German Queen Tomato Plant Leaves Are Turning Yellow & Wilting

Wilt and Blight

• Yellowing leaves and wilt are most commonly caused by infectious tomato diseases, such as verticillium wilt, fusarium wilt and early blight. These diseases can be prevented by rotating where you plant your tomatoes each year and avoiding areas that have previously suffered from disease. Watering at the base of the plants will also reduce the chances that wilt and blight will establish themselves. Once the tomato plants have become infected, no treatment is available. Dig up the tomato plant, being careful to remove all affected parts so that it does not spread and damage other healthy tomato plants.

General Conditions

• A number of general growing conditions can cause wilting and yellowing leaves. Foremost among them is a lack of moisture. Like all tomatoes, “German Queen” tomatoes benefit from steady irrigation, keeping the soil moist 1 inch below the soil surface. When tomato plants are stressed due to a lack of water, they will yellow and wilt. Smog and over-pruning can also stress the plant, causing the leaves to wilt and yellow. In the case of smog, heavy levels may further damage the plant by causing blossoms to drop and poor growth overall. Leaf roll is also a common problem, with wilting leaves as one of the primary symptoms, according to the University of California, Davis. No known cause exists for the leaves stiffening and rolling upwards, although having a shade cover has been shown to help.

Insects

• In the case of yellowing and wilting leaves due to insect infestations, holes often accompany these other symptoms, letting you know that insects are the cause of the problem. Aphids damage tomato plants by sucking the sap from the leaves and stems of the plant, causing them to wilt. You can treat aphid infestations by spraying the underside of leaves with neem oil or an insecticidal soap.

  Nematodes can also cause yellowing and wilting in “German Queen” tomatoes. As very tiny roundworms that feed on the roots of the tomato plant, nematodes damage the roots to the extent that they are unable to absorb nutrients. As the damage progresses, the top of the tomato plant will begin wilting and turning yellow, and the damage will progress downwards. Nematodes are difficult to treat in an established tomato plant, so all you can do is avoid planting in the same place next year.

Planting Times

• Transplant times can affect the overall health of the plant, and lead to wilt and yellowing in the leaves. Transplant “German Queen” tomatoes when daytime air temperatures are 65 degrees Fahrenheit or higher. If your garden suffers from fluctuating temperatures early on in the season, protect your plants with row covers or small cloches. “German Queen” tomatoes require a minimum of six to eight hours of full sun each day. A lack of sunlight can lead to yellowed leaves and poor growth.