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Why Are My Tomatoes White Inside – Disease Or Normal?

The anticipation a gardener experiences when tomato plants begin to produce fruit and the excitement as tomatoes ripen are some of the greatest joys of gardening. Producing healthy ripened tomatoes can be challenging as many adversaries can negatively affect the success of your harvest. One result of some adversary conditions can be white spots within the tomato. When this happens, what gardeners want to know is why are my tomatoes white inside?

There are a few possible reasons a tomato may be white on the inside. These reasons could include sunscalding, internal white tissue disorder, or insect feeding. 

Read on to learn more about why your tomatoes may be white on the inside and best practices to keep your tomatoes healthy.

3 Reasons Why Tomatoes Are White Inside

When tomatoes turn white inside, it’s pretty concerning. Here are some of the possible reasons why this happens.

Sunscald

While tomato plants will exhibit the healthiest growth in environments with 6 – 8 hours of direct sunlight a day, there are situations where conditions can be too sunny or hot for tomatoes to thrive. Sunscald is a term used to explain the effects on tomatoes that are overexposed to the sun’s rays in extremely hot weather.  

Sunscald may first be identified by white or gray spots on the skin of the tomato and can also lead to a white core inside the fruit. Sunscald is best prevented by tucking the tomato back into the shade of the plant. However, if the plant has been heavily pruned due to disease, there may be little natural shade remaining to protect the fruit. In these situations, you have two best options:  

Option 1: Construct a shade structure for the tomato. Shade can be created with an umbrella, screen, or cloth, so the fruit is not exposed to more than 8 hours of direct sunlight per day. A challenge of this solution is that you need to be available to move the shade throughout the day to ensure that the tomato is getting enough but not too much sun to prevent or halt sunscald.  

Option 2: Harvest the tomato early. As lovely as vine-ripened tomatoes are, sometimes the best solution to sunscald or other fruit issues is to harvest the tomato early and let it ripen off the vine.  

Internal White Tissue Disorder

Internal white tissue disorder is not identifiable on the outside of a tomato, so it can be quite surprising to find these white sections of the fruit when you slice into what appears to be a healthy, ripened tomato. This disorder is most common among vine-ripened tomatoes and can result from extreme heat during the ripening process. 

Internal white tissue disorder appears on the vascular tissues inside tomatoes and can range from minimal damage, where much of the tomato is still edible, to maximum damage, where almost all of the internal fruit tissue has developed this white defect.

Some tomato varieties are more susceptible to this disorder than others. Many online resources are available to identify which types of tomato plants are more or less likely to develop internal white tissue disorder.  

Insect Feeding: Stink Bugs

Tomatoes are prone to a myriad of pest issues depending on the geographic location in which they are being grown as well as other environmental factors. If you are finding white spots inside your tomato, this may result from stink bugs feeding on your fruit.  

Stink bugs are known for their unearthly appearance, including a sharp pointy mouth. They are able to use this adaptation to puncture fruit and draw out its sweet juices.

As stink bugs are pulling out the fruit’s juices, they are also inserting yeast inside of the tomato flesh, stopping the fruit production in that area. If you have found stink bugs in or around your tomatoes, the white spots you find inside your tomato may result from this yeast.

In larger tomatoes that are close to harvest, it is most likely that this yeast will only damage a portion of the fruit; however, in smaller tomatoes that still need more time to develop, the stink bug may stall its development, interrupting your harvest.  

Stink bugs and other pests can be prevented using organic pesticides such as neem oil or a soapy water mixture. Spraying either of these solutions on your plant at sunset each evening will result in the most successful pest prevention.

If you are already seeing stink bugs on your tomato, a pesticide will still help, but the best method to get rid of them is to pull them off the plant and its fruit, relocating them far away from your crop.  

Additional Tomato Pests

Tomatoes are susceptible to a variety of pests that can affect the plant and its fruit. Aphids and hornworms are the most common pests for tomato plants.  

Aphids are tiny and can go unnoticed until there are so many they are covering much of the plant. While they are too tiny to pluck off, they can be treated with neem oil or a soapy water mixture.

Some recommend a strong stream of water to knock them off the plant, but this typically has to be done repeatedly and can lead to other diseases from too much moisture on the plant leaves and vines. If aphids go untreated, they will take over and kill the tomato plant.  

Hornworms are camouflaged when on the tomato plant, so it takes a close eye to find them at first, but when you start to identify large portions of leaves and fruit eaten by a hornworm is probably present.

The best way to deal with hornworms is to remove them from the plant and place them far away from your tomato crop, or they will find their way back. If hornworms go untreated, they will consume your entire tomato plant.  

Additional Tomato Diseases

In addition to pests, there are a variety of diseases that can infect your tomato plants. Two of the most common diseases are powdery mildew and blight.  

Powdery mildew most often occurs when too much moisture has reached the tomato leaves. It is identifiable by white spots that will start to appear on the plant’s leaves.

If you notice these spots on your plant, remove any leaves or fruit with the white spots immediately to prevent further disease growth. Powdery mildew can be prevented by ensuring your tomato plants are appropriately spaced apart from each other, regular pruning, and watering the roots with a drip system instead of spraying the entire plant.  

Blight is a tomato disease that is growing more common in environments that have wetter growing seasons. It is a soil-based fungus that is nearly impossible to get rid of once it appears. Yellowish-brown spots or lesions can identify blight on the leaves of the plant.

Once a plant with blight begins producing tomatoes, the fruit will appear to have similar spots to what can be seen on the leaves before rotting off the plant. If blight is identified early, you can attempt to prevent it from spreading by removing any infected leaves or fruit. You can prevent future blight by planting your next tomato crop in a different location for up to two growing seasons to allow the soil time to get rid of the fungus.  

Final Tips For Maintaining Healthy Tomato Plants

Although tomatoes can be negatively affected by a variety of pests and diseases, they are still one of the most satisfying plants to grow. There is no comparison to plucking a healthy tomato off the vine and immediately biting into it. The main task of gardeners to keep their developing and mature tomato plants healthy is an observant eye and quick action when issues arise.