Help with blackthorn tree!

Asked June 24, 2017, 3:04 PM EDT

Hello, I am currently growing a blackthorn tree (prunus spinosa) and for a while he was looking great. Up until about 3 weeks ago I noticed some yellowing to his leaves and yellow dots on newer ones, but the yellow doesn't go to the veins. I thought at first it could be mildew or mold but doesn't look like it. I took a nutrient test of the soil and found out there was little nitrogen in the soil so I started giving him fish emulsion. I'm going to attach photos because I really need help figuring out if this is a macronutrient problem such as nitrogen deficiency or micronutrient deficiency such a manganese? What should I do to help him so his leaves go back to normal color? What should I use to fix this problem Benedictions

Denver County Colorado trees and shrubs spider mites

1 Response

That flecking and bronzing resembles the damage seen with spider mites. Trying shaking a branch held over a white piece of paper to see if little red "dots" fall onto the paper. Those little red dots are spider mites and they travel fast.

Here is a fact sheet from CSU Extension about spider mites. It also has some photos and you can see those photos look very similar to your photos.

http://extension.colostate.edu/topic-areas/insects/spider-mites-5-507/