Tackling Tomato Purple Leaf Disorder

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.

Advertisement

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.

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.

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.

Top Articles
25 Years of Project GREEEN’s Growth in Controlled Environment Agriculture

11

Leave a Reply

Avatar for Anonymous Anonymous says:

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

Avatar for Anonymous Anonymous says:

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.

Avatar for Anonymous Anonymous says:

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

Avatar for Anonymous Anonymous says:

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.

Avatar for Jerry Jerry says:

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.

Avatar for Gabriel Olsen Gabriel Olsen says:

Gabriel in Hollywood California, growing Tomato Champion and Early Girl on the roof, I have about 11 tomato plants of different variety including cherry and cherokee purple but so far only the Champion and Early girl which are next to each other are affected. First affected plant was the corner most westfacing plant and also the largest. Starts were purchased from Certified Plant Growers in Norco and Home Depot Hollywood, CA on Sunset.

Avatar for GarySutt GarySutt says:

Rutgers from seed grown in new soil with vermiculite in 3′ pots. Curl and blue veins became visible about a week ago. I am removing all affected leaves and stems. Well developed and still very green tomatoes look very good although I did remove one deformed tomato yesterday.

Avatar for richard richard says:

they mention it starts after transplanting mine are seedlings only 4 weeks old hope i don’t lose them

Avatar for amy a bowen amy a bowen says:

I live in New Mexico. I have all my tomato plants set up in a dog kennel that are covered with a fine mesh bug cloth and watered with a drip set up in large individual tubs. All the tomato plants that are next to each other now have the purple leaf symptom. In order -from the door back-Gardener’s Delight Cherry, Rosella Purple Dwarf, Sungold cherry, Luck Cross, Mr Snow Dwarf, Black Cherry (last in the row was Paul Robeson -it did not have the symptoms). So it was all types. This row was on the east side. I questioned that it was because of the sun. The leaves did not look sick just purple on their top surface. These plants were all grown from seeds – different seed companies. Paul Robeson was a seed I collected from last years plants. I believe the Sungold was the first that exhibited it -but not sure. I just removed it because it was not producing and looked sad. I did grow some sucker transplants they all look fine and are outside the cage. I was going to replace the sucker baby from the sungold in the place on the Sungold that I removed-but now I’m concerned that the plants next to it will infect it? The plants on the west row have no symptoms.
It would be nice to understand this symptom. I’m so glad I found this sight because I could not understand why I could not find information for this. I even just added magnesium to some of the worst before I found this sight.
Amy

Avatar for darby darby says:

12 years later…any update?

Advertisement