KSU Turfgrass Blog

How to mow your yard. A Rebuttal of a Consumer Reports Article

Rodney — Tue, 01 May 2012 20:07:44 +0000

I’ve been getting a few questions about a article in the recent Consumer Reports magazine. The article was written to help homeowners save time and reduce their workload in maintaining their landscape. The article had some good tips. But I need to clarify one of the tips that was presented regarding the 1/3 rule of mowing. Just to remind you of what the 1/3 rule is. It states that you should never remove more than 1/3 of the leaf tissue when you mow. I’ll explain more about the benefits of the 1/3 rule below. One of the important facts of the 1/3 rules is that during some of the rapid growing times of the year, like the spring and fall for cool season grasses, you may need to mow every 4-5 days instead of just once a week. But it also means during the slower growing times like July and August, unirrigated tall fescue/Kentucky bluegrass lawns may not need to be mowed but every 9-14 days.

When mowing, only remove 1/3 of the leaf tissue. Which means for tall fescue that you want to maintain at 3.5 inches high, never let it grow higher than 4.6" before you mow it.

So the article was written to save people time in maintaining their yard. Consumer reports quoted a well know turf scientist as saying, “Most domestic grasses can thrive with 50% or more of the blade removed.” The article went on to state that ‘you can let the lawn grow to about 5 1/2 inches before mowing. …it will reduce mowing frequency by about 25 percent…. Hours saved annually: up to 10.’ I think these statements made by the turf researcher and Consumer Reports are incorrect and misleading. I’ll explain where the problem is below.

Why do we recommend the 1/3 rule?

There are several reasons for following the one third rule, but the most important are: 1. Health of the grass plant and lateral spread, and 2. Clipping management and Environmental sustainability.

Health of the Grass Plant:

The researcher states that the plant will tolerate mowings that remove 50% or more of the leaf blade without undue harm to the plant. In the article he says, “(the 1/3 rule) was inspired by research conducted in the 1950′s by scientists at the U.S. Department of Agriculture who were evaluating Kentucky bluegrass as a forage grass. If you are feeding cows, the 1/3 rule will give you the most rapid leaf production. But if your goal is a good-looking lawn, we’re now saying it is OK to take more off.” I agree that strictly speaking from the health-of-the-lawn perspective, removing more than 1/3 of the leaf blade would probably not cause too much harm to the individual grass plant. But there is more to the lawn than just one plant. Frequent mowing that comes by following the 1/3 rule stimulates lateral growth (sideways, across the lawn), and that is the type of growth we want. We want the grass to spend it’s energy and time spreading out across the lawn, not spend all of it’s energy growing up in to the air. This will create a thick, dense lawn that will look beautiful, be comfortable to walk and play on, and reduce weed populations. So if we take the turf researcher’s recommendation and remove 50% or more of the leaf blade each time we mow, the grass will be growing tall and not necessarily spreading out, possibly reducing the density of the lawn. So we want to continue to follow the 1/3 rule to make sure we are mowing frequently enough at the right height to insure that the lawn continues to spread out and stay thick, rather than grow tall and spindly.

Clipping Management and Environmental Sustainability:

The second and equally important reason for following the 1/3 rule is clipping management. Most people bag their lawns, because they are not following the 1/3 rule and they leave large, unsightly clumps of grass on the yard. So they bag it, to prevent the piles of grass from disrupting the appearance of the lawn and to prevent the piles of grass from accumulating that can actually smother and kill the lawn in spots. But by following the 1/3 rule, the clippings are cut small enough that they can be easily distributed across the lawn with a side discharge or with a mulching mower. So if you took the Consumer Report’s advice and decided to start letting the grass grow to 5.5 inches or more before you mow, odds are that the clippings will not be easily dispersed back into the lawn, and you will have to bag it. I haven’t evaluated every lawnmower out there, I suppose some mowers can successfully mulch that much grass without having to bag it, but most homeowners buy inexpensive mowers that are not the best mulchers and the homeowner will still end up bagging to prevent clumps of cut grass laying on the lawn. .

I can’t stress it enough. Don’t BAG. First and foremost, those clippings contain nutrients and by recycling those nutrients back into the lawn you can reduce your fertilizer needs by 25-33%. Secondly, in some city’s those clippings end up in the landfill. Landfill space is becoming smaller and smaller and we don’t need to be adding grass clippings to the landfill when they can be recycled back into the yard. Now, some city’s like Olathe, will collect the yard waste and compost it for their residents, and some people compost their plant material on their own property. In those instances, removing the clippings isn’t so bad, but it is still a lot of time and work and it will increase the amount of fertilizer you need to apply to your yard. So keep the clippings on your yard as much as possible.

The article also stated ‘You should also bag clippings during a lawn-disease outbreak, in which case they might need to be taken to the landfill instead of being added to your compost pile.’ This statement is not true for almost all lawns in Kansas and Missouri. The fungal diseases that attack tall fescue and Kentucky bluegrass are predominately Brown Patch and Dollar Spot, respectively. The organisms for these diseases are already in your soil, and collecting the clippings will not greatly reduce the severity or the spread of these diseases. The only time I’d be concerned about collecting and composting clippings is if you are applying pesticides. Read and follow the label. Most pesticides have a statement that says the clippings should not be collected for compost until 30 days have past, but some products have much longer wait times. Read the label of your product to be sure. Or just don’t bag. (Do you see a trend here?)

So Follow the 1/3 rule and don’t bag your clippings.

With that being said….

I do know that there are times like when you go on vacation, or it is raining and raining and you can’t get out in the yard and mow frequently enough. Think of the 1/3 rule and don’t bag rule as ‘guidelines.’ Try to following it as much as you can, but don’t loose sleep about it when mother nature or outside forces prevent you from mowing often enough. Usually what I recommend in those situations where the lawn has gotten away from you and is really shaggy is one of two choices: 1. Mow it and bag it and then get back to following the rules. OR 2. Mow it 2 or three times. First, raise the mower as high as it will go and mow it and mulch or side discharge the clippings back into the yard. Then lower the mower a notch or back to your original setting and mow the yard again, either that same day or the next day. Mow and repeat if necessary until you get back to your recommended height. And then get back to following the rules.

For more information about proper mowing or proper care and maintenance of the grasses in your lawn, check out the Publications Section over at KSUTurf.com. Homeowners can also get more help from their local extension office.

Weedy grasses lurking in lawns

Megan Kennelly — Wed, 25 Apr 2012 20:10:52 +0000

This time of year, weedy grasses such as annual bluegrass and rough bluegrass can hang out in lawns, landscapes, and golf courses, barely detected. However, once summer stress kicks in, these grasses decline faster than the surrounding turf leading to brown “patches” that may be mistaken for diseases. Even in spring, the off-color of these grasses can be mistaken for disease or other problems.

Here are some photos of rough bluegrass in a fescue/Kentucky bluegrass lawn. The light green color was mistaken for a disease, and they called in some help from the local golf course to check it out. He astutely identified the problem not as a disease, but patches of rough bluegrass. In the turf stand it is visible as the apple-green areas among the deeper green surrounding turf. When summer stress hits, these will turn decline quickly.

(click to enlarge)

Annual bluegrass produces a lot of seed, though, so it can bounce back. Rough bluegrass also recovers, with stoloniferous spread. These grasses can be introduced in seed – one more reason to use high quality seed!

Thanks to Ross Uhrmacher, Quarry Stone Golf Course, Chanute KS, for passing along the story and the photos!

Large patch in zoysia

Megan Kennelly — Wed, 25 Apr 2012 19:59:57 +0000

It’s been pretty dry lately, (and what’s up with these 90+ temps???) but the forecast calls for cooler temps this weekend with chances of rain in some areas. Those conditions could cause mild large patch symptoms to flare up.

In our research plots there are hints of large patch showing up in inoculated areas of zoysia. In this plot you can just barely see two patches emerging, each ~2-3 feet across, with the margin more prominent than the center. You might want to zoom to see better – just click the photo to enlarge, then hit the back button to return to this page.

We’ll see how they look after the weekend weather.

2011 drought could lead to 2012 cankers and borers

Megan Kennelly — Wed, 25 Apr 2012 19:49:38 +0000

2011 was marked by extreme drought conditions in many parts of Kansas. The 2011-2012 winter was also dry. Drought stress can predispose trees and shrubs to canker diseases and borers.

There is information about canker diseases of trees here:

http://www.ksre.ksu.edu/library/plant2/mf2658.pdf

KSU Entomology has information about borer identification and management at these 2 sites:

http://www.ksre.ksu.edu/library/entml2/MF2735.pdf

http://www.ksre.ksu.edu/library/entml2/mf2736.pdf

Not quite right…

Megan Kennelly — Fri, 13 Apr 2012 19:27:29 +0000

No, that’s not how to use mulch around a tree:

Thanks to Zane Raudenbush, KSU PhD student, for sending this my way. He saw it on the road on the way to some research plots. I always appreciate photos (serious or funny) from out there in the trenches, so send them my way when you find something interesting.

There is some info about mulching, planting trees, etc, at these sites:

http://www.ksre.ksu.edu/library/HORT2/MF2133.PDF

http://www.ksre.ksu.edu/library/hort2/mf402.pdf

Summerpatch, summerpatch, sum-sum-summerpatch

Megan Kennelly — Fri, 13 Apr 2012 19:16:46 +0000

I received a question the other day about summer patch in Kentucky bluegrass. I had been thinking about summer patch that morning and was planning to write about it this week. Normally, early May is when that particular disease is on my radar but since everything is early, the time to think about it is now.

The symptoms tend to show up when summer heat and drought fire up, but the infection occurs in mid/late spring. The fungus is soilborne and attacks roots. If you have a site with a history of this disease, fungicides may be helpful. When the daily max soil temperatures at 2-3 inches deep are consistently (3 days in a row) above 65, that’s a good time to make a first application. Follow up 28 days later, or according to label intervals.

You can get some soil temperature data info at the Kansas Weather Data Library:

http://www.ksre.ksu.edu/wdl/

At the upper left, you can choose “Kansas Weather and ET Data” and from there you’ll find a page with a map and also a pull-down menu. Choose a site near you, select a range of dates, and you can get highs, lows, and soil temps usually at 2 and/or 4-inch depths. Or, better yet, invest in some of your own soil temperature equipment.

There is more information about summer patch at the summer patch link HERE

Warm Spring: Grub/Insecticide Application Timing?

Rodney — Mon, 09 Apr 2012 13:31:23 +0000

I’ve been getting some questions about grubs and timing of insecticides with this warmer than usual spring. Bob Baurenfeind, K-State Horticulture Entomologist wrote the following article for the KSUTurf blog to help address some of these concerns, read on below.

There have been recent inquires as to how the mild winter temperatures (December – February) and “summertime” March temperatures might influence 2012 grub control decisions. This relates to the use of the following alphabetically listed active ingredients (and respective systemic insecticide products): chloraniliprole (Acelepryn), clothinidin (Arena), imidacloprid (Merit) and thiamethoxan (Meridian). These insecticides are cited for their extended residual effectiveness.

In Kansas, the grubs of historical and primary concern are “annual” white grubs, which are the larvae of “masked chafer beetles.” Substantial consumption of plant roots weakens turf. Major damage is attributed to third instar (developmental stage) grubs which ravenously consume roots to satisfy their ever-increasing nutritional requirements. Resultant visual damage (generally becoming evident in September) consists of thinned, wilted, yellowed and/or dead stands of turf. The following illustration depicts the seasonal life history of masked chafers.

The key to grub control is targeting/killing the smaller /less damaging 1^st and 2^nd instars which (given their smaller size) are most susceptible to insecticides. While different product labels specify their products be applied early in the season (April and May), it is more prudent to apply materials at the initiation of beetle emergence and egg laying activities to ensure sufficient/fresh concentrations of insecticide at the time needed to eliminate early instar grubs. Thus, in Kansas, mid-June through July roughly corresponds to the seasonal appearance of beetles and subsequent egg production.

The initial/introductory aforementioned inquiry stems from current reports of ongoing May/June beetle activities. Flights of early-season May/June beetle species (Phyllophaga fusca, P.vehemens and P. congrua) typically begin in early April. My earliest catch was April 5, 2003, with the latest being April 29, 1999. On average, flights begin in mid-April. Thus the fact that there already have been reports of activity at the end of March is not “extremely early”.

Regarding masked chafers: only time will tell whether they emerge earlier-then-usual. Because the recommended timing of systemic insecticide applications hinges on the onset of masked chafer flights, at this point in time, I would wait for that event to occur. At that time, then, apply automatic preventative insecticide applications (if that is the chosen practice). This will provide the aforementioned full concentration of product to reduce populations of grubs while in their early developmental stages.

April showers bring May flowers, diseases, and basement floods

Megan Kennelly — Fri, 06 Apr 2012 22:00:47 +0000

What’s been going on around the state?

Weather data library

First- here’s a reminder about the KSU Weather Data Library. If you have never checked out this resource it is worth a look:

http://www.ksre.ksu.edu/wdl/

At the upper left, you can choose “Kansas Weather and ET Data” and from there you’ll find a page with a map and also a pull-down menu. Choose a site near you, select a range of dates, and you can get highs, lows, and soil temps usually at 2 and/or 4-inch depths. Here’s an example of the type of data you’ll get:

Date	Max Air Temp	Min Air Temp	Total Precip (in)	Avg RH	Avg windspeed	ET (grass)	ET (alfalfa)	Max 2″ soil temp	Min 2″ soil temp	Max 4″ soil temp	Min 4″ soil temp
4/1/2012	89.2	55.2	0	60.6	6.91	0.23	0.32	75.8	59.3	68.6	61.4
4/2/2012	88.2	59.7	0	60.4	10.47	0.29	0.43	77.6	64.7	70.5	64.5
4/3/2012	74.3	54.5	0	71	5.15	0.15	0.19	75.4	61.9	68.7	63.1
4/4/2012	60.3	51.9	0.88	86.4	5.54	0.05	0.07	64.5	59.1	65.5	60
4/5/2012	61.9	43.6	0.03	79.1	4.79	0.08	0.11	64.3	54.2	62.1	57.6

From there, you can take averages over the past week, take the data and turn it into graphs (if that’s useful for you), etc etc.

Fire blight in ornamental pear:

A classic symptom of fire blight is a “shepherd’s crook” shape to the branch tips, but the disease can also attack the spur branches. The pear sample below came in today. Crabapple can also be affected.

We had warm, wet weather during bloom in many areas. The bacteria that cause fire blight can infect the blossoms during those types of conditions, then the bacteria spreads down into the spur. From there, it can spread into branches. What to do about fire blight? Prune out affected branches. The best time to do this is winter. But, if pruning in summer, do it when there are several days of dry weather in the forecast and disinfest tools between pruning cuts. Tools can be dipped into 10% bleach (mix 1 part bleach with 9 parts water). The bleach solution loses activity quickly so must be made fresh. Tools can also be dipped in70% alcohol.

Large patch in zoysia:

The cool, wet weather this week has been perfect for large patch development. Usually zoysiagrass would be just barely greening up by now, with large patch symptoms appearing in late April or early May. But, along with early plant growth the diseases are popping up earlier. There is some information about managing large patch at this website: http://www.plantpath.ksu.edu/ksu.edu/doc1282.ashx

Yellow patch:

There may be some lingering symptoms of yellow patch

Dollar spot

I haven’t personally seen dollar spot yet, but I have heard that it is active in some areas

Fairy ring

We get early-season fairy ring every year at Rocky Ford when the turf hasn’t been fertilized yet:

We just fertilized for the first time, so those rings will disappear as the turf greens up now that it has had something to eat!

In putting green sites with a history of normal summer fairy ring now might be a good time for preventative applications. Applications at soil temps of 55-65 have been successful in a number of studies, and I know several superintendents who have had success with that as well.

Organic matter

A putting green sample came in last week where the actual disease problem was yellow patch, but there were also significant organic matter layers, as shown in the photo below. That indicates the need for aerification and topdressing. When summer heat/stress kicks in, that organic matter can retain water and reduce root vigor. NOW is the time to boost turf health. Build your roots so that when things get brutal in the summer, your turf is more prepared to withstand it.

Fall Seedings not greening up

I’ve had a few calls and emails in recent weeks about fall 2011 turf seedings not emerging well from winter. It was a dry, dry fall and winter. Even in sites with irrigation, the irrigation might not have been enough… I think that is the case with some of the failed plantings. The juvenile turf went into winter a bit dry, then it dried even further.

Basement floods

Yup, those darn April showers… for the most part, I welcome them. They do trigger a few diseases, but these gentle rains have overall been great for plant growth.

But I didn’t welcome them into the basement! D’oh! Next time, April Showers, stay outside

(an unfortunate side-effect of some minor construction at the house… all is OK now!)

Cedar apple rust

Megan Kennelly — Fri, 23 Mar 2012 18:49:33 +0000

This post is mostly copied from 2011. The thing is, in 2011, these diseases were not active until mid-April. So, this year, they are about 3 weeks earlier!

The birds are singing, the tulips are blooming, and junipers (also called red cedars) are “blooming” in another fashion. Cedar apple rust is here. The pathogen (a fungus) spends part of its life cycle on a juniper tree, and the other part of its life cycle on apples, crabapples, hawthorns, or quince. To simplify, we’ll just call them “apple hosts.”

In spring, orange “horns” poke out from brown, brain-like galls on junipers.

Here in Manhattan, this week’s rains triggered the galls to pop out in all their ooey-gooey glory:

There is a similar disease called quince rust that forms globs (instead of long tendrils) of orange goo on twigs and branches of junipers.

And, hawthorn rust produces galls similar to cedar-apple rust, but smaller and less dramatic:

Those jelly-like orange masses on the junipers produce spores that infect the apple hosts. Once infection occurs, leaf spots on apple leaves develop in 1-3 weeks (see below). Eventually, fungal spores are produced in these leaf spots on the apple tissues. The spores are spread by wind and rain back to junipers starting in about July. Without both hosts the fungus can’t complete its life cycle.

The disease is looks dramatic on junipers, but it does not cause much harm.

The rusts can cause problems in the apple host, however. If infection is severe many leaves drop off early and the tree is weakened due to reduced photosynthesis. If your tree only gets a small amount of rust each year it probably won’t be an issue for long term tree health.

Management options (for apple hosts):

1) Resistance:

For new plantings of fruiting or flowering apples, consider planting a rust-resistant variety. Information on crabapple cultivars is available here: (click on the word ‘flowering’)

flowering

2) Tree care:

For any apple tree, proper pruning will allow air movement through the canopy. This practice reduces the leaf wetness that promotes disease. Maintaining overall tree health will also help prevent the disease.

3) Fungicides

Homeowners with a bad history of this disease (severe defoliation) might consider preventative fungicide sprays on the apple hosts when leaves are out and the orange galls are active. For best control, applications should continue through May or as long as the orange galls are active.

Products with the active ingredients myclobutanil or propiconazole are examples of materials available to homeowners that are labeled for cedar apple rust management in flowering crabapples and non-fruiting apples. Some myclobutanil products are labeled for fruiting apples. However, in all cases, make sure you check the label carefully. For example, the myclobutanil product “Immunox Plus” is labeled for rust on flowering crabapples, but not for fruiting/eating apples, as it contains an insecticide along with the myclobutanil ingredient. In contrast, “Immunox Multi-Purpose Fungicide” is labeled for fruiting apples. If your local store does not carry products for fruit trees you can find internet sites which carry different products. More active ingredients are available for commercial landscapers/tree care professionals.

Commercial fruit growers should consult the 2012 Midwest Tree Fruit Spray Guide, available here:

http://www.plantpath.ksu.edu/p.aspx?tabid=587

More info on pine wilt

Megan Kennelly — Thu, 22 Mar 2012 22:06:07 +0000

Background:

Pine wilt is caused by the pinewood nematode, a microscopic worm. The nematode is spread by the pine sawyer beetle. The nematode feeds and multiplies in the tree’s resin canals, causing wilting and death in several weeks to several months. The nematode and beetles spend the winter in the infected tree. In spring, the beetles emerge starting around May 1, carrying nematodes to new trees and continuing the cycle of infection.

The disease is common in the eastern half of the state, and it is spreading west around 10 miles per year. Scots pines are particularly susceptible, and many Scots pines in eastern Kansas have been killed. Austrian pines are also susceptible. Western Kansas is not yet infested. In the last few years there have been several isolated pine wilt cases in western Kansas. Some of those findings were affiliated with infested fire wood coming from the east. Some of these introductions have been eradicated through scouting and timely sanitation (trees cut down and wood chipped or burned by April 1).

Symptoms:

In Kansas, new pine wilt infections are most visible from August to December. Trees wilt and die in a short period of time, from several weeks to a few months. In the first stages, the needles turn grey or green, then yellow and brown. The discoloration sometimes occurs branch by branch, sometimes all at once. The brown needles stay on the tree for up to a year after the tree has died. Another key symptom is reduced resin. On a healthy tree, sticky resin bleeds from the site of a wound. In contrast, if a tree has pine wilt the resin is often reduced or absent, and branches become dry or brittle.

There is a website with color photos and descriptions at the following link:

http://muextension.missouri.edu/explorepdf/miscpubs/mx0858.pdf

So, what can we do?

1) Sanitation

The most important step is sanitation. If a tree is suspected to have pine wilt, contact your local K-State Research and Extension office, the Kansas Forest Service, or the K-State Plant Disease Diagnostic lab (clinic@ksu.edu). If the test is positive, the tree should be cut down by May 1 at the latest, before the beetles emerge. In fact, April 1 would be a better deadline just to make sure no beetles emerge AND to make sure there is time to destroy the wood by May 1. Cut the tree to the ground—don’t leave a stump. Chip or burn the wood immediately to destroy the beetles and nematodes. Don’t keep pine wood around for firewood.

2) Avoid stress

The beetles are attracted to drought-stressed trees, or trees affected by other diseases or insects. If possible, provide water during dry periods to prevent drought stress.

3) Preventative injections

There are several products on the market for prevention of pine wilt. There is nothing available to cure pine wilt. The products all contain 2% of the active ingredient abamectin, and are injected into the tree. They need to be applied by a trained tree care professional.

One product, Greyhound, and its injection system, was studied by the Nebraska Forest Service. An injection system that is now called the “pine infuser”, usually marketed with the abamectin product Pinetect, was studied at K-State. In both studies, trees with preventative injections using the tested injection equipment had about an 80-90% survival rate compared to 40-50 % in untreated trees.

So, it is not a 100% guarantee, but it did increase survival. Remember: it only works preventatively—there is no curative activity.

Abacide 2 is another 2% abamectin product labeled for pine wilt. However, I have not been able to find any data about how well the injection system (small capsules) used with Abacide 2 works for pine wilt. [If anyone out there has seen such data/studies, let me know.]

The label and other information about Greyhound and its injection system is available here:

http://www.arborsystems.com/?page_id=131

Information about Pinetect and pine infuser is available here:

http://www.treecarescience.com/arborceuticals/nematicides/pinetect

Information about Abacide 2 and capsules is available here:

http://www.mauget.com/index.cfm?PageID=19&ID=1&productid=2

Keep in mind – injections can be costly, in the tests they didn’t work 100% of the time, and they need to be repeated every two years.

4) Prevent new infestations: (especially in western half of Kansas)

Don’t import pine firewood from contaminated areas. Be wary of pine nursery stock from infested areas, and monitor nursery stock carefully. If pine wilt is introduced, remove the tree, and continue to monitor surrounding pines to make sure it has not spread. Careful scouting and sanitation can eliminate sporadic outbreaks before they get out of control. Contact K-State (clinic@ksu.edu), the Kansas Forest Service, or Kansas Dept of Agriculture with questions.

FAQ’s for pine tip blight

Megan Kennelly — Thu, 22 Mar 2012 21:20:22 +0000

Pine tip blight is a fungal disease that can affect Austrian, Scots, ponderosa, and mugo pines. The disease is most severe on mature trees (20 years or older). Repeated infections over several years can kill large sections of trees or entire trees. Here are some Frequently-Asked-Questions about tip blight.

1) What is the pathogen?

Tip blight is caused by a fungus that has been called both Sphaeropsis and Diplodia over the years. Don’t let the name changes trouble you. The most important consideration is to recognize the disease, and to be able to distinguish it from other pine problems.

2) When does disease occur?

Tip blight is a spring disease. The fungus survives the winter in previously-infected tissue. Then, during spring rains, the fungal spores splash around and infect the newly developing pine shoots (candles) just as they start to grow, which is usually in mid-late April. Warm temperatures this year could cause earlier-than-normal growth.

3) What are the symptoms of pine tip blight?

The symptoms become obvious in late May or early June when the infected shoots and needles are not growing right. The shoots are stunted, and the emerging needles are stunted and brown (see image at the top of this page). Small, sticky resin droplets often form on the infected needles. The damage usually starts in the lower branches and works its way up over several years. In trees that have been repeatedly infected for many years, damage is distributed throughout the crown. In addition to infecting the newest growth, the fungus can invade older tissues when trees are highly stressed or if they are wounded (by hail, storm damage, etc). Interestingly, white pines are not susceptible to the tip blight phase, but they are susceptible to this “canker form” of the disease if they are wounded.

In late summer or fall, tiny black spore-producing structures (called pycnidia) are formed on the scales of 2-year-old cones — it looks like black pepper has been shaken onto the undersides of the cones. Click on the photo below to zoom and see the black specks.

Tip blight can be confused with winter damage or infestation by the pine tip moth. However, winter damage usually causes shoot or needle death before the new needles emerge in the spring, and it is sometimes restricted to one side of the tree (the side facing the prevailing wind). Unlike tip blight, the tip moth causes a hollowed-out area in the tip/bud area, and the larvae are sometimes present. Plus, tip moth is more common in young trees.

In extreme cases tip blight can be confused with pine wilt. To avoid confusion, look carefully at the symptoms and compare them to the descriptions and photos here and in other resources. Pines can be infected with both diseases simultaneously. If there is any doubt, bring a sample to your local K-State Research and Extension office to be forwarded to the K-State diagnostic lab.

For more color images of tip blight, please visit the following website:

http://www.ksre.ksu.edu/library/plant2/l722.pdf

Printed copies of the fact sheet can be ordered by calling (785) 532-5830

Managing tip blight:

4) Does pruning help?

Removal of dead branches can improve the appearance of diseased trees, if there aren’t many affected branches, but pruning out disease will not prevent infection. Many of the spores are produced on cones that remain attached to the tree. In addition, tissues that look healthy can secretly harbor the tip blight fungus. That is, there are “hidden infections” that we can’t even see. Usually, pruning for tip blight means pruning off lower branches first, since they tend to be the first to become infected. Then the pruning task moves up the tree as the disease progresses over the years. If a tree reaches a point where it is no longer pleasing or functional for the site, “one-cut pruning” (ie, tree removal) might be the best possibility.

5) What other tree care should I provide?

Trees should be adequately (not excessively!) watered and fertilized to maintain tree vigor. This will help a tree fight off tip blight on its own.

6) Should I use a fungicide?

This is a tricky question. The trouble is, unlike smaller plants like wheat, tomatoes, or soybeans, there aren’t many studies out there to tell us about tip blight “thresholds.” As a general rule, if a tree has at least 30-50% of branches infected, the fungus is pretty well entrenched and it will be difficult for fungicides to really knock the disease down. And, if there is a lot of canker type infection, it is hard for fungicides to work. If a smaller portion of the canopy is affected, and it is mostly the tip-blight phase, fungicides are more likely to be successful over time. Finally, consider the aesthetics and site-enhancing value of the tree. In trees where the disease is caught early, and fungicides are used at the right time each year for multiple years, the disease can be managed successfully and it might be worth the investment. Spraying for one year only is not likely to help much.

7) Okay, so what is the right time?

The critical time for fungicides is when the new shoots are expanding in the spring. If fungicides are applied at this time, new disease can be prevented. It is not a one-shot-deal. Fungicides will likely be needed each year to protect new annual growth. Each year, the first application should be made when new shoots start to elongate, which is usually around the third week of April. The tree should be sprayed again 10 to 14 days later, and possibly again 10 to 14 days after that if it is a wet year and the site has a history of disease. The timing should be adjusted slightly depending on host development in the spring, since every year is different. Spraying after this critical time will not be effective, because infection has already occurred and cannot be “cured.” Once you see symptoms it is too late.

8.) What should I spray, and how should I spray it?

Several fungicides are labeled for pine tip blight (Sphaeropsis/Diplodia). Thorough coverage is essential. A high-pressure sprayer may be needed to deliver the fungicide to the tops of tall trees. Homeowners should consider using a professional tree care service, especially for large trees where getting good coverage is difficult. Commercial products are listed in the website listed above (under #3).

9) What about injections?

Fungicide injections have been studied, but so far results have been inconsistent and injections are not recommended at this time.

Two more great articles about crabgrass germination.

Rodney — Wed, 21 Mar 2012 15:06:58 +0000

Just to share some great articles about crabgrass germination.

Dr. Patton and Dr. Street of Purdue and Ohio State posted 2 great reads that expand on my recent article about crabgrass. Dr. Patton’s article has some great research citations.

When Will Crabgrass Germinate?: With the rapidly warming weather,several are asking “When will crabgrass germi… bit.ly/AozTtA

— Purdue Turf Science(@BoilermakerTurf) March 16, 2012

Soil Temperatures and Crabgrass Germination – Written by Dr. John Street of @osuturf bit.ly/GJ0YFy via @AddThis

— Ohio Turfgrass FNDN (@OhioTurfgrass) March 21, 2012

Buffalograss Greening up: Round-Up for weeds?

Rodney — Wed, 21 Mar 2012 14:45:49 +0000

Typically in Feb and March I get calls from people wanting to control weeds in their buffalograss lawns. And they have heard that they can spray Round-Up (glyphosate) on their lawn to control weeds. Yes this is true. You can spray Round-Up on dormant buffalograss. Since the buffalograss is ‘sleeping’ and not growing, it will not absorb the herbicide and it will not be injured. So Round-Up applications can be an cost effective, easy way to control a many broadleaf and grassy weeds.

The problem is that buffalograss begins to grow in the spring sooner than most people think. For that reason, I usually only recommend spraying glyphosate on buffalograss on warm days late in the fall, early winter (Nov-Dec) or even Jan. But be careful spraying in Feb and March is really not recommended. Buffalograss starts to green up early. And if you look at the lawn it looks completely dormant, until you get down on your hands and knees and inspect the grass. (See pictures below.) I’ve seen many late treated buffalograss areas get set back. Fortunately, I haven’t seen many of them get killed, but they were definitely stunted and slow growing for most of the season.

So if you have broadleaf weeds in your buffalograss, spray it with a broadleaf herbicide. 2,4-D is the chemical that can injure buffalograss when it gets hot. So most people are spraying Surge or Trimec Bentgrass formula. I also have used Drive (quinclorac) for many years on my buffalograss at the center to control actively growing clover and crabgrass.

While standing over this plot, the buffalograss looks completely dormant.

But when you get down and inspect it, the buffalograss has started to green up. No Round-Up here. It will injure the buffalograss.

Here's a variety that has really started to green up. NO Round-Up here either.

Winter Weeds. I’ve seen a Bunch!

Rodney — Wed, 21 Mar 2012 14:22:39 +0000

I don’t know if it was the exceptionally warm weather or the over-abundance of weak and damaged lawns from last summer/fall, but I’ve seen an exceptional amount of winter annual weeds like henbit and common chickweed, just to name 2 that I’ve seen.

I’m guessing that it is a combination of the two. The warm winter may have helped to improve seed germination. And definitely, anytime the lawn is weak, and thin more sunlight can reach the soil surface which helps germinate more seeds. Both weeds are winter annuals. Which means they germinate from seed in the fall and they will die over the next few weeks. And they will disappear from the landscape until next fall if they germinate again.

Typically, it is always easier to kill weeds when they are young and small, so we usually recommend spraying broadleaf controls for these two weeds late in the fall when you see the young small plants. But most homeowners don’t see the weed or get concerned enough to do something about it until it starts to flower and really grow big at this time of the year. You can use any common post emergent broadleaf control like Trimec, WeedBGone, etc. Control at this time of year while it is so big, may take a 2nd repeat application.

Feel free to send me any pictures of some of your weedy lawns.

Here’s a small patch of common chickweed and a close up.

Here is some pictures of Henbit.

Henbit Closeup

Henbit Closeup 2

Henbit is in the mint family of weeds and has a square stem.

Crabgrass or Knotweed germinating, don’t panic!

Rodney — Mon, 19 Mar 2012 21:03:25 +0000

I posted some pictures on Twitter over the weekend of some Knotweed germinating.

Don’t forget knotweed germinates before crabgrass. So if you see germinating seedlings probably knotweed. Like this. twitter.com/KSUTurf/status…

— KSUTurf (@KSUTurf) March 18, 2012

Close up of knotweed germinating near edge of street. twitter.com/KSUTurf/status…

— KSUTurf (@KSUTurf) March 18, 2012

Remember that Knotweed is a summer annual broadleaf weed. It germinates fairly early in the spring…earlier than crabgrass (which germinates earlier than goosegrass). I occasionally get calls at this time of year where people on concerned they missed the opportunity to get their pre-emergent herbicide down because they see all these young seedlings like below and they assume it crabgrass. Most of the time is knotweed. Look closely at the leaves. When it germinates, it has two small leaves like grass leaves, but shortly after germination the leaves begin to get wider and take on that normal broadleaf weed shape.

I don’t usually recommend using a pre-emergent for controlling knotweed. It is best to try and alleviate the compaction, reduce the traffic, increase the density of turf by seeding and fertilizing and use a post-emergent broadleaf chemical to control it after it is done germinating.

But crabgrass is going to be germinating very very soon. Read more about it in this recent article. So get your pre-emergent down soon.

Newly germinated knotweed. Notice how the young stuff looks like a grass. But the older leaves on the left are more wide and look more like a traditional broadleaf weed.

Crabgrass Germination: Do I put down preventer now?

Rodney — Mon, 19 Mar 2012 20:36:09 +0000

With the unseasonably warm weather, we’ve been getting this question a lot lately. Crabgrass is an annual weed and must come back from seed each year. Since, crabgrass must germinate from seed each year, we can control crabgrass by applying a pre-emergent herbicide to the soil that will kill young germinating crabgrass seedlings. This is the step 1 of most 4 or 5 step lawncare programs. For the pre-emergent herbicide to be effective, it MUST be applied BEFORE the crabgrass seed germinates. (with one exception….Dimension, dithiopyr, has a little post-emergent activity, so it can be put down, right as the crabgrass is germinating and it will kill young, 1-2 leaf, crabgrass plants and prevent new ones from germinating.)

Environmental Cues

We often talk about using environmental cues to determine when is the best time to apply our pre-emergent herbicide. Typically, the time to apply pre-emergent herbicides is when the forsythia bush flowers or when the redbud tree blooms. During most years, I think the forsythia bush blooms fairly early in the spring. So I usually tell people when they see the forsythia blooming it is not too late, crabgrass has not germinated yet….but it is time to go get your preventer and get it applied soon.

Redbud in bloom

Forsythia bush in bloom

Soil Temperature

Another option is to use soil temperature. Crabgrass typically germinates when the soil temperature is between 57-64F at a one inch depth. K-State has a weather data library and many of the locations have soil temperature probes. You can check out the weather station at the Olathe Horticulture Research Center and you can see the soil temperature has been climbing over the last week from 57F to a high of just over 64F on Friday. To find the soil temperature at a station near you, go to the Weather Data Library. There is a report of soil temperatures for the last week in the left hand column, but it is at the 4″ depth. If you click on the first link, Kansas Weather & ET Data a map will appear. Click on the station on the map that is closest to you (or use the drop down menu, top-right). Choose your date range, and place a check mark in the 2″ soil temperature check box. Hit the Submit Query and your report will pop up.

So What To Do This Year?

I haven’t looked at all the weather stations around KS, but I’m gonna guess that now is the time that everyone should be getting their pre-emergent down. Yes it is about 2 weeks earlier than the average year. And I’m not a weather man, it could get really cold soon and stay cold, but it might not. So I would get your Step 1, your pre-emergent down on your lawn now.

Spring Seeding?

Remember, crabgrass preventers also kill turfgrass seedlings. So if you are going to seed, recently seeded, or if you dormant seeded DO NOT apply crabgrass preventers.

Which Ones?

There are a variety of pre-emergent chemicals on the market and most of them work. But in our tests at KSU and most of the research I’ve read, Dimension (dithiopyr) and Barricade (prodiamine) consistently provide the best control of crabgrass.

Weather Station at Olathe Center

UPDATE:

Like I said above, I’m not a meteorologist, but according to NOAA it looks like the next 6-10 days and the next 30 days are going to be above the average temperature for this time of year. So I still stand by my recommendation to get you Pre-emergent on now.

Time to think about pine diseases

Megan Kennelly — Mon, 19 Mar 2012 15:17:08 +0000

Got dead pines? Cut ‘em down! And, chip or burn ASAP (by April 1 if possible). Don’t leave stumps or logs.

In the eastern half of Kansas, if you have a completely dead pine, it’s best to assume that you have pine wilt. And, even in the western half, there’s really no reason NOT to cut and destroy dead pines. We do get sporadic pine wilt infections there. When in doubt, you can send a sample for testing.

We did lose a lot of pines last year due to heat/drought alone, with no pine wilt involved. BUT, to be on the safe side, if the tree is totally dead, it could be pine wilt. You might as well cut and destroy.

But, don’t forget that there are several other diseases of pines. If you have pine tip blight or Dothistroma needle cast and you plan to use fungicides, you should be thinking about those diseases fairly soon, too.

For an overview of pine diseases in Kansas, how to diagnose them, and how to manage them, check out this website:

http://www.ksre.ksu.edu/library/plant2/l722.pdf

Wild Garlic, Wild Onion and Star-of-Bethlehem

Rodney — Thu, 08 Mar 2012 18:20:59 +0000

Ward Upham from the Hort Rapid Response Center had a great article in the Horticulture Newsletter. I’ve posted a copy of the article below.

Wild garlic (Allium vineale) and wild onion (Allium canadense) are two closely related plants that can become weed problems in home lawns and landscapes. Though wild garlic and wild onion look much alike, each has an odor that is characterized by its name – wild garlic smells like garlic and wild onion smells like onion. These plants are perennials that can also reproduce by seeds and aerial bulbils. Bulbils form at the top of the stem and are oval and smooth. Wild garlic also reproduces by underground bulb offsets, but wild

onion does not. Both species produce a clump of plants that is unsightly in a lawn. Control recommendations are the same though we now have a couple of new additions to our arsenal.

Traditionally we have used 2,4-D or 2,4-D + MCPP + Dicamba (i.e., Trimec, Weed-Out, Weed-B-Gon). These products should be sprayed during March on a day that is at least 50 degrees. Newer products are Weed Free Zone and Speed Zone. Both are combination products that contain a formulation of Trimec plus carfentrazone. These are more active at temperatures near 50 degrees, which is lower than traditional products. A spreader-sticker added to the spray should help any of these products be more effective. At times, the spreader-sticker is already mixed into the weed killer; no additional amount is needed. These herbicides are also effective on dandelions.

Unfortunately, we have not had a good chemical control for star-of-Bethlehem in the past. That is now changing. A study from the University of Tennessee showed that Dismiss (sulfentrazone) gave excellent control of Star-of-Bethlehem with a single application. Other products with sulfentrazone such as Q-4 and Surge may need repeat applications. On the homeowner side, Spectracide Weed Stop 2X contains sulfentrazone but will require repeat applications.

Another second study from Virginia Tech showed 96% control of star-of-Bethlehem one month after treatment by using Quicksilver, a formulation of carfentrazone at the rate of 4 fl. oz per acre. Quicksilver is a commercial only product, and therefore is not available to homeowners. However, both Speed Zone and Weed Free Zone contain carfentrazone and may have activity. Remember to add a spreader-sticker. (WU)

RetailWorks – Spring training for garden centers

Megan Kennelly — Thu, 12 Jan 2012 22:16:47 +0000

KSU is presenting a workshop for garden center managers and employees on Friday, February 17. For full details, visit http://www.hfrr.ksu.edu/p.aspx?tabid=1030

Friday, February 17

8:00-8:25 Registration and coffee

8:25 Opening Comments

8:30-10:00 How Growers and Grower Retailers Can Utilize Their Websites to Increase Profitability — Timothy Howard

10:00-10:45 2011 Horticultural Odyssey: What Worked and What Didn’t — Jason Griffin

10:45-11:00 Break with refreshments

11:00-12:00 Who Will Take Care of the Nursery When I’m Gone? — Gregg Hadley

12:00-1:00 p.m. Lunch

1:00-1:45 Rock Solid Perennials and Shrubs for Kansas — Eric George

1:45-2:15 How to Distinguish your Independent Garden Center from the Big Box Stores — Barbara Meyer

2:15-2:45 Creating Cost Effective Signage for Your Garden Center — Timothy Howard

2:45-3:00 Break with refreshments

3:00-4:00 Bug-B-Gone: Pesticides and How They Kill Insect And Mite Pests - Raymond Cloyd

*Qualifies for pesticide recertification: 1 hr 3A (Ornamental) & hr 3B (Turf)

4:00-4:30 p.m. Growing Your Business with Social Media — Cheryl Boyer

Contact person:

Cheryl Boyer, crboyer@ksu.edu

Commercial grounds workshop in Manhattan, Feb 7

Megan Kennelly — Thu, 12 Jan 2012 22:07:02 +0000

K-State Research & Extension – Riley County is offering a commercial grounds maintenance program on Tuesday, February 7. Pesticide recertification hours are available for some of the presentations. For full details, go to http://www.riley.ksu.edu and on the right-hand side scroll down the list of events until you see this workshop. The full flyer is there, and a website for registration .

Time: 9:00 – 4:00

Location: Pottorf Hall, CiCo Park. 1710 Avery Avenue, Manhattan KS

Program:

9:00 am – Annual Flower Planting/Seasonal Care – Alan Stevens
10:15 am – Break
10:30 am – Landscape Irrigation Scheduling – Cathie Lavis
11:45 am – Lunch On Your Own
1:00 pm – Turf and Ornamental Disease Update** (1 credit each, 3A and 3B) – Megan Kennelly
2:00 pm – Pruning Shrubs – Gregg Eyestone
3:00 pm – Break
3:15 pm – Ornamental Insect Update* (1 credit 3A) – Bob Bauernfeind

Event organizer:

Gregg Eyestone
Riley County K-State Research & Extension
geyeston@ksu.edu
785-537-6350