By monitoring University extension reports from around the country, our team of staff arborists at TheTreeGeek.com is able to predict which tree pests to watch out for in your area, and advise you how to effectively protect your tree from their damage. Here are 5 pests to be scouting for this week.
Ash-lilac borer
Ash-lilac borer, Podosesia syringae, is a clear-winged moth that affects ash, privet, and lilac, especially stressed plants. Look for thinning canopy, limb dieback, and /or sprouts at the base of the tree. Sawdust-like shavings may be found at the base of the tree or coming out of ¼” round to oval holes on the bottom ten feet of the trunk.
What can you do about it?
Treatments of Tengard® sprayed on the trunk and upper branches must be done right now to prevent the newly hatched larvae from boring into the tree. Don’t confuse this with emerald ash borer, another borer on ash trees. Emerald ash borer have D-shaped exit holes with no sawdust-like excrement coming from them. Ash-lilac borers have larger, round to oval-shaped exit holes with sawdust excrement coming from them.
Peachtree borer
Peachtree borer, Synanthedon exitiosa and Synanthedon pictipes, is known to attack peach, nectarine, apricot, cherry, and plum trees. Look for wet spots on the bark, most often near the base of the tree, with oozing gummy sap with sawdust like excrement in it. Leaves on a portion of the tree may turn yellow and wilt, often leading to die back in the canopy.
What can you do about it?
Peachtree borer prefers trees that are stressed due to drought; therefore, the treatment strategy involves cultural practices like watering and mulching, as well as providing insect control with bark sprays of Tengard® or Carbaryl 4L when most of the adults have emerged.
Black vine weevil
Black vine weevil, Otiorhynchus sulcatus, feeds on the leaves of yew, rhododendron, hemlock, and many nursery species. Look for crescent shaped sections removed from broadleaf leaves and tips that have been chewed off of evergreen needles.
What can you can do about it?
Bunching burlap around the base of plants can be used as a trap. Weevils will feed on the plant during the night and hide in the burlap during the day. The burlap can be removed and checked for adults. Foliar spray applications of Up Star® Gold applications should be used to control adults before they lay eggs. These applications need to be repeated at 30 day intervals throughout the early summer. Soil applied systemic insecticides, such as Xytect™, should be applied in the very early spring for current season control or the late fall for next season control.
Powdery Mildew
Powdery mildew, Blumeria graminis, is a common disease on a wide variety of plants throughout the United States. This disease infects plants during high humidity in the spring and occurs most commonly on the upper side of leaves, but also infects stems, buds, flowers, and fruit. Look for white, powdery mycelial and conidial growth on leaves, stems, buds, or fruits during the growing season.
What can you do about it?
Cultural controls include spacing plants appropriately, removing dead plant material, pruning for air flow, and not watering from overhead. Late summer applications of nitrogen fertilizer can also cause problems by increasing foliage growth. If fungicides like Myclotect ™ or Cleary 3336™ are required, they should be used as a preventive spray in the spring. This is a disease that is relatively easy to control, but monitoring is very important.
Lecanium Scale
Lecanium scales represent a group of common soft scales that infest a wide range of tree species throughout the United States including, but not limited to, oaks, maples, linden, and birch. Of the many types of lecanium scale, the most common are fletcher scale on arborvitae and yew, terrapin scale on maples and peach, hickory lecanium scale on hickory and elm, and globose scale on stone fruits. Look for twig dieback, stunted plant development, premature leaf drop, and the presence of sooty mold giving a blackened appearance to the leaves and branches.
What can you do about it?
If planned ahead of time, soil applications of Transtect™ in the early spring for the current season’s control, or Xytect™ in the late summer/ early fall for next year’s control work very well. Foliar sprays of RTSA Horticultural Oil or Up Star® Gold should be timed to coincide with egg hatch.
Check us out next week for another update. In the meantime, feel free to contact us at 888-637-6694, we are here to help!
