Escarole is a broad-leaved chicory grown as a leafy green. The outer leaves are slightly bitter and the blanched inner heart is milder. It is more cold-tolerant and heat-resistant than most lettuce, which makes it useful for extending the salad and cooking-green season in upstate New York.
It grows best in cool weather and bolts in summer heat, so it is usually grown as a spring or fall crop. Sow in early spring or mid-to-late summer for a fall harvest, which often produces the best heads because plants mature in cooling weather. Tie the outer leaves over the center about two weeks before harvest to blanch and sweeten the heart.
Downy mildew
Yellowing on top of leaves with grey-purple fuzz underneath. Spreads rapidly in humid conditions.
Remove affected leaves. Improve air circulation. Avoid overhead watering. Copper spray as preventive.
Aphids
Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.
Lettuce Drop (Sclerotinia)
Lower leaves wilt and collapse onto the soil; a white, cottony mold forms at the crown and base, often with small black resting bodies. Plants rot at the base and die.
Remove and destroy infected plants and surrounding soil debris. Avoid overwatering and improve drainage and airflow. Rotate away from lettuce and other susceptible crops for 2–3 years. Do not compost infected material.
Bacterial Soft Rot
Rhizomes turn mushy and foul-smelling; foliage yellows and pulls away easily at the base. Often follows borer damage or overly wet soil.
Cut away all soft tissue back to firm rhizome, let it dry, and dust the cut with sulfur. Improve drainage and avoid burying rhizomes. Destroy badly infected plants.
Slug and Snail Damage
Large irregular holes chewed in leaves, with slime trails on foliage and soil.
Hand-pick at night, set beer traps, or apply iron phosphate bait. Remove debris and mulch where they hide.
Aster Yellows
Deformed, greenish flowers, stunted growth, and yellowed foliage. Flower centers may produce tufts of leafy growth instead of normal petals.
No cure. Remove and destroy infected plants immediately to stop spread. Control leafhoppers, which transmit the disease, and remove nearby weed hosts.