Q: I have a spruce tree that is about 20 feet tall and the needles on the bottom half of the tree are falling off. This is only happening on the north side of the tree. The south side is OK. I was wondering if you had any ideas what I might do to save it?
B S. of Highland
A: There are two possibilities that could cause this problem to your spruce.
One is spruce spider mites. These mites suck the sap from the undersides of the needles. As a result, the green pigment disappears from the needles and they turn brown. You can check for this by using a white piece of paper and tapping the infected needles. If you find small black specks the size of pepper grains and they move on the paper, then you have spruce spider mites (Oligonychus unuguis). They first appear between April and June. The eggs that produced them were laid last October. They can produce another generation within 17 days and can produce large numbers in a short period of time. You should use Orthene Insect Spray or Iosotox Insect Killer on the infected areas every seven to 10 days. You also may notice these mites again in early fall or next spring.
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The other possibility is a plant disease caused by a fungus known as canker or dieback (Cytospora kunzei). This disease enters a tree through a wound, kills the surrounding healthy tissue and expands through the wood in different directions. When the disease encircles a branch, the branch dies and the needles turn brown. Sap then will ooze from the dying branch. Eventually, you will see small black spots which are spore bodies developing in the bark. To control this problem, you will need to prune off and destroy, preferably by burning the branches. But you also will need to sterilize your pruners with rubbing alcohol after each cut.
Do not prune during wet weather.
Avoid wounding your trees with lawn mowers or weed eaters because this opens up more wound sites. Keep your tree watered if the tree does not receive one inch of rain per week.
With the hot, dry weather that we have had, here’s a word of caution about applying pesticides to plants. Make sure you have read the instructions on the label because Alberta spruces (the small delicate looking spruce) easily can be killed by applying a miticide if the air temperature is above 85 degrees. The pesticide will volatilize and kill the needles. The mites will die because they will starve to death as a result. If it’s too hot, an alternative is using water from a hose to spray the mites and reduce the number without killing your plant.
Q: I am having problems with my tomato plants. They started producing green tomatoes, but there are no new blossoms being produced. What is wrong?
C. S. of Belleville
A: The hot temperatures are to blame. Whenever temperatures are above 90 degrees, the tomato pollen doesn’t pollinate. If the flowers are not pollinated, they fall off the plant.
There is a product called Blossom Set that you can apply to the flower once it opens. This product contains a plant hormone which tricks the plant into forming fruit, but usually no seeds are produced with this product.
Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Editor Maureen Houston, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to email@example.com.
Do it now:
- Water your plants and check on them frequently, especially those growing in containers.
- Remove any spent flowers to keep your flowering annuals producing more flowers throughout the summer.