Tackling Tomato Purple Leaf Disorder

Tackling Tomato Purple Leaf Disorder  Watch Video

Red is the color most associated with tomato, but purpling in both fruit and leaves is also possible. While purple fruit is characteristic of certain cultivars, purple leaves are most often caused by stress or disease. In most people’s minds, purple tomato leaves are the result of nutritional deficiencies, primarily of phosphorus, nitrogen, or potassium.  Since 2006, unusually large numbers of tomato plants with purple leaves have been observed in several tomato fields in Hillsborough, Manatee, and Miami-Dade counties.  Foliar analysis of nearly 500 samples of purple and normal colored leaves showed that this purpling was not due to nutritional deficiencies. The disorder was named tomato purple leaf disorder (TPLD) and multiple studies were conducted by a task force to understand the disorder and to identify its cause. Following is a summary of what we know to date.

Symptoms Of TPLD
Initial symptoms of TPLD appear between six to eight weeks after transplanting and could be somewhat confused with mild phosphorus (P) deficiency. The key diagnostic difference between TPLD symptoms and the symptoms of P deficiency is that symptoms of P deficiency first appear on the lower leaf surface, causing vein purpling, and then extend to the whole leaf. By contrast, symptoms of TPLD appear primarily on the upper leaf surface, without affecting the veins, and gradually spread to the entire leaf surface.

Often, when one leaf overlaps another, TPLD only develops on the surface portion exposed to sunlight, with the shaded leaf tissues remaining green. No deformation or bronzing of the affected leaves has been observed. Instead, these leaves appear to senesce prematurely. The intensity of the purple color and the extent of purpling vary among leaves on the same plant, among plants of the same cultivar, and among cultivars. This disorder has been seen in all types of cultivated tomatoes (i.e. grape, cherry, round, and Roma types). Grape tomatoes seem to have the most severe symptoms. The effect of TPLD on yield is unknown.

Distribution And Incidence In Commercial Tomato Field

Initial studies in two affected fields in South Florida show that incidence of TPLD symptoms were less than 1% at 11 weeks after transplanting. However, four weeks later, incidence in the same field increased to more than 90%. At the same time, an adjacent field under the same management practices, which was four weeks younger than the previous field, exhibited less than 25% incidence. No clear pattern of distribution was observed with respect to incidence within a row or in relation to the prevailing sun and wind direction.

 

Searching For Answers

Many different tests for known pathogens of tomato using standard microbiological, serological, and nucleic acid-based methods were negative. This indicates that the causal agent is something new. The mechanism of transmission is still not known for sure, but greenhouse studies indicate that there is some transmissible agent.  Some of the studies suggest that TPLD is caused by an infectious agent, like a virus or viroid. There is some evidence to suggest the presence of a virus similar to the whitefly-transmitted Tomato chlorosis virus. However, it is not clear if this virus is the cause of TPLD or is only part of the cause. There is some evidence that suggests a viroid may also play a role in the disorder. However, more research will be necessary to clarify the current results and confirm the identity of the causal agent.

Leave a Reply

5 comments on “Tackling Tomato Purple Leaf Disorder

  1. FL tomatoes are vital ag biz! There are solutions. All natural, GREEN, very economical solutions to help plants naturally. Vibrantly healthier plants are LESS Vulnerable and Naturally able to better Resist diseases, pests, also appears increased resistance to frost. Healthy plants are more productive plants.
    Given the choice between destroying the plants, and trying a GREEN alternative? I can say: Use our products to help plants until the condition goes way. You just might be amazed. CleanPlantsHappyPlants.com 941-320-5591

  2. Seedlings begin in excellent shape, including early flowering. Adult plants under produce, fail prematurely. Pervasive purple gradually overcomes a variety of plants. A few plants generate new growth without purple leaf coloring.
    Location: Michigan (Detroit area)

    Second season of infection, purchased plants from same local supply. Self started seedlings also became infected.

  3. FL tomatoes are vital ag biz! There are solutions. All natural, GREEN, very economical solutions to help plants naturally. Vibrantly healthier plants are LESS Vulnerable and Naturally able to better Resist diseases, pests, also appears increased resistance to frost. Healthy plants are more productive plants.
    Given the choice between destroying the plants, and trying a GREEN alternative? I can say: Use our products to help plants until the condition goes way. You just might be amazed. CleanPlantsHappyPlants.com 941-320-5591

  4. Seedlings begin in excellent shape, including early flowering. Adult plants under produce, fail prematurely. Pervasive purple gradually overcomes a variety of plants. A few plants generate new growth without purple leaf coloring.
    Location: Michigan (Detroit area)

    Second season of infection, purchased plants from same local supply. Self started seedlings also became infected.

  5. Hello! I live a few blocks from the ocean in Kill Devil Hills NC.My tom`s have been in the ground for over 2 1/2 months.This morning I noticed the TPLD on a "Cherokee Purple".It seemed to happen over night…just for the records.

Disease Control Stories
Laurel wilt-damaged avocado tree leaves
Disease Control
May 6, 2016
Avocado Tree Killer On The Move In Florida
Devastating laurel wilt disease now reported in 61 of 67 counties. Read More
potato field_featured
Crop Protection
May 6, 2016
Late Blight Hotlines For Potato Growers Up And Running For 2016 
Offering management information for five key potato-growing regions, the hotlines provide data on weather threats, disease pressures, and scouting. Read More
Downy Mildew in Spinach for web
Crop Protection
May 5, 2016
Michigan Researcher Leads $2.3-Million Grant To Combat Downy Mildew In Vegetables
Michigan State’s Mary Hausbeck along with a multistate research team will work to enhance and refine early detection methods, allowing growers to identify the pathogen’s presence in the air -- before it infects fields. Read More
Choosing the right fungicide can be critical as shown here by the stark contrast between a fungicide-treated garlic leaf (right) and an untreated leaf covered with a pathogenic rust fungus.
Photo credit: S. T. Koike
Crop Protection
April 30, 2016
How To Elect The Right Fungicide For The Job
Fungicide application is one tool of a successful IPM program for crop diseases. Used judiciously and appropriately, these chemicals are powerful allies in the fight against the fungi and bacteria that attack crops. Read More
Torrey Farms onion crop
Crop Protection
April 25, 2016
Ranman Fungicide Registered For Downy Mildew Control In Bulb Vegetables
Product features a zero-day pre-harvest interval, allowing application up to the day of harvest. Read More
Scab disease on a cucumber
Cucurbits
April 20, 2016
Sidestepping Scab Critical For Florida Cucurbit Growers
Learn how to ID, the survival and spread, as well as management methods for this vegetable disease. Read More
weed free watermelon field
Crop Protection
April 18, 2016
Researchers From Clemson University Offer Tips On Managing Watermelon Diseases
A new online spray guide is designed to help growers deal with three major diseases that affect watermelon leaves in the Southeastern U.S. Read More
The Latest
Cucurbits
May 21, 2016
Cucurbit Yellow Stunting Disorder Virus …
Learn how to identify, the survival and spread, as well as management methods for this vegetable disease. Read More
Disease Control
May 19, 2016
Native Plants Reduce Need For Vineyard W…
Scientists in eastern Washington are finding drought-tolerant alternatives to roses at the end of vineyard rows that not only save Read More
Crop Protection
May 16, 2016
New Fungicide For Lettuce And Strawberry…
The product from Summit Agro USA is for use to control botrytis gray mold in strawberries and Sclerotinia drop in lettuce. Read More
Disease Control
May 6, 2016
Avocado Tree Killer On The Move In Flori…
Devastating laurel wilt disease now reported in 61 of 67 counties. Read More
Crop Protection
May 6, 2016
Late Blight Hotlines For Potato Growers …
Offering management information for five key potato-growing regions, the hotlines provide data on weather threats, disease pressures, and scouting. Read More
Crop Protection
May 5, 2016
Michigan Researcher Leads $2.3-Million G…
Michigan State’s Mary Hausbeck along with a multistate research team will work to enhance and refine early detection methods, allowing growers to identify the pathogen’s presence in the air -- before it infects fields. Read More
Crop Protection
April 30, 2016
How To Elect The Right Fungicide For The…
Fungicide application is one tool of a successful IPM program for crop diseases. Used judiciously and appropriately, these chemicals are powerful allies in the fight against the fungi and bacteria that attack crops. Read More
Crop Protection
April 25, 2016
Ranman Fungicide Registered For Downy Mi…
Product features a zero-day pre-harvest interval, allowing application up to the day of harvest. Read More
Cucurbits
April 20, 2016
Sidestepping Scab Critical For Florida C…
Learn how to ID, the survival and spread, as well as management methods for this vegetable disease. Read More
Crop Protection
April 18, 2016
Researchers From Clemson University Offe…
A new online spray guide is designed to help growers deal with three major diseases that affect watermelon leaves in the Southeastern U.S. Read More
Crop Protection
April 18, 2016
Valent BioSciences Announces Biorational…
Valent BioSciences Corporation has announced plans to construct a new state of the art Biorational Research Center as an expansion Read More
Crop Protection
April 6, 2016
Fungicide Receives Registration For Down…
With a zero-day pre-harvest interval, Ranman can be applied up to the day of harvest. Read More
Crop Protection
April 1, 2016
Take Control Of Bacterial Spot And Spo…
Preventive measures needed to keep these two diseases in check. Read More
Crop Protection
April 1, 2016
The Problem With Powdery Mildew In Pumpk…
Do your best to reduce the chances of getting the disease in pumpkins, but be prepared with the proper plan of action if it shows up. Read More
Crop Protection
March 30, 2016
Bayer Nematicide Gets The Nod For Use On…
Velum Prime is a non-fumigant nematicide offering disease control benefits. Read More
Crop Protection
March 29, 2016
New Race Of Downy Mildew In Spinach Name…
This race was able to overcome most of the race 1-15 varieties evaluated. Read More
Disease Control
March 24, 2016
Bottom Rot Leaving Some Florida Lettuce …
Learn how to ID, the survival and spread, as well as management methods for this vegetable disease. Read More
Crop Protection
March 16, 2016
Marrone Bio Innovations To Distribute Is…
The biofungicide will be distributed to agricultural markets in California, Oregon, Washington, and Arizona. Read More
[gravityform id="62" title="false" description="false"]