What’s that green beetle…

Green Beetles Blog post

All plants are wonderful. However, it is highly unlikely to find a plant that has absolutely no insect problems. This year we have been seeing a couple of unusual beetles wreaking havoc in our vegetable gardens and they can be found on our trees and shrubs as well. Japanese Beetles and Green June Beetles have been more problematic in southeastern Nebraska this year than most other years.

Japanese beetles are an invasive insect from Japan, where it is not a major pest due to the natural predators found there. This pest was first found in the United States in a New Jersey nursery in 1916 and was likely introduced in infested iris bulbs from Japan.  Since this initial introduction, Japanese beetle populations have steadily expanded westward.

Japanese beetles are problematic insects as both larvae and adults. The larvae are one of the four most common types of white grubs found in Nebraska. As a white grub, larvae feed on the roots of our grass, causing large brown dead 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 food plants are roses, lindens, and grapes amongst others. 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 often left behind but the rest of the leaf is chewed away. In some cases, they will consume the entire leaf. This can stress the plants, and in high populations of beetles can even kill the plant.

Green June Bug vs JB

Green June beetles are often being found this year as opposed to other years. They are very large, usually more than one-inch in length. They are dull green with some brownish coloration to the elytra and a tan border along the margins of their elytra, which are the hard wing coverings on a beetle. 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 the plants and as an immature, they are also a white grub species.

These 2 green beetles can be controlled through multiple methods. As larvae, they are best controlled with insecticides applied to the lawn in the months of May, June, and July. There are many different options available including the most common grub control, Merit which contains imidacloprid. Pesticides can be used on the adults in plants, however, be sure to avoid use of pesticides directly on the flowers of these plants to avoid harming pollinators. Imidacloprid, sevin, eight, or other general insecticides can be used on trees and shrubs to control the beetles. In low adult populations, you can hand pick the beetles off of plants and throw them into a bucket of soapy water to kill them and not harm any pollinators.

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Yard and Garden: July 7, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for July 7, 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: Bob Henrickson, Assistant Director of the Nebraska Statewide Arboretum

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 has 10 lilacs growing in a lawn which are now getting a gray film on the leaves. What is causing this problem?

A. This is due to powdery mildew. This is a common problem on lilacs. Lilacs often get this disease if they are planted too closely together reducing air flow or if they are planted in heavy shade. If these plants are not growing in either of these environments, it is likely due to the wet spring we saw this year. Fortunately, this disease is not very damaging to the plants and there is no need to treat for it.

2. A caller has many American elm trees growing in his pasture that seem to suddenly be dying this year after the leaves turn brown and curl up on the branches.

A. Unfortunately, this is likely due to Dutch Elm Disease, which is still present and active in Nebraska. Many of our trees can grow for a few years and then the trees get large enough and conditions become conducive, that it shows up and kills the trees fairly quickly. The only management strategy is to remove and destroy the infected trees to reduce the spread to other trees.

chicory, Joseph M Ditomaso, Univ of CA-Davis, bugwood

Photo of Chicory from Joseph M DiTomaso, University of California-Davis, Bugwood.org

3. What are the blue flowers blooming along the roadside now and can the seed be purchased somewhere?

A. That is chicory, a non-native plant often used in roadside mixes. The seed can be found in some roadside mixes or at local seed sources.

4. A caller has a sunset maple with leaves that are curling and falling off the tree. What could be wrong with the tree?

A. This could be due to herbicide drift. Trees stressed by herbicide drift will often lose their leaves and push new growth. As long as they are producing new leaves that are not curled, the tree will likely be fine. However, many years of damage from herbicide drift can cause more stress and even possibly death.

5. This caller has voles in their yard. How can these be controlled?

A. Snap mouse traps can be placed in the runs perpendicular to the runs. These traps will catch and kill the mice. Here is a guide on vole control

6. A caller has a copper-colored beetle in her elm trees that are causing holes in the leaves. What would this be and how can they be controlled?

A. This could be a Japanese Beetle, an invasive insect from Japan. It is a green beetle with copper-colored wings. These beetles need to be controlled as they can do a lot of damage quickly. They chew on the leaves causing a skeletonization of the leaves as they leave behind the leaf veins. They can be treated with a insecticide containing imidacloprid.

7. A caller has a grass that grows in her lawn. The grass grows in a large circle about the size of a dinner plate and tends to turn brown in any kind of drought when the rest of the lawn does fine, but thrives in higher moisture content. What would this be and how can she make her lawn look more uniform?

A. This could be a cool season weedy grass species. They are often found in our lawns growing in a large circle. I would recommend spot spraying the areas of this different type of grass and then reseeding. This would be best done this fall. Be sure to spray the spot while it is still green and actively growing and use a product such as glyphosate. Overseed the areas in September.

8. This caller has hollyhocks with brown spots on the leaves. What could this be from?

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. A caller has peach trees that have developed some insects in the peaches making them unedible. What can be done about that?

A. There are a lot of different insects that feed on the fruits of peaches. The oriental fruit moth is one. For any fruit tree, either deal with some insect and disease damages throughout the years or keep your trees on a spray program. Spray every 10-14 days throughout the growing season with an Orchard fruit tree spray that contains two insecticides and a fungicide. Avoid spraying during full bloom. For more information, visit food.unl.edu/local-food-production

10. This caller has a sycamore that has shed some leaves and is now shedding bark. What is wrong with the tree?

A. The shedding bark could be normal. Sycamore trees have an exfoliating bark that is normal to give it the camouflage bark appearance. It may have been hit earlier this spring with anthracnose causing the leaves to drop. Anthracnose is a minor, but common, disease of sycamore trees. It is more prevalent in wet weather, such as this spring. There is no control for it, but the tree should be fine.

11. A caller has been trying to seed grass where a septic tank was and can’t get it to grow. What is wrong?

A. At this point in the year, it would be best to wait until fall to plant grass seed due to the heat, humidity, and lack of rain. However, if you have been trying in the spring and fall and can’t get it to grow, I would recommend getting a soil test done of the soil where this problem is occurring. This will help tell if the soil has other problems because of the septic tank or what was put back into the hole. It was also determined that this is an area around a large tree with a great deal of shade, if the area is too shady for grass, try a groundcover or a carex species that will grow better in more shade.

12. When is the best time to spray for bagworms?

A. Now would be a good time since the bags have emerged. Make sure you spray before the bags are 1 inch in length for best control. You can use any general insecticide for controlling bagworms such as sevin, eight, bifenthrin, tempo, or Bt can be used for a safer control method. Bt will not harm bees and other beneficial insects.

13. A caller has a Norway Spruce that is 8 feet tall. It has been drying up since this spring and looks like it is dying. The tree has been planted here for 5-6 years and is watering slowly every 2 weeks since the trees were planted. What is causing it to die?

A. This could be due to overwatering. The roots of the trees need to breathe in between waterings. If the caller is filling a moat around the trees with water every 2 weeks for this many years, it would be excessive.

14. The final caller of the day wondered if the yard could be sprayed to help with chiggers? He also wondered when the time was to use sedgehammer on the lawn?

A. Nothing can be sprayed on the lawn to entirely help with chiggers. The best defense against chiggers would be to use insect repellent that contains DEET and to wear light colored clothing. Sedgehammer is best used before June 21st or the longest day of the year to help reduce the populations of nutsedge for next year. However, it can still be used this late in the year to kill what is in the lawn this year.

Yard and Garden: July 1, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for July 1, 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: Bob Henrickson, Assistant Director of the Nebraska Statewide Arboretum

1. The first caller of the day wants to use weed fabric and white rocks around the foundation of his house. Is this a good idea?

A. This can be done, but as horticulturists, Bob and I are always for more greenspace and less rocks. The weed fabric will work for a short time but often weeds will germinate through or on top of the fabric and it is hard to remove or change after the fabric is in. A good option would be to plant shrubs and perennials in there to help hide the foundation to the siding. Wood chip mulches will help with weed control around the plants.

2. A caller has a problem with ground squirrels in their lawn.

A. a trap can be built to control ground squirrels. The Internet Center for Wildlife Damage Management has a good guide for 13-lined ground squirrels.

3. A caller has bees in their sand play area. What can be done about it?

A. The best control for this would be to cover the sandbox so the bees cannot burrow into the sand to build their nest. If this can’t be done, you can sprinkle a little sevin in the holes where the bees go to nest. This is not the best option if you have kids playing in the sand because the chemical would not be safe for that. Otherwise, spraying the sandbox with water or soapy water will deter and possibly kill the bees.

4. This caller has a bald cypress tree that had lacebugs last spring. This year it hasn’t leafed out on the branches, most of the leaves are on the trunk. What can be done for this tree?

A. Removal and replacement. When a tree only leafs out on the trunk there is some reason that the flow of water and nutrients is not going through the whole tree. This could be due to borers or some type of root issue. Even with trees that are 8 years old, they could have had a root injury or been planted too deeply or had a stem girdling root that is now causing death of the tree. There is no cure for this at this point in the trees life.

5. A caller has a new lawn that they are trying to rejuvenate. What would the process be?

A. They are watering 2 times a week with a sprinkler for a couple of hours at a time, this should be sufficient. Stick with what you have been doing and don’t abruptly reduce it. Fertilize with the holidays: Arbor Day, Memorial Day, Labor Day, Halloween. So at this point don’t fertilize until the fall. Fertilizing in hot weather can cause more stress or leaf burn. For weed control, use crabgrass pre-emergent in the spring with the Arbor Day fertilization and use 2,4-D in the fall.

6. What to do when planting a tree that is badly rootbound?

A. It is hard to fix a tree when the roots are already rootbound. Once they begin to grow in a circular pattern, they will continue to do that for life, and damage doesn’t always show up until the tree is 10-15 years old. It is best to look at the roots before purchasing to choose a smaller tree with healthy roots. Also, when you get it home, remove the excess topsoil from the top of the rootball to ensure that it gets planted at the correct depth.

7. An email question came in to ask what to do for stump removal where they cut down and removed some shrubs?

A. Keep cutting the suckers off as they regrow and mulch the area if you just want to be rid of the plants. If you want to replant into the area, you will have to remove the stumps by digging them out or using a stump grinder to grind them out. Do not use Tordon in this area as it is against label regulations and it will not speed up the process and it can kill other desirable plants.

8. A caller has a firethorn plant with spidermites that they see on the plant every year and it causes them to loose many leaves each year. What can be done for them?

A. A strong stream of water will often work for spidermites. If the population is too high you will have to use insecticidal soaps. If this is an annual occurrence you may want to remove these shrubs and replace them with something that isn’t so problematic in this area.

9. What do you do for sandburs?

A. Sandburs are an annual grass, so crabgrass pre-emergent herbicides in the spring will help reduce the population by stopping germination. At this point in the year you can use a post-emergent grass herbicide such as Drive. Keep the area mowed to reduce the seed production for next year.

10. A caller has honeysuckle that is now invasive through his yard. What can be done to eliminate the honeysuckle plants? Also, is hickory a good tree for Nebraska? Why don’t we see hickory trees planted more?

A. Continual cutting of the honeysuckle will eventually kill it. You may want to try to dig up the plant to help reduce the problem. You can also treat the stump with roundup and/or 2,4-D. Use 2,4-D products in the spring or fall, it is now too hot to use this product without possible damage to desirable plants. Hickory is a great tree for Nebraska, it is just underutilized. Good hickory tree choices for Nebraska include Shagbark Hickory, Bitternut, and King Nut. Shagbark Hickory was the Great Plants of the Great Plains Tree of the Year Selection in 2011.

 

Japanese Beetle, 7-16 Acreage

Japanese Beetle adult on the left and immature on the right. Photos by Jim Kalisch, UNL Entomology.

11. A walk-in listener brought in a green beetle to be identified.

A. This is a Japanese Beetle. It is identified by the green metallic color, gold elytra, and white spots along the sides of the abdomen. This is an invasive insect from Japan that feeds on over 300 species of trees and shrubs, it favors roses and plants in the rose family. It will cause a skeletonization of the leaves as the adult feeds. As immatures they are a white grub that feeds on the roots of our turf. Management of white grubs in the turf will reduce the population. As adults, they can be controlled with general insecticides such as sevin, eight, bifenthrin, malation, or others. Don’t use insecticides on the flowers or flower buds to help with pollinator populations.

12. The final question of the day was from an email asking what chemicals do you use for bagworms?

A. Bagworms can be controlled with Bt, spinosad, sevin, eight, malathion, or tempo. The treatments need to be completed before the bags are smaller than 1/2 inch in length. You can also remove bags as they are seen and throw them into a bucket of soapy water to kill them without pesticides if you can reach them all.