How To: Identify common shrub & tree diseases

John White (Doña Ana County Extension Agent) talks to Natalie Goldberg (Extension Plant Pathologist) about Powdery Mildew that affects many plants. They look at a Japonica that is heavily infested. Powdery Mildew is enhanced by shaded condition despite the dry climate. It starts with a spot spore infection that will easily spread by the wind or by rubbing. Control methods are difficult and involves a lot of routine applications of chemicals (ornamental fungicide) to keep it in check once the plant is infected. In addition, the plant would have to be pruned to keep it airy and fallen leaves, debris and excess inoculums will have to be cleared from the plant . Most control methods are pre-emptive that is before the infection starts.They also look at slime flux (bacterial wetwood) problems that affect fast growing and weak wooded trees like the willow, elm, mulberry and cottonwood. Once infected it will stay with the trees for the rest of its life although it can be controlled by good water management and fertilizer. Recommendations include preventing freeze injury and sun damage.