Downy mildew
Pathogen : Peronospora trifoliorum
Favorable Conditions : cool from 40-80F, optimum around 65F, wet 100% relative humidity
Transmission : dormant spores in old , dead leaves
Susceptible parts : young leaves
Symptoms : Early stage : pale green to yellowish green,chlorotic (yellow) spots on the leaflets
intermediate stage :mottle yellow, necrosis (die tissues)
severe stage : distortion
The infected stems produce bunchy, rosette-like growth.
Mycelium : bluish-gray mycelium and spore underside of the infected leaves
Pathogen : Peronospora trifoliorum
Favorable Conditions : cool from 40-80F, optimum around 65F, wet 100% relative humidity
Transmission : dormant spores in old , dead leaves
Susceptible parts : young leaves
Symptoms : Early stage : pale green to yellowish green,chlorotic (yellow) spots on the leaflets
intermediate stage :mottle yellow, necrosis (die tissues)
severe stage : distortion
The infected stems produce bunchy, rosette-like growth.
Mycelium : bluish-gray mycelium and spore underside of the infected leaves
Management :
1. Early cutting
2. Resistant varieties
3. Seed treatment with Methalaxyl
Fungicide.
1. Early cutting
2. Resistant varieties
3. Seed treatment with Methalaxyl
Fungicide.
Reference : http://pnwhandbooks.org/plantdisease/alfalfa-medicago-sativa-downy-mildew
http://www.ipm.ucdavis.edu/PMG/r1100711.html
http://www.ent.iastate.edu/imagegal/plantpath/alfalfa/downymildew/1355.77downymildew.html
http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=9470
http://cropwatch.unl.edu/web/cropwatch/archive?articleID=1551954
http://www.ipm.ucdavis.edu/PMG/r1100711.html
http://www.ent.iastate.edu/imagegal/plantpath/alfalfa/downymildew/1355.77downymildew.html
http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=9470
http://cropwatch.unl.edu/web/cropwatch/archive?articleID=1551954