Cranberry Girdler Rears its Ugly Head

 Posted by: Alison O'Connor, Larimer County Extension

Doesn’t it seem weird that we have a type of sod webworm called cranberry girdler that lives in lawns in Colorado? Because this insect is a pest of cranberry bogs, Douglas-fir, and true fir…along with cool season lawns. Weird.

Regardless of its preferred hosts, these guys can do damage. Quickly. And I’ve seen a number of lawns this fall with damage. For example, there was this lawn in Loveland, which was the worst damage I’ve seen. All of the brown areas are dead. This lawn was a mix of fine fescue, tall fescue, and Kentucky bluegrass.

As for the actual insect, it appears to be a western problem in states like Utah, Colorado, and Wyoming. There’s not a lot of information about it, nor much research. (Utah State University has the best publication.) It’s a sod webworm that does its feeding and damage in late summer into fall. The damage looks a bit like drought stress, until you tug on the grass. Then it peels up like a cheap toupee.

Cranberry girdler can kill lawns by chewing through the roots, resulting in browning and the resulting toupee. Identification of this pest can be hard because it looks like most other sod webworms—grayish, smallish, with an orange-brown head measuring about ¾” long at maturity. The adult is a small moth with three black dots at the base of the wings, a buff color, and measure about ½” wide.

Adult moths (which emerge from overwintered larvae) emerge in mid-June and actively mate for 6-8 weeks. Eggs are laid on turf blades and hatch 9-11 days later. The larvae burrow into thatch or grass crowns, where they feed for two months. And that’s when we start to see damage (August-September).

Larvae will burrow deeper into the soil when temperatures start to cool. I think that’s why we’re seeing damage so late this fall—we really haven’t had cooler daytime temps, so the larvae were still feeding near the surface and easy to spot in late September.  

Now, you will be hard pressed NOT to find some sod webworms in your lawn, but there is a threshold you should consider before treatment. First, how widespread is the damage? If it’s a significant percent of the overall lawn, then treatment could be considered. Do you have the ability to water in products? If so, then treatment can be considered. But just because you see little white moths flying about doesn’t justify treatment. Many lawns will do well with some sod webworms present—especially those that are properly maintained.

A couple of things about treatment. The first is that if you have damage this fall, you should consider a spring-applied treatment for control next year. A promising (and easily available) product for homeowners is acelepryn, which is found in Scotts GrubEx. Apply this in late May to early June, watering it in with at least ½” of water. This product will control sod webworms and all white grubs (here’s looking at you, Japanese beetle).

But this fall, acelepryn or other recommended insecticides (beta-cyfluthrin, carbaryl, and chlorpyrifos) will not work quickly enough to kill damaging larvae. One of the few options is trichlorfon (sold as Dylox) and can work as a “rescue” treatment. This should be applied by a lawn care professional. Prior to application, water the lawn well with at least ½” of water and after application, apply another ½” of water. While very effective, this insecticide only lasts a couple days, so timing is important. It will not work if the caterpillars have pupated deeper into the soil.

And what do you do with the damaged areas of the lawn? You’ll have to reseed or re-sod. Seeding now (in early October) will not likely be super successful, so waiting until spring would be a better option. You could sod into late fall, as long as you can water.

So chalk it up to another 2020 “kick-you-while-you’re-down” problem. Boo cranberry girdler. Boo.

What is a Pollinator Syndrome?

Posted by: Lisa Mason, Arapahoe County Extension

Colorado has a wide variety of pollinators! This week on Instagram, the CSU Extension Pollinator Committee took over the Colorado Master Gardener account to showcase some of the awesome pollinator species we see in Colorado. Follow us on Instagram and learn more here.  

Speaking of the wide variety of pollinators, let’s talk about pollinator syndromes.

A bumble bee (Bombus sp.) visiting a Shangri-la sage (Salvia moorcroftiana x indica), a Plant Select plant. Photo: Deryn Davidson

What is a Pollinator Syndrome?

In general, research has shown that plants have specific flower traits that attract pollinators, and the plants provide the pollinator with nectar and pollen rewards. These attractive traits can include flower color, odor, shape, and availability of pollen and nectar. Some plants even have nectar guides that are markings showing where the pollinator should go to collect the reward. Different traits will attract different pollinators. Why would a plant evolve with traits to attract pollinators? Because visiting pollinators will facilitate plant reproduction. This relationship benefits both the plants and the pollinators.

For example, bird pollination is called “ornithophily.”  In Colorado, hummingbirds are primary bird pollinators. We know that hummingbirds generally prefer to visit flowers that are red, orange, or white. The flowers tend to be funnel-shaped, hang loosely on the plant, and have plenty of nectar deep in the flowers. For other birds around the world such as sunbirds, honeycreepers, and honeyeaters, the plants tend to have strong perch support for the bird to land. Flowers that attract birds typically do not have an odor because birds don’t need the scent to find the flowers. You might also notice that the flower petals tend to curve outward to make it easier for a hummingbird in flight to drink nectar.

A female broad-tailed hummingbird (Selasphorus platycercus). Note the pollen on her head. Photo: Nancy Klasky

The USDA Forest Service compiled a chart of pollinator syndromes for the major groups of pollinators. 

A wide variety of research is available demonstrating different pollinator syndromes. I want to share two research studies with you.

Darwin’s Prediction of the Long-Spurred Orchid

In the 1860’s, Darwin studied orchids including the long-spurred orchid, Angraecum sesquipedal. He predicted the flowers were pollinated by a long-tongued moth because the flower has a long spur approximately 12-inches long! The nectar sources are located deep in those long spurs. When Darwin received a specimen of this orchid, his wrote, “…good heavens what insect can suck it” (Darwin, 1862b).

At the time, no pollinators had been observed pollinating these orchid flowers. Scientists predicated the pollinator could possibly be the species, Xanthopan morganii, and subspecies, Xanthopan morganii praedicta, commonly called the Morgan’s sphinx moth because they have a proboscis length (tongue-like tube) that averages over 8 inches long. More than 130 years later after Darwin’s prediction, documentation of this moth pollinating the orchid was finally published beginning in 1993 (Arditti et al., 2012). To learn more, I recommend reading this journal article.

Pollinator Syndromes in Columbines

Another research example that we see in Colorado shows that columbines (Aquilegia spp.) have evolved to attract different pollinators depending on their spur length. This adaptation is considered a “pollinator shift” when the plant adapts to the traits of a pollinator (Whittall and Hodges, 2007).
 

Besides the spur length, note the other traits the columbines show to attract their designated pollinator. Image credit: Whittall and Hodges, 2007

Your Garden and Pollinator Syndromes

If you are looking to plant flowers to attract pollinators, you can use pollinator syndromes as a general guideline, but we recommend doing additional research and reading about pollinator-friendly plants that grow well in your area. For instance, to support pollinators, avoid double flowers. Many double-flowered horticultural varieties typically do not have pollen and nectar available for flower visitors.

Here are some resources for pollinator-friendly plant and habitats:

• CreatingPollinator Habitat
• AttractingNative Bees to Your Yard
• AttractingButterflies to the Garden
• Low-Water Native Plants for Pollinators

 
References

Arditti, J., Elliott, J., Kitching, I. J., Wasserthall, L. T. ‘Good Heavens what insect can suck it’ – Charles Darwin, Angraecum sesquipedale and Xanthopan morganii praedicta. Botanical Journal of the Linnean Society 169, Issue 3, 403-432 (2012). https://doi.org/10.1111/j.1095-8339.2012.01250.x

Darwin CR 1862b. Letter 3411-Darwin, C. R., to Hooker, J. D, 25 January 1862. Available at: http://www.darwinproject.ac.uk/entry-3411

Whittall, J., Hodges, S. Pollinator shifts drive increasingly long nectar spurs in columbine flowers. Nature 447, 706–709 (2007). https://doi.org/10.1038/nature05857

2020 "Best Of..." Winners from the Colorado State University Annual Flower Trials Announced!

Posted by Dr. Jim Klett, Colorado State University, Department of Horticulture and Landscape Architecture

Approximately ninety five professional and advanced Master Gardeners rated over 1,150 flowering and foliage plants over the week of August 3-8, 2020. We were not able to have an official evaluation day due to COVID 19 and University ruling on not having public gatherings on University property.

The garden is planned and maintained each year by the Department of Horticulture and Landscape Architecture with guidance from a committee of growers, flower seed companies, and public garden horticulturists. 

The following are the winners for "Best of Show", "Best New Variety", "Best Novelty" and "Best Container". For more information on these and other outstanding annuals from 2020 trials visit www.flowertrials.colostate.edu

Best of Show – Dahlia ‘Lubega® Dark Velvet’ from Benary+

This was a ‘show stopper’ due to the strong contrast between the dark purple/velvet foliage and beautiful bicolor blooms. Plants were extremely attractive all by themselves with the dark foliage coloring and uniform compact growth habit.  The prolific flowers were held high above the plants to create maximum show. Blooms had single petals which attracted many bees. Plants did not have any sign of powdery mildew even late in the season.

 

Best Novelty – Colocasia ‘Heart of the Jungle™’ from Proven Winners

This plant makes a dramatic statement to any landscape with its large, dark foliage. The impressive size and shape creates a very tropical and exotic appearance. It is grown for the beautiful foliage which makes a great structure plant in the garden. It does best in full sun.

 

Best New Variety – Centaurea ‘Snowy Owl’ from Terra Nova

Unique silvery foliage made this plant a standout in the garden. Large, velvety leaves added an interesting textural element.  The beautiful gray color made a great combination with other plants. It was highly visible in the garden and very uniform.

 

Best Container – Petunia ‘Bee’s Knee’ from Ball FloraPlant

The abundant flowers and great two tone yellow color provided exceptional flower power on very vigorous and well branched plants. It was noted for having the best yellow of any petunia in the trial.  The color held up very well in the high light intensity of Colorado. 

Preparing an asparagus bed

 

By Irene Shonle, El Paso County

So, your gardening season may have been abruptly shortened by the Sept 8/9 cold snap, but as the days warm back up, you can begin to think about next year – a gardener is ever optimistic, right?

One of the things I am planning for next year is to plant asparagus – I will put them in a sunny corner of the yard next to my rhubarb and horseradish, in my perennial edible section.  Perennial edibles are very rewarding, in that if you plant them well from the get-go, they will reward you for decades to come.  I am prepping my asparagus bed now in the fall to make life easy for me in the spring when the crowns are usually more available.

To plan for an asparagus bed, take these things into account:

1.      How many people will you be feeding?  Are you crazy for asparagus, or more moderate?  Plan on 5 crowns per person on the low end and 20 per person for those who can’t get enough.

2.      How much room do you have (in a sunny location with good soil)? Ten crowns need about a 4-by-8-foot bed (Rows of asparagus should be at least 2 feet apart, allowing two rows to fit in a 4-foot wide bed).  Asparagus is frequently sold in lots of 25 crowns, which would require about 80 sf.

 

Because asparagus is a one-and-done investment, it is worth taking a little time to prepare the bed properly.  First, make sure you choose a sunny spot – asparagus will be more productive in full sun. The site also has to be well-drained. If you see pooling water after a rain (that sticks around a while), that will not be a good site. You could choose to plant asparagus in a raised bed, if that is your only site option.

 

Asparagus is sensitive to any competition from other plants, so remove all grass, weeds, and any other existing vegetation from the planting area, including roots.  If the area you want to plant is quite weedy, and has been so for a while, consider taking next year to get the weed situation under control, and planting the following spring.

 

Asparagus likes rich, non-acidic soils. The last is usually easy to provide in Colorado, but the former requires some soil amendments.  Loosen the soil to a depth of 6 or 8 inches over the entire planting area with a tiller or shovel. Spread 2 to 3 inches of compost or well-rotted manure over the planting area and mix it into the soil.  If you want to protect the bare soil from weeds, mulch with leaves or weed-free straw. You are now done for the winter!  Congratulations.

 

Come spring, you will need to order your plants online, or purchase from a local garden center. It’s best to get the varieties where the spears are all-male, as they are the most productive, since they do not spend any energy producing seeds.

 

Dig a trench 12 inches wide by 6 inches deep where the crowns are to be planted, keeping the rows about 2 feet apart. Plant crowns about 12 inches apart. Spread the roots and cover the crowns with two inches of rich soil, amended with compost or a slow release fertilizer. As the spears begin to grow,  fill the trench with soil two inches at a time.

 

At this time, you need to muster patience - you just water and wait.  One of the hardest parts of planting asparagus is to refrain from picking anything the first year. Newly planted crowns should be left to form "ferns," which provide food for the roots. The second spring after planting, a few shoots can be harvested, but just once or twice. Leave the rest to feed developing roots. The third year , however, is where your patience pays off, and you can harvest away!

 

Asparagus should be fertilized in the spring just before spears emerge and again right after the last harvest in June for older plantings. Use 1 to 1.5 pounds of an all-purpose garden fertilizer, such as 10-10-10, per 100 square feet.

 

Pull or carefully dig any weeds that come up in the beds to keep out competition.

Turning the page on a successful 2020 grape season in Colorado

Posted by: Miranda Ulmer, CSU Viticulture Extension Specialist  

With grape harvest coming to an end, we are reflecting on what a year 2020 has been for us all, even the grapes in Colorado! However, despite many challenges, it has been a successful year. It all started when the 2019 harvest ended abruptly due to a cold front moving across the state in the beginning of October while fruit was still on the vines. Not only did this compromise the 2019 harvest, but it could have potentially affected the 2020 season as well. However, since we also experienced a freeze in April, just as the buds were about to break, it is hard to determine which event could have caused damage. You may recall that the freeze that occurred in April is what killed the majority of Colorado’s peach crop. The grapes were luckier in that they break bud later than the peaches, so only the early varieties were potentially compromised, and to a much lesser degree than the peaches.

 

Just as some of us wish we could fast forward through 2020, this season was the earliest season on record for grapes in the last 20 years. This can largely be attributed to the hot summer we experienced where it felt as if it didn’t drop below 100 degrees for two months straight. I had forgotten what 80 degrees felt like, but thankfully I have recently been reminded 😊.

 

As icing on the cake, the Pine Gulch Fire began burning 18 miles North of Grand Junction just as harvest was about to commence this year. The Grand Junction/Palisade region is home to Colorado’s largest grape growing region, and based on feedback from long-term industry members, has never experienced a fire of this magnitude in this close of proximity before. Smoke from nearby wildfires has the potential to cause smoke taint in grapes and wine resulting in off flavors and aromas. Luckily, preliminary results have shown that samples from the Grand Valley are below the threshold of concern for smoke taint. We (CSU and Western Colorado Community College) are collecting data from all across the Grand Valley to better understand how smoke taint can be prevented and/or managed in the future.

 

A smokey harvest at CSU- Western Campus 

Grand Junction, Colorado

Colorado grape growers are used to facing the many challenges that come with growing grapes in Colorado, including the cold winters, unpredictable spring and fall temperatures and extremely dry conditions. 2020 involved a few more unexpected challenges, but growers across our state rose to the occasion. Hats off to the Colorado growers and winemakers for another successful grape season. Support local & drink Colorado wine!

Pueblo Edible Landscapes Project

By Sherie Shaffer, Horticulture Agent, CSU Extension-Pueblo County

This summer, our Master Gardeners in Pueblo County didn’t have a lot of chances to volunteer in the community due to COVID-19. Luckily they were able to participate in a few COVID safe projects, one of them being a partnership with a local organization, The Pueblo Food Project, called the Edible Landscapes Project.

This project is an initiative to provide fresh produce to anyone who wants or needs it, and also to provide education to the community on growing food.

The project had three public sites, each with 2-3 volunteers working at them. Through the PFP, the volunteers were given a budget to buy plants and prepare their planters. Edible plants were added to each site, and signage was added to encourage passers by to take any produce that they wanted. Any excess produce is being donated to local food banks.

Later on in the year, signage was added that explained what was growing the plots and gave information on how to use it, nutritional value, and growing tips. Videos were also made that showed off the gardens and promoted them to the community.

Community members definitely took advantage of the fresh produce up for grabs. I live just down the street from the Mineral Palace Park site, where I walk almost daily, and have seen countless people picking produce and just marveling at the magnificent plants growing there.

We are at the end of the season, and we did have a freeze a couple of weeks ago, so the plants are starting to lose their luster a little bit, but that being said they do still look pretty good. Here are some photos of one of the sites that I took today, complete with a photobomb by my bloodhound, Layla. To see the gardens earlier in the year and get a personal virtual tour from our Master Gardeners, check out the videos linked above.

Plant Hardiness is More than a Zone Number

Posted by: Kara Harders, Peaks and Plains Regional Small Acreage Specialist

If you have lived in Colorado for a while you have probably lamented (or heard people lament about) the constant influx of new residents. Colorado really is a state unlike the rest. It isn’t hard to work out why so many people find it appealing to live here: mountains, 300 days of sunshine, low humidity, all four seasons of the year, boating/rafting/kayaking, hunting/fishing, wide open spaces, the big city, I could go on but I think I’ve made my point.

If I had to make a list of drawbacks in Colorado it would be short – wildfires, drought, and home prices come to my mind first, but we are currently (9/9/2020) experiencing one of our phenomenons that is less glamorous: wacky early/late cold snaps.

While Colorado is not unique to this issue, it is among the most common places for it to happen, and it’s hard on plants. It can make plant selection tricky too, have you ever used or seen the Plant Hardiness zone map?

Image courtesy of USDA-ARS

This map is super handy for identifying plants that can grow in different areas based on the “Average Annual Extreme Minimum Temperatures”, essentially, how cold can the plants handle. This is useful information and can help guide decisions about what to plant, where to plant it, and if you can expect it to need additional protection.  What this map doesn’t have is a “Areas that Experience Strange Unpredictable Temperature Swings During Odd Parts of the Year” score, I don’t think there is a handy chart for that.

An example of what I am talking about is the Kiwiberry or Cold Hardy Kiwis. The University of Minnesota (in Minnesota, which according to the map, is certainly cooler than Colorado) has been researching the plant, experimenting with species and cultivars, and looking into growing practices for more than 30 years. It does well enough in Minnesota they even looked in possible invasive qualities of the plant. However, when grown in Colorado, the Kiwis failed (even in high tunnels). Why is that?

It is because of days like Tuesday and Wednesday of this week when we experienced a 70 degree temperature swing in 48 hours, or in mid-April this year when it got down to single digits after being in the 70’s the week prior.

While the Kiwis are hardy to -20 degrees, they cannot handle the climactic whiplash that is Colorado. They need an intercontinental climate, an area where it gets cold then stays cold; gets warm then stays warm. In the Kiwi’s case, the warm spells in the late winter and early spring trick them into budding out and blooming.  In experiments done in Hidden Mesa (Douglas County) the late spring frosts kill not only the blossoms, but often the vines too. (Photo to upper right: Kiwiberry, photo by University of Minnesota) 

Similar problems arose in the fall when the first hard frost can happen before the plants have had time to harden off, often killing them. Even in high tunnels the plants slowly died back to nothing, while plants such as raspberries did fine. 

Try to keep in mind the effects late/early freezes can have on perennial plants. Even plants that are designed to handle the swings can suffer when they are too dramatic, and plants not designed for the shifts often don’t stand a chance. To better your odds, try to research plants and varieties proven to do well in our special climate. This is a link to a PowerPoint by Andy Hough (thanks Andy!) from Douglas county with tons of information on hardiness specific to the front range: https://www.douglas.co.us/documents/small-fruit-in-colorado-presentation-may-2015.pdf/