CSU Plant Diagnostic Clinic

Insecticidal Soaps

2011-08-25T14:28:00.000-06:00

This past week in the Diagnostic Clinic, we received some photos of a Japanese Maple whose younger leaves were exhibiting curling at the edges. No insects were found and so the search began for the cause of the damage. As more information was forthcoming, it was also noted that the new buds on some of the blue spruces were turning brown as well. We also learned that a nearby plum tree had recently been sprayed with an insecticidal soap. Since the symptoms on the Japanese Maple and the Spruce were associated with new growth, not the older growth and no insects were found, it appeared that there was most likely an abiotic issue. So we did some research and discovered that insecticidal soaps can cause phytotoxicity damage to certain plants if sprayed at the wrong time, and that newer growth on Japanese Maple is extremely susceptible to damage from insecticidal soaps. An excellent fact sheet from Cornell University provided the information that we based our diagnosis on, which also indicated that if the insecticidal soap was applied when temperatures were above 90F, it could increase the incidence of phytotoxicity damage. The link for the fact sheet can be found at http://ccesuffolk.org/assets/Horticulture-Leaflets/Using-Insecticidal-Soap-In-Your-Home-Garden-Or-Landscape.pdf.

The take-home message from all this is that reading the label is important to make sure your plants won't be unnecessarily harmed by the use of any product.

Update from the Clinic...........

2011-07-08T16:36:00.000-06:00

This year we have seen a variety of diseases that usually don't happen frequently in Colorado. We have confirmed anthracnose on Ash from Aurora, and just this morning, found anthracnose on Oak here at the CSU campus. http://www.ext.colostate.edu/pubs/garden/02930.html is a link to the fact sheet on Sycamore Anthracnose, but control measures would be similar for Ash and Oak.

We are also seeing samples of Oak Leaf Blister on a regular basis this year. http://www.umassgreeninfo.org/fact_sheets/diseases/oak_leaf_blister.pdf is a fact sheet from U of Mass on oak leaf blister that shows some really nice pictures of the blisters on oak leaves. Older blisters can often be confused with anthracnose.

We are also still seeing effects of the prolonged fall/winter (2010-11) drought on trees and shrubs. Winter watering is critical in our area for survival of trees and shrubs. http://www.ext.colostate.edu/pubs/garden/02926.html is a fact sheet that talks about healthy trees and tree roots and provides insight on what can affect the growth of a tree via the roots.

There may be some residual effect of the cool temperatures in May and June on vegetable production in the home garden.  The coolness has pushed back fruit set on a lot of the warmer season vegetables, so be patient with your plants.

Lastly, there are a lot of aphids out there. A blog post from Gardening After Five has some recommendations on control, http://gardeningafterfive.wordpress.com/2011/07/08/year-of-the-aphid/.

Wheat Virus Survey......it's not too late!

2011-06-09T10:45:00.003-06:00

If you are a Colorado wheat grower and your wheat is looking a little yellow or sickly, we are offering again this year (at no charge to the grower/submitter) to test wheat samples for five different viruses (virus screen). We test for Cereal Yellow Dwarf Virus-rpv (CYDV-rpv), Barley Yellow Dwarf Virus-pav (BYDV-pav), High Plains Virus/Disease (HPV), Wheat Streak Mosaic Virus (WSMV) and Triticum Mosaic Virus (TriMV). It's not too late to submit your samples to the Diagnostic Clinic this season. Samples should contain at least 4-5 symptomatic plants so that we have enough leaf material to test. Information included with the sample should include location of the field, county, variety of wheat (if known) and contact information of the grower or submitter so that we can let you know what the results were. Our mailing address is Plant Diagnostic Clinic, E215 Plant Sciences Bldg, Colorado State University, Fort Collins, CO 80523-1177. If you would like to call and let us know a sample is on the way, our phone number is 970-491-6950.

Wind vs Tree.........

2011-06-07T10:01:00.001-06:00

Yesterday here in Fort Collins, about 3 p.m., we experienced a microburst wind event with a bit of rain. Didn't think too much of it, as this happens quite frequently as temperatures start to warm up and high and low pressure areas collide. However, it did some damage on campus. A mature linden tree, approximately 40 feet in height was apparently blown over by the wind. On closer inspection, it appears there may have been some pre-disposing factors that contributed to the demise of the tree. It looked like it was planted incorrectly and there was some butt rot involved. I'm posting photos of the trunk and the entire tree for you to decide.

Luckily no one was hurt nor was any property damaged, i.e. cars, etc. Above photo is of the complete fallen tree as taken from the east side of NESB.

Left photo: Looking southeast from NESB

Colorado Wheat Update

2011-06-06T10:34:00.000-06:00

The wet, cool weather most of the eastern part of the state experienced the past week or more was very conducive to stripe rust development. Yet, I still have not had any confirmation of stripe rust in the state. However, Dr. Bob Harveson, U. Nebraska reported stripe rust in an irrigated wheat field from western Scotts Bluff Co (south of Morrill). Therefore, it is entirely possible there are ‘hot spots’ of rust out there. If you have seen stripe rust, please email me with some images or send me some samples. The weather outlook for the next week isn’t that favorable for stripe rust development so I am hoping we are in the clear. Remember if you decide to make a fungicide application (which I am not advocating), make sure you follow the label concerning plant harvest intervals.

We have received a smattering of virus disease samples. Barley yellow dwarf is fairly common with some wheat streak mosaic. But we certainly don’t have the virus problems of some previous years.

Ned Tisserat

Extension Specialist and Professor

Wheat Disease Update from Oklahoma

2011-06-06T10:23:00.000-06:00

Wheat Disease Update –06-Jun-2011

Bob Hunger, Extension Wheat Pathologist

Department of Entomology & Plant Pathology

Oklahoma State University

Oklahoma: Harvest is occurring or starting across all of Oklahoma, so observations and reports of disease occurrence are about at an end. The only disease observations that have come to my attention are a number of samples from the OK panhandle that came into the diagnostic lab last week and tested positive for various combinations of wheat streak mosaic virus, wheat mosaic virus (high plains virus), Triticum mosaic virus, and barley yellow dwarf virus. This is similar to the panhandle of Texas where Dr. Jacob Price (Plant Pathology Research Associate, Texas AgriLife Research, Amarillo, TX) has reported that, “During this wheat season 214 samples were submitted to the GPDN diagnostic lab in Amarillo from counties in the northern Texas Panhandle. Of these, many were found to be infected with single and multiple infections of Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), Wheat mosaic virus (WMoV), and Barley yellow dwarf virus (BYDV). The most prevalent viruses found were WSMV and BYDV at 31 and 21%, respectively. Thirteen percent of samples were found to be infected with TriMV and of these samples 93% were also infected with WSMV, as has been seen in previous years. Only 4 and .01% of the samples were found to be infected with WMoV and CYDV, respectively. These results are similar to previous years.”

Clinic Update

2011-05-19T08:13:00.000-06:00

Since the weather has not been cooperating, we have not received many samples in the clinic so far this season. It's still pretty cool and moist. We have received several samples of turfgrass with Necrotic Ring Spot already this spring. As soon as soil temperatures start warming up, we expect to see more. Information on control can be found here: http://www.ext.colostate.edu/pubs/garden/02900.html. There are both cultural and chemical controls, but be advised that NRS is a difficult disease to cure.

We have also received a couple of samples of wheat with Tan Spot (Pyrenophora tritici-repentis). This disease can show up anytime April-June and appears as small brown, oval lesions with tan centers usually with a yellow halo around the lesion. It is always a good idea to get confirmation of this pathogen before deciding to spray as magnesium and chloride deficiencies can mimic tan spot. This disease overwinters in old wheat stubble and germinates in early spring after a prolonged wet period (usually 24 hours or more). Asexual spores are spread by wind and keep the disease cycle going, infecting new leaves. North Dakota State University has an excellent fact sheet on control measures that can be found at http://www.ag.ndsu.edu/pubs/plantsci/pests/pp1249w.htm.

With the recent moisture we can also expect to see Gymnosporangium rusts, most often Juniper-Hawthorn rusts. This disease will manifest first as orange, gelatinous masses on juniper causing some discomfort for homeowners. These brightly colored galls often look like some alien being has landed in the landscape. After they dry, the galls become dark brown and will stay on the junipers but will not generally harm the plant, only causing aesthetic damage. Cooperative Extension Plant Talk has a script on this disease that can be found at http://www.ext.colostate.edu/ptlk/1450.html.

Recently planted vegetables will be set back a bit with this cooler weather. Be patient with your landscape as the roots need some warm soil temps to really get your plants going.

ODC (tm): Is This "Stuff" for Real and How Does It Work?

2011-02-07T15:00:00.001-07:00

Originally posted 4.12.10, this post is from the Kansas State University Department of Entomology Newsletter, March 26, 2010 authored by Raymond A. Cloyd, Professor and Extension Specialist in Ornamental Entomology/Integrated Pest Management. Dr. Cloyd is affiliated with the Department of Entomology at KSU in Manhattan, KS.

The entire publication can be found at http://www.entomology.ksu.edu/DesktopDefault.aspx?tabid=756, look for issue #1, March 26, 2010.

"We have received numerous inquiries regarding the product Organic Disease Control or ODC (tm), and its supposed effectiveness against insects and diseases. This product contains chitosan (0.25%) as the active ingredient and is being marketed by AgriHouse, Inc., (Berthoud, CO) with claims that the product protects trees from attack by pine beetles and blue stain mold. First of all, it is important to discuss the characteristics of the active ingredient. Chitosan (poly-D-glucosamine) is a common polymer present in nature in the cell walls of certain fungi and insects, and the commercial formulation is prepared from chitin that is found in the shells of crustaceans (e.g., crabs and shrimps). Chitosan is supposed to enhance, stimulate, or boost the plants immune (or defense) response. Well, how does it do this? It has been proposed that chitosan is active on the octadecanoid pathway. What happens in this pathway is that linolenic acid is converted to jasmonic acid resulting in the transcriptional activation of genes associated with defense that "turns on" compounds and/or enzymes such as proteinase inhibitors and polyphenol oxidase. In other words, chitosan may elicit or activate plant defense responses. However, the mechanisms affiliated with this process are not clearly understood.

Currently, there is no quantitative information (based on scientific studies) on the efficacy of ODC (tm) against the mountain pine beetle (Dendroctonus ponderosae) in lodgepole or ponderosa pine. Furthermore, the publications (#672 and #5322) referred to in the in-house blog (http://agrihouse.wordpress.com/) do not contain any conclusive data to substantiate the claims being made associated with this product. In fact, one of the publications presented only one years' worth of data (1996) and did not even test for activity against bark beetles. Additionally, the methodology or procedures used (inoculation) are questionable. I have listed four publications at the end of this article that discuss the potential role of chitosan; however, none of these are studies that have conducted or include evaluations against wood-boring beetles."

Dr. Cloyd goes on to talk about the claims made regarding ODC (tm) and his questions to each of the claims. If you are interested in reading the rest of the article, I encourage you to click on the KSU link above to access the full story. The bottom line, according to Dr. Cloyd, is that "overall, this appears to be an example of an 'aggressive marketing' strategy, which may cause confusion among homeowners/consumers. As such, this supports the value of extension at land-grant universities because it is our responsibility as extension personnel to provide un-biased information to homeowners/consumers so they can make sound pest management decisions based on the results from 'sound' science.....not mis-information."

Good Advice on Winter Watering

2010-12-21T10:47:00.000-07:00

These articles come from two posts on another blog that I follow, and I thought I would post them here as well. Along the Front Range, we are in a moderate to severe drought, depending on where you live. With no appreciable moisture since the end of July, it's a challenge to keep our plants healthy. Winter watering can help. Check out these posts on Gardening After Five.

http://gardeningafterfive.wordpress.com/2010/12/14/give-your-trees-a-drink/

http://gardeningafterfive.wordpress.com/2010/12/20/winter-water-is-for-lawns-too/

Updated MPB Information

2010-11-18T11:47:00.000-07:00

I thought a recent post by Dave Leatherman, retired CSFS Entomologist, regarding Mountain Pine Beetle would be beneficial as an update on the behavior of the beetle along the Front Range and questions we are receiving regarding when to spray.

"If less than a full compliment of beetles hits an urban tree (i.e. an 'unsuccessful' attack from the viewpoint of the beetle), two patterns have been common the last several years:
1. a band of pitch tubes at mid-trunk, with very few on the basal and upper parts of the trunk, or
  2. a gradation of pitch tubes, heaviest at the base, fizzling out about 10 feet above the ground.

The great, great majority of such trees survive, at least the initial attack. These sorts of trees, however, do seem prone to re-attack, sometimes later in the same season, sometimes the following summer. If the trees have high value, rigorous inspection to determine the success of the attack is in order. IF the tree will not die from the attack in question, preventive spraying is warranted. The historical spray timetables have become problematic and spraying anytime during the April to early November period might be warranted, depending on the specific circumstances and wishes of the consumer.

Three things seem clear: 1) the flight season of the beetle is not just late July thru early August anymore (more like April thru early November, with two peaks, one in July-early Aug, and the other mid Oct-early Nov), 2) with the flying beetle population being diluted at any one time over a period of month, successful attacks resulting from a single attack are fairly rare among urban trees, and 3) foliage fading in relation to when observers first see pitch tubes is all out of whack.

For urban areas in CO, NE, and WY and the MPB attacked trees I have seen of late, the following statements apply:

The hosts are overwhelmingly either Scots or Ponderosa pine, the pitch tubes are often large and 'runny' (as would be characteristic of unsuccessful, 'pitch-out' type tubes);
IF the attacked trees die, they didn't die of a single attack; most attacked trees display pitch tubes of varying hardness (indicating initial and later attacks);
IF the attacks are successful and result in a big emergence of beetles, the trees are usually still green-needled (at least not obviously brown) when this occurs;
Emergence is usually in October or November (but sometimes 'on schedule' in July-August);
Relying solely on external evidence is more dangerous than ever because of the above;
A hatchet/under-bark-peek is more needed than ever to make a proper diagnosis (and because of the preponderance of strip attacks, looking under the bark on more than one side of the tree is a wise move).

In urban areas, assuming the trees are of suitable diameter (6 inches or more at breast height), I would put pines into three categores: Likely to be attacked, sometimes attacked, and rarely attacked. The likely to be attacked pines are Scots, Ponderosa and Lodgepole. The sometimes attacked would be Limber and Bristlecone. The rarely attacked pines are Austrian, Mugo, Pinyon, Spruce and other pines."

Another Tree Problem

2010-10-14T10:14:00.000-06:00

Dr. Ned Tisserat, Extension Plant Pathologist, was asked by the city forester in Boulder to come take a look at some Red Oak trees that were declining in one of the parks in the city. The symptoms are branch dieback with borer holes in the trunks of the trees. After further investigation, it appears that the branch dieback may be associated with Kermes scale, but the borer holes in the trunk caused by a flat-headed borer were unusual. Dr. Tisserat isolated Fusarium solani from an area surrounding the borer galleries, but also noticed a gummosis on the branches. This gummosis was in close proximity to the Kermes scale. Isolations were done and the gummosis was the result of a bacteria which was identified as Brenneria (Erwinia) quercina. This bacterium has been previously associated with 'Drippy Nuts Disease' on oaks in California and with an oak decline in Europe. More investigation is needed to understand if the Kermes scale is contributing to the bacterial infection, where the bacterium is originating from and how the flat-headed borer is involved in the infection process, if at all.

Tomato/Potato Psyllid

2010-09-07T14:52:00.000-06:00

This year along the Front Range of Colorado has been devastating for fresh market potato producers and home gardeners alike. The culprit this year is an insect, the tomato/potato psyllid, which comes to us courtesy of the southern states and Mexico. They arrive via the southerly air currents that bring us other pathogens like wheat rust. This insect injects a toxic saliva into the plant that causes the potato to turn yellow with curled leaves. Potatoes are smaller or non-existent, reducing harvest yields considerably. Dr, Whitney Cranshaw, CSU Extension Entomologist, was interviewed recently by 9News reporter Adam Chodak. The video link is attached.
http://www.9news.com/video/default.aspx?bctid=603977271001

Update on Thousand Cankers Disease

2010-08-03T11:38:00.000-06:00

The following is an excerpt from an email sent to several listservs by Whitney Cranshaw regarding a new confirmation of Thousand Cankers Disease in Tennessee.
"Thousand cankers disease of walnut has been confirmed from Tennessee. This was first identified about 10 days ago with a sample we received from Knoxville, but a formal announcement has been pending per the Tennessee Department of Agriculture's wish to delay announcement for further confirmations. As this has been done, and I see an AP report on the internet, I think that we can now let it be generally known.

The known infestation is in and around Knoxville. As this is a fairly recent find, the extent of the infestation has not been delimited. But the extent of the infestation suggests that this disease (i.e., the walnut twig beetle and its associated fungus, Geosmithia morbida) has been there for a decade or more.

This is a disaster of tremendous proportion. It had been my deepest hope - clearly a naive hope - that this problem would stay bottled up in the western states where black walnut, Juglans nigra, is planted but not native. I had long ago given up that black walnut would survive in the West and that is a sad situation, but not tragic. Now that it is irrevocably established in the center of the native distribution of Juglans nigra, there are no geographic/ecological barriers to prevent its ultimate spread throughout the US. Furthermore, the fact that the disease appears to be progressing as a lethal tree killer in Tennessee as it has been doing for 10-20 years in the Rocky Mountain States answers the question as to whether this is a regional problem.

It also suggests that there may well be many other infestations in the Midwest that have gone undetected. This is a very difficult disease to detect in early stages. Apparently in Tennessee, as in our area, what attracted attention were plantings that showed symptoms of apparent drought stress. But it is not drought stress nor related to drought. For some help with this situation we have a web site: http://www.colostate.edu/Depts/bspm/extension%20and%20outreach/thousand%20cankers.html. There are sheets on diagnosis, Q & A, and a fact sheet (that needs a bit of updating). Also available are links to pictures and powerpoint talks, including the version of "Nightmare on Walnut Street" that I presented at the ISA meeting last week in Chicago.

I am assuming that there will now be a scramble to have state quarantines become a reality. As I understand it, following Missouri's lead, that Nebraska, Kansas, Michigan and Indiana have or are in the process of enacting state quarantines that restrict movement of certain Juglans material that originates from TCD-affected states. And this disease is a deal breaker. It is relatively slow to develop, at least compared to DED or EAB, but its progress will be inexorable. My guesstimate from watching it in urban settings is that about 30 years after this is introduced into a city, all the black walnuts will be dead. That is based on the disease taking 10-20 years to show symptoms after the initial point infestation and 10-15 years for it to progress across a city once the first symptomatic tree is detected. How this disease will progress where there are native stands affecting the epidemiology will undoubtably change things in ways we will all have the unfortunate chance to see in the upcoming years.

However, containment/slow the spread is still something we need to throw ourselves into. The longer you can delay the introduction of the disease (by movement of fungus contaminated walnut twig beetles), the longer your black walnuts can survive. Perhaps with dedicated effort we can push back the ultimate effects of this disaster for a generation or two in many areas, giving us valuable time to develop means of managing it and finding resistant cultivars."

Posted by Whitney Cranshaw, 8.2.2010

Wheat Virus Survey Results

2010-08-03T10:51:00.002-06:00

Since wheat harvest is now finished and we are headed into corn season, I thought I would share the general results of the wheat virus survey. In this survey we test for five known wheat-infecting viruses, Cereal Yellow Dwarf Virus (CYDV, formerly known as BYDV-rpv), Barley Yellow Dwarf Virus (BYDV-pav), High Plains Virus (HPV), Wheat Streak Mosaic Virus (WSMV), and Triticum Mosaic Virus (TriMV). A total of 368 ELISA's (enzyme-linked immunosorbent assay) were performed in the diagnostic clinic. Of all the ELISA's run, 252 of these were for the wheat breeding program. There were a total of 116 wheat samples sent in to the clinic from growers, extension agents and crop consultants. The results of those 116 samples were 79 virus positive and 37 virus negative. The results reported here are the compilation of the 79 virus positive wheat samples from growers and do not include the results of the wheat breeding program.

39 samples had single virus infections; the sample was positive for only one of the five viruses tested.

CYDV (3 positives)
BYDV-pav (13 positives)
HPV (6 positives)
WSMV (14 positives)
TriMV (3 positives)

40 samples had co-infections; meaning the sample was positive for two or more of the viruses tested.

32 samples were co-infected with 2 viruses
7 samples were co-infected with 3 viruses
one sample was co-infected with 4 viruses
there were no samples that tested positive for all five viruses

Of the 32 samples that were positive for two viruses, 17 of those samples were positive for WSMV and TriMV.

Overall, WSMV is still the number one wheat virus in our state, either singly or co-infected with other viruses.

Summer Reminder--Don't Move Firewood

2010-05-27T09:23:00.000-06:00

Yesterday a news release was sent out from the Colorado Department of Agriculture reminding folks who are planning to go camping not to take firewood with them, but instead to 'Buy It Where You Burn It'. The concern is that insects and diseases can be transported by moving wood from different parts of the country and even within the state.

The complete article can be found at http://www.colorado.gov/cs/Satellite?blobcol=urldata&blobheader=text%2Fhtml&blobkey=id&blobtable=MungoBlobs&blobwhere=1251632560946&ssbinary=true.

More Stripe Rust News

2010-05-26T11:03:00.000-06:00

This morning we received information that stripe rust has been confirmed in the southern panhandle of Nebraska. It was found in two fields south of Chappell, NE located in Deuel County. One field was irrigated and the other field was dryland. The irrigated wheat was in the boot stage and the dryland wheat had the flag leaf emerging. This information was provided by Drew Lyon at the Panhandle Research and Extension Center in Scottsbluff, NE.

So what does this mean for Colorado growers? If we have another round of cool, wet weather, the impact of stripe rust could be severe. We are already receiving spotty reports from the Northeast area of CO as well as western Kansas and with this new information, chances are it is in the NE part of the state. If the temperatures warm up and we start drying out, we may not see much stripe rust, but Mother Nature never was very good about letting us know her intentions. As far as we know, the stripe rust resistance in varieties such as Bill Brown, Hatcher, Hawken, Infinity CL, Snowmass, TAM 111, Thunder CL, Winterhawk, Yuma/Yumar is still holding. There is mounting evidence that the resistance in Jagger, Jagalene and derivatives of these varieties may have been broken.

Stripe Rust is in Colorado!

2010-05-21T10:28:00.000-06:00

Posted by Ned Tisserat and Scott Haley on the Cereal Rust Survey listserv: Multiple observations of stripe rust on wheat have now been made in Eastern Colorado. We just received three samples in the Diagnostic Clinic yesterday that confirms these observations. Infections thus far are most prevalent in the southeast part of the state but it appears to be moving north as would be expected. Infections at this point appear to be at low levels, but good moisture and continued moderate temperatures may promote its continued development. Wheat in SE Colorado is mostly a few days either way of the heading growth stage. If you are out scouting fields and find rust, we would like to have samples sent to the Diagnostic Clinic so we can forward them to WSU for race typing.

Some Insect-Issue Thoughts and Predictions

2010-05-21T10:21:00.002-06:00

Whitney Cranshaw, CSU Entomologist/Extension Specialist is providing his thoughts on insect issues that we may or may not see this summer:

"This part of the state has had quite a spell of unusual weather. Last fall we had a severe cold snap on October 13 and a very cool winter, often with some snow cover. It has been above average with moisture, continuing the trend of last summer, and this spring has been very cool, with everything delayed. Based on those conditions and some other things, I am going to guess on a couple of insect related events."

Yellowjackets: Down. The cold, wet spring is going to have the colonies get off to a slow start. Furthermore last year wasn't great for them and the winter may have knocked out some queens.

Honey Bees. Very rough start. Late summer/early fall conditions were poor for setting up winter stores that allow colonies to survive winter. Then this spring was late with bloom. We now have abundant blooming, but weather is usually too cool for foraging. Altogether this has to be very stressful for colonies and I suspect many starved out.

European mantids (aka 'praying mantid'). Down. At least around here this is a marginally adapted insect. It tends to be abundant in seasons when the previous winter was mild. Last winter was not and I suspect that many of the eggs were killed.

Tobacco budworm. Down. Another marginally adapted insect that will freeze out if the overwintering pupae freeze. Last winter there was a lot of deep soil freezing, which should have dinged the populations.

Squash bugs, Striped cucumber beetles. Down. At least around here these also are marginally adapted insects. They tend to be abundant in seasons when the previous winter was mild. Last winter was not and I suspect that the overwintering adult stages of both of these had above average mortality.

Mites on lawns. Way down. Good winter moisture in many places made clover mites a minor issue this year.

Miller moths. Down. Low numbers were present last year and few eggs likely were laid in fall. There have been no reports of cutworms active in crops yet, further suggesting that the insect numbers are low. Plus, with all the moisture there will be abundant flowering of native plants which will provide an abundance of nectar sources for the moths; they will not aggregate around landscape plantings as occurs in drought years. Flights will be later than normal, below normal in total number of moths, and will be dispersed so people will not notice them as serious nuisance pests.

Aphids on trees and shrubs. Up. Cool, wet springs usually signal prolonged, heavier activity of many aphids at least until the end of June when natural enemies (e.g. lady beetles) come roaring back.

Slugs. Up. Last season was a building year. They should be in great shape heading into the 2010 season.

Isn't Spring in Colorado Wonderful?

2010-05-12T10:05:00.002-06:00

Wow! It's May 12th and in a normal environment we would be admiring bedding plants placed around the patio and watching our vegetable transplants slowly acclimate to their new surroundings in your garden. But we live in Colorado where spring snowstorms seem to come out of nowhere and all of a sudden our gardens and landscapes are turned into 'plantsicles' under the weight of the snow. Driving into the CSU campus this morning I noticed that the damage on the west side of Fort Collins appears to be worse than the central or east side of town, although there is still plenty of damage to see.

I did make a few observations this morning on the damage that has occured:

The trees that are damaged most heavily appear to be trees that are in full flower (crabapples especially seemed hard hit) or fully leafed out.
Trees with a spreading habit rather than upright also seem to be harder hit.
Trees that have not fully leafed out, such as Lindens, appear to have very little to no limb breakage.
Trees with a pyramidal shape (some of the ornamental pears, etc.) also appear to have very little to no limb breakage.

The recommendation would be to get out and inspect your landscape as soon as feasible for any signs of breakage or damage. http://www.ext.colostate.edu/mg/gardennotes/616-MatureTrees.html will provide information on when and how to prune trees, if needed, as well as providing information on when or if there is a need to hire a certified professional arborist. Here on campus this morning, the tree crews were already out pruning trees and cleaning up fallen branches. The road around the Oval was closed to traffic to allow crews to get the job done. The elms around campus have really taken a beating this season with the early fall snowstorm and now the late spring snowstorm. Hopefully all the damaged trees will survive in good shape. As always, if you have any questions, you can contact the Plant Diagnostic Clinic at CSU or contact your local County Extension Office for more information.

Official CSU Protocol on Medical Marijuana

2010-03-25T09:38:00.009-06:00

There has been much discussion between Extension Agents, Specialists and Diagnosticians regarding diagnosis of disease or insect problems related to medical marijuana. The following protocol has been vetted by CSU Legal Counsel and Extension Administration:

The General Counsel's staff at Colorado State University has informed CSU Extension of the following in regards to medical marijuana. These restrictions apply to all CSU Extension staff members to include Master Gardener Volunteers.

1. While the use of medical marijuana is legal in the state of Colorado, marijuana remains a schedule 1 illegal drug under Federal law and as such, Colorado State University Extension cannot be involved with this item.

a. Assistance with medical marijuana plant health questions will not be provided.
b. Individuals requesting such information will not be provided referral information.

2. Our offices are considered drug free workplaces as CSU is a Federal contractor.

a. Marijuana plants and/or plant parts are not permitted in CSU Extension offices.
b. Marijuana plants or plant parts delivered to or left at CSU Extension offices will be turned over to legal authorities for destruction.

3. If CSU Extension employees or volunteers (including Master Gardeners) assist medical marijuana growers, they will be acting outside the scope of their employee/volunteer role and assume personal liability for any legal action that may be taken against them.

Based on this information from General Counsel, the Plant Diagnostic Clinic will not accept marijuana plants for diagnosis, nor can we offer assistant via phone or email.

CSFS Talking Points on ODC

2010-03-25T08:59:00.009-06:00

Here in the clinic, we've received several phone calls regarding the effectiveness of a product on the market called Organic Disease Control or ODC. The product is a colloidal chitosan which states that it will increase resin production in trees to help reduce attacks by Mountain Pine Beetle. Sky Stephens, Colorado State Forest Service Entomologist, has provided talking points regarding this product. To date, no testing has been done to determine the impacts of Agrihouse ODC on mountain pine beetle in lodgepole or ponderosa pine. One point from the information provided is that until specific testing is done to determine the impacts of ODC on mountain pine beetle, CSFS encourages landowners to use well-tested products with a proven track record to protect important pine trees on their land.

CSFS Talking Points Regarding ODC (pdf)

Pine Wilt Nematode and Mountain Pine Beetle Along the Front Range: Is There a Connection?

2010-02-15T09:42:00.000-07:00

We've received several samples in the Diagnostic Clinic this month of Scots pine that have been hit with Mountain Pine Beetle (MPB) from areas along the front range and one of those samples also had Pine Wilt Nematode (PWN) (Bursaphelenchus spp.). So we are asking ourselves, which came first, MPB or PWN? And, is one exacerbating the other? To see if we can answer this question, we are collecting samples of MPB hit Scots pine that are being cut down in counties along the Front Range to process for PWN to see if there is any correlation. The specific counties we would like samples from are Larimer, Weld, Boulder, Adams, Jefferson, Denver, Arapahoe and Douglas. The samples should be from trees no higher than 6000 ft elevation. The samples should be collected from branch areas closest to the trunk and should be no more than 3 inches in diameter and about 6-8 inches in length. Samples will be processed at no charge to the submitter. Samples should also be sent within 1-2 days of the tree being cut down. Samples can be sent to the Plant Diagnostic Clinic, E215 Plant Sciences Bldg, Colorado State University, Fort Collins, CO 80523-1177. If you have any questions, feel free to call us at 970-491-6950.

Dr. Tisserat's Turf Presentation at ProGreen

2010-02-09T19:05:00.000-07:00

Dr. Tisserat's ProGreen presentation on common turfgrass diseases and their control. If you weren't able to make it to ProGreen or just want an extra copy, the presentation is in PDF format and the link is below.

ProGreen Turfgrass 2010 Presentation

Answering Questions About Spraying for MPB and Other Bark Beetles

2010-01-29T13:24:00.000-07:00

I've fielded several phone calls this week regarding Mountain Pine Beetle/Ips Beetle and whether homeowner trees in the urban areas should be sprayed for prevention of MPB/Ips attacks. I asked Fort Collins Assistant City Forester Ralph Zentz, and his reply is as follows:

"In the Front Range urban areas, the main host is still Scotch/Scots Pine (about 80% or more). Austrian pines are rarely hit and I have not seen or heard of any othe them being killed by MPB in any of the communities. Ponderosa is the second most hit species of pine in our cities, but lodgepole, pinyon, bristlecone, eastern white pine and others have been hit as well. Mortality in scotch pine runs about 10% when they are hit; the same is true for Ponderosa.

In the foothills and mountains of the Front Range, the MPB population is building in the native Ponderosa according to Dave Leatherman, Entomologist, formerly with CSFS.

Spraying should occur prior to May, however there may be a few earlier flights, but (in my opinion) not enough to warrant earlier spraying. It is critical that people realize that just because a tree is hit, it does not mean it will be killed from the pest. 10% or less mortality is reported from all the communities from Colorado Springs north to Fort Collins."

In a previous blog posting, there is a link to 'Mountain Pine Beetle Information' from October 30, 2009 that provides the most recent information compiled by the Colorado State Forest Service and Colorado State Extension. Scroll down to the date and the link is at the end of the posting.

The links to fact sheets from CSU Extension on MPB and Ips/Engraver Beetles are posted here. These sheet should also provide information for concerned homeowners.
http://www.ext.colostate.edu/pubs/insect/05558.html
http://www.ext.colostate.edu/pubs/insect/05528.html

As always you can call the Plant Diagnostic Clinic with your questions, or contact your local County Extension office for the latest information.

New Colorado Dept. of Agriculture Regulations on Japanese Beetle

2010-01-04T10:56:00.000-07:00

Colorado Department of Agriculture is instituting new regulations for the importation of plant material into Colorado that will protect Colorado by reducing the introduction of Japanese Beetle into the state. These regulations will take effect on January 1, 2010. Links to the regulations, a presentation to Extension Horticulture Agents and Best Management Strategies for Control of Japanese Beetle are at the end of this post. These new regulations have no effect on what growers can ship out of Colorado. These regulations only affect plant material (which includes, among other items, soil, compost, manure, and grass sod) imported into Colorado from states east of Colorado. Any questions regarding these new regulations can be directed to Laura Pottorff, Colorado Department of Agriculture, Nursery Program Manager, 303-239-4153.

Best Management Strategies (PDF)
Presentation to Extension Horticulture Agents (PDF)
CDA Regulations effective 1.1.2010 (PDF)

Wishing Everyone.............

2009-12-22T11:50:00.000-07:00

Happy Holidays and a Joyous and Prosperous New Year.

Corn Ear Mold Update

2009-11-09T10:08:00.000-07:00

I just wanted to provide an update on corn ear molds. We are getting a lot of questions here in the clinic regarding Fusarium and the potential for mycotoxins. We are seeing Fusarium on corn, but whether or not it will lead to mycotoxins is debatable. The information we are gathering says it depends on the moisture content of the corn going into storage. Amy Ziems, Diagnostician from the University of Nebraska, has posted the following to our GPDN listserv: "In Nebraska we are experiencing a tremendous amount of grain mold. Currently the harvest is approximately 3 weeks behind due to all the wet weather we have been experiencing the past 2 months also majority of the corn in the field is testing between 18-40% moisture. In the lab we have been seeing a few of the common ear molds such as Diplodia and Fusarium ear rots, however we are seeing a lot of corn with green/black sporulation on the ears and cobs. The green/black sporulation is a combination of several different saprophytic fungi including Alternaria, Pithyomces and Ulocladium. Attached are a couple of photos of the "moldy" corn. Our current recommendation here is dry the corn below 15% within 24 hrs after harvest prior to storage. We are feeling that these fungi have the potential to cause some major damage during storage if the moisture levels are not dropped significantly. We are also receiving a lot of questions regarding mycotoxin testing with the fusarium ear molds being detected." Amy has also provided a list of companies that do mycotoxin testing. If you are interested in having your corn tested, please feel free to contact me at the diagnostic clinic and I will be happy to provide you with the list or I can direct your sample to the nearest lab for you.

Additionally, Tamra Jackson, Extension Plant Pathologist & Corn Specialist at UNL, has posted a video talking about corn ear molds as well as a newsletter explaining corn ear molds. The video can be viewed at http://marketjournal.unl.edu/103009, scroll down to corn ear mold/Tamra Jackson to view the specific video. The newsletter can be found at http://cropwatch.unl.edu/web/cropwatch/archive?articleID=1904835.

Updated Mountain Pine Beetle Information

2009-10-30T10:18:00.000-06:00

Irene Shonle, Director of Gilpin County Extension, in cooperation with the Northern Front Range Mountain Pine Beetle Working Group, has just put together a 12-page newspaper-style publication on mountain pine beetle (MPB). It is a pretty thorough, up-to-date document on what homeowners can do with infested trees. It also includes information on the likely transition to the Ponderosa Pine zone and how treatment options should differ in lodgepole and ponderosa. The contact information contained in the document is specific to the Front Range of Colorado, but the rest of the document is applicable anywhere.
If you are a home- or land-owner in an area that is being affected by MPB, this publication will provide the best research-based information available. The link below will open up a PDF file with the document that can be printed or saved to your own computer for future reference.

Mountain Pine Beetle Infomation (PDF)

Update on 2008 wheat virus survey

2009-10-26T08:47:00.000-06:00

Last week, the blog mentioned the wheat virus survey from 2008. http://www.apsnet.org/online/feature/virus/ is the url for the entire article, but I thought I would post a bit of the pertinent data here. "A total of 754 wheat samples were collected in the nine Great Plains states during the 2008 survey (Table 1). Due to various factors a small number of the samples were not tested for all five viruses. Therefore, results were standardized and presented as the percentage of the plant samples tested for each virus. The number of samples from each state varied from 21 to 307 (Table 1). The predominant virus detected in each state was WSMV, and this virus was detected in 47% of the plant samples (Table 1). WMoV (19%) and TriMV (17%) were the second and third most commonly detected viruses (Table 1). The aphid-transmitted viruses BYDV-PAV (7%) and CYDV-RPV (2%) were infrequently detected compared to the mite-transmitted viruses. Co-infection of a single plant by WSMV plus WMoV (13%) or WSMV plus TriMV (13%) was the most common co-infection detected. Five percent of samples were co-infected by all three mite-transmitted viruses and only 0.4% of samples were co-infected by both aphid-transmitted viruses." The table referenced is available at the url previously listed. Hopefully by next spring, we should have the data from 2009 compiled and ready for publication.

New Service at the Diagnostic Clinic

For all those interested in having plants or soil tested for herbicide damage, I have found a lab that can test for almost any type of chemistry. The one thing needed is that we need to know what chemistry to test for as they don't have a 'chemical screen'. It is rather expensive for this testing (and they only test for one chemistry at a time), but if you or your client needs this information, it may be worth the cost in order to have a definitive answer. Here at the diagnostic clinic, we can ship your sample to the testing lab, invoice you or your client for the cost of testing and shipping and forward the report(s) to either you or your client.

If you have any comments or would like answers to frequently asked questions, please feel free to leave a message. We'll try to get you an answer.

2009-10-19T13:08:00.000-06:00

Hi! Welcome to the newly created CSU Plant Diagnostic Clinic blog. In an attempt to use more of the available technology to increase our visibility and to keep folks informed about old and new plant problems, we have created a blog. Our hope is that we will be able to post about once a week or so on diseases/insects that we are seeing in the clinic as well as new information that may be of use to our clients.

This time of year is generally considered our slow time so we are slowly catching up on data entry and getting ready for our winter fungicide trials. Again this year we will be actively seeking participants for our winter wheat virus survey. Growers, extension agents, and crop consultants are encouraged to send symptomatic plant material to the Plant Diagnostic Clinic for free virus screening. The viruses we are screening for are WSMV, CYDV, BYDV-pav, WMV (formerly HPV) and TriMV. If you have a request for any other virus testing be sure to let us know and we can probably accommodate that request. As always, we appreciate any information that you can send us with the samples (location, variety, name of submitter, etc.). The data from the 2008 growing season was compiled by Mary Burrows at Montana State University and published in Plant Health Progress. Mary is again compiling the data for the 2009 growing season and will be publishing the results soon. Your help in providing samples for testing is appreciated.