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Sunscald

Sunscald

Disorderalso: Sunburn

A physical disorder, not a disease, in which intense direct sun burns exposed fruit, leaving pale, blistered, leathery patches. Sunscald shows up on tomatoes and peppers, especially when leaf cover is lost to disease, heavy pruning, or pests, and on fruit that develops on small, sparse plants. The damaged tissue then invites secondary rots.

🔎 How to spot it

Look for a whitish, yellow, or tan patch on the side of the fruit that faces the sun, usually the shoulders or upper side. The area is at first soft and blistered, then dries into a flattened, papery, leathery, sometimes wrinkled patch. The dead tissue is often later colonized by black mold or soft rot. Leaves and other plant parts are not affected.

🥀 Damage it causes

Sunscalded fruit is disfigured and downgraded, and the killed tissue is an open door for molds and soft-rot organisms that can rot the whole fruit. Losses climb when a disease, pest, or hard pruning has thinned the canopy and left many fruit exposed to direct sun.

🔬 What causes it

Sunscald is caused by intense direct sunlight and heat killing the cells in the fruit skin, much like a sunburn. It happens when fruit that grew shaded is suddenly exposed, most often after leaves are lost to leaf-spot diseases, insect feeding, or over-aggressive pruning, or when fruit forms on small plants with little canopy. Green and recently exposed fruit are most vulnerable.

🛡️ Prevent it

Keep plants leafy and healthy so the canopy shades the fruit: manage the leaf diseases and insects that strip foliage, and avoid heavy pruning that bares the fruit. Choose varieties with good leaf cover, space and feed plants for vigorous growth, and use cages rather than heavy staking. In intense heat, light shade cloth over the plants can protect exposed fruit.

🧯 If it is already here

Damaged fruit will not heal, so pick and use or discard sunscalded fruit promptly before secondary rots set in and spread. Then address the cause by restoring leaf cover: treat the underlying disease or pest, ease off on pruning, and shade the plants during heat waves. Leaving scalded fruit on the plant only invites mold into the canopy.

💡 Good to know

Because sunscald is usually a downstream effect of losing leaves, the real fix is protecting the foliage, so a sudden rash of sunscald is often a sign of an underlying leaf disease or pest problem worth investigating. It is most common after midsummer defoliation and on the first exposed fruit, and the south and west sides of the plant take the worst of it.

🌱 Plants it affects

104 plants in the library can be affected by this problem

Aji Amarillo PepperAmish Paste TomatoAnaheim PepperAnjou PearAroniaAsian PearAtlantic Giant PumpkinAunt Molly's Ground CherryBanana PepperBartlett PearBeach Plum🍅Beefmaster TomatoBetter Boy Tomato🍅Big Beef TomatoBig Boy TomatoBing CherryBlack Beauty EggplantBlack Cherry TomatoBlack Krim TomatoBlack Tartarian CherryBosc Pear🍅Box Car Willie TomatoBraeburn AppleBrandywine TomatoCarolina Reaper PepperCayenne PepperCelebrity TomatoChampagne LoquatCherokee Purple TomatoChokecherryContender PeachCornelian CherryCortland AppleCosmic Crisp AppleCubanelle PepperDamson PlumEarly Girl TomatoElberta PeachFairy Tale EggplantFantasia NectarineFresno PepperFuji AppleGala Apple🍅German Queen TomatoGhost PepperGranny Smith AppleGreen Bell PepperGreen Zebra TomatoHabanero PepperHawthornHoneycrisp AppleHungarian Wax PepperIndian HawthornIndigo Rose TomatoItalian EggplantJalapeño PepperJapanese EggplantJuliet Grape TomatoKellogg's Breakfast Tomato🍅La Roma IV TomatoLemon Boy TomatoMcIntosh AppleMethley PlumMontmorency CherryMoorpark Apricot🍅Mortgage Lifter TomatoMr. Stripey TomatoNanking CherryOrange Bell PepperPadrón PepperPimento PepperPineapple TomatoPink Lady ApplePoblano PepperPomegranatePrickly PearPurple Bell PepperQuaking AspenQuinceRainier CherryRed Bell PepperRed Delicious AppleRedhaven PeachRegent SaskatoonRoma Tomato🍆Rosa Bianca Eggplant🍅Rutgers TomatoSan Marzano TomatoScotch Bonnet PepperSerrano PepperShishito PepperStanley Plum🍅Striped German TomatoSugar AppleSugar Maple🍅Sungold Cherry TomatoSweet 100 Cherry TomatoSweet Banana PepperTexas Scarlet Flowering QuinceThai Chili Pepper

For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.