Emerald Ash Borer and Camels


By John Wilson, Extension Educator

In my 38-year Extension career, I never remember talking so long about a pest that wasn’t even here! I’m sure part of the reason is that emerald ash borers (EAB) are so devastating to ash trees. Since its arrival, EAB has killed hundreds of millions of ash trees.

EAB was first discovered in the United States in 2002 near Detroit in southeastern Michigan. I attended a conference in Michigan in the summer of 2007 and saw the devastation first hand. By then, EAB had spread through most of Michigan’s lower peninsula as well as into the upper peninsula, Ontario (Canada), neighboring states, and to an isolated outbreak in Maryland. The Maryland area was over 300 miles away from the closest confirmed case of EAB at that time.

The Maryland outbreak is significant because it shows how EAB can move over long distances. On its own, the adult EAB is not a strong flyer, according to the USDA Forest Service, and most will move less than two miles a year. (About 1% of the mated females may disperse up to 12 miles.) With help from humans, however, it is a great traveler. It has been known to travel large distances, migrating in firewood or nursery stock from infected areas.

Currently, the closest confirmed infestation to Nebraska is in Union County, Iowa, about 80 miles east of Plattsmouth on Highway 34. Other infestations have been confirmed in the Kansas City area as well as in Boulder, Colorado.

Our current recommendation is to not start treating for EAB until its presence has been confirmed within a 15-mile radius of your ash trees. Thus, at this time, we would not recommend treating any ash tree in Nebraska for EAB.

I’m sure many of you thought I’d completely lost my mind (and you might have a point) when you saw a reference to camels in this column’s title. Let me explain.

Last summer I was visiting with an older gentleman who lived near Pierce. When he found out what I did for a living he was quick to ask what I knew about emerald ash borer. I explained that it will almost certainly get here – someday, but I would not recommend treating for this pest until it has been confirmed within 15 miles of his home.

He told me he recently went to a large chain nursery and asked them about EAB. They told him he needed to start treating his ash trees immediately and sold him a treatment costing several hundred dollars.

I asked him if he knew that same product would be 100% effective on preventing camel damage to his ash trees. He glared at me and snapped back that he wasn’t worried about camel damage, he didn’t have any camels. Before I could respond, his glare turned to a big grin and all he said was, “I get it!” He also mentioned that he would be returning any unused product. When I counted my many blessings that night, I included that I would NOT be the person at the nursery accepting the product he returned.

EAB adults are small, metallic green beetles. They are about 1/2 inch long and 1/16 inch wide. Several other green insects are easy to mistake for EAB, but you can distinguish EAB based on body shape. If you look at EABs from above, their body is shaped like the head of an ax, blunt and flat across the head and tapered toward the tail. One other unique characteristic is that when their wings are spread like they are flying, the top of their body which is normally hidden by their wings is reddish in color.

Adult EABs emerge in late May to late June, leaving a “D-shaped” hole in the trunk. Females lay eggs about two weeks after they emerge and these eggs hatch in one to two weeks. The tiny larvae bore through the bark and into the cambium, the area between the bark and the wood, where nutrient levels are high.

EAB larvae injure ash trees by feeding under the bark where they damage the conductive tissue or “plumbing” of the tree, disrupting the flow of moisture and nutrients. The larvae eventually form a pupa and the new generation of adults emerge the following May or June to begin the cycle again.

Understandably, homeowners are concerned about losing their ash trees to the EAB. However, it is important to not begin insecticide treatment too early as premature treatments can have negative consequences. Some treatment involve drilling holes around the trunk through the bark and into the cambium to inject a systemic insecticide. Research has shown that healthy trees can be injected seven to 10 times before trunks become so damaged that trees begin to decline.

The drilled holes also open the trunk to insect pests and decay fungi. Drilling may break through the internal barriers in the trunk the tree is using to wall off internal decay, causing decay to spread. Also, the insecticide itself can cause internal damage. This is why treating ash trees for EAB is not, and will not, be recommended for trees until it has been found within 15 miles of a tree’s location… or if you are concerned your ash trees might be overrun by camels.

For more information including images to help identify this pest and the damage it causes, visit the Emerald Ash Borer Information Network at http://www.emeraldashborer.info/ or contact your local Nebraska Extension office.

Open Winter Injury


John Wilson

John Wilson

By John Wilson, Extension Educator

We are in a very similar situation to where we were about this time last winter. While most of us are enjoying the lack of snow and wondering how long it will last, many plants in our landscape are suffering because of the “nice” winter. A winter with little precipitation and no snow cover increases the risk of winter dessication injury to plants.

Many of you may remember this from last year when perennials and woody ornamentals failed to green up in the spring. Evergreen trees and shrubs are most susceptible, but lawns and perennials can also be injured. Tender and marginally hardy plants were hardest hit.

When there is little snow cover, questions about the need to water during winter rise. While winter watering can be done IF the ground is not frozen and air temperatures are above 40 degrees Fahrenheit, it is important to understand winter watering, even rainfall or melting snow, can also cause plant injury.

For example on lawns and herbaceous perennials, plant crowns absorb moisture and rehydrate. If a rapid drop to freezing temperatures occurs soon after, water taken up by the plant crown freezes. Ice crystals that form then damage or rupture plant cells, and possibly cause death.  This is known as crown hydration injury. It sometimes occurs naturally in late winter when snow is melting, or when an early spring rain is followed quickly by freezing temperatures.

If you would decide to irrigate when soils are not frozen and air temperatures are above 40 degrees, be sure to apply water about mid-day so it has time to percolate into soil before freezing occurs night. Avoid excess watering so it does not pool around plant stems.

If you decide to do winter watering, evergreen trees and shrubs should be a priority. Evergreens are most susceptible to winter drying and more costly to replace if severely injured or killed.

While all plants continue to lose moisture during winter, evergreens lose more moisture due to their foliage being green all year. It is not uncommon for evergreens to turn light brown after spring arrives.

The most common cause of spring browning is winter drying, not cold temperatures. The evergreens Arborvitae and Japanese Yew are most likely to sustain winter dessication injury. Any evergreen grown in a high wind area, near pavement, or on the south side of a home is also more susceptible.

Correct summer and fall watering is most important in preventing winter dessication on evergreens. Water could be applied during winter if dry conditions persist. Again, only water when the soil is not frozen, air temperatures are above 40 degrees F, and at mid-day so water soaks into soil and does not pool and freeze around plant crowns at night.

For valuable plants growing in exposed location, a physical barrier made of burlap, weed barrier fabric, or snow fencing can still be put into place to provide protection. Anti-transpirant sprays could also be applied according to the label. Mid to late winter is often when the majority injury due to dessication occurs.

If evergreens turn brown, owners wonder about plant survival. If only the foliage dies, the plant should leaf out again in spring if buds are viable. If woody tissue is killed, that portion of the plant will not recover. When injury occurs, wait until late May before pruning or removing winter injured evergreens to allow time for regrowth.

Picking the Perfect Christmas Tree


By John Wilson, Extension Educator  

 

John Wilson

John Wilson

Besides Black Friday sales, the day after Thanksgiving often is the day families will select and put up a natural Christmas tree. Artificial tree sales increased in the past, but those sales have leveled off and now there’s a return to having a traditional tree.

A natural Christmas tree is an environmental friendly way to celebrate the holidays. The average artificial Christmas tree has a life span of 6 years before it ends up in a landfill. A live Christmas tree, while used only one season, can become valuable mulch, a winter bird feeder, or even used as a fish habitat after the holidays.

So how do you pick out the perfect tree? The best way to obtain the freshest tree is to harvest it yourself at a local Christmas tree farm. This way you are guaranteed a fresh tree rather than one that may have been harvested several weeks earlier. A list of Nebraska Christmas tree growers is available on the Nebraska Department of Agriculture website. If cutting your own tree is not possible, here are some ways to check the freshness of a Christmas tree.

First, give the tree a light but vigorous shake. Only a few interior needles will fall out of a fresh tree. If a pile of brown needles appears on the ground, particularly from the branch tips, it is not fresh. Next, reach into a branch and gently pull the needles through your hand as you move out towards the tip. The needles should bend, but remain firmly attached, as your fingers run across them.

Regardless of whether you buy a tree from a lot or cut it yourself, once you get it home, leave it outside in a shady area while you set up the stand. The choice of a stand is probably the most critical factor in maintaining the freshness of the tree once it’s in your home. The stand should hold one-half to one gallon of water as a new Christmas tree may absorb this much water per day. A good rule-of-thumb is a tree will use one quart of water per day for every inch of trunk diameter at the base. If you have a tree with a 3-inch trunk, it may use about three quarts of water per day.

Make sure you start with a clean stand. Before setting up the tree, wash the inside of the stand with a solution of three tablespoons of bleach in a pint of water. After washing, rinse the stand with fresh water. This will reduce the growth of microorganisms that may also plug up the tree’s pores.

Just before you bring the tree in the house cut off the bottom inch or two of the trunk. This will open the sap-filled pores which transport water into the tree. The base cut should be square, not slanted. The angle makes little difference in the amount of water absorbed and it may expose part of the base to air sooner if the water level runs low. Once the tree is in the stand, add water and then never let the stand become empty. If the stand becomes empty for more than six hours, the tree’s pores plug up. Water uptake will be significantly reduced, the tree will dry out, and the needles will soon begin to fall.

If the tree stand does dry up, there is nothing that can be done other than pull the tree out of the stand and re-cut the base… not a pleasant task once the lights and ornaments are already up. Nothing needs to be added to the water in the stand to improve needle retention. Commercial “tree fresher” products do not significantly increase the life of the tree and the home remedies such as aspirin, sugar, soft drinks and vodka do not work and may be harmful to pets that may drink from the stand.

Finally, place the stand in a spot that receives only indirect sunlight and is not near a heat duct, entry door, or other drafty location. This will reduce water loss from the tree and prolong its freshness.

For more information on Christmas tree selection and care, contact your local Nebraska Extension office.

Wimpy Wasps


By John Wilson

Extension Educator

I recently made a stop at a business in town and was surprised to see seven large wasps hovering around the edge of the sidewalk. They looked quite intimidating and I noticed several people give them a lot of room as they walked by. Actually that wasn’t necessary because these large wasps are our perennial mid-summer visitor, the cicada killer.

Each year, people will bring large wasps in a variety of containers to the Extension office while the less daring just describe what they see around their homes. The description usually goes something like this… “It’s a large yellow and black wasp that kept buzzing around the same place in the lawn.” or “It’s a huge hornet that keeps coming back and won’t go away.” or my favorite, “It’s the biggest wasp I’ve ever seen and it scares the bejeebers out of me.”

These are all fairly accurate descriptions of the cicada killer. These large black and yellow wasps, up to two inch long, tunnel in disturbed areas, creating soil mounds and cause concern about stings. In spite of their menacing appearance and seemingly aggressive behavior, these wasps only rarely, if ever, sting. As one insect expert described them, they are a wimp in the wasp world. They are not a threat unless stepped on with bare feet or a person tries to hold one in their hands.

These wasps dig a tunnel in the soil about a half inch in diameter. They get their name, cicada killers, by the next step in their life cycle. After digging a tunnel, they find a cicada and sting it which paralyzes the cicada, but does not kill it. Then they drag this cicada into their tunnel and lay an egg on it. When the egg hatches, the cicada provides food for the larva. It will eventually form a pupa and then the adult wasp hatches out next summer.

These soil-nesting insects hone in on what are, to them, major landmarks… a stick or a small stone… and use these to locate their nest. When someone moves into the area, suddenly the landmarks seem different, so the wasps dart around, reassessing their position. The wasps are not aggressive, but it looks that way. In spite of their intimidating appearance, these wasps can and should be ignored.

Although the cicada killers are not a problem, there are other insects that do deserve our attention. These include crickets, boxelder bugs, Asian lady beetles and other insects that intentionally or accidentally get into our homes. I’m just starting to see crickets now and the others will be looking for shelter later this summer. This is a good time to spray around the foundation to form a barrier to control them before they get into your home and also to seal up any cracks or crevices where they might actually get it. A little prevention now will go a long way to preventing problems later.

For more information about insects that might be invading your home, contact your local UNL Extension office.

Tomato Problems


By John Wilson

Extension Educator

John Wilson

John Wilson

Nothing is more frustrating to the home gardener than to watch their tomatoes slowly ripen, only to discover the bottom of the fruit has turned black and started to decay.

Blossom-end rot is a serious disorder of tomato, pepper, and eggplant. Growers often are distressed to notice that a dry sunken decay has developed on the blossom end (opposite the stem) of many fruit, especially the first fruit of the season. This nonparasitic disorder can be very damaging, with losses of 50% or more in some years.

The symptoms of blossom end rot on tomato and eggplant usually begins as a small water-soaked area at the blossom end of the fruit. This may appear while the fruit is green or during ripening. As the lesion develops, it enlarges, becomes sunken and turns black and leathery. In severe cases, it may completely cover the lower half of the fruit, becoming flat or concave. Secondary pathogens commonly invade the lesion, often resulting in complete destruction of the infected fruit.

On peppers, the affected area appears tan, and is sometimes mistaken for sunscald, which is white. Secondary molds often colonize the affected area, resulting in a dark brown or black appearance. Blossom end rot also occurs on the sides of the pepper fruit near the blossom end.

Blossom-end rot is not caused by a parasitic organism but is a physiologic disorder associated with a low concentration of calcium in the fruit. Calcium is required in relatively large concentrations for normal cell growth. When a rapidly growing fruit is deprived of necessary calcium, the tissues break down, leaving the characteristic dry, sunken lesion at the blossom end.

Blossom-end rot is induced when demand for calcium exceeds supply. This may result from low calcium levels or high amounts of competitive cations in the soil, drought stress, or excessive soil moisture fluctuations which reduce uptake and movement of calcium into the plant, or rapid, vegetative growth due to excessive nitrogen fertilization.

There are several things you can do to manage blossom end rot:

 

  • Maintain the soil pH around 6.5. Liming will supply calcium and will increase the ratio of calcium ions to other competitive ions in the soil.
  • Use nitrate nitrogen as the fertilizer nitrogen source. Ammoniacal nitrogen may increase blossom-end rot as excess ammonium ions reduce calcium uptake. Avoid over-fertilization as side dressings during early fruiting, especially with ammoniacal forms of nitrogen.
  • Avoid drought stress and wide fluctuations in soil moisture by using mulches and/or irrigation. Plants generally need about one inch of moisture per week from rain or irrigation for proper growth and development.
  • Foliar applications of calcium, which are often advocated, are of little value because of poor absorption into the plant and movement to the fruit where it is needed.

 

 

If your tomatoes have blossom end rot and it hasn’t damaged the whole tomato, you can remove the damaged portion of the tomato and eat the rest. It does not affect the edibility of the rest of the fruit.

For more information on blossom end rot, contact your local UNL Extension office.

Eliminating Mosquitos


John Wilson

John Wilson

Nothing spoils working in your garden or an enjoyable evening in the backyard quicker than being swarmed by mosquitos. The recent rains have provided relief for farmers and homeowners, but they also cause problems for anyone working outside. Rain creates ideal sites with standing water for mosquitoes to develop.

To reduce this problem, eliminate mosquito breeding areas that catch and hold water. Check for leaf-clogged gutters, puddles, bird baths, old tires, cans, bottles, lagoons, and children’s wading pools. Drain water from these when practical. Rinse out your bird bath weekly.

Still water in birdbaths, ponds or lagoons may also be treated with Bacillus thuringiensis, or Bt, in the form of biscuits, available at some garden and hardware stores. The sustained release of the active ingredients of these products may provide up to 30 days control of mosquito larvae. These products specifically attack mosquito larvae and will not harm fish or birds or wildlife that drink the water.

Only female mosquitoes possess piercing-sucking mouthparts and require a blood meal to produce viable eggs. Eggs are laid in batches between blood meals. A single female may deposit several hundred eggs in her lifetime. Under favorable conditions, a new generation of mosquitoes can be completed in less than a week.

To keep mosquitoes out of your home, check all doors, windows and window screens, to make sure these are tight and in good repair. Screens should be 1/16th-inch mesh or smaller to prevent mosquito entry into the home. Keep porch lights off as much as possible in the evening. Or, replace traditional white light bulbs with yellow ones to help reduce the attractiveness of your home to mosquitoes and other night-flying insects.

To prevent mosquito bites when working outside, wear long-sleeved shirts and full length pants. Two layers of clothing are more difficult to penetrate by biting mosquitoes. Wearing light-colored clothes will reduce also your attractiveness. Work outdoors when it is cooler, or when there is a brisk air movement or strong sunlight. Different species of mosquitoes have specific feeding periods, but many are most active in the early evening hours, generally from 5 to 9 p.m.

But, because female mosquitoes are attracted to the carbon dioxide that we exhale, using an insect repellent while outdoors may be the most important method to prevent mosquito bites. You can use repellents containing DEET. These come under numerous brand labels and many formulations such as lotions, gels, aerosols, creams, and sticks.

Mosquitoes are always a nuisance, but they can also pose a health risk because of their potential to transmit West Nile Virus (WNV). In humans, WNV causes flu-like symptoms such as fever and muscle weakness. WNV can also cause encephalitis (an inflammation of the brain), disorientation, convulsions and paralysis. People over 50 and those with weak immune systems are especially vulnerable to the disease and should take extra precautions to avoid mosquito bites.

The Elkhorn Logan Valley Public Health Department will be working with the Nebraska Department of Health and Human Services West Nile Virus Surveillance Program this summer to monitor for West Nile virus. West Nile is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird and in turn the mosquito can transmit the virus to humans.

This year, testing will only be done on corvid species of birds (blue jays or crows in our area). If you find a dead bird, and it is in good condition and has been dead less than 24 hours, please double bag the bird in sealable plastic bags, freeze it, and immediately contact the Elkhorn Logan Valley Public Health Department at 877-379-4400. Testing will only be conducted on birds that are in good condition with no evidence of maggots or rotting.

The goal of the surveillance program is to collect dead birds for submission to a laboratory for testing. Finding the virus in birds provides an indicator to public health officials of the level of the virus in the area and the risk to human beings of contracting the disease.

For more information on mosquito control, or on the WNV Surveillance Program, contact your local UNL Extension office.

The Great Tomato Challenge


John Wilson

John Wilson

Over the years, I’ve observed an informal competition between gardeners to see who can produce the first ripe tomato. I’ve actually had people stop me in the post office or grocery store to tell me how close they were to having that first tomato… or first BLT sandwich! Their “green thumb” efforts are being challenged again this year by Mother Nature.

We’ve had a lot of rain and driving winds, perfect conditions for early blight to develop. Early blight usually starts on the lowest leaves and gradually moves up the plant. Once a leaf is infected, you cannot cure it, but you can prevent it from spreading to other parts of the plant with a fungicide labeled for use in the garden. You will need to repeat these applications every 10 to 14 days… or more frequently if it rains… to protect the new growth. Always observe the waiting period between a fungicide application and when you can safely harvest and eat your tomatoes.

Other things you can do to help prevent the disease this summer is to mulch your tomatoes if you haven’t done so already. In addition to helping keep a more constant moisture level in the soil and preventing the soil from getting too hot around the roots which injures them, mulching also reduces the likelihood of soil particles containing this disease from splashing onto the leaves.

That leads to the second thing you can do to help prevent this disease… always water tomatoes at the base of the plant, not with a sprinkler. A sprinkler, or rain, splashes soil on the plant… and they also keep the foliage wet. The disease needs moisture on the leaf surface for the spore to germinate and infect the leaf. You can’t control the rain, but don’t add to the problem with overhead irrigation.

Staking or caging tomatoes will help reduce the severity of this disease because it keeps the plants upright and promotes better air circulation which causes the foliage to dry faster which reduces the possibility of infection occurring. It also prevents the fruit from coming in contact with the soil which may lead to blemishes or decay… and it makes harvest much easier.

To prevent this disease in future years, clean up all plant debris from tomatoes, potatoes, peppers and eggplant this fall and remove it… because the same disease can infect all four of these plants. Don’t put this plant material in your compost pile or till it into the soil. The disease overwinters on plant debris and could infect these plants next year. Also rotate where you plant these in your garden so you don’t plant any of them in an area next year where any were planted this year.

One other thing that occasionally foils competitors in the great tomato challenge is when they fertilize their plants, particularly with a nitrogen fertilizer. It’s almost amusing (to me, not to them) when someone calls in and asks why their dark green, healthy looking, six foot tall tomato plants are not putting on any tomatoes. These calls usually come with a statement like, “These are the best looking tomato plants I’ve ever grown… and they aren’t setting any tomatoes!”

Tomatoes like nitrogen fertilizer and applying it early will promote these monster plants… BUT… nitrogen fertilizer also keeps plants in a vegetative state (growing leaves and stems) rather than letting them transition to a reproductive state (setting on fruit). Delay fertilizing your tomatoes until they have already set on a couple tomatoes that are the size of a marble. Then fertilize in moderation because overfertilizing is one of several factors that contributes to blossom end rot. We’ll talk more about blossom end rot another day as tomato harvest draws nearer.

For more information on disease control in tomatoes, or other vegetables in your garden, contact your local UNL Extension office.

Spring Questions


John Wilson

John Wilson

 

With alternating warm and cool temperatures one didn’t know what to do. It seems that spring may finally be here to stay. Along with the arrival of spring comes a variety of seasonal questions. I’ll try to answer a few of those here.

FIRST, there is nothing you can put around your house to repel snakes. Moth balls don’t work! Human hair doesn’t work! Ultrasonic devices don’t work! The only way to keep snakes out of an area is to build a snake-proof fence around the area you don’t want snakes. This may not be practical or eye-pleasing in the landscape. The more practical method is to discourage snakes by making an area less inviting to them.

Snakes like areas where they feel secure and protected. Eliminate those areas and you will discourage, but not necessarily eliminate, snakes. Rake up leaves that might have blown in and use a weed-eater on tall grass that you can’t quite get with the mower along the foundation. Pick up stacks of boards  and move any firewood that you didn’t use away from your home.

SECOND, if you haven’t done so already, now is the time to put crabgrass preventer on your lawn. (I put mine on early this week!)  This will only kill germinating seeds so it won’t control weeds that have already emerged. These products will also kill germinating grass seed so do not apply it to areas where you reseeded or overseeded your lawn.

If you had a lot of problems with crabgrass or spurge in your lawn last year, make a second application around the first of July. The treatment now can be a combination with a lawn fertilizer, especially if you haven’t fertilized your lawn yet this spring. However, an application in mid-summer should not include fertilizer.

THIRD, insect pests, such as ants, lady beetles and clover mites, are making their spring appearances in homes. Last fall these insects made it part way in… in cracks in the foundation or under siding… and spent the winter there in a protected area. Once it warmed up this spring, they made their way inside rather finding their way back out.

Once inside, vacuum up insects or use an aerosol insect killer. The better solution is to find the cracks or crevices where they are getting in and seal it with caulking so they can’t get in next year. Not only will this keep insects out, but this should also help with your heating bill.

FOURTH, some evergreens have needles that recently are turning brown, starting at the tips and working back to the base of the needle. This condition is called winter desication, also known as winter scorch or winter burn. The injury actually occurred last winter, but is just showing up now. It is not caused by an insect or disease, so there is nothing to spray to treat it.

Keep these plants well watered through the summer and next fall before the ground freezes. Adding an organic mulch like wood chips helps hold moisture in the soil. Light injury will be hidden when the plant puts on its new growth later this spring. Heavy injury may kill some branches or the entire plant. If in doubt, wait to see what the plant looks like after new growth has developed, then decide whether its coming out of the injury or whether to prune out branches or remove the entire plant.

FINALLY, any rhubarb that has come up and gets hit by a late frost is still safe to eat. There is a garden legend… that’s kind of like an urban legend, only it just pertains to the garden… that if rhubarb is frosted it becomes poisonous. There is a toxic compound in rhubarb leaves, so the leaves should never be eaten, but this compound doesn’t move into the stalks if the plant is frosted.

Spring Lawn Care


 

By John Wilson

Extension Educator

Despite some of the advertisements you may have seen or heard recently, the best advice I can give you now is to slow down on lawn care, especially fertilization and crabgrass control. For cool season turfgrasses like bluegrass and tall fescue, lawn care in late March and April should include hand raking to remove debris, edging, mowing, core aeration, power raking and seeding, overseeding or sodding.
For the season’s first mowing, mow lawns at a height of about two and one-half inches. It is not necessary or recommended to “mow as low as the mower will go”. This can scalp turfgrass and result in root loss or slowed root growth.
Core aerate with a machine that pulls out soil plugs to relieve soil compaction and encourage root growth. This is one of the most important practices we can do for lawns. If possible, core aerate once a year. Homeowners tend to power rake often, but core aeration should be done more often than power raking.
Power rake if the true thatch layer exceeds one-half inch. You can measure true thatch by cutting a plug out of the lawn. True thatch is the reddish brown mat found between the soil and the base of grass blades. It is made up of dead roots, rhizomes, and stems.

John Wilson

John Wilson

A small amount of thatch, up to one-half inch, is beneficial. It protects the plant crown from temperature extremes and traffic. Too much thatch can lead to root growth in the thatch layer making it more susceptible to drought damage; and fertilizers are tied up in thatch and become less available to roots.
True thatch is most common on highly maintained lawns. It builds up whether grass clippings are caught during mowing or left on the lawn. Core aeration will slow the build-up of thatch; but once the true thatch layer exceeds one-half inch power raking is needed to remove it.
Seeding, overseeding, and sodding cool season grasses can take place throughout the month of April. The sooner these can be planted the better to allow time for establishment before the heat of summer. Ideally, soil temperatures should be at least 40 degrees Fahrenheit for grass seed to germinate. Seed will germinate quicker at soil temperatures around 45 to 50 degrees F.
Delay fertilization until late April. Research has shown early spring fertilization, when soil temperatures are still cold, leads to an increase in diseases, such as summer patch; increased heat stress due to a less vigorous root system and possible loss of nitrogen due to leaching or run-off.
Delay applying preemergence herbicides for crabgrass control. These products kill the seedling as the seed germinates and begins growth. They are only effective when the seed is germinating. Crabgrass is a warm season grass and optimum soil temperatures for germination are 60 degrees, so most crabgrass germinates from mid May through June. So delay preemergence applications until the first of May so they are full strength when crabgrass is germinating.
For more information on spring lawn care, contact your local UNL Extension office.

Protecting Stored Grain


By John Wilson

Extension Educator

It seems like when we flip the calendar over to March, we expect some warmer temperatures. But it looks like the weatherman may have put our springlike weather on hold for a week. While warmer temperatures will be a welcome relief, it also will reveal some problems that started last fall, but were postponed by the colder winter weather.

Spring can be a challenge for folks with grain in storage on the farm in a normal year, but the weather last fall during harvest was anything but normal. Poor drying conditions forced many farmers to put grain in storage at unusually high moisture levels. The grain was held over the winter by cooling it to slow losses. But as air temperatures and grain warm, the chance for grain spoilage increase dramatically.

John Wilson

John Wilson

Periods of warm weather will warm grain near the bin walls, particularly on the south and west sides of the bin, while grain on the north side and near the center of the bin remain cooler. This uneven warming will cause moisture movement within the grain and condensation in the cooler parts of the grain mass.

If the temperature of the grain is below freezing, moisture will freeze between the kernels, forming a block of frozen grain. When you aerate the bin, air will move around, rather than through, these areas. When that grain eventually thaws, it creates a moist area in the grain and increases the likelihood of spoilage.

So how do you avoid this problem when you can’t control the weather? Every couple of weeks you should check the grain temperature with a probe thermometer. Check the temperature of the grain around the bin walls and also near the center of the bin. If there is more than a 10 degree difference between any of the readings, turn on the fans to push a temperature front through the grain to equalize the temperature.

As you gradually warm the grain this spring, try to keep the grain temperature within about 10 degrees of the average outside temperature. Whenever you run the fans, use this as a time to monitor grain conditions. Have someone else turn on the fans while you are positioned by a roof vent or opening in the roof.

If that first blast of air coming out the vents is musty, more humid, or warmer than the outside air, this indicates a problem developing in your grain. You need to run the fans continuously to reduce the problem, monitor this bin more frequently, and then use or sell this grain as soon as possible.

One important safety consideration. Before entering a bin, be sure you have a safety harness or rope connected to yourself and have someone outside the bin that can pull you to safety if you should break through a crusted area. Last fall’s less than ideal drying conditions increase the potential for grain bridging and forming air pockets below the surface. If you break through the bridge, it is likely you will not be able to get out on your own.

For more information on managing stored grain, contact your local UNL Extension office.

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