Fruit Diseases

(November 2010)

I live out on the north side of a small mountain in the Ferndale area.  I try to grow things on our ten acres, with modest success. I set out blackberries a couple of years ago, beside a small running creek, but not below water level. This summer, they developed some black spots and a couple of vines passed on, the remainder did produce a couple of quarts.  I am thinking they had  some kind of a rust perhaps, because I do have oaks and cedars in our area. Should I be applying some type of dust such as rotenone?

There are several things that could be impacting your blackberries, but from the sound of it, it isn’t insects, so rotenone would not be affective.  I also don’t like dusts.  If you are going to spray, we need to properly identify the disease (with leaf samples next year) and then find the appropriate fungicide.  There is one disease called double blossom (or rosette) that affects blackberries that is not curable. It is common when we have wild blackberries nearby that can spread the disease.  It causes excessive thorniness on the stems and deformed almost double blossoms—thus the common name.  It can kill plants, but usually in a slow manner.  Pruning out infected canes helps.  There is a rust disease that affects blackberries that is controllable. It produces very bright orange spores that can be rubbed off.  Cedar apple rust does not affect blackberries, but does affect apples.  There are other leaf spotting diseases as well as stink bug damage to the fruits.  If you have the problems again next growing season, bring in a sample or take a picture and send it in so we can properly identify the problem before recommending a control.

(April 2010)

I am having difficulty with my fruit trees.  Last year my peach tree produced lots of peaches, but they all dried up around the seed before they ripened. I also noticed that quite a few of the leaves and small branches dried up and died.   My apple tree made really good apples but the leaves dried up and died and I noticed yellow spots on the leaves that had several round dots in them. I assumed these to be some kind of insect eggs. The apples also had dark spots on them. I have already cut them back and am hoping that you can suggest some kind of spray, preferably something natural that I can use to solve these problems

Fruit trees can be challenging for the home gardener, especially peaches which have numerous insect and disease issues.  Brown rot is the most destructive and can wipe out a crop seemingly overnight, especially when we have periods of rain, which were almost constant last year.  Pruning is something you will need to do annually, but a spray schedule is also necessary to produce quality fruit.  Purchase a home fruit spray which has both an insecticide and a fungicide mixed together.  There are organic products as well as non-organic. Start spraying when two thirds of the flower petals have fallen and then continue throughout the growing season, about every 10 days to three weeks depending on the weather.  Your apple tree sounds like it was infested with cedar apple rust.  This disease has two hosts--Eastern red cedars and apple trees.  By the time you see yellow spots rimmed in orange it is too late to spray to control it. The key is to do preventative sprays the first few weeks following bloom.  Orange gelatinous masses form on cedar trees releasing spores which then infest the apples.  Typically apple diseases are a bit easier to deal with since you can usually peel off the damage and still eat the fruit.  Spray schedules, cultural information and pruning guides are available on our Extension website at: http://www.arhomeandgarden.org/

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