Recently, I tasked a student worker (C. Richards) to put together some videos with the following goals in mind: (1) Tell people what we do in less than 2 minutes, and (2) highlight some of the stuff that we would like to see from folks who submit samples (i.e.. how to sample or how to package).  I am glad to present the debut of Crime and Pathogen – enjoy… [ somehow I just get this "bad boys....what you gonna do when we come from you..." song out of my head when I see this].  I hope that more video project will follow along soon.

Click here to view the embedded video.

A CG infected tree and I. Notice the light green/yellow branch and the size of that tree in comparison with the one next to it.

A week ago I was sitting in meetings in Florida.  This was a trip with other researchers, extension personnel and citrus growers from Texas to the University of Florida Citrus Research & Extension Center in Lake Alfred.  The discussion included various lesson learned from the situation in Florida.  These information were shared by their research, extension personnel and the Florida citrus growers.  Their situation was unique in that Citrus Greening (CG) first hit Florida in 2005.  At that time, they did not know much about the disease and how it would affect the orange tree, nor did they know of good effective management methods.

Some of the lessons learned there has helped Texas to stave off the disease a little longer such as the importance of insect vector (Asian Citrus Psyllid) management by area-wide spray program.  Texas AgriLife Extension Service has also been busy around the state educating volunteers and the general public to this disease, soliciting help to detect this problem early and to understand  the need to not “import” plants from affected states such as Florida. Now that CG is in Texas, what next?  It was interesting to note that the Floridians encouraged continued vigilance for early detection and aggressiveness in response.  Essentially two possible responses to go along with an aggressive psyllid spray program: (1) Rogue/destroy infected plant as soon as they are identified or (2)Nutritional therapy – where management and delivery so nutrients to the plant can help the tree to continue to produce (even in the presence of the bacterial causal agent).

So what now?  What do we need to do now that the disease is in Texas?

Affected trees (7 year old) in a relatively new grove. Note the fruit drop and sparse foliage. What you might not have realized is that the tree should be 2-3 time that size. Admission by the grower that they did not act until 30% of the groove was affected. By then it was more difficult to limit and manage the problem.

The situation currently is that Texas Department of Agriculture placed an emergency quarantine zone of 5-mile radius from the “hot spot”.  This is a small area when you consider how big Texas is.  Texas Citrus growers in the Rio Grande Valley (RGV) are participating in area-wide spray to stop movement of the psyllids. Texas AgriLife Extension Service agents and volunteers there are busy trying to get the word out to homeowners and encourage them to treat their backyard citrus plants as well.  A spray program is only effective when you limit (or eliminate) any sanctuary for the insect vector.  Furthermore, all of us who have a citrus bearing plant or two in our backyard do WANT fruit.  This disease can and usually will result in fruit drop and eventual plant death. The scary part is that a homeowner may lose production in one or few trees in their backyard, but a commercial grower could potentially lose their livelihood.

Citrus Greening, aka Huanglongbing, disease is in Texas. It is still localized.  All of us in Texas still have important roles to play to ensure that this disease stays limited.  Preventative and proactive actions seems natural to those in the commercial citrus growing area of this state. For the rest of us, it is still important to keep our eyes open for possible symptoms. Still, do not “import”   citrus plants from affected states such as Florida and Louisiana, AND the quarantine part of Texas (Hidalgo county).  Beside it is against the law – there is a Federal Order against the movement of plant material from quarantined states.  It may be obvious that this problem is of more importance in parts of east Texas and the gulf coast where citrus can be grown.  But all of us in Texas can participate in keeping our citrus safe.

A characteristic foliar symptom caused by CG on orange tree is leaf mottling that is uneven. Note the lack of symmetry (one side of the midrib is different from the other) in the damage on this leaf.

If you do see or suspect Citrus Greening, please contact Texas Department of Agriculture or your local AgriLife Extension Service office.  They can collect and submit samples for further testing at the Texas Plant Disease Diagnostic Lab (a NPDN-member lab).

For more information about Citrus Greening, check out the following citrus resource page on the plant clinic website.  Additional information can be found at:

http://texascitrusgreening.org

http://saveourcitrus.org

If you are interested in learning more about the history of this disease: how it came in FL and the damage it caused, and other related stuff, check out the Florida Department of Plant Industry website on Citrus Health Response.

Photos were taken last week in Polk County, FL.

Less than 20 days into the new year, something that we had been expecting but hoping that it would never show up in Texas SHOWED UP.  Citrus greening, a disease caused by Candidatus Liberibacter asiaticus, was found and confirmed in Hidalgo county (in the Rio Grande Valley).  An emergency quarantine has been established in the immediate area to limit the movement of potentially infected plant.  We still do not know the extent of the spread but hope that it is limited to that one tree.  See Texas Department of Agriculture press release. (http://bit.ly/zh85YD) and more information about citrus, check out http://saveourcitrus.org .

How does or can this news impact us?  It depends….If you are a citrus grower who are exporting plants and fruit, it may mean that you might lose some business and/or have increased cost associated with treatment of plants and fruit prior to export.  If you are the public that like citrus or citrus product, they may be an increase in prices of those product and/or a potential reduction in availability of the product.

Let us all hope that any of those scenarios would not happen.  There are still things that can be done.  We can all continue to be VIGILANT. For growers and people that have citrus trees in their yards: continue to be on the lookout for symptoms of this disease and treat for the vector (Asian Citrus Psyllid).  Most of all, DO NOT  bring in citrus plant material from areas that have this disease found (there is a quarantine for this) such as Florida, Louisiana and the quarantined part of Texas.  Now that this disease is in Texas, we can still limit its range with continued vigilance.

Several other citrus problems looms ahead.  Disease such as citrus black spot, citrus canker and citrus leprosis are some diseases that are not currently present in Texas. We would hope that they never show up, but realistically it probably will.  By now, you may have realized the first two steps in dealing with diseases of agricultural importance. 1 – keep it out if at all possible and 2 – If it gets in, limit it from moving about.   Both these steps requires us to be on the lookout.  For us at the Plant Clinic, that means continue to have the ability to test for these diseases as well as developing educational materials and training folks (AgriLife agents to the homeowner) about the disease and what to look for.

Additional information about citrus greening can be found at http://texascitrusgreening.org  and the citrus greening page on our Plant Clinic website (under HOT TOPICS)

The 2012 Citrus Greening symptoms calendar is still available at the Plant Clinic (come by and pick up one or more) or can be downloaded from our citrus greening information page.

Welcome to 2012.  I hope that in the next few week I will be able to share with you other things that are happening at the Plant Clinic and the activities that are upcoming.

HLB Symptom: mottling

A few minutes ago, I got an email from a colleague requesting to post the following email from Bret Erickson of Texas Citrus Mutual in regards to dormant sprays for the Asian Citrus Psyllid.  This is primarily directed to our citrus growers in the Rio Grande Valley.  If this caught your attention, check out the HOT TOPIC page on Citrus Greening for more information about these psyllid and the disease that they vector.  And if you know a producer, pass the word along.

Thanks.

Lime samples to be tested for the presence of the Sweet Orange Scab pathogen.

This time last year, we were working with Citrus specifically looking for sweet orange scab – a disease caused by the fungus Elsinoe australis.  Then soon after, we started to see some downy mildew on basil.  This was the uncommon basil disease that did occur the previous year.  Around this time, I also got to work on some Palm Lethal Decline (aka Phoenix Palm Decline) which is caused by a phytoplasma.  In 2011, conditions were dry all over. The hard drought put a bunch of stress on many different types of plant.  A large number of our sample come from urban areas.  We saw landscape plants and trees that were exhibiting drought stress for a large portion of 2011.  We had quite a few of specimen that came in with root rots which we suspect was due to stressed plant and overwatering (from our visceral reaction to the drought).  We also answered lots of phone calls and emails from folks that were wondering why their plants were not doing well.  Around August, we started getting calls and samples of roses with the dreaded Rose Rosette syndrome.  This disease caused by a virus where once it gets into the plant, there is no remediation.

Sign of downy mildew on genovese basil plants.

Last year was also a year which brought on some budgetary issue.  Cuts to both the State and Federal budget resulted in major evaluation of how we can continue to provide a quality service while meeting our mission to support our AgriLife Extension personnel and to better the lives of the people in Texas and beyond.  2011 saw a rise in the routine diagnostic fees, going from $30 to $35, and an addition of a out-of-state surcharge of $20 per sample.  The Federal budget cut to the National Plant Diagnostic Network fund mean less funding for personnel at the Plant Clinic. Grass root efforts continue to help ensure that there will be funds that will be committed to safe-keeping the food and plant materials of the United States through this networks of diagnostic clinics for rapid detection and response, as well as an educational outlet to the general public to be on the look out for these potential invaders.

2011 was an interesting year with the extra dry conditions and the severe budget strains. I look forward to a better and perhaps more prosperous 2012.  Wishing all a Happy New Year and  may it be a prosperous one for you.

The Texas Plant Disease Diagnostic Lab

will be closed from

December 23, 2001 to January 1, 2012.  

Christmas poinsettia

Today has been a hectic day trying to get everything done so that we can really go on a break. The student workers are off on their semester break. Things in the labs still continues. As with most biological type work, things must go on living.  So someone will have to come in to check on the cultures.  Lately, we had been getting some rains throughout Texas.  It is also interesting to note that we are seeing both root rots and anthracnose on submitting samples (mostly bedding plants or ground covers). This is to be expected as the plants has been through a stressed situation and now there is lots of moisture and nicer conditions for pathogen to thrive.

A quick look back at this year made me realize that there were many good and bad things.  I will try to compile them for the next blog post. In the mean time, I hope that everyone will stay safe and enjoy this holiday season. Perhaps with the rest, ideas and plans for spring planting will form.  Do remember, a good plan will include and consider situation or conditions which will prevent disease issue.

Happy Holidays, Merry Christmas & a Happy New Year

from the crew at the Texas Plant Disease Diagnostic Lab (Kevin, Sheila, Bobbi, the student workers).

Recently, I came across a news report which mentions a slump in Indonesian cocoa exports in part due to a disease called Vascular-Streak dieback. That report also noted that Indonesia was the 3rd largest cocoa producer in the world.  This made me wonder when cocoa prices are going to increase.  Then it hit me – Here I am, 1/2 a world away and wondering if some problem on the other side of the world is going to impact my wallet.  Wow. That is what a microscopic fungal pathogen can do.  Some might argue that with our human advances in long distance travel contributing to a global economy is making this a big problem.  They would be correct… and these advances also contribute to the easier dissemination of potential pathogens (that is a topic for another blog post some day).

Plant diseases and their impact on society and the world did not appear recently.  In fact, plant diseases has impacted olden civilizations such as the Roman empire which had to deal with a rust disease (cause by a fungal agent) by appeasing the gods, Robigo and Robigus (side note – the Romans did not know that they were dealing with a plant disease!).

excerpt from Plant Pathology: past to present

Then in the mid-1800s, a disease called “late-blight” (causes by Phytophthora infestans) destroyed the potato crop in Ireland and resulted in death, hard-times and emigration of many Irish to America. This was all before the era of airplanes.  Such is the impact of plant diseases.  Fascination with this history and prospects on future outbreaks is why I am a PLANT PATHOLOGIST.

To find our more about plant disease in history, I would suggest downloading the FREE “coloring” book – Plant Pathology: past to present from the American Phytopathological Society website site (click here).  It is a fun way to learn a little of where and how plant diseases crossed paths with humans.

A few days ago in our local newspaper was an insert magazine, the American Profile.  Smack on the cover was the chestnut tree with the tagline ” Rebirth of the Chestnut tree”. (here is the link to the article online: http://bit.ly/ttgJxC ) I thought this is great as folks will read a little bit about how the disease commonly known as Chestnus blight, caused by the fungus Cryphonectria parasitica, came to America and cause much damage in the early 1900s. This article concentrated on current progress on research and development of resistant cultivars. For some good reads about this disease – check out this website from Penn State (http://bit.ly/s7aSjx).  Two recommended articles from that site is “Chestnut blight – introduction to the US” which has a more detailed history of the problem as compiled by Dr. Anagnostakis at the Connecticut Agricultural Experiment Station  AND “Tracking the Chestnut Blight”.

On a different note, a press release this week highlighted a new online disease identification tool added by the USDA Center for Plant Health Science and Technology (CPHST).  This tool was design to help the “frontline” surveyors and first detectors to identify 24 disease and common disorders of citrus. It is also helpful to anyone who might be interested.  There are lots of photos and an interactive key to help with problem identification process.  Check out the Citrus disease identification tool at http://www.idtools.org/id/citrus/diseases/index.php.

So the question is “Why dye the plant?”.  Short answer, to get a color that is desirable but not natural to the plant in question.  In the case of the introduced anthurium, it was to get that vibrant yellow in the flowers and the spadix of the plant.  Surprisingly, this is NOT NEW.  Dye-infused orchids have been available to consumers in the US.  Apparently, there is an effective method in getting the dyes into the flowers and keeping them there for a good while.  It is also interesting to note that flowers from new growth revert to their original color (typically white – surprise, surprise!).

As a curious plant lover – I would say “cool!” but I alway want that special color.  This is kinda nice but… color does not stay. Hence, the best use for this are as show plants that needs to be replaced once blooms are done.

As a inquiring plant pathologist, I would wonder what would this method of dye-infusion do to the rest of the plant.  Will it stress the plant and make it more susceptible to certain diseases?  To get to that answer, research must be done.

As a entrepreneuring plant pathologist, I am wondering how can we use this technique (and if it cost-effective) to transport pesticide into the plant where it might reside for several months, thus allowing the pesticide to provide long term protection to the plant.

I like to think that the questions I have are interesting.  One of the things that drew me to this article was the discussion that was generated.  Comments from folk liking it to folks who vehemently dislike it.  Sentiments are high when you hear things like ” fake plant”.  In defense of the plant – the plant is indeed real, only that human messed with a few showy parts.  Whadya think?    What will they think of next….

The past several weeks has had me running to several different meeting. Most notable was the National Plant Diagnostic Network meeting in Berkeley.  It was interesting to note some of the new technologies for detection of pathogens.  It struck me that many of these tools help us to identify the pathogen only. Many of these technologies are also limited.  For example, test for a particular group of pathogen affecting a certain crop or testing for a group of viruses.  It was still incumbent for a person to make the decision as to which test or detection method to use to best identify the possible pathogen.  This realization gave me both a feeling of fear and comfort.  Fear – that with the reliance of these tools, the “old-timey” practical knowledge of observation and logical analysis of cause-effect would be lost or eroded in the coming generations of plant pathologist, entomologist and agronomist.  Comfort because those that chose to pursue the classical approaches to practical and applied science of agriculture/ horticulture/ plant sciences would do well for themselves as they will be a need for these people….hopefully.

While in the present, the Plant Clinic will continue to help educate the general public in Texas and beyond to the wonders of pest and pathogens of plants.  The latest issue of First Detector Network News (November 2011 issue) has been posted and contain some interesting articles which are easy to read and informative.  The highlight (in my opinion) is the news release and links to a “NEW” citrus pest ID tool designed to help our survey teams but is most useful to the general public too.  This newsletter can be accessed at http://sepdn.org/newsletter.