With the beginning of spring we are starting up our frequently asked question pages again. We do not often post FAQ pages in the winter because there are only so many questions we get during the dormant season. Keep in mind that the data here is for the Portland, OR area and may not apply to other climates.
Tomato varieties with desirable fruit can be grafted onto the root system of another tomato that has superior vigor and disease resistance. This results in a plant that defends better against pests, diseases, and temperature extremes while producing earlier and more abundant harvests. This technique has been fairly unknown in our neck of the woods, but the method is used more commonly worldwide. More locals are now hearing about it and we can hardly keep our shelves full.
When planting the grafted tomatoes, do NOT bury the graft. Many gardeners have traditionally buried the stem of tomatoes to produce more roots early on, but you do not do that with grafted tomatoes. Handle the plant gently, and note where the graft is so that it is above the soil. As the plant grows, remove any side shoots that form below the graft, as those will not be the type of fruit that you wanted.
This spring has practically been a repeat of last year with frequent showers continuing well into June. For that reason, many of our fruit bearing trees have been heavily affected by leaf affecting fungal diseases. Here are highlights of some of the most common problems. As generalizations for cultural control, try to avoid overhead irrigation or unnecessary wetting of leaves, and give all fruit trees as much direct sun as possible. Do not crowd fruit trees with other large shrubs or trees. The gardener can apply fungicides to control the spread of the diseases. Some such products should be applied before the growing season starts and can only be planned for later on, and some fungicides are for use in the growing season to halt the spread of the disease. Feel free to use a web search for pictures of the ones mentioned below, and contact us for fungicide recommendations.
"My nectarine tree has weird, curly growth on the leaves, and most of them are distorted in this way. What is going on?"
This is peach leaf curl, also called Taphrina deformens or possibly a related species. It can also affect apricots and of course peaches.
"My pear tree has little brown spots on the leaves. It didn't seem serious at first, but it is spreading now to many of the leaves."
This is probably apple scab, and it also affects apples and crabapples. It will also leave growths on the fruit that resemble scabs. The fruit is edible but not pretty.
"There are little random holes in the leaves of my flowering plum. Is something eating it?"
This is not an insect, it is shothole fungus or coryneum blight. It is a fungus that affects cherries, plums, laurels, apricots, and other members of the genus Prunus.