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Spring brings a fresh start to every living thing. Each part of nature, both plants and pests, puts forth her best effort to complete another life cycle. The homeowner has the option of letting nature determine the outcome or try to alter the competition between plants and pests. Homeowners have the privilege of timely use of natural, mechanical and chemical methods to alter this outcome of the phrase “green and growing or pest destroying”. These become survival skills in this competitive world of Horticulture. University of Nebraska Extension in Adams County office staff receives and welcomes numerous calls on vegetation and pest management to assist homeowners.

Rechecking the past two weeks calls to the horticulture desk lets you know you are not alone in seeking help to keep nature in balance. My ledger reads: profuse seeding of maples and elms; yellowing of river birch, maples and oaks; aphids on the roses; sycamore anthracnose; slugs in the garden; bagworms in the evergreens; controlling suckers from the trees; seedling trees in the lawn; fruit trees, shrubs, evergreens and tree pruning; spider mites on about anything growing; lawn applied weed control chemicals effect on Linden trees; and maple bladder gall mite.

Every kind of pest seems to be out there, chewing or sucking its way through a life cycle of its own. Let’s work our way through the pests listed above with a line or two of the pest, how to identify it, when to control and how to control. I’ll give a one liner on the management question as they appear.

***The 2010 profuse seeding of elm and maples will not kill trees. Heavy seeding turned the trees to a dingy gray brown color before the seeds matured, which caused considerable concern. This lack luster appearance became history as the seeds fell off. Normal sized leaves should re-appear and fill in the sparse looking limbs. Water well along the drip line of the tree and maintain adequate fertility.

***River birch, maples and oaks find it difficult to gather adequate micro-nutrients such as iron from highly alkaline soils. This shortage results in leaves turning yellow, usually with green veining, and often progressing to browning of the leaf margins. The addition of iron sulfate and sulfur assists the tree in balancing needed nutrients. We tend to recommend injection treatment for oaks and soil treatment for maples and birch trees.

***Aphids, a diamond shaped insect, pierce the plant and suck up liquids. Though usually green, they seem to match the leaf and stem color of the plants they are attacking. Aphids on roses are very common and if left unattended, can cause leaf distortion and stunt bud development. Rapid buildup occurs during warm days and cool nights. Monitor frequently. Control can be as easy as spraying with water, or using one of the three types of chemicals that have non-residual, residual or systemic characteristics.

***Sycamore tree anthracnose becomes more prevalent during wet seasons, and is the most serious disease to the sycamore tree. It appears as frost damage and kills back the twigs 8-10 inches. Copper based fungicides are available, though costly, for early spring application. At this time of the year, we wait and watch, without removing the tree.

***Slugs in the garden continue to menace the gardener in times of high humidity and cool temperatures. Slugs are terrestrial mollusks, not true insects. Slugs play havoc on most garden plant leaves and fruiting bodies. Old remedies such as beer in shallow dishes will attract some slugs and is still a method of control. Iron phosphate and metadehyde products appear to be replacing hand picking or the beer approach for control.

***Bagworms start to hatch in late May from those little (up to 2 inch long) brown bags hanging from the evergreen branches. It is possible to hatch from 500 to 1000’s of worms from each bag containing eggs from a female bagworm. Tiny bagworms immediately start building cone-shaped bags, which are enlarged as the caterpillars feed and grow. Removing and destroying the previous year’s bags before May is most helpful. Since we are already in the month of June, recommendations for control call for thoroughly spaying the foliage with an insecticide while the larvae are small. A second application of insecticide in early July gives better control.

***Removing suckers, actually new shoots arising from the roots of the tree, are often a concern. It is a natural response for many trees, especially aspen, sumac, plum and chokecherry. Cutting off the sucker shoot is still the best method of containment. A new product “SuckerStopper RTU” may be effective. The concern of using chemicals is the possibility that it can travel through the root system, back to the tree and destroy more than suckers.

***Do not confuse sucker shoots with seedling trees. Millions of new maple and elm seedlings may appear by late August in our lawns and gardens due to heavy seeding this spring. These little trees, starting from seed, are called seedlings and can be controlled with lawn safe broadleaf herbicides.

***Pruning of evergreens can be done anytime. Pruning of spruce and pine trees is usually done by the first of July which allows time for the tree to set new buds for next spring. Pruning of fruit trees should be done when they are still dormant, preferably in February or early March. Trees that are considered “bleeders” should be pruned after most of the years’ growth has occurred, usually around the end of July. This includes maples, willows, birch and walnut. Oaks should never be pruned during the warm months of April thru September. Remember, we no longer cut branches flush with the tree trunk, but rather just outside the collar attachment of the limb to the tree trunk. Our rule of thumb for flowering shrubs is to prune spring flowering shrubs after they bloom (snowball or forsythia), summer and fall flowering shrubs in the early spring (hydrangea) and non-blooming shrubs (privet), whenever you are in the mood. Several varieties of plant cultivars (like spirea) have either spring or summer blooming times so check carefully before pruning to determine optimum pruning dates.

***Spider mites belong to a group called the arachnids. Like slugs, they are not true insects. These 8 legged creatures (mites) are difficult to see, as they appear like dust on the bottom side of the leaves. The two-spotted mites attack the foliage of ornamental, vegetables and fruits. They are oval, green to yellow in color and have two dark spots on their backs. Spruce spider mites attack many of the conifers, especially spruce, arborvitae, junipers and pines. Young spruce spider mites are pale green, adults may be reddish, dark green or nearly black with pink legs. Pest mites remove chlorophyll and sap from host plants resulting in bleaching, yellowing or browning of the foliage. To monitor, strike the leaf or plant sample over a white piece of paper and note if the dust like material moves when held in sunlight. A stiff stream of water washes mites to the ground. If a miticide is warranted, select the least toxic material whenever possible.

***Damage to Linden trees from weed control applied to lawn has not been a problem until recently when lawn weed control chemicals included dicamba. This product is a formulation in “Tri-mec “that has now become commonplace as a weed killer. Please read the chemical label or check with your lawn service if you have a Linden tree in your yard. Do not blanket apply liquid herbicides or use “weed and feed” fertilizers within the tree root zone. The root zone’s radius is two and one-half times the height of the tree.

***Maple bladder galls are those wart-like growths on the top of the maple leaves. Galls are present every year, though the abundance varies greatly from year to year and from tree to tree. Maple bladder galls are caused by extremely small mites that have overwintered on the tree trunk under the bark, and move up the trunk of the tree to the newly developing and unfolding leaves. The gall is the trees response to irritation caused by the mite’s feeding. The mite continues to feed during the summer and lays eggs within the gall. Galls appear green or red and will turn nearly black by fall. It is not practical to spray. Galls are not of significance to the tree.

The next two weeks will bring different questions. Note that lawn questions, the largest grouping of question makers at the office, aren’t even mentioned today. Maybe later.

About the author: Don Siffring

Don Siffring is a 6 year Master Gardener with the University of Nebraska Extension in Adams County. He is a professor emeritus with the University of NE, Institute of Agriculture. Don works part-time as a Horticulture Aide with UNL Extension in Adams County. Don and his wife, Bev, retired to the Hastings Community in in 2003 to be closer to their married daughter and husband, Christi and Brian Berns of Bladen.