Why are my tomatoes developing large white spots? Is it the heat?

by Elaine P.
(Edmond, OK, USA)

Q. Tomatoes have developed large white spots. What could be causing them?

A. There are at least 2 possible causes to consider.

1. Stink bugs. These nasty pests stick their snouts underneath the skin of a tomato, inserting enzymes that transform the tomato flesh to liquid. The bugs then suck the liquid. Once the fluid is removed, then discolored spots remain on the fruit surface. Spots often are white, yellowish, or light green. Check your tomatoes to see if the areas around the spots have pin pricks and if the areas underneath the skin are softened and decimated. If stink bugs are your culprit, you can control them by hand picking, spraying them with streams of water, or treat with kaolin or insecticide.
   
2. Tomato sunscald. Caused by too much direct sun on ripening green tomatoes, sunscald appears as light patches on the fruit's exterior, which can become gray or white. You can prevent sunscald by limiting tomato pruning and providing extra shade during prolonged hot, sunny spells.