Summer 2010 UPDATE 7/25/2010
FUNGAL LEAF DISEASES. This spring has been a very wet spring and that has resulted in more common and more severe fungal leaf diseases. Anthracnose in sycamores and ashes is common, but this year we have seen many maples with black necrotic areas in the leaves, leaf distortion and leaf fall due to maple anthracnose. This does not need treatment and in fact it is too late to treat or prevent this problem. When there is severe defoliation or if there are other stresses such as heavy scale infestations, these trees can be treated with an antifungal and nutritional product that can suppress fungal disease and help the tree to re-foliate. Treatment of the scale at the same time is possible. The good news is that the anthracnose is usually not a serious problem for the tree and a healthy tree will push out some new leaves to replace the leaf capacity lost.
Flowering trees such as crabs, cherries and hawthornes have also been hit hard with leaf fungal spots, scabs and blights and are having leaf distortion and leaf fall this spring, even those that have been treated with anti-fungal sprays or injections. Again, the tree will probably respond by putting out some new leaves if needed.
SCALE INSECTS. The soft scales- cottony maple scale and lecanium scale in shade trees are very bad this year. In many cases they are not particularly harmful to the tree or shrub, but can be a nuisance with the honeydew and sooty mold problems on surfaces where the sap drips.
Soil insecticides for smaller plants and trunk injected insecticides for larger trees can be very effective in controlling these pests. Insecticide sprays should NOT be applied to trees with these scales during May or June. Sprays in August can give some measure of control if complete coverage of the underside of the leaves can be achieved (very difficult). Sprays at any time may actually exacerbate the problems by killing the predator insects without really controlling the scale insects. See scale treatment page.
DUTCH ELM DISEASE. We are seeing dozens of elms dying from Dutch Elm Disease in the tri-cities. Every year many nice elms die from this disease. The disease is not treatable, but is preventable with injected fungicides. If you have a nice elm tree and want to keep it, injected fungicides have been proven to be 99% effective in proper doses given by macro-infusion. See injection page.
WARM SEASON MITES. The warm season spider mites got an early start in this very warm spring and summer. We are seeing damage in burning bushes, Alberta spruces, boxwoods, nest spruces and others. Honey locust spider mites have started defoliating locust trees, especially trees in stressful settings like treelawns and parking lots.
SPRING 2010 as of May 4, 2010
NEEDLE SCORCH OF PINES. Spring of 2010 has been unusual in several ways. We had less precipitation than normal in the winter and so far the spring has been unusually warm and dry. These factors combine to stress many trees, particularly evergreens, including large pines. Because evergreens have foliage the year round, they are losing water through that foliage even in the winter. When there is inadequate water in the ground, the needles can dry out and become "scorched" or brown. We have had many calls this spring specifically regarding pine trees. The problem is mainly a problem of the old needles and if the tree is healthy it will produce new needles this spring and will look better in a few weeks.
SCALE INSECTS. The warm spring has resulted in the scale insects waking up early and many are already producing alot of honeydew drippage on surfaces below. Spring is an excellent time to treat trees for this problem and we have already injected dozens of trees for scale control this year.
ASH BORERS. We have observed much more damage in ash trees this spring, particularly in the Midland area. We are now treating ash trees even though many have not leafed out fully as yet.
EVERGREEN FUNGAL DISEASE. Because of the warm spring, the evergreens are already putting out new growth and will soon be due for fungicide sprays if they have needlecast disease. If they have tip blight, they should have had one spray by now.