Catfacing is a term that describes tomato fruit that is misshapen, with indentations and scarring. It looks like a webbing. In most parts of the country the cause is thought to be cold weather during blossoming. We rarely have that problem in Arizona’s Sonoran desert.
In our part of the world the more likely culprit is high levels of soil nitrogen along with erratic watering. Catfacing is the result of the blossom sticking to the fruit as it forms. Blossom ends are often scarred or lumped and deep cavities penetrate the fruit. Other impediments to flower bud development can also result in catfacing.
The syndrome is more prevalent on large-fruited varieties than medium-fruited varieties. Excess nitrogen, aggressive pruning, and accidental exposure to hormonal herbicides should be avoided. It may also be aggravated but hot pollination during fruit set – and that’s a tough thing to avoid here.
Don’t despair, though. There is nothing wrong with a catface tomato. If left to ripen it can be harvested and eaten.
Sunscald occurs in fruit exposed to direct sun in hot weather. Tomatoes, peppers and chilies are particularly vulnerable to sunscald. It causes bleached and blistered areas to develop on the exposed surface, eventually becoming dry and papery.
Sunscald is most prevalent on the green fruit. White or yellow blisters will develop on the sides of the fruit that are facing the sun. With continued exposure to the sun, the damaged areas may become papery, flattened, and grayish white. Black mold may grow in the papery patch and cause the fruit to rot.
Strategies to avoid sunscald.
1. Maintain healthy plants with plenty of foliage. Water tomatoes thoroughly on a regular basis. Fertilize with a low nitrogen or slow release fertilizer at planting and at full blossom. Mulch lightly when the soil has warmed.
2. Cover exposed fruit with a lightweight material, such as shade cloth, in order to provide them with some shelter from intense sunlight. Here’s more information on providing shade to your plants.
3. Practice controls for leaf diseases in order to prevent defoliation that leaves the fruits more vulnerable to sunscald. These practices may include crop rotation, proper sanitation, and the use of fungicides.
4. Plant varieties that are tolerant to disease. Select varieties that tolerate Septoria leaf spot and early blight, two of the most common defoliating diseases.
The best prevention is to use at 40 to 50% shade cloth as temperatures heat up. Also, maintain healthy foliage by protecting against defoliating diseases.
Source: Missouri Botanical Garden, Maricopa County Cooperative Extension.