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
Late blight shown in a tomato
Disease ControlLate Blight Identified In Indiana, Michigan
July 28, 2015
A potato field in Michigan and a potato and tomato field in Indiana have documented the disease. Read More
downy mildew symptoms on basil
Disease ControlRed Lights Slow Down Growth Of Downy Mildew On Basil
July 22, 2015
University of Florida scientists say the technology may help growers manage the disease and reduce chemical inputs. Read More
Bacterial wilt of curcurbits
CucurbitsWin The War Against Bacterial Wilt Of Cucurbits
July 22, 2015
Learn how to identify, the survival and spread, as well as management methods of this vegetable disease. Read More
Disease ControlStone Fruit Rots Rampant In East
July 21, 2015
The incidents of fruit rots in both sweet and tart cherries and peaches and nectarines are quite high in Pennsylvania Read More
UF/IFAS scientists Edward Evans and Jonathan Crane study diseased avocados in a South Florida grove.
Disease ControlDeadly Disease Cutting Down Florida Avocado Trees Likely To Push Up Prices
July 17, 2015
The economic impacts of laurel wilt disease management costly for domestic producers. Read More
tomato plants showing signs of Fusarium wilt
Disease ControlGrowers, Scientists Setting Sights On Soilborne Disease
July 14, 2015
Further removed from methyl bromide, nasty maladies like Fusarium are finding a way back into fields. Read More
Crop ProtectionEarly Blight And Septoria Leaf Spot Rampant On Pennsylvania Tomatoes
July 8, 2015
According to a news release from Penn State University, early blight and Septoria leaf spot are present in Pennsylvania tomato Read More
The Latest
Crop ProtectionLettuce Disease Gives E. Coli A Boost
July 31, 2015
E. coli prefer cut, injured, and young lettuce leaves. Read More
Crop ProtectionNew Fungicide Targets Key Diseases
July 30, 2015
This disease control tool hits two different parts of the fungal life cycle. Read More
Disease ControlNew Disease Control Tools For Fruit And Nut Growers
July 29, 2015
Apple scab is a big problem for growers in the Midwest and East. But, a new fungicide boasts efficacy against Read More
Late blight shown in a tomato
Disease ControlLate Blight Identified In Indiana, Michigan
July 28, 2015
A potato field in Michigan and a potato and tomato field in Indiana have documented the disease. Read More
downy mildew symptoms on basil
Disease ControlRed Lights Slow Down Growth Of Downy Mildew On Basil
July 22, 2015
University of Florida scientists say the technology may help growers manage the disease and reduce chemical inputs. Read More
Bacterial wilt of curcurbits
CucurbitsWin The War Against Bacterial Wilt Of Cucurbits
July 22, 2015
Learn how to identify, the survival and spread, as well as management methods of this vegetable disease. Read More
Disease ControlStone Fruit Rots Rampant In East
July 21, 2015
The incidents of fruit rots in both sweet and tart cherries and peaches and nectarines are quite high in Pennsylvania Read More
UF/IFAS scientists Edward Evans and Jonathan Crane study diseased avocados in a South Florida grove.
Disease ControlDeadly Disease Cutting Down Florida Avocado Trees Likel…
July 17, 2015
The economic impacts of laurel wilt disease management costly for domestic producers. Read More
tomato plants showing signs of Fusarium wilt
Disease ControlGrowers, Scientists Setting Sights On Soilborne Disease
July 14, 2015
Further removed from methyl bromide, nasty maladies like Fusarium are finding a way back into fields. Read More
Crop ProtectionEarly Blight And Septoria Leaf Spot Rampant On Pennsylv…
July 8, 2015
According to a news release from Penn State University, early blight and Septoria leaf spot are present in Pennsylvania tomato Read More
Crop ProtectionDowny Mildew Reported In Ohio Cucumber Fields
July 8, 2015
According to a disease update from Ohio State University Extension, downy mildew was reported in cucumbers on farms in West Read More
BerriesRainy Weather Causing High Risk For Phytopthora In Berr…
June 29, 2015
With the rainy weather the Midwest has recently received, the conditions for Phytophthora diseases increases. An increased risk for oomycetes, Read More
Disease ControlQuintec Fungicide Receives Label For Bacterial Spot Sup…
June 26, 2015
Quintec fungicide from Dow AgroSciences, known as an effective treatment for suppressing bacterial spot in peppers, is now available to Read More
Crop ProtectionDowny Mildew Makes Early Appearance In Michigan Cucumbe…
June 23, 2015
An alert sent by Michigan State University (MSU) Extension confirms the presence of downy mildew on cucumber leaves in Michigan. Read More
Apples & PearsDon’t Neglect Overwintering Fire Blight Cankers
June 22, 2015
Canker blight has been seen in Pennsylvania orchards, thanks to ideal weather conditions as of late. Kari Peter of Penn Read More
Disease ControlFMC’s RHYME Fungicide Labeled In California And Arizona
June 18, 2015
RHYME fungicide is now labeled for use in California and Arizona  for control of powdery mildew and black rot in Read More
BerriesCaptan Gold 4L Fungicide Now Registered In California
June 16, 2015
ADAMA has received EPA approval for Captan Gold 4L liquid fungicide for use on strawberries, tree fruits, and other specialty Read More
Disease ControlYeasts Found On Plum Surfaces May Protect Against Patho…
June 16, 2015
Some naturally occurring yeasts may be useful for protecting stone fruits against pathogens that attack after harvest. Scientists at the Read More