Kansas State University

search

K-State Turf and Landscape Blog

Category: Insects

Mimosa Webworm Article on Entomology Blog

By Brooke Garcia

Have you been out in the landscape lately and noticed a webbing on mimosa and honeylocust trees? Mimosa Webworm has been very prevalent on both of these trees in Kansas. Their webbing protects them from enemies and the potential of being sprayed by an insecticide. To learn more about the Mimosa Webworm, as well as understanding how to manage this landscape pest, visit the Entomology Blog: https://blogs.k-state.edu/kansasbugs/2020/07/31/mimosa-webworm-3/

Abundance of Caterpillars in the Garden

By Frannie Miller

This post has been provided by the Extension Entomology e-Newsletter.

This week as I have been out in my own yard and garden I have noticed an abundance of different types of caterpillars. Identification of caterpillars can be difficult because so many of them look really similar, but often if you know what plant they feed upon it will give you a clue.

The first image is of a caterpillar sent to me by a friend asking what it was. She found it feeding on her pansies, which were a hold over plants from spring. These caterpillars are known as pansyworms. They usually grow to be 1 ¼ inches long with a characteristic deep-orange color with black striped sides which feature spines. These caterpillars will take bites out of the leaves, but the resulting variegated fritillary butterfly will add color to the garden.

Panysworm image: Courtesy of Cheryl Boyer

Then I found a few yellowstriped armyworm caterpillars feeding on some of my flowers. I picked them off as I did not want them to feed on those particular plants, but allowed them to feed elsewhere. These caterpillars turn into a somewhat drab grayish-brown moth.

Yellow Striped Armyworm

Finally I spotted a mass of small caterpillars feeding on sunflowers in the garden. The sunflowers were not ones I plants and had come up as volunteer so I have decided to let the caterpillars eat on these plants. It is difficult to for me to identify the exact species from a picture, but they will turn into some sort of checkerspot butterfly.

I have chosen to not use any insecticides to control these particular caterpillars, but options such as Bacillus thuringiensis subsp. kurstaki (Btk) and spinosad can be used when caterpillars are small. If you are going to use these products, remember to read and follow the label.

Checkerspot Caterpillar

Sometimes we don’t notice the caterpillars until they are larger and hand picking may become the best control option.

The damage caused by Japanese Beetles

By Brooke Garcia

Japanese beetle is popping up throughout most of Kansas, and it is feeding on many common landscape plants including roses, littleleaf linden, Virginia creeper, and grape. The Extension Entomology e-newletter recently posted a blog that highlights information related to management, chemical treatment, as well as biological information about the beetles. They are one of the most destructive insect pests on horticultural plants, and they cause a lot of problems for professionals and homeowners alike in landscapes and gardens. Raymond Cloyd also notes that, “the larva or grub is a turfgrass insect pest in home lawns, commercial settings, and golf courses.”

To read more, visit the Extension Entomology post, Japanese Beetle Adults Are Here!

Japanese Beetle Adults Feeding On Leaf (Auth–Raymond Cloyd, KSU)

Tips for submitting a ‘digital sample’ to plant disease diagnostic lab

By Lucky Mehra

When it comes to plant health, physical samples are best. However, sometimes it is not practical to send physical samples, such as with large trees or shrubs. A digital sample can be a good alternative or a good first step. By ‘digital sample’ we mean submitting digital images of the plant problem to the KSU plant disease diagnostic clinic.

Consider the following tips to take the photos and provide all the relevant information to help us diagnose the problem quickly and correctly.

Pictures

The main component of a ‘digital sample’ is the set of digital images itself. Take the following types of pictures to help us understand both the ‘big’ and ‘small’ picture of the problem. Make sure that the plant or plant part is in focus when taking pictures. Some phones are pretty good at auto focus, but most of the time you will need to tap on the screen at the point of interest to guide your camera to focus at a particular point.

  • Take pictures from a distance to give us the landscape view or the ‘big picture view’. It should include the whole tree/shrub along with neighboring plants (Fig. 1).

Fig. 1. The Hawthorn tree in the foreground has leaf spots. This image is to give an overall view of the landscape. For example, proximity of the tree to the concrete and adjoining trees.

  • Photo of the affected plant(s) i.e. the plant(s) showing the problem.
  • Photo of the affected plant part, whether it is leaf, flower, stem, twig, or root (FIg. 2).

Fig. 2. Affected leaves of the hawthorn tree.

  • Try to take a close-up shot of the problem symptoms (Fig. 3). If there are signs (actual parts of the pathogen i.e. fungal mycelium or other structures) present on the plant part, try to zoom in, tap to focus, and then take the photo. Take multiple photos to ensure that you will have at least a few good quality ones. If you have access to a microscope, you can bring the affected plant part to your home or office and focus it under the microscope. With some patience, you can also take really good macro shots with your phone through the eyepiece lens. Many of our students take photos this way in the lab. 

Fig. 3. An example of close-up images of a hawthorn leaf (top side of leaf on the left, and underside of leaf on the right) with yellow spots taken with a phone camera, without any additional lens attachment.

Additional essential information

Sometimes, the plant problem is very peculiar, and it is easy to identify by just looking at the photos you submit (e.g. yellow spots on hawthorn leaves shown above are the symptoms of Cedar-hawthorn rust); however, most of the time it is not possible to diagnose a problem only based on photos. We need much more information from you to help us with the correct diagnosis. Provide as much information as you can. Please see below for the type of information that will be useful to us when making the diagnosis.

Site history and pattern

Make sure to provide information about the site where the shrub or tree is located. That information may include soil type if known, soil pH, slope, distance to the concrete sidewalk or road etc. 

Are there any drainage problems? Is this the only plant affected? Are other plants of the same species affected? If yes, what is the pattern of these plants in the landscape i.e. is there a cluster of affected plants or the distribution is random? Are other plant species affected?

Plant pattern

Tell us about the affected plant part whether it is leaf, stem, flower, twig, stem or root. Additionally, report the location of symptoms on the plant. Some problems tend to occur on younger leaves, others are specific to older leaves. All this information can help us rule out some issues and narrow down the diagnosis.

Timing of the symptom appearance.

Was there any weather event such as temperature (too hot or too cold) or moisture extremes (e.g. heavy rainfall) prior to the symptom development. We can download these data from a local weather station as well, however, rainfall events can be non-uniform over the whole area covered by a weather station. So if you have onsite information about the weather data, report it to us.

Chemical history

Any history of chemical or fertilizer application should be provided. This can help the diagnostician in figuring out if the problem is arising due to chemical exposure or due to a biotic agent.

Euonymus Scale

By Brooke Garcia

This is the time during the summer season when Euonymus Scale may be extra noticeable on evergreen euonymus. The scale insect will appear as small, white dots covering the planting. If you are wearing darker clothing and come into contact with the shrub, you may notice the white “debris” coming off of the plant. The plant can quickly become infested and covered with this insect. Euonymus Scale is capable of killing the plant if left untreated. Keep a watchful eye on plantings during this time. There are cultural strategies that can be incorporated into the garden to reduce the likelihood of this insect becoming a problem, but it is extremely prevalent and may require chemical treatment.

Euonymus Scale Infestation On Euonymus Plants Located Near Building (Auth-Raymond Cloyd, KSU)

For more information about the biological characteristics of this insects, as well as cultural and chemical practices that can aid in prevention and/or treatment, visit the K-State Extension Entomology post here: https://blogs.k-state.edu/kansasbugs/2020/07/02/euonymus-scale-4/

New publication on oak leaf itch mite

(Megan Kennelly, KSU Plant Pathology)

In my neighborhood, and many communities across Kansas, we had an outbreak of oak leaf itch mites with a peak a couple of years ago. If you have itch mites in your area this year, you’ve had them before, or you simply have oak trees around, here is a new information sheet from KSU Entomology about this topic:

https://www.bookstore.ksre.ksu.edu/pubs/MF2806.pdf

With raking season upon us, take extra care if you do have them active in your area this year.

Curled leaf symptoms:

Unhappy person with itch mite bites during windy raking season a few years ago:

Warm-season Turfgrass Lawn Care Reminders

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Now that the summer weather is finally here it is time to start thinking about maintenance on warm-season turfgrass.  Below are some monthly reminders for everyone that has warm-season turf.


Bermudagrass and Zoysiagrass

May – August 15
Fertilize with 1 lb. of nitrogen per 1,000 square feet per application. Follow the recommendations on the bag. More applications will give a deeper green color, but will increase mowing and may lead to thatch buildup with zoysiagrass. Bermudagrass can also have problems with thatch buildup but thatch is less likely with Bermuda than zoysia. Bermudagrass – Use two to four applications. Zoysiagrass – Use one to two applications. Too much nitrogen leads to thatch buildup.

One Application: Apply in June.
Two Applications: Apply May and July.
Three Applications: Apply May, June, and early August.
Four Applications: Apply May, June, July, and early August.

Remember to look and see if you are using a quick release nitrogen source or a slow release nitrogen source.  If you use a quick release source then it is immediately available but only lasts a couple weeks.  Thats why you would have to make a couple of applications like it is listed above.  If you are going to use a slow release source it will tell you on the bag how long the product will last.  Therefore, you might not have to make as many applications.

So generally you want to use a total of 2 to 4lb. of nitrogen per 1,000 square feet per year for bermudagrass and 1 to 2 lb. of nitrogen per 1,000 square feet per year for zoysiagrass.

June
If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. June is a good time to core aerate a warm-season lawn. Core aeration will help alleviate compaction, increase the rate of water infiltration, improve soil air exchange and help control thatch.

Late-July through August
If you see grub damage, apply a grub killer. If Imidacloprid has been applied, this should not be necessary. Grub killers must be watered in immediately.

For more information check out the Zoyisagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1451

For more information check out the Bermudagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=586


Buffalograss

June

Fertilize with 1 lb. of nitrogen per 1,000 square feet during June. More applications will give a deeper green color, but can encourage weeds. If it is felt that a second application is needed, apply in July.

If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. Again, I would only treat if grubs have been a problem in the past. Note that the whole area may not need to be treated. The beetles that lay the eggs for the grubs are attracted to lights and moist soil and those areas are most likely to be infested.

Late-July through August

If you see grub damage, apply a grub killer. If imidacloprid has been applied or if grubs have not been a problem in the past, this should not be necessary. Grub killers must be watered in immediately.

For more information check out the Buffalograss Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1447


Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

Weekend Warrior Turfgrass Lawn Care

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Finally I think we have turned the corner into Spring.  With that, I see more and more of my neighbors, and myself, working in the yard.  I get excited when the turf starts to turn green.  But before I get too carried away I want to get out on the right foot and planning is everything.  To help help you plan out your lawncare program below are monthly calendars for tall fescue, Kentucky bluegrass, buffalograss, bermudagrass and zoysiagrass.

Bermudagrass and Zoysiagrass Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-guide-to-bermudagrass-and-zoysiagrass-lawns/

Buffalograss Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-buffalograss-lawn-guide/

Tall Fescue and Kentucky Bluegrass Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-tall-fescue-and-kentucky-bluegrass-lawn-guide/

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf