1
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Life cycle of Apple scab disease

Apple    Srinagar

At which inoculum stage is venturia inequalis easy to curb, and what are the effective fungicides other than triazoles in curbing out mycelial growth?


Posted by: waseem shafi (7 points) waseem shafi
Posted: March 25, 2016


Juan Tizcare├▒o Iracheta commented,
You and Dr. Narayana have an error. It is V. inaequalis
almost 3 years ago.



Answers

1
point
Apple scab, Venturia inaequalis overwinter on plant debris. With suitable temperature and moisture it produce ascospores and released into air.

Management:
1. Collect and burn the fallen leaves and twigs to prevent ascospres production.
2. Trimming and pruning of infected young shoots (the diseased shoot have cracked, rather coarse bark) and burning in the winter also removes overwintering spores.
3. Or apply urea (2 Kg/acre at pre-leaf fall stage spring and dolomitic lime (2.5 ton/acre) in autumn over fallen leaves to accelerate decomposition.
4. Systhane (triazole) is very effective as preventive, curative and eradicant.
5. If scab out break is spotted you can use Captan (contact fungicide) because it is not prone to resistance. (Captan blocks the ability of fungus to produce energy)
Captan 50% WP @ 1000 g in 300-400 l of water/acre
Or Captan 75% WP @ 666.8 g/ acre in water required to distribute 10-20 l/tree


Posted by: Dr. Ravishankar Narayana (8 points) Dr. Ravishankar Narayana
Posted: March 25, 2016


waseem shafi commented,
It's not possible to destroy debris at mass level particularly when there are many resources for overwintering beyond peripheries.
over 3 years ago.

Sheila Kern commented,
accidently I was also finding the answer to this question, and I am happy to see that David Hughes and Dr. Ravishankar Narayana explained it in depth with clarity.
I am working on the project and this information is helpful.

almost 3 years ago.



1
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To add some additional details.

The addition of urea can occur 2-3 weeks before green tip (when the leaves start). This can be combined with removing old material.

Here is a really good video that explains this https://www.youtube.com/watch?v=4WAuP...

There is also a very extensive document here that talsk about how the modelling of ascopsore release can be calculated. http://www.ipm.ucdavis.edu/PMG/r41004...
But we cannot assume that works for your region.


Here is Dr Daniel Cooley of the University of Massachusetts saying that a model developed in a nearby US State (New Hampshire) was not effective at predicting scab outbreaks in Massachusetts.
https://www.youtube.com/watch?v=5XISX...

What is useful to know beyond the general advice is what stage are you at? How big of a problem has scab been in the past?


Posted by: David Hughes (43 points) David Hughes
Posted: March 25, 2016


waseem shafi commented,
What about metiram plus pyroclastrobin preparation
over 3 years ago.

Dr. Ravishankar Narayana commented,
Metiram+Pyraclostrobin combination fungicides are recommended against powdery mildew, early and late blights, white mold and black dots particularly for potato, chill, grape and tomato crops. It act as protectant by inhibiting germination of spores.
over 3 years ago.

JackPonting commented,
A very detailed and well explained concept of Life cycle of Apple scab disease


almost 3 years ago.



0
points
A very detailed and well explained concept of Life cycle of Apple scab disease



Posted by: JackPonting (1 point) JackPonting
Posted: January 16, 2017




0
points
accidently I was also finding the answer to this question, and I am happy to see that David Hughes and Dr. Ravishankar Narayana explained it in depth with clarity.
I am working on the project and this information is helpful.


Posted by: Sheila Kern (1 point) Sheila Kern
Posted: February 9, 2017




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