Common Garden Diseases and Solutions by Mary Small

POWDERY MILDEW- White or gray, flour-like substance on leaves, stems, flowers. Thin plant if growth is dense. Keep water out of plant canopy or apply it when it will dry fast. Apply sulfur or potassium bicarbonate or horticultural oils at first sign of mildew.










EARLY BLIGHT(tomato)- Lower leaves yellow; spots of concentric rings found on lower leaves. Keep water off foliage, or apply when it will dry fast. Chlorothalanil fungicide may be applied at first sign of infection.











FIREBLIGHT(crabapple)- Stem tips brown, bend over like shepherd’s crook and shrivel. Drops of bacterial ooze on branches. Prune branch 6-12 inches below visible signs of infection. Treat pruning tool between cuts with 1:9 bleach mixture or rubbing alcohol. (Clean tools when done.) Thin tree branches. Avoid over-fertilization.












CYSTOSPORA CANKER(aspen, cottonwood)-Sunken discolored areas on trunk and/or branches. Dark “pimples” found in cankered area. Branch dieback. Prune out affected branches below visible signs of infection. Keep tree healthy.










LEAF SCORTCH-Leaves brown on edges and in between veins. Often found in hot dry weather. Apply water to plant’s root zone during hot dry weather or when scorch appears.

The Noises of August by Donna Duffy

Cicada, photo courtesy CSU Extension

You’ve probably noticed that it's a noisy place out in the backyard with all that insect racket going on. Interestingly, only a few groups of insects communicate by rubbing their body parts together. What you are hearing are most likely cicadas, crickets and katydids. As you might suspect, it’s the males making all that commotion!

Aphids on Shade Trees By Joyce D’Agostino

Aphids photo by Joyce D'agostina

This summer I noticed some distinctive leaf curling on one of our shade trees. In checking it confirmed that there were aphids (lots of them) infesting this tree. The leaf curling in one sign of the damage that these insects can do. It is not only unsightly but left unchecked it can do damage to your tree.

Fortunately there are some solutions to reducing or ridding these insects from your plants. Aphids are very small, soft bodied insects. Using your hose on a hard stream, you can target the areas with a strong blast of water. This is very effective and if used regularly will reduce the population of these insects on your trees and plants. Check an area first with the water hose setting to ensure that you don’t damage the plant.  I noticed when I used this method that it did help remove a lot of the aphids from the curled leaves.  

Ladybeetles and Green Lacewings are also great natural predators of aphids. If you see these insects in your garden, moving them to the aphid area is very helpful.  Both of these insects are known to be able to eat a large amount of aphids, so make them a great non chemical use to help with aphid control.

Refer to these bulletins for more information on identifying and controlling the aphids.

http://www.ext.colostate.edu/pubs/insect/05511.html

http://www.ext.colostate.edu/pubs/insect/05594.html

http://www.ext.colostate.edu/pubs/insect/05550.html