NDSU Extension - Traill County


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Soil field Day

Why do my trees look like that?Iron Chlorosis

Iron Chlorosis Edition

I have received multiple calls and home visits with homeowners wondering why there trees are looking the wrong kind of green. The trees that are looking “off” are showing symptoms of iron chlorosis. Learn more about the signs to look for below:

The main symptom of iron chlorosis is yellow leaves with green veins. The trees to make chlorophyll, the green pigment that traps sunlight for photosynthesis, use iron. There is no predicting if or when a tree will be affected by iron chlorosis; a tree can be healthy for many years, then suddenly become chlorotic. Iron chlorosis can be the first step in a decline spiral that eventually kills the tree.

Some species are more susceptible than others are to reduced iron. Silver maple trees are especially vulnerable. Silver maple is one of the parents of the Freeman maples such as Autumn Blaze® or Sienna Glen®; these hybrids are slightly susceptible to iron chlorosis, but not as much as silver maple. River birch and red oak are less sensitive than silver maple, but more sensitive than most other tree species.

Most of North Dakota’s soils have enough iron in them to support healthy plant growth. However, sometimes the iron is in a form that is not available to plants. The culprit is usually high soil pH. The soil is not acidic enough to keep iron in the available form. Low soil oxygen can also cause iron to be unavailable. Trees are more susceptible to iron chlorosis if they are growing in flooded or compacted soils. Even low temperatures can reduce iron availability.

Can chlorotic trees be “fixed” or “saved”? As with most things, the answer is “it depends.” In the case of iron chlorosis, prevention is more effective than after-the-fact treatment.

Determining the cause of the low iron availability is critical to developing a treatment approach. Obviously, we cannot change the weather – low-temperature induced chlorosis cannot be prevented. However, flooding and compaction – and therefore low soil oxygen – can be mitigated by improving drainage or aerating the soil.

For chemical treatment products, there are a lot of manufacturers’ claims. What does the science say? It’s not conclusive. Everything works some of the time, but nothing works all of the time.

If the cause of the chlorosis is high soil pH, then there are two options – lower the pH or add iron in an available form. Soil pH can be lowered by adding elemental sulfur or by adding acid-forming fertilizers. Some experts recommend combining these approaches by applying iron sulfate to the soil. Treatments must be repeated every two-to-three years. Iron can also be added as a chelate. Chelated iron comes in many formulations, so ask your local garden center what formulations are on hand.

Iron can also be added directly to the tree, either as a foliar spray or as a trunk injection into the vascular system. Iron chelate sprayed onto the leaves offers a quick fix to the problem, but the effects are often short-lived. Trunk injections have shown mixed results. Sometimes, injections are effective and trees regain their health and vigor. However, if the damage is too severe, then trees will not recover.

Watering Young Trees

Newly planted trees may lose 95% of their roots from the nursery field to your yard. They require your attention, especially during these warm summer months.

How often should I water?
For the first summer, trees can be watered every 2–3 days when needed. In future years, the tree should be monitored weekly until it’s overcome its shock.

How long is a tree in shock?
A young tree suffers 1.0 to 1.5 years for every inch of its trunk caliper (measured at 6 inches above ground).

How much water?
One rule of thumb is a tree requires 10 gallons of water per week for every inch of caliper. If you water about 3 times a week, then a tree would get 3.3 gallons per inch of its caliper during each irrigation. Water only if the soil is dry. Get a metal rod and check 8 inches deep. Keep the soil moist but not soggy.

What Happened to my Tree?

Tent Caterpillar Edition

Tent CaterpillarIt started by getting a call in the office last week, “Something happened to my tree! The leaves, they were here and now they are almost gone!”

Forest tent caterpillars (Malacosoma disstria) and Eastern tent caterpillars (Malacosoma americanum) are feeding on tree foliage this time of year. The eastern tent caterpillars make the webbed tents in the forks of tree branches, which are used as shelters and resting places. People consider the webbed tents unsightly in trees. The forest tent caterpillar does not make any webbed tents, but they wander around in masses of larvae and crawl over trees, picnic tables, patios, lawns, etc. which people consider extremely objectionable. Fortunately, they do not bite. Large numbers of forest tent caterpillars crushed on roads causes the roadway surfaces to become greasy and slippery. They infest many trees hosts: ash, aspen, basswood, birch, chokecherry, cottonwood, elm, maple, oak, pin cherry, poplar, and other hardwoods.

There is one generation per year for either species. Both overwinter as eggs. Larvae hatch in early spring. For the forest tent caterpillar, the keyhole shaped spots along their backs and broad bluish lateral bands easily identify larvae. For the eastern tent caterpillar, larvae are black and somewhat hairy with a whitish-yellow stripe down the middle of the back, narrow broken orange-colored subdorsal stripes, and lateral white and blue markings. In five to six weeks, the larvae pass through five larval instars and are about 2 inches long. Mature larvae then form silken cocoons to pupate. Adult moths will emerge from cocoons during early summer (late June or early July).

Damage: larvae of both species cause defoliation. Light defoliation has little effect on tree health. Two or more years of moderate-to-severe defoliation by forest tent caterpillar is necessary to affect radial growth and cause branch and twig mortality. When populations of eastern tent caterpillars are high, whole trees can become covered with webbing and defoliated.

Pest Management: Bt (or Bacillus thuringiensis var. kurstaki; Dipel, Thuricide), a natural occurring soil bacterium, works well to control young caterpillars and conserves beneficial insects. Other insecticides available to homeowners include: acephate (Orthene), azadiracthin (Azatin), carbaryl (Sevin), esfenvalerate (Bug-B-Gon), malathion, permethrin, spinosad (Conserve), or other insecticides registered for trees. Always read, understand and follow the insecticide label directions.

Invite Butterflies to Your Yard!Butterfly Gardens

Would you like to add some excitement to your garden? Invite butterflies! Their delicate wings and fluttering movements are absolutely enchanting.

It’s easy to attract butterflies—simply give them what they want. Start with sunshine. Select a sunny site that is sheltered from our harsh winds. Butterflies love to sunbathe. Create a warm resting spot for them by placing dark rocks in the garden Butterflies will enjoy the freedom of flight once their bodies have warmed to 85 to 100 degrees.

Next, provide plenty of flowers. Select flowers that make nectar available from spring through fall. Butterflies are attracted to purple, orange, yellow, red and dark pink flowers. Popular choices include blazing star, butterfly bush, phlox, cleome, coneflower, sedum, goldenrod, cosmos, dianthus and zinnia. Don’t forget milkweed—it’s essential for monarchs.

Butterflies need water. Puddles of water provide the hydration and minerals needed for good health and successful breeding.

Limit pesticide use to a minimum. Chemicals that kill insect pests will kill butterflies. Spray pests with insecticidal soap. Soaps will not leave residues that threaten butterflies.

Butterflies need a home to raise their young. Grow plants for butterflies to lay eggs upon and for the emerging caterpillars to eat. Popular choices include birch, butterfly bush, oak, hackberry, willow, dill, parsley and hollyhock.

Traill County Weed Board Program Available for Landowners

Now that spring is quickly turning into summer, weeds in the county are now in their peak of growth. The Traill County Weed Board has a program available to assist landowners with controlling these weeds.

Limited cost share funds to control noxious weeds on non-cropland areas in Traill County are available. Cost share funds up to $500 for private landowners and $1000 to townships are provided at a 20% (cost share participant) 80% (Traill County Weed Control Board) ratio. Cost share funding applications must be turned into the NDSU Extension/Traill County office no later than October 15, 2019.

To request an application for cost share, or if you have questions about this program, please contact the Traill County Extension office at (701)636-5665 or email .

Emerald Ash Borer – Focus on Firewood

In honor of ‘Emerald Ash Borer Awareness Week’, I felt it was certainly fitting to focus on firewood as the camping season is upon us! On its own, EAB travels about ½ mile per year. With human help, it travels 55 miles per hour or even more! Please, don’t move firewood. 

Campground managers, foresters and many others are encouraging their clients “Don’t move firewood” this summer and throughout the year. Movement of infested firewood has been one of the main methods of long-distance dispersal of emerald ash borer (EAB). The legal regulations regarding firewood movement can be rather confusing, with some examples listed below. In order to avoid the hassle, simply “Buy it where you burn it.”

• A federal quarantine is in place around all of the known EAB-infested areas of the U.S. Moving firewood and other ash products out of the quarantine area is illegal unless very specific, highly detailed rules are followed. 

• ND Forest Service – prohibits out-of-state firewood at their campgrounds, but they will provide a free bundle of firewood for each paid campsite. Additional firewood is available for $3.00 per bundle. 

• US Army Corps of Engineers – at campgrounds in North Dakota, firewood must originate within 100 miles of the campground, unless it has been officially certified as pest-free. 

• MN Department of Natural Resources – in Minnesota, regulations were amended in December 2017 regarding firewood use on DNR lands including state parks: http://www.dnr.state.mn.us/firewood/index.html.

Controlling Ticks  
Wood Tick

With the warm spring weather, tick season is upon us. Three species are found in North Dakota: American dog tick, Rocky Mountain wood tick, and winter tick . Of these, American dog tick is the most common species. Lyme disease is vectored by the black-legged tick, also known as deer ticks. Fortunately, the black-legged tick does not occur naturally in North Dakota, but is brought in from neighboring states. The Center for Disease Control and Prevention (CDC) recommends the following strategies for preventing tick bites:

Minimizing direct contact with ticks by avoiding woody and high grass areas and walking in center of trails, if possible. Ticks are most active in May through August in North Dakota.

• Use repellent with 20-30% DEET (N,N-diethyl-m-toluamide) on exposed skin and clothing. This should provide several hours of protection. Or wear clothing treated with permethrin.

• Quickly find and remove any ticks from body by using a tweezers. Grasp tick close to skin and pull straight up to avoid breaking off the tick’s mouthparts in the skin. Clean bite area with rubbing alcohol or soap and water.

• Inspect and bath yourself within 2 hours after coming indoors to find any ticks crawling on you and to remove them before they attach to feed on your blood. Ticks like to hides in hair, armpits and other areas that may be difficult to inspect.

• Wash any clothing that you were wearing soon and then dry in high heat for an hour to kill any ticks. Otherwise, ticks can attach to you later after hitchhiking on your clothes into your home.

• Reduce tick habitat near home.

• Keep lawns mowed around home.

• Place a 3-ft wide barrier of wood chips or gravel between lawns, patio or play areas and wooded areas to prevent tick movement.

• Exclude wildlife (especially deer) that may be carrying ticks into your yard.

• Some insecticides registered for control of ticks by homeowners in residential areas include: carbaryl (Sevin®), cyfluthrin (Tempo®, Powerforce™), permethrin (Astro®, Ortho® products, Bonide® products), and pyrethrin (Pyrenone®, Kicker®). Always read and follow the EPA approved label on the product container.

Traill County Courthouse


NDSU Extension/Traill County
114 Caledonia Ave. W.
Box 730 (mailing address)
Hillsboro, ND 58045
Phone:  701-636-5665   
Fax: 701-636-5666

Office Hours:
8 a.m. - 4:30 p.m., Monday-Friday
Summer Office Hours:
(Memorial Day - Labor Day)
7 a.m. - 4:30 p.m.,  Monday-Thursday
8 a.m. - Noon, Friday

Related Links:
NDSU Extension
North Dakota Department of Agriculture

Traill County
City of Hillsboro
Cities of Mayville-Portland
City of Hatton

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