

12. ANY QUERIES:
Contact at: ranabhatsambat@gmail.com