Yard and Garden: September 17, 2021

This is the Q&A for the Yard and Garden show for September 17, 2021. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am. 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. This is the last show of 2021, but we will return in spring of 2022.

Guest Host: Laurie Stepanek, Forest Health Management Specialist with the Nebraska Forest Service

  1. The first caller of the show asked if it is ok to use grass clippings for mulch around his dogwoods?

A. Grass clippings can be used as a mulch, but be careful with it. The grass can mat together and restrict the movement of water into the soil where the roots need it. Wood chips would be better so this doesn’t happen. Larger sized wood chips mulch are best to reduce this problem.

2. A listener brought in a sample of oak trees he has been having problems with all summer. They are planted in a row and some of the trees are just fine while others are turning brown on the ends and have lighter green leaves. What is causing this?

A. There are multiple problems on these trees. The ends of the branches are turning brown due to twig girdler insects. This is a small insect that feeds on the inside of the branch cutting it off from the main plant, but not all the way across. So the dead branch tip stays in the tree and turns brown, causing a flagging appearance. In storms or high winds, those branch tips will fall to ground. Pick them up and destroy them as they fall. There is also Kermes scale on the end of the branches. The twig girdler would have only started causing problems in the late summer, the Kermes scale can be a problem through the season. There is also some damage from iron chlorosis in the tree and some powdery mildew due to the high humidity this year.

For treatment options, there is no need to do anything for the twig girdler, that isn’t very harmful to the tree and pesticides aren’t very effective. There is no need to manage the powdery mildew either as it isn’t very harmful to the tree and those leaves will fall off the tree soon. Just rake up the leaves at the end of the season to help reduce the disease next year. Iron chlorosis can be treated with a trunk injection in May or June of next year. The Kermes scale is the most damaging of all of these problems. Suggested treatments for kermes scale include a soil drench of imidacloprid in the fall, a trunk spray of dinotefuran in the spring, or injections. Applications of dormant oils in the late winter to the twigs can be effective but may be impractical due to the size of the tree.

3. This caller had a location where some trees were removed recently. He had the stumps removed and filled in with soil and new grass is growing in the areas. He is now finding 2-inch holes in those areas and it seems to be caving in a bit. What is causing that?

A. It could be that there are still some roots deep in the soil that weren’t removed and they are continuing to decay allowing the soil to settle more. From that loose soil, something is likely taking advantage of the location, such as a vole. Just continue to fill in around the caving-in areas as needed. Snap mouse-traps will work for voles.

4. This caller has a 30-year-old peony plant that she has already dug up with plans to divide and transplant. The root ball is very large, should she use a saw to get it apart?

A. No, I would stay away from a saw. Using a saw may do a lot of damage to the plant or the roots, it would be better to use a spade to get the pieces apart. Be sure to keep at least 2-3 nodes or eyes on each root section for plant growth and replant them at the same depth. If peonies get planted too deeply in the soil, they will not bloom.

5. When can a peony be cut back in the fall?

A. It is best to wait until they turn brown in the fall before cutting them back. This will allow them to build sugars all summer and then move those sugars from the plant back down into the roots for winter storage. They will bloom better next year if they are left standing until they turn brown in later fall, typically in October.

He also was curious about what to plant in a privacy hedge that can be only about 15 feet tall?

A. Yew, arborvitae, serviceberry or privet would make good selections for a shorter privacy hedge.

6. A caller wondered if bindweed can be sprayed now?

A: You can spot spray bindweed with glyphosate products, such as Roundup, anytime of the year. Spraying with 2,4-D products should only be done when the weather cools down such as at the end of September and into October. This will reduce herbicide drift from 2,4-D products that can damage other plants.

He also has a spruce tree that is dying off. He called this spring and it was determined to have needlecast disease. He sprayed this spring for it, should he spray anything on the trees this fall to help with the disease?

A. No, there is no need to spray in the fall. Just spray twice in the spring.

7. A listener brought in pictures and samples from his oak trees. One of the trees is fully brown and the other has very spindly, deformed leaves. What is wrong?

A. The tree with very spindly, deformed leaves has herbicide injury. From the amount of damage on the tree, it is likely that it will not recover from this damage. The other tree is near an area where a new sidewalk was added a few years back. They did stay back away from the main root area when it was installed, but the damage is likely from that. Even staying quite a distance back from the trunk of the tree will still put stress on the roots and reduce the ability of the roots to get oxygen. It is likely that both should be removed and replaced.

8. The final caller of the year has lilacs that are looking thin and losing leaves early. She would like to do a rejuvenation cutting on them to clean up the plants. When can she cut it back?

A. A rejuvenation cutting on lilacs is best done in the fall, so anytime now when it is cooling down. You can cut the shrub back to 6-8 inches above ground and it will regrow. This will help with problems it may be dealing with. It is likely that this shrub is struggling with pseudocercospora and Ash-lilac borers and removing all the above ground plant material will get rid of the insect and disease issues, at least for a while. If she starts to see the borers again, she can spray the lower branches with permethrin in the spring to help reduce that problem.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

Yard and Garden: September 10, 2021

This is the Q&A for the Yard and Garden show for September 10, 2021. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am. 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. This is the first of 2 fall shows which will conclude on September 17.

Guest Hosts: Kait Chapman, Extension Educator and Urban Entomologist from Lancaster County Extension & Steve Karloff, District Forester with the Nebraska Forest Service

  1. The first caller of the show asked about his barn. He has noticed there is sawdust developing around the walls and what looks like borer holes in the studs. What is it and will it be a continual issue to deal with?

A. There is a chance that this is either from carpenter bees or carpenter ants. The carpenter bees will have much larger holes than the carpenter ants. From the discussion, he has holes that are about the size of a pencil so this damage would be from carpenter bees. The best management is to go out and spray some sevin into the holes, the dust can work better in this instance. After a few days go out and plug the holes because empty nests left behind will be re-inhabited by more bees. This will be a continual problem to watch for.

2. A caller is growing Brussels sprouts and something is eating the leaves. What is it and how can it be managed?

A. It is likely a cabbage looper or cabbageworms. Spraying with sevin or eight will control them. Be sure to follow the label instructions when applying and the PHI, pre-harvest interval, to know how long to wait after applying before harvesting.

3. This caller planted morning glory plants and they haven’t bloomed yet. Why won’t his plants grow? He has them planted in a good location next to his deck.

A. The call was lost before more questions could be asked, but if they are in too much shade that could affect the ability of the plant to bloom. Also, if the deck is right into a heavily fertilized lawn, that could cause problems with high nitrogen. It will cause the plants to grow great but not produce flowers, which is what it sounded like his problem was.

He was also curious about managing daddy-long-legs in his farm building.

A. Controlling daddy-long-legs shouldn’t be necessary because they are not harmful to us. You can vacuum those that are seen if too many are present, but pesticides shouldn’t be necessary for this critter.

4. A caller is growing sweet potatoes that have developed 1 bad-looking potato in each hill. All the rest are fine. What is causing this and how can it be controlled? She sent photos to help out.

A. It looks like a disease called black rot on the potatoes. There really is no need to treat for it this late in the season. It would be best to rotate the potatoes to a new location in the garden next year and avoid locations where morning glories were in the garden, planted or wild plants. Do not use the damaged potatoes as seed stock for next year.

5. This caller has a pine tree in his line of trees that is turning brown. Will this move to the other trees in the line? He isn’t sure which pine tree he has, but it is a long-needled pine.

A. This could be one of many different diseases that affect pine trees, all of which can be spread to other trees in the row. There is a needle blight and a tip blight that are both spread quite easily. The time for spraying the trees is in the spring, not right now.

6. This caller is planting grass in a location. What advice can you give to help get the stand established?

A. The window for seeding is quickly closing. The later the seeding is in September, the higher the chance is that it will be damaged from frost. Typically, we recommend seeding from late August through mid-September, so she still has a little time. She wants to control weeds in the area first which will push her seeding back farther into the month. Using glyphosate products such as Roundup can be used prior to seeding, follow the label recommendations on how long to wait after applying prior to seeding. Most would be a week or less for glyphosate. Be sure to not use the extended control or other Roundup products with additional pesticides in them. After spraying and seeding, use a stiff-tine rake to get good seed to soil contact for best growth. Keep the new seed moist until it germinates, this wouldn’t be a lot of water, but more often short bursts of irrigation.

After I mentioned it getting late for planting, she asked if that will affect her planting perennial plants?

A. No, those are plants not seedlings developed. As long as the plants get in prior to frost with a good mulch layer, they will be fine. Newly seeded turfgrass will be injured by an early frost because the new grass plants wouldn’t be fully hardened off to cold temperatures if it hits too early. Perennial plants would be fine.

7. The last caller of the day wants to know when to spray weeds in his lawn?

A. Wait until it cools off more for the fall so that the pesticide doesn’t move to non-target plants in the heat we are still experiencing. It is best applied in temperatures below 80-85 degrees. Also, once the temperatures start cooling off more, the weeds will push more of their reserves into their roots and will take the herbicide down easier. I usually recommend 2 applications in the fall for a better kill of the weeds. I like to go with the end of September or early October and again 2-4 weeks later or in mid-October. If you space them out with 2 weeks between, you can get a third application at the end of October. As long as the daytime temperatures are above 50 degrees, the weeds are still green, and the ground is not frozen, the pesticides will still be effective. 2,4-D products will work best. 

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

Using Pesticides Correctly

We are getting closer to fall which is a great time to work on improving your lawn. Late September and early October are great for spraying lawn weeds. When dealing with pests in your lawn, be sure to use pesticides correctly for the best success and for the least amount of damage to the environment.

Pesticides

Pesticide is the general term for any insecticide, herbicide, fungicide, etc. Insecticides are specific to insects, herbicides are specific to weeds, and fungicides are specific to fungi. The first step in using pesticides is to correctly identify the pest you are dealing with to ensure you are using the correct chemical for the pest. Then determine all the methods that can be used to control the pest and use the best choice.

Timing

Timing of pesticide applications is critical. For example, fungicides should be applied as a preventative on fungi before they show up. Once you begin to see a fungus on your plants, in many cases, it may already be too late to fix the damage with a fungicide.

When discussing weeds, the type of weed and its growing cycle makes a difference on when and how to manage it. Winter annuals such as henbit become a problem for us in the spring, but they are best controlled in the fall with a pre-emergence herbicide or in the later fall with a post-emergence herbicide.

Summer annuals such as crabgrass should be controlled in the early spring with a pre-emergence herbicide. Treating crabgrass in the late summer, such as August, is not effective. In the late summer these plants are very large and difficult to control. Also, they only have a few more weeks left in their life before they die from frost. The new plants next spring are those that germinate from seed, not from those plants you see today.

Perennial weeds come back every year and often flower in the spring or through the summer, but they are best controlled in the fall with post-emergence herbicides. In the fall plants are moving nutrients into the roots for winter storage, they will more readily take herbicides with them to work better.

As for insecticides, it is much easier to kill a young, early-stage larvae, rather than a full-sized beetle or even a large, late-stage larvae. For example, insects such as white grubs should be controlled with granular insecticides applied to the lawn as the eggs are being laid so that the first stage out of the egg feeds on the granules.

Application Methods

Always read and follow the label because the label is the law. Also, be sure to wear the correct Personal Protective Equipment or PPE such as gloves, long pants, long-sleeved shirt, and eye protection that is listed on the label when applying pesticides. Apply pesticides at the label recommended rates. Pesticides applied at incorrect rates can cause resistance to occur making the pesticide ineffective.

When using pesticides pay close attention to the weather. Do not apply pesticides on windy days, as the spray droplets are easily picked up in the wind and blown to non-target plants. Certain chemicals, such as 2,4-D and Dicamba can volatilize or turn into a gas to move to non-target plants to cause damage or death when the pesticide is applied when the temperature is above 80 degrees Fahrenheit for the following 72 hours.

Using Pesticide around Vegetables and Fruits

During gardening season, use caution when utilizing pesticides in the garden, remember food safety practices. Make sure that the pesticide is labeled to be used on the plant you plan to use it on. If that plant isn’t on the label, the pesticide cannot be used on it. Also, follow the PHI or Pre-Harvest Interval, which tells you how long to wait from application of the pesticide until harvest. And finally, follow the re-application interval to know how long to wait before applying the pesticide again.

*Reference to commercial products or trade names is made with the understanding that no discrimination is intended of those not mentioned and no endorsement by University of Nebraska–Lincoln Extension is implied for those mentioned.

Oak Branch Dieback

I have been getting a lot of calls lately about oak tree issues. The ends of the branches are turning brown, in most cases they are currently staying on the tree. Twig girdler and twig pruners are showing up in our oak trees again. Most of the time they work inside the branches, basically pruning the tree during the late summer, but the damage typically isn’t seen until late summer to fall when the branches fall out of the tree due to wind.

Twig Girdler

Twig girdler is a cerambycid beetle, or longhorned beetle. This insect will chew a v-shaped groove in a circle all the way around the twig, girdling it. The center of the twig will be jagged while the outer edge is smooth. These will feed from August through October allowing the branches to fall over that time or shortly after due to wind. After creating the groove in the wood, the female will lay an egg in the portion of the branch that eventually falls to the ground. The larvae cannot feed on healthy wood, so it is able to feed on the dead branch after it falls to the ground. These larvae will then overwinter in the dead branch on the ground. In the spring they will pupate in that branch and develop into adults to start the process over again.

Twig Pruner

Twig pruner is another type of cerambycid beetle, or longhorned beetle. The lifecycle of the twig pruner is very similar to that of the twig girdler; however they will usually chew on the small branches from the inside out. Twig girdler insects will drill a small hole into the branches in the spring and then grow throughout the summer. In the late summer, the full grown larvae will chew rings through the branch until they have made it through the whole branch, except for the bark layer. The larvae then move into the portion of the branch that eventually falls to the ground or hangs in the tree, dead. The pupae overwinter in the dead portion of the branch and emerge the next year to start the process over again.

Differences between these two insects

Twig girdler and twig pruner insects are very similar, however with twig girdler, the branch is smooth on the outer edge and with the twig pruner, the branch is jagged on the outside edge of the branch. The Twig girdler insect works its way into the branch while the twig pruner insect works from the center of the branch outward, but neither go all the way through the branch. Twig girdler overwinters as larvae and the adults don’t emerge until the late summer, while the twig pruner overwinters as pupae and the adults emerge in the spring.

Management in Oak Trees

The damage from twig girdler and twig pruner is not very harmful to the tree itself, but mainly looks unsightly for the homeowner, and makes for a large mess in yards. Control for both of these insects is very easy. Because in both insects they overwinter in the fallen dead branches, the best management method would be to pick up the fallen branches and destroy them by burning them prior to beetle emergence next year. Any broken branches should also be removed before the spring in case they are infested. Chemicals are not usually recommended because they are not very effective and it really isn’t necessary.

Yard and Garden: July 30, 2021

This is the Q&A for the Yard and Garden show for July 30, 2021. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am. 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. This is the last show of the summer season for 2021. We will have 2 fall episodes on September 10 & 17.

Guest Host: Jody Green, Extension Educator and Urban Entomologist from Douglas/Sarpy County Extension

  1. The first caller of the day planted new apple trees. He has been watering twice a week and now the trees have brown spots on the leaves. What is causing the brown spots and how can they be controlled?

A. It is most likely that these trees are susceptible to cedar-apple rust or apple scab. They will need to be sprayed in the spring every year or they will have spots on the leaves every year. It won’t kill the tree to have either of these diseases but it they will look bad most of the season. Use a copper fungicide in the spring or an orchard fruit tree spray to manage the disease. For more information on managing fruit trees, visit the UNL Local Food Production website.

2. How can you manage Japanese Beetles? Do you need to manage the grubs as well?

A. Japanese beetles are best managed by hand picking and destroying or spraying plants with an insecticide. At 7pm, the beetles are bunched up. Place a bucket of soapy water underneath plants where they are bunched and tap on the branches to knock the beetles into the bucket. You can also use sevin to control them. Don’t use traps, those attract more than you have. Grub control can help but won’t eliminate the problem because they will still fly in as adults from nearby locations. Treating grubs will help with the damage to the lawn but not necessarily with the damage to other plants from adults.

3. This caller has cedar-apple rust on his apple trees. Is there a fall treatment to help the trees?

A. No, fall treatments wouldn’t be effective because fungicides are a preventative not a cure so they need to be sprayed before fungi appear. It is best to spray the trees in the spring to protect the new leaves as they are emerging. Here is a NebGuide to view for more information on Cedar-apple rust.

4. A caller sent a photo of insects that are damaging his knockout roses. What are they and how can they be managed?

A. These are Japanese beetles. They are difficult to control and have no predators here. Japanese beetles are best managed by hand picking and destroying or spraying plants with an insecticide. At 7pm, the beetles are bunched up. Place a bucket of soapy water underneath plants where they are bunched and tap on the branches to knock the beetles into the bucket. You can also use sevin to control them. Don’t use traps, those attract more than you have. 

5. When should fall crops be planted?

A. They can typically be planted around the end of July to the beginning of August in southeast Nebraska. You can figure out a good date range by using the seed packet. It will tell you how many days to harvest. Use that number and count back from the first frost in your area. You should add 14 days for a fall factor because the plants will grow a little slower and have less light in a day. The average first fall frost date for Gage County is the end of September to the beginning of October. There is a good NebGuide on fall gardening that will help with all of your fall gardens.

6. This caller planted hydrangeas this spring. Has now been watering every other day with a water wand but they look sad because the flowers are turning brown. What can be done to improve the plant?

A. The flowers are fading due to natural bloom time ending. This is a natural process for the plants and nothing to be worried about. You can cut the spent blossom off of the plant if desired to clean up the look of the hydrangea.

7. A caller has some peonies that were accidentally cut off. What will happen to the plants since they were pruned at the incorrect time of the year?

A. It isn’t the best time of the year for the peony, but it should be just fine. Peonies need to be left to grow through the season to allow them to build sugars for the next year. They shouldn’t be pruned back until they turn brown in the fall. However, in this case, it was accidental and the plant will survive. It may mess up the blooming for next year and you may not get as many blooms or any at all, but it should be fine.

8. This caller has 10-12 hills of pumpkins. He is trying to grow large pumpkins for his fall display. The vines have a lot of blooms on them. Should he remove excess blooms to focus on 1-2 for larger pumpkins?

A. Yes, that is what a lot of the “largest pumpkin winning” growers will do. Allowing the plant to produce many pumpkins will push the growth into a lot of pumpkins and they may not grow as large, but forcing the energy into just a few pumpkins per vine should lead to larger pumpkins.

9. The final caller of the show has plants that are flopping over and have a dead center. This is many different kinds of plants growing in rock mulch with drip irrigation that runs twice a day for 20 minutes each time. What is wrong with them?

A. This is likely due to over irrigation. Run the irrigation system with a catch can to know how much water is being applied each time the system runs, but the plants should only receive 1 inch of water per week. Perennials only need to be irrigated once per week for that. It seems that the plants are developing a root rot because they are not allowed to dry out a bit between watering and that is causing them to flop over.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

Yard and Garden: July 23, 2021

This is the Q&A for the Yard and Garden show for July 23, 2021. 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 30, 2021. 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: Bob Henrickson, Horticulture Program Coordinator for the Nebraska Statewide Arboretum

  1. The first caller of the day purchased 3 oriental poppy plants. Now the plants seem to be gone. Did the rabbits eat them? Will they come back next year?

A. It is most likely that the plants went dormant for the year. Poppy plants are early bloomers and then they go dormant for most of the spring. They will come back next spring just fine. It is natural for this plant.

2. This caller has some cannas that are growing in a large flower pot. Now that they are done blooming, what should be done with the flower stalk?

A. You can cut the flower stalk off once it is done blooming to clean the plant up. Leave the leaves on the plant until the fall to allow the nutrients to build in the bulb.

3. A caller planted an orchard a couple of years back. He had an apricot that died last fall after dropping leaves early. He now has an American Elm tree with leaves that have turned brown and are falling off the tree. He also has a snow crab tree that looks stressed and similar to what happened to the apricot. Is there something that is affecting all of these trees?

A. These would be from different issues on each tree. One disease or insect wouldn’t cause these problems to such different trees. The American elm is likely succumbing to Dutch Elm Disease. This disease isn’t as much of a problem anymore because we don’t have very many elm trees, but as the elm grows it will eventually die from this disease and there is no prevention or cure for it. It should be removed before it becomes a hazard. It is hard to tell what happened to the apricot tree a year later, but they are not long-lived tree species in Nebraska. The crabapple likely has either apple scab or cedar apple rust. The tree can be sprayed in the spring, but at this point this year it is too late. These diseases will not kill the tree but will make it look bad for the season. Here is more information about cedar-apple rust.

He was also curious about a locust tree. Is there anything that can be done to control the seed development?

A. No, there is nothing to reduce the amount of seed pods that are developed on the tree.

4. What can you do to manage iron chlorosis in a pin oak tree?

A. The best management is to have a professional arborist inject the tree with iron. There are granules available, but they are not very effective.

She also wondered about her endless summer hydrangeas. Should they be pruned to get them to rebloom?

A. You can cut off the spent blossoms from the tree if desired. It doesn’t help to get it to rebloom, but will clean up the look of the plant.

5. This caller is working on getting a new area in Beatrice designated as a Nebraska Statewide Arboretum location. What needs to be done after the tree inventory is completed?

A. After the inventory is complete, you can move onto the application which can be accessed through the NSA website under ‘Become an Affiliate Site‘.

6. The final caller of the day asked how to kill poison ivy growing in his grass? He doesn’t want to kill the grass or the clover growing in the area.

A. If this is a mowed area, mowing more often would help. You can also try to smother the grass in that area by placing black plastic over the area for the rest of the summer, fall, and winter. This would kill the grass and clover as well, but they can easily be reseeded in the spring. You can also paint a triclopyr product on the leaves of the poison ivy but be careful and wear long sleeves, pants, closed-toe shoes, and gloves to protect yourself.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

In the Garden

This time of year our gardens are really growing well, but in some cases so are the problems. I thought I would take some time to describe some common problems we are seeing in the garden currently.

Poor production

In unfavorable weather, we don’t see reduced or stalled out fruit production on our vegetable plants. Some of our plants have no fruits developing at all while others have fruits on the plant that simply won’t ripen. When it gets so hot and it stays that way for many days in a row, that is not optimal conditions for production. When our days get hotter than 85 degrees Fahrenheit and our night’s stay warmer than 70 degrees, tomato production slows and can even stop altogether until conditions improve. Pollen can even become sterile in very hot conditions. There is nothing you can do for poor production due to heat, except to wait.  Eventually your fruits will develop.

Blossom End Rot

Blossom end rot is another plant problem we have been seeing this year. It is shown in the photo for this blog. Blossom end rot is an environmental problem that affects many of the plants in our garden including tomatoes, peppers, cucumbers, squash, zucchini, and watermelons. This is actually a calcium deficiency within our plants. Calcium is often found in adequate quantities in Nebraska soils, however, it cannot be moved throughout the soil and into the plant without even moisture. So, the problem isn’t due to lack of calcium, it is due to uneven moisture in the soils. In Nebraska, especially in the beginning stages of plant development, moisture is typically uneven due to heavy rains in between dry spells. Using calcium on your plants will not help this issue. Give the plants time and they should begin to develop normal fruits with no blossom end rot on them later in the season. Typically, we only see blossom end rot for the first couple of harvests in a season. You can still eat the fruits that develop with blossom end rot, you would just need to cut the rotten portion of the fruit off.

Squash Bugs and Squash Vine Borer

Squash bugs and squash vine borer are coming to take over our gardens soon. This is the time of year to watch out for these problematic, common insects found affecting our cucumbers, zucchini, and the other cucurbits. Pay attention to your garden to help prevent damage. You can scout for the eggs of the squash bug. You will notice a group of tiny, copper colored eggs gathered near the intersection of the veins on the underside of the leaves. Remove and destroy the eggs as you find them to reduce the population. For squash vine borer, wrap the base of the plant in aluminum foil to stop the females from laying the eggs on your plant. You can use insecticides for both of these, just be careful to do it in the evening when the bees aren’t flying and don’t spray the flowers with insecticides to help with pollination. Also, remember to follow the PHI or Pre-Harvest Interval to know how long to wait from pesticide application to harvest.

Heat Stress

Wilting is occurring lately on many of our plants due to the very hot weather we have been dealing with. When you notice wilting on your plants, water them to help them through the extreme temperatures. When plants are wilting due to heat or drought stress, they will often look much better or completely recovered in the mornings and be wilted later in the day. Again, this is something we cannot fix for our plants but they should survive.

Yard and Garden: July 16, 2021

This is the Q&A for the Yard and Garden show for July 16, 2021. 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 30, 2021. 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: Kyle Broderick, Plant Pathology Extension Educator at UNL

  1. The first caller of the day has damage to a young Autumn Blaze Maple in her yard after an older ash tree fell on it following the storms last weekend. The top of the maple bent over but didn’t break. Will the top straighten back up?

A. It should straighten up on its own, it just may take a little while, give it more time. Don’t do anything to it and it should be fine since it didn’t break. Keep an eye on it and watch for cracks that may develop from this damage. Keep it happy with a 2-3 inch deep mulch ring and adequate water.

2. This caller has a question about Japanese beetles in a linden tree and a birch tree. The birch put on new leaf growth after the damage, but the linden hasn’t yet and still looks terrible. Will the linden be ok?

A. It should be fine. Lindens don’t do a lot to push new leaf growth this late in the year but the damage from Japanese beetles doesn’t usually kill them. The tree will look rough through the rest of the year, but it will be fine next spring. You can spray sevin on the tree next year, but you have to wait until after the flowers are completely done next year. This late, or after bloom on lindens, the majority of the damage is done and the beetles are finishing up their life cycle for this year.

He was also curious about a yucca plant. When can he cut the flower stalk off and when can he cut the leaves back?

A. You can cut back the leaf stalk anytime after blooming is complete. Cutting back the leaves should be done in the fall after the leaves turn yellow.

3. A caller has lilacs that were planted 3 years ago and they seem to be growing slow. They are only 2 feet tall. What is causing that?

A. They could be a shorter variety. If not, they may not be receiving enough water. Keep them well-watered but don’t overwater. Irrigate around each plant for about 20-30 minutes once a week if we aren’t seeing much rainfall. Mulching around the plants will help too.

4. This caller had a landscaper put in a raised bed garden for her. She didn’t plan for it to be made out of concrete and wanted it larger, but it is 3 feet by 7 feet and it is 2 concrete blocks deep. Now, her green beans and tomatoes are having troubles and not producing. Is the concrete too hot for the plants?

A. The lack of production right now is due to the environment. When the weather gets very hot and stays warm even through the nights, it reduces the production of our plants. Give them time and they should pull through it. It could also be from herbicide injury. There is nothing we can do for herbicide injury once it has happened.

5. A caller has some caterpillars that are eating her sunflowers and okra plants. What is it and what can be done for them?

A. They are likely checkerspot caterpillars. They are not terribly harmful to your plants but will cause what looks like a lot of damage, they won’t kill the plants. In the okra it may be necessary to spray the plants with sevin or eight to prevent damage to the production or the fruits themselves. This caterpillar does turn into a beautiful butterfly, so if you can avoid spraying it will be beneficial for pollination.

6. What are the large green worms found on tomato plants?

A. Those are tomato hornworm caterpillars. They can do a lot of damage to tomato plants in a very short time frame. The plants should survive, but the caterpillars should be removed. You can pick them off with your hand and put them in a bucket of soapy water to kill them. You can also use sevin, eight or bifenthrin if you need to.

7. This caller has coneflower plants with leaves that have turned yellow and brown. What is wrong with the plants?

A. This could be from cercospora leaf spot on the plants. This is mostly cosmetic damage and does not need any pesticides to manage it. You could submit a report to the plant diagnostic clinic in Lincoln to be sure. Visit go.unl.edu/plantclinic to submit your sample.

8. A caller has fruit trees that have powdery mildew on the fruits, making them soft and rotten. He sprayed a couple of times this year, how many times does he have to spray?

A. Powdery mildew is just a problem on the leaves of the tree, not on the fruits and it wouldn’t make the fruits soft and rotten. This is likely from a fruit rot disease instead of powdery mildew. If he is using orchard fruit tree sprays, which he is, that should work against most disease and insect issues if used properly. Spray every 10-14 days through the summer from as soon as pink is noticed in the buds in the spring. Avoid spraying during bloom and stop as the fruits are nearing harvest. Be sure to read and follow the label.

9. The final caller of the day asked what the best management plan is for creeping Charlie?

A. Creeping Charlie is a difficult to control perennial weed. It is best to spray perennial weeds in the fall when they are moving sugars into the roots, they will take the pesticide into the roots as well and you will get a better kill on the weeds. Spray twice in the fall, late September and again in mid-October. Spraying twice in the fall will help manage the weed, but it will not be fully eliminated after only one year, it will take multiple years of fall applications to help.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

Yard and Garden: July 2, 2021

This is the Q&A for the Yard and Garden show for July 2, 2021. 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 30, 2021. 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: Dr. Paul Read, Professor of Viticulture at UNL

  1. The first caller of the day has holes in the ground along the foundation of her house. What is causing it?

A. This is from Antlion immatures. This is a type of insect that as an adult looks very similar to a damselfly or dragonfly but it has knobs on the end of the antennae unlike the straight antennae of damselflies. These holes that look like an inverted ant hill are where the immature antlions stay. They have very large mandibles and they wait at the base of that “pit” for smaller insects to fall in so the antlion can grab it with its mandibles and eat it. They are harmless to us and our plants. If plants are grown in the area they will go away. They are usually only in the bare locations in the shade from our house.

2. This caller is growing many different peppers in his garden and the leaves are turning black. He rotates the plants from year to year to a new row in his garden and he mulches and waters with a soaker hose. What is causing this and why has he had this problem for 3 years in a row?

A. This caller sent photos to my email for further investigation and I sent them on to Kyle Broderick, UNL Plant Pathologist. This is due to bacterial leaf spot, Kyle has been seeing a lot of samples with this disease in the last week or so. It’s caused by a very common bacteria that survives in the soil. Watering from the base is great, but if you have rains like Lincoln got a couple of weeks ago it didn’t matter and there was still a bunch of soil splash. Not a lot to do for management aside from removing infected leaves. Copper is sometimes effective at slowing the spread, but fails under high disease pressure.

3. A caller has tomatoes with a lot of blooms but isn’t producing any tomatoes yet. What is causing that?

A. This is common this time of year. Give the plants some more time and they should start producing. Tomatoes are self pollinated but high temperatures can affect how well the plants get pollinated.

4. How do you control squash bugs?

A. Sevin, eight, and bifenthrin are the products labeled for use in the garden. It would be best to switch between chemicals and spray as often as the label allows. Be sure to watch the PHI, pre-harvest interval for how long to wait after spraying until harvest can begin again.

5. This caller has an oak tree that is 30-35 feet tall and now the leaves are curled up and when a truck is parked underneath the tree it gets a sticky substance on it. What is the problem?

A. Aphids will do this. They suck the juices from the leaves which causes them to curl under. Aphids also produce honeydew as an excrement which will drip down onto vehicles parked under trees they are on. They are a minor problem in the tree. It is best to leave it alone and allow predatory insects to manage the aphids with no need for chemical controls. They are typically only a problem for 2-3 weeks in the summer.

6. Another caller has some oak trees that are 23 years old and the leaves are getting brown spots and turning black. This is more on the south side and more on the tips of the leaves? What is wrong?

A. This could be from leaf scorch, especially since the damage is on the south side. He did say there was similar damage on the ornamental pear nearby as well. So, with that information it could be from herbicide injury. With either of these problems, there isn’t much that can be done. Keep the tree healthy and well-watered to help it through this added stress.

7. A caller has cherry trees that are starting to develop cherries, but it seems to be just the pit and the skin, no fleshy part of the cherry is in the fruit. What is causing that?

A. This could be from lack of water, especially when the fruit is developing. There could be a disease in the tree as well, but if the leaves all look healthy and the skin on the fruits looks healthy, it is likely from an environmental condition. Be sure to water the tree during dry conditions.

8. How do you get rid of voles?

A. Snap-type mouse traps are best for voles. Place them perpendicular in the runs from the voles.

This caller also has some bushes that died on the top from the winter extreme cold temperatures. Should he prune that out?

A. Yes, the extreme cold in February damaged a lot of plants this spring. If it isn’t green yet, it should be pruned out. Prune back to the green area still alive in the shrub.

9. This caller wondered when is the best time to spray the yard for perennial weeds like dandelions?

A. The fall is best. When the weeds are taking sugars down into the roots for winter storage, they will take the pesticide with and it will kill the roots. It is best to spray the lawn with a 2,4-D product in late September and again in mid-October.

She also wanted to know when the best time is to prune cedar trees?

A. They can be pruned most anytime, but the best time is from mid-April through mid-August.

10. The final caller of the day wanted to know when she can prune peonies back?

A. It is best to wait until fall to prune peonies. Allow the plants to grow through the summer so they can build sugars to grow and flower early next spring. In the fall, the plants will turn yellow and brown, at that time they can be cut off.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

NEW THIS YEAR: If you would like to hear the full recording of this show, Listen to the Podcast found at: https://yardandgarden.buzzsprout.com

Garden Pests

Summer is a great time of the year. Our plants are beautiful and we have wonderful gardens to provide us with fresh produce for months. However, when an insect comes in and damages those plants or destructs our vegetables before we can eat them, it is very disappointing. (Photo above is of a Japanese Beetle, photo by Jim Kalisch, UNL Emeriti)

Japanese Beetles and Green June Beetles

Japanese beetles are an invasive insect from Japan. Japanese beetles are problematic insects as both larvae and adults. The larvae are one of the white grub species found here. As a white grub, larvae feed on the roots of our grass, causing large, brown spots in the turf that are easily lifted up like a rug from the floor. Adult Japanese beetles are 7/16 inch-long, metallic green beetles. The elytra, or wing coverings, are copper. These beetles can be distinguished from similar looking beetles by the six tufts of white hair along both sides of the abdomen.

As adults, Japanese beetles feed on over 300 species of plants including trees, shrubs, fruits, vegetables, field crops, weeds, and other ornamental plant species. Some of their favorite foods are roses, lindens, and grapes among others. They can also be found on many of our vegetable plants including tomatoes, peppers, and potatoes. Adult beetles feed on the foliage, flowers, and fruits of these plants. They feed on the upper surface of the leaves and cause a skeletonized pattern to the leaf where the veins of the leaf are left behind but the rest of the leaf is chewed away. This can stress the plants, and in high populations of beetles can even kill the plant.

Japanese beetles are often confused with green June beetles which are much larger and without the tufts of white hair along the abdomen. Green June beetles will feed on ripe fruits and vegetables like tomatoes, corn, and grapes. They will feed on the fruits and the leaves of these plants.

Both beetles can be controlled through multiple methods. Pesticides can be used on the adults, however, be sure to avoid use of pesticides directly on the flowers to avoid harming pollinators. In the garden, sevin or eight can be used to control the beetles. In low populations, hand pick the beetles off plants and throw them into a bucket of soapy water to kill them and not harm pollinators.

Squash Bugs and Squash Vine Borer

Squash bugs and squash vine borer are seen in our gardens every year. Squash bugs cause yellow speckling on the leaves and feeding damage on the fruits. You may also see rusty colored eggs on the underside of the leaves that can be removed and destroyed. Squash Vine Borer causes rapid death and wilting of the plants. These pests feed on plants in the cucurbit family, which includes zucchini, squash, cantaloupe, watermelon, cucumbers, pumpkins, gourds, etc. Squash vine borer can be controlled by wrapping the stem of your plants with aluminum foil to stop the females from laying their eggs on your plants. Other controls include Carbaryl (Sevin), Permethrin (Eight), or bifenthrin (Bifen). This will need to be reapplied often through the growing season. It is best to switch between at least two of these products to avoid resistance development.

Always follow the label recommended rates and how often to reapply. Follow the PHI or pre-harvest interval listed on the label when harvesting fruits and vegetables after using chemicals. The PHI is how long to wait from using a pesticide until harvest can resume for food safety. Spray the undersides of the leaves and the base of the plant thoroughly.  All sprays should be done later in the evening to avoid damage to bees and other pollinators.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.