Yard and Garden: June 30, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for June 30, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Connie Fisk, Cass County Extension Educator

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.

1.The first caller of the day wanted to know if he could fertilize his tomatoes, potatoes, and cucumbers with the same fertilizer?

A. Yes, the same product could be used for all three of these crops. Be careful when fertilizing to not use too much Nitrogen during the bloom period which will cause the plants to grow large but not produce any fruits. Also, too high of Nitrogen for the plants can lead them to grow large and dense which can lead to more fungal diseases.

2. A question came through email asking what would cause red spots on strawberry leaves?

A. This could be either due to leaf scorch or leaf blight. The leaf scorch will have red spots that have a red or purple center and the leaf blight will be a red spot with a gray center. For both of these diseases, you can use Captan fungicide.

strawberry leaf diseases comparisons

3. How soon can peonies be cut off?

A. Peony leaves should be left on the plant through the growing season and can be removed in the fall when the leaves turn yellow. Otherwise, this time of the year you should only remove the flower stalks. Leaving the leaves on the plant will help the plant build sugars to help it bloom early next year.

4. A caller planted Karl Forester Reed Grass in 2 locations in his landscape at the same time this spring. One location, the grasses are doing well, but in the other location, the grasses are much smaller and not growing well. The worse plants are on the east side of the house while the good grasses are on the west side of the house. What would cause them to grow so differently?

A. The east side of the house would be in more shade than those plants growing on the west side. Most of our grasses like to be grown in full sun, this difference in sunlight could cause the difference in growth. Because they are in different locations, a nutrient deficiency could be causing the few on the east side to be growing less. Add a general fertilizer to help with growth.

5. This caller is applying a fertilizer with 24% Nitrogen every 7 days to her tomato plants. Is this too high of a percentage of Nitrogen for the plants to grow well?

A. The percentage isn’t as important as how much is applied. Applying a fertilizer every 7 days is too often. For most vegetable gardens, fertilizing three times a year will be sufficient. With this high of Nitrogen in the soil the plants will not produce and may grow too large and develop diseases in the deep canopy.

6. A caller had golf ball sized hail a couple of weeks ago that hit his tomato plants. The plants are still growing and have leaves on them. Will they be ok?

A. Yes, they should be fine. Keep them mulched to help reduce competition with weeds and keep them uniformly watered as needed. Don’t fertilize the tomatoes because they are stressed from the storm damage and fertilizing a stressed plant will increase the stress.

7. This caller wondered if grass clippings will negatively affect the soil in his vegetable garden? He had been using the grass clippings for a couple of years and now his vegetable plants don’t look as healthy as before he started using grass clippings.

A. After discussions, the caller said he had been using herbicides on his lawn and using the grass clippings on his garden. Pesticides can have a long residual on the grass clippings and this can negatively affect the plants. Especially if he was using broadleaf herbicides such as 2,4-D for dandelions. Broadleaf herbicides will damage vegetable plants which are all broadleaf plants. It would be best to avoid using his grass clippings if he is to continue using herbicides on his lawn. He can use other types of mulch such as straw, woodchips, newspaper, cardboard, or grass clippings from a neighbor who isn’t using herbicides on his or her lawn.

8. A caller has hollyhocks that have copper colored, round spots on the leaves and the leaves are falling off. What is the problem and what can be done to improve the flowers?

A. This is likely due to hollyhock rust, a common fungus of hollyhocks. Remove the leaves as they develop the disease and destroy the leaves and plant parts removed in the fall cleanup. Fungicides can be used if necessary, such as a liquid copper fungicide.

9. Do weeds need to be controlled in sweet corn or will the plants grow tall enough and shade them out soon?

A. Weeds should always be removed to reduce competition and lead to better overall plant growth. You can hoe the weeds out and use mulch between rows.

10. This caller has squash plants growing in black containers that are growing in potting soil. They are not thriving, what could be the problem?

A. The pot could be getting too hot because it is black. It would be beneficial to add mulch around the container or paint it another color to keep the roots cooler inside. It also could be drought stressed. Plants grown in a container get drought stressed sooner and need to be watered more than those growing in the ground because they have more limited root space. It also might be beneficial to add a general fertilizer to help the plants grow better.

2015-04-15 11.03.06

Kabatina Tip Blight

11. A caller has flagging on cedars that is causing the tips of the branches to turn brown. What would cause this damage to 20 year old cedars?

A. This could be due to bagworms which would be very small yet. Bagworms can be sprayed with any general insecticide. It also could be due to drought stress or Kabatina tip blight. There is no fungicide control for Kabatina. The best management is to cut out the affected areas.

12. This caller has sweet corn growing in his garden. The corn is about 2 feet tall and is now tasseling and it is very light colored. What would cause this problem? He is watering his garden for 1.5-2 hours every night.

A. This is likely due to overwatering. Vegetable gardens need about 1 inch of water per week, watering every night is not necessary and that much water would cause the nutrients to leach down through the soil, which would account for the lighter green coloration. The corn will likely not produce this year since it is already tasseling.

13. A caller wondered if the wood chips being produced from all of the downed trees would be safe to use as mulch around living plants or if there would be an issue with insects in the mulch?

A. This would make a good mulch for your plants. If there was an insect in the trees being chipped, the chipping process will kill it.

14. This caller has grapes that were hit by herbicide drift this spring. The leaves were all the size of a nickel and deformed, but the plants are not pushing new growth. What should they do to help the grape plants make it through this stress? Should they fertilize the plants?

A. Unfortunately, grapes are very sensitive to herbicide drift. 2,4-D can drift about 1/2 miles and Dicamba can drift about 1 mile, so it can move from a long way and grapes will be the first to know. If these are mature plants and they are pushing new growth, they should be fine. Don’t fertilize the plants, this will add more stress to the situation. Keep them well watered to help them through.

15. A maple tree was recently hit by hail. Now the trunk and branches have wounds on them. Should anything be done to cover these wounds?

A. No, don’t apply anything to the tree or cover the wounds with anything. Allow the tree to go through it’s normal processes to seal up the damage to reduce decay further into the trees.

16. A caller has cantaloupe plants that are not growing well. They have very small leaves but they are flowering already. What can be done to help them grow better? They are growing in a garden with many other vegetable crops that are growing much better.

A. Remove the flowers that are developing on such a small plant. When plants try to push flower growth and fruiting, they reduce their growth. Removing the flowers will push the plants to try to grow more before they begin flowering.

17. This caller is growing strawberries that have been growing for a few years. They bloomed and looked healthy this year, but the strawberries produced were very small. What would cause this problem? Also, what will help stop strawberries from rotting if they ripen on the ground?

A. The plants should be thinned at the end of the year to help increase the size of the berries. They also could be dealing with an issue of poor pollination. The cool, wet weather this spring led to low pollination because the bees don’t like to fly in the rain. Poor pollination may lead to development of the fruits, but at a much lower size than normal. Poor pollination can also cause the plant to drop small fruits from the plant before they mature. Mulch the strawberry beds with straw to help keep the berries from laying on the soil and rotting as they mature.

18. A caller from the Geneva area has an ash tree. Should he be treating for Emerald Ash Borer now?

A. No, Emerald Ash Borer (EAB) has only been found in Greenwood and Omaha in Nebraska and we recommend waiting until the beetle has been found within 15 miles of your tree before beginning treatments to reduce injury to the trees and to reduce the amount of insecticides in the environment. There is no need to treat for a problem that we don’t have yet.

19. This caller has one apple tree and needs to get a second tree for pollination. What would be a good variety?

A. It is necessary to plant a second variety of apple tree to help increase pollination. Look at the local nurseries to find good choices that go with the variety you already have planted. They will have a chart to show which trees pollinate which.

20. A caller has a fungus in the lawn every year. This fungus shows up in different locations throughout the yard every year and she treats with a fungicide every year. Is there anything she can do to make it so she can stop treating every year?

A. If you see the fungus in your lawn every year, you would need to treat for it earlier in the year before the fungus appears. If the fungus is present before treatments begin, they will not stop the damage that is already present.

*A caller later on the show suggested that these spots may be due to a dog urinating in the lawn, which can cause brown spots similar to many of our summer fungal diseases. There is no way to stop the brown spots left after a dog urinates on it, you would need to walk the dog somewhere else to do his or her business.

21. The final caller of the day has tomatoes that are growing well and they are now 3.5 feet tall, however, they have no blossoms on the plant. What would cause this?

A. This would be due to high Nitrogen levels in the soil. It cannot be fixed at this time, but don’t add any additional fertilizer to the garden for a couple of years to bring the level back down.

EAB: What to watch for??

EAB

Photo by Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org – See more at: http://www.insectimages.org/browse/detail.cfm?imgnum=5473689#sthash.6HVDSdAf.dpuf

Emerald Ash Borer, EAB, is an invasive insect that was first found in Nebraska in the summer of 2016 when it was found in Omaha and in Greenwood Nebraska. Previous to this discovery, EAB was found in Missouri, Iowa, Kansas, and Colorado for the closest confirmed presence of this insect to Nebraska. Now that it has been found in Nebraska, there are more concerns for the residents.

One of the common calls I have received lately is determining if a poorly growing ash tree is infected by Emerald Ash Borer or if the insect on the tree is an Emerald Ash Borer beetle. It is hard to determine by looking at the tree if it is infected by EAB, but there are some signs to look for on your tree.

The signs of EAB infestation include suckering at the base of an ash tree, decline in the tree from the top of the canopy downward through the tree, 1/8 inch D-shaped exit holes along the trunk and branches, increased woodpecker damage, S-shaped Serpentine galleries underneath the bark of the tree. One of the first signs is that the tips of the branches will be bare of leaves. If you notice any of these symptoms in your ash tree, you should contact your local Nebraska Extension Educator.

EAB Damage Collage

As for the beetle itself, which would be flying as an adult now, it is a ½ inch long metallic green colored beetle. It has a bronze-purple color under the elytra. Elytra are the hard wings on a beetle. There are a lot of green colored insects that are often confused with EAB. There are tiger beetles, Japanese beetles, Green June beetles, green ground beetles, green stink bugs, and many other green borer beetles.

EAB Look-Alikes Chart -3200px - Updated May2017

If you find any green bug on your tree make sure you bring it to your local Extension Office. The best way to transport insects is to scoop them up and put them into a zip-top baggie or old pill container or old sour cream or butter container and bring it in for proper identification. If you find an insect over the weekend or cannot get into the Extension Office right away, place your insect in the storage container and put it in the freezer to preserve it until a professional can identify it.

At this point, Emerald Ash Borer has only been found in Omaha and Greenwood in Nebraska. The recommendation is to wait to treat for Emerald Ash Borer until it is found within 15 miles of the tree’s location. There are chemical treatments that are effective against EAB. Homeowners can use a soil application, but this is most effective on trees less than 15 inches in trunk diameter. If the tree is larger, professional tree care companies can use a trunk injection. Wait until the insect is found within 15 miles before any treatment is done because the injections wound the tree and we want to wait as long as we can before we begin wounding our trees. A homeowner should also decide if the tree is in good health and a good location before beginning treatments. Planting ash trees at this time is not recommended. If you will not be treating your tree, it might be a good idea to start a new tree nearby to replace the ash tree when the time comes.

At this time, the only thing we can do to help with the ever-expanding problem is to not move firewood or wood products.  Buy wood locally when camping and leave unburned firewood at the campsite when you leave. Also, determine if you have an ash tree in your landscape and watch the tree for signs of this beetle.

Fall…Plant a Tree, Clean up the Garden

fall-tree-planting-blog-post

Fall is a great time of the year. The heat and humidity has finally been reduced and we can enjoy going back outdoors again. It is a great time of the year for planting to get things in the ground before it freezes and we can start doing other chores in our landscape to keep it looking beautiful throughout the winter months.

Fall is a great time to plant a new tree in your landscape to add fall interest to your yard. When choosing a tree and location in your yard, the first thing to consider is overhead and underground utilities, future construction sites, and the mature size of the plant.  Large trees should be planted a minimum of 15 to 20 feet away from buildings and a minimum of 20 to 25 feet from overhead power lines.  Purchasing a three to six foot tree usually saves money, gets the tree started faster and will outgrow more expensive, larger alternatives.

Health and longevity of the tree starts with good planting practices. First, remove the tree from the container and remove all wraps and ropes around the rootball, including the burlap. Next, shake off the excess soil and find the main rootball. The area where the lateral roots begin should be just below the soil surface. After you have determined the actual size of the rootball, dig a hole twice as wide and only as deep as the roots. Backfill into the hole with the soil that was removed when digging the hole to avoid creating a wall that roots cannot penetrate from one soil type to another. Add a mulch ring to all trees. The ring should be 2-3 inches deep and at least 2-3 feet wide around the tree. The tree can be staked if in a windswept location but the staking equipment should only be left on for one growing season.

With the threat of Emerald Ash borer now in Nebraska, this fall would be a good time to plant a tree as a replacement for an ash in your yard. With Emerald Ash Borer still only in the Omaha area, this portion of Southeast Nebraska doesn’t need to do anything for treatments or removal of ash trees yet. Treatments should not be done until Emerald Ash Borer is found within 15 miles of your tree. However, if you have decided that your ash tree is not in the condition to treat or you don’t want to spend the money to treat it annually, a replacement tree is the next best option. If you start a new tree nearby now, by the time EAB gets here and we have to remove trees, you will already have one started with a good amount of shade provided.

pruning tools-K. Todd

Pruning Tools Photo courtesy of Kim Todd, UNL Department of Agronomy and Horticulture

Fall is also a great time to get out and clean up our landscape beds. Replenish the mulch around the plants and remove the leaves of herbaceous perennials once they have turned brown in the fall. It is vital to wait until those leaves turn brown in the fall because while they are still green, they are still taking nutrients back into the roots of the plant that will help kick start the plant early in the spring. Wait until spring to cut back roses and butterfly bushes. These plants have a hollow stem and can have more winter dieback if they are pruned in the fall. Don’t prune any spring flowering shrub in the fall or you will be pruning off the flower buds for next spring. Wait until the trees are dormant before pruning them in the fall. If pruned too early, new growth can occur which will be more vulnerable to dieback in freezing temperatures.

Yard and Garden: May 13, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for May 13, 2016. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 5, 2016. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Fred Baxendale, Horticulture Entomology Specialist, UNL

1. The first caller of the day wanted to know when to transplant Peonies? She also wanted to know if she moved them away from the black walnut tree would that help them grow?

A. It is best to transplant peonies in the fall, but it can be done in the spring as well. It would be fine to move them in the spring as well. It would be beneficial for the plant to be moved away from the black walnut tree to get away from the toxicity produced by the tree as a form of natural weed control for the tree to other plants. Black walnuts produce Juglone which reduces growth and, in some cases, kills the other plants so the black walnuts have less competition for water and nutrients. Planting things 50 yards from the tree will get it out of the zone where damage can occur.

2. A caller has a rose that is old and has grown to 6 feet tall. When can he transplant it? Also, what are the red “ticks” he found around his gardens when he has been working in them recently?

A. Roses are hard to transplant. Do the transplanting in the early spring of the year and take as much of the rootball as can be dug up when it is moved to help the shrub overcome the transplant shock. Maintain adequate water once it is moved. The red “ticks” would be clover mites. These are not damaging to the plants but can leave red marks on house siding and if inside on the walls and curtains. You can treat these with permethrin or insecticidal soap.

3. This caller has Peonies that accidentally got cut back drastically this year. Will they live through this and should she do anything for them?

A. They should be fine but they probably won’t bloom this year. Make sure they are adequately watered and they will regrow by the end of fall. They should be fine again next year.

EAB Damage Collage

Signs of an Emerald Ash Borer Infestation from Boulder Colorado

4. A caller has 2 ash trees in her yard. She has heard about Emerald Ash Borer and wanted to know if there was anything she could do to protect her trees?

A. Emerald Ash Borer (EAB) has not been found in Nebraska and we recommend waiting until EAB has been found within 15 miles of your trees before you begin treating them. It takes 2-4 years for the damage to show up in our trees once it is here, so you will have time to treat them when it does get here. In the meantime, don’t move firewood here from other locations and increase the diversity in your landscape to help fill in holes that may appear when EAB takes out your ash trees. Also, watch your trees for signs of EAB including top dieback, suckering at the base of the tree, increased woodpecker damage, bark falling off, and D-shaped exit holes and alert Nebraska Extension if your trees exhibit any of these signs of damage.

5. This caller has a 10-year-old red maple that has struggled to leaf out the past couple of years. The middle of the tree is entirely void of leaves. Should he remove the center of the tree?

A. Removing the center will not fix the problem. This could be a root issue or it may have been improperly planted which would take around 10 years to show signs of damage. This tree is near the end of its life and removal of the entire tree should be contemplated. There could be borers in the tree but that would be a secondary issue and using an insecticide on them wouldn’t fix the whole problem with this tree.

6. This caller planted a Bradford Pear 2 years ago, it is leaning now. What can be done to correct the leaning?

A. Don’t stake the tree to try to pull it back to the correct position. When we stake a tree to try to pull it back upright, this can cause a girdling issue to the tree and it is very damaging to the tree. Because this tree has only been planted for 2 years, it would be a good idea to try to dig it up and reposition it.

7. A caller has steep hills around his yard and doesn’t want to have to mow it. What groundcover choices would he have to grow instead of grass?

A. Buffalograss, dwarf sumac, crown vetch, or potentilla would all be good choices for this type of growing environment.

8. A caller wanted to know if she could use vinegar for weed control in the flower garden?

A. It is best to use pesticides that are labeled for use in the garden. Pesticides for weed control have been rigorously researched to ensure that they work properly and cause limited harm to the environment if applied correctly. When we use non-gardening products in the garden, there isn’t always research to know how those products will work in the garden and it may cause more problems to our plants or it may cause problems if they get into stormwater. If you want to avoid pesticides, it would be better to use cultural and mechanical methods of weed control such as hand pulling and using mulch for weed control.

9. This lady has ant hills in her lawn, what can she use to control them?

A. Ant colonies would be spreading now. Leave them alone now, but if they start to overrun the lawn or come inside, you can spray them with permethrin or bifenthrin. If they are not taking over the lawn, they are a predator insect so if you don’t need to control them, they can be beneficial for other bad insect management.

10. This caller has a barberry that she wants removed. Should she call Diggers Hotline before digging it up? Also, how can she remove and kill daylilies growing in her landscape?

A. Always call Diggers Hotline before you do any type of digging. It is a free service that will help you before a problem occurs. As for the Daylilies, the best option is to dig them up. Using pesticides on them would need repeated applications over many years. When you dig them up, you can offer them to your friends and family.

11. How can you control bromegrass in flowers and in strawberries?

A. In the flower garden, you can spray a Grass-B-Gon product to control the grass and not harm the flowers. Do not spray this to where it hits your lawn or any ornamental grasses. As for the strawberries, this product is not labeled for use in strawberries or other edible crops, so mulching and hand pulling would be the best option. You can also paint Glyphosate (Roundup) products on the leaves of the grass among the strawberries and not harm the strawberries.

crane fly, David Cappaert, Bugwood

Crane Fly photo by David Cappaert, Bugwood.org

12. What are the giant mosquitoes this caller has been seeing flying around? What do they do? Are they mosquito killers?

A. These would be crane flies. They are not harmful to us. They feed on nectar when they are adults, but can sometimes be a problem in the turf. They are not mosquito killers, they are in the same order as mosquitoes and look like a large mosquito, but do not eat them. The immatures live in moist environments.

13. Would it be ok to spray a 2,4-D product this weekend?

A. Yes, 2,4-D can turn into a gas and spread to non-target plants if the temperatures for 72 hours after spraying is above 80 degrees Fahrenheit. So, with this cool down predicted where the temperatures will be in the 60’s for the weekend, this would be a great time to spray. Just make sure that the wind speeds are very low.

14. This caller has onions that the tops are dying back on. They tops curl up and die, why is that?

A. Onion thrips can cause streaking on leaves, this may be from onion thrips. Onion maggots will feed on developing bulbs as well. It could also be from a root rot issue. Dig up one of the onions that are not looking healthy and inspect the bulb for signs of insects or disease.

15. A caller has a recently planted black oak tree that has all of the leaves stripped off of it.

A. It could be from canker worms. They are a short-lived problem in our oak trees. Using the Eight product will help to control them.

16. This caller transplanted walking/winter onions. The bulbs are developing below ground and on top they are flowering but not developing the bulbs on top of the plant. What would cause that?

A. Try to fertilize the plant to help it with nutrients that may be missing from the growth of the plant.

Yard and Garden: May 8, 2015

Yard and Garden Green Logo

This is the Q&A for the Yard and Garden show for May 8, 2015. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2015. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Graham Herbst, Community Forester with the Nebraska Forest Service

1. This caller has pampas grass growing in her yard that last winter had problems with winterkill. What would be a good alternative ornamental grass she could plant?

A: Pampas grass had a lot of problems with winterkill last spring due to the dry, cold, windy winter conditions we faced in the winter of 2013-2014. Pampas grass is on the edge of its hardiness zone in Nebraska, but there are many other options for native grasses here. Maidenhair grass, or Miscanthus, is a great choice for a large native grass and it has many varieties to choose many different qualities. Big Bluestem and Little bluestem are great native choices, as well as switchgrass, sideoats grama, and many more. Ornamental grasses give us winter interest and habitat and food for wildlife during the winter months.

2. A caller had a sewer that was dug out and filled with soil. She then seeded new turfgrass on the area that has come up and is growing well. This spring the area sunk back down 6 inches. What can she do to level this area out?

A: You can remove the grass from that area, gathering 4-6 inches of soil and roots with it. Add soil to bring that back up to level with the surrounding lawn, and replace the grass piece back on top. Keep this grass well-watered until it becomes established, it will act like a piece of sod. The other option would be to back fill the location with soil and reseed the area with turf seed.

3. A caller has orange odd-looking structures hanging off of her cedar trees. What is this? Will it harm the tree?

Winter gall of Cedar-apple rust.

Winter gall of Cedar-apple rust.

A: These would be the galls from a disease called cedar-apple rust. This disease requires 2 hosts to complete its lifecycle, a cedar and an apple or something else in the Malus family such as a pear or crabapple. This disease overwinters on cedar trees as a hard, brown, odd-shaped structure on the branches and with spring rains they open up to look like orange, gelatinous, galls that are reminiscent of an orange octopus. This is when the spores are spreading to the apple trees. This disease causes no real damage to cedar trees, but on apple trees it causes lesions on the apples and leaf spots. Here is a NebGuide on Cedar-Apple Rust.

4. This caller has 3 apple trees and this winter one of them has not bloomed nor leafed out. Is the tree dead?

A: Check the tree for living tissue by scraping the bark off to expose green or brown tissue underneath. If it is green, it is still alive, if it is brown it is dead. Also check the branches for flexibility, if they bend they are still alive if the break they are dead. Give the tree a few more weeks to see if it comes out of it later this spring.

5. This caller has moles in their yard. How can they be controlled?

A: Moles can be controlled with traps. These traps will euthanize the mole in the hole to be left behind after control has been achieved. These have the best effect if the mound is pushed down 2-3 times prior to placing the trap in the hole, this will show if the tunnel is an active one before the trap is placed in it. Here is a guide from the Internet Center for Wildlife Damage Management on Mole Control.

6. This caller has voles in their yard. How can they be controlled?

A: Voles are controlled with snap traps that we typically use for mice. Place 2 traps in the run from the voles, or the area where the grass is damaged. Place the traps perpendicular to the runs and place them facing in different directions in the run. So, for a vole run that goes North to South, place one trap facing east and one facing west. Here is a guide from the Internet Center for Wildlife Damage Management on Vole Control.

7. This gentleman had used Scotts liquid turf builder on his lawn and it is not working to green up the lawn or to reduce the weeds found in his lawn. He also has a zoysiagrass lawn that is not growing as well in some portions of his lawn as it has in the past. What would be causing these problems and how can he improve these?

A: Broadleaf weeds are best controlled in the fall so it is best to apply a broadleaf weed killer, such as 2,4-D, 2 times in the fall, such as September 30 and October 15. Even in the spring, some control can be achieved, but they will require more than one application as they are tough weeds to kill. The zoysiagrass may have experienced some winterkill so it might be wise to take plugs from the area of the lawn where it is growing well and move them into areas of the lawn where it is not growing so well.

8. This caller has ash trees that are getting oval-shaped holes in them and ants on the trunk of the tree. Did the ants do this to the tree? How can it be managed?

A: These ants are probably carpenter ants. Carpenter ants do not harm your trees, they will just burrow into wood that has already begun to decay for some other reason. Carpenter ants on a tree do not require treatment. The holes are most likely due to native borers of the ash tree, such as red-headed ash tree borers or ash-lilac borer. These borers can be controlled with a trunk spray with chemicals such as sevin or eight or apply a soil drench with an imidacloprid product around the base of the trunk. This doesn’t sound like it is Emerald Ash Borer because the holes from EAB are D-shaped, not rounded or oval.

9. This caller has an ash tree and wants to know when he should treat it? He has heard that it takes up to 5 years for the systemic insecticides to move throughout the tree into the canopy, if this is true should he treat now.

A: Systemic insecticides take only a couple of weeks to move throughout the entire tree and they only last for 1 or 2 years depending on which chemical is used. It is best to wait until Emerald Ash Borer gets within 15 miles of the tree before treatment begins because treatments are costly, damaging to the tree, and not necessary until the borer gets closer. Trunk injections wound the tree and after repeated years of treatments it causes a great deal of stress to the tree, so there is no need to treat and harm the tree prior to when it is necessary.

Emerald Ash Borer

I had the wonderful opportunity to travel on a professional development opportunity to Colorado last week. I traveled with horticulture and entomology colleagues from across the state to Colorado Springs, Boulder, Denver, and Fort Collins to study how they deal with an almost constant drought and to see the damage from Emerald Ash Borer.

Xeric Gardens in Colorado Springs, CO.

Xeric Gardens in Colorado Springs, CO.

I had a blast at the Denver Botanic Gardens and learned some great information regarding Xeric gardens, or water conserving gardens. I also saw some great new plants to try in the annual and perennial trial gardens at Colorado State University, but my favorite part of this professional development trip was visiting with the Extension faculty from Colorado State University about Emerald Ash Borer (EAB).

Denver Botanic Gardens

Denver Botanic Gardens

Boulder, Colorado is the first and only county to have found EAB in Colorado. We were informed of the steps that Boulder County and the Colorado State Department of Agriculture took to help reduce the spread of this invasive insect into other counties and towns in Colorado. We were then taken to a site with massive damage from EAB to see what this insect does to the trees. It was good for me to see it live for myself to know what to look for in Nebraska.

Photo by Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org - See more at: http://www.insectimages.org/browse/detail.cfm?imgnum=5473689#sthash.6HVDSdAf.dpuf

Photo by Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org

As of today, Emerald Ash Borer has not been found in Nebraska, but we should be on the lookout for it as it has been found in Iowa, Missouri, Kansas, and Colorado. EAB is a small, metallic green, wood-boring insect that is invasive. It came to the United States via wood-packing materials from China and was first discovered in Michigan in 2002. Because EAB is an invasive insect, it has no natural predators to keep the population in check.

Emerald Ash Borer attacks healthy and stressed true ash trees, it does not attack mountain ash which is not a true ash species. EAB larvae feed on the inner bark of the ash trees, which causes a disruption of the flow of water and nutrients throughout the tree. If you have an ash tree that exhibits any of these signs, please let me know so we can check it out to ensure EAB does not get into or go unnoticed in Nebraska.

EAB Damage Collage

The damage from EAB can show up in your ash tree as

  • Top dieback
  • Sprouting at the base of the tree
  • Increased woodpecker damage
  • Larval galleries under the bark of the tree
  • 1/8 inch D-shaped exit hole
  • Bark cracks
  • Reduced size of the leaves still on the tree

Insecticide treatments are available for Emerald Ash Borer but are not recommended until the insect has been confirmed within 15 miles of your trees. The insecticides used can be applied either via a soil drench or trunk injection. Trunk injections are only to be done by trained professionals. Insecticide treatment efficacy depends on the size of the tree, the insecticide used and how it is applied, and the damage the tree has already acquired. If it is a high value ash tree, treatments can be effective, but are not feasible on a large quantity of trees.