Lettuce: Anthracnose categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Lettuce anthracnose magnifiedPhoto by: R.S. Byther Biology Anthracnose of lettuce is a fungal disease favored by cool, wet weather. The disease is also known as shothole because of the characteristic symptoms. Lower leaves develop small, water-soaked spots which quickly darken and enlarge. The […]
Lettuce: Aster yellows categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Biology Aster yellows is caused by a phytoplasma which is a microorganism found in the phloem tissue of a plant. The phytoplasma is spread by leafhoppers and can also affect carrot, onion, potato, celery, and other crops, weeds, and ornamentals. Initial symptoms […]
Lettuce: Beet western yellows virus categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Biology Beet Western Yellows is a virus which affects many garden plants and weed species. The virus is transmitted by aphids, including the green peach aphid. Older leaves are affected first. Yellowing begins at the margin and progresses inward, with […]
Lettuce: Bottom rot categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Lettuce bottom rotPhoto by: R.S. Byther Biology Bottom rot of lettuce is caused by a soil-borne fungus that is common in wet soils. Head lettuces, particularly the ‘Big Boston’ types, are attacked as they near maturity. The stems and midribs of lower […]
Lettuce: Damping-off categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Damping-off of cucumber seedlingsPhoto by: R.S. Byther Biology Damping-off is caused by fungi that remain in the soil for long periods of time. Seeds decay without germinating. Seedlings may be infected and fail to emerge from the soil. Emerged seedlings are also attacked, […]
Lettuce: Downy mildew categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Lettuce leaf infected with downy mildew fungusPhoto by: R.S. Byther Biology Lettuce downy mildew is caused by a fungus which survives the winter on wild hosts and weeds. Light green or yellowish areas on the upper leaf surface are in places where […]
Lettuce: Lettuce big vein virus categories: Lettuce Lettuce Diseases Vegetables last review date: 2022-12-07 12:00 Lettuce big vein virus symptomsPhoto by: R.S. Byther Biology Lettuce Big Vein Virus is transmitted by a fungus which inhabits the roots. Virus infection causes tissues next to veins to become clear, resulting in an enlarged appearance of the veins. […]
Lettuce: Aphids categories: Lettuce Lettuce Insects Vegetables last review date: 2025-12-03 10:13 Aphid colony on leafPhoto by: A.L. Antonelli Biology Aphids are small, soft-bodied, pear-shaped insects. They may vary in color from yellow to green to dark. Aphids typically feed in colonies on the leaves, often preferring the newer growth. Infested leaves turn yellow and […]
Lettuce: Slugs categories: Lettuce Lettuce Insects Vegetables last review date: 2025-02-26 04:05 Slug damage and slimePhoto by: R.S. Byther Biology Slugs are common garden pests in western Washington. They resemble snails, but lack shells. They may vary from as little as 1⁄4″ up to several inches in length, depending on age and species. Slugs often […]