Infected Pear and Linden Trees
Hello: I have a pear tree several years old. It still produces pears. It has small pears about the size of a nickel on it now. The leaves have these little black spots on the underside of the leave and top. I did spray a leaf with insecticidal soap a couple of days ago. I also put nutritional spikes around the base of the tree. Is there something else maybe I should be using?
Also I have a new linden tree. Just planted last year. Something has been eating the leaves of the tree. I saw little raised red bumps on a couple of the leaves one day. So I removed the leaves that had those. There was ants (little black ones) on the leaves, small (2) spiders could be seen one day, and little flies also. I have sprayed with insecticidal soap couple of days ago and put nutritional spikes around base of the tree. Is there anything else I should be doing? Or is there another product I can try and use? I would hate to loose both trees due to problems which occurred via insect somehow.
Thank you for your question concerning two trees. All gardens have insects and other pests that cohabit with plants without destroying one or the other. Most infestations do not destroy trees and your trees will likely remain healthy. However gardeners can go a long way toward minimizing the risk of serious damage to plants by using good housekeeping techniques that give their favourite plants the edge.
It is good to hear that your pear tree will bear fruit this year. That means it has been successfully pollinated- a problem for pears. These few points might help you maintain a healthy tree. A healthy tree has the best success to fight of distructive pests. A pear tree needs lots of sun. If it has been in the same spot for a few years make sure other trees are not shading it. It has a deep root, and need a clay based loamy soil (i.e. not sandy soil). Mulch around a pear trees trunk with rotted manure (the best!) or straw. It needs soil moisture, so watering in dry seasons in imperative. Light pruning is recommended in early spring to promote air circulation which helps control disease and promotes healthy fruit. Fertilizer is discussed in the link I have added to the bottom of this email. We can’t confirm what caused the black spots on your trees leaves. Fungus may be a possibility because of the wet spring. Bring a leaf into a reputable nursery and they may help you with identification and suggest an appropriate treatment. Meanwhile keep doing what you are doing. And think about the suggestions for good care above. Remove leaves that are noticeably infected and discard in the garbage (not compost). And next year consider dormant oil spray.
Regarding the Linden tree’s little red bumps- again these bumps may be an insect or fungus. Pick off the leaves with the most bumps and put them out for trash. Rake around the tree to remove all infected leaves that have fallen off the tree. Your description rules out several serious infestations common to linden trees. Since it is a new tree, the problem may have originated in the nursery from which you purchased the tree. Again our best advice is to pick off an infected leaf and bring to a reputable nursery where they may give specific product advice. There are many caterpillar-like larvae that could be the culprit eating the occasional leaf. At this time of year that is normal and will not effect the health of your tree. Pick any of these off the tree if you see them. Ants may mean you have some aphids or spider mites on the tree. You would notice them as tiny throngs of grey-white insects lining the stems at the base of the leaves. They are waxy. Take your garden hose, and give the tree a good hard spray to remove them if you see them. It is most likely that both your trees will have a healthy summer. But you will do well to bring a sample of the infected leaves for appropriate treatment if the situation becomes more noticeable.