white rust albugo parasite on the leave.

agriculture albuginaceae albuginales albugo amaranthus aphididae aphidoidea blister brassica candida convolvulus crop cruciferous crucifers disease eumycota farm farming fungal fungi fungus garden green growth harmful infect inoculum insect juncea leaf leave like nature oomycetes organic outdoor parasite pest plant puccinia pucciniaceae pustules rust sap spore spot sucking vein viridis white yellowish