Plant Diseases - Symptoms
Plants stunted in growth (sickly, yellow color; lack of soil fertility or soil pH abnormal): Use fertilizer and correct pH according to soil test. Use 2 to 3 pounds of complete fertilizer per 100 sq. ft. in absence of soil test. Plant at proper time. Do not use light-colored mulch too early in the season. Apply sufficient phosphate at planting.
Plants growing in compacted, poorly-drained soil: Modify with organic matter or coarse sand.
Insect or disease damage: Use a regular spray or dust program and apply iron to soil or foliage for iron deficiency.
Leaves with holes, yellowish and dropping, or distorted in shape: Shows damage from insects. Use recommended insecticides at regular intervals.
Leaves with spots, dead or dried areas, or powdery or rusty areas: Denotes plant disease. Use resistant varieties. Remove diseased plants and use a regular spray program.
Wilting even though sufficient water is present: Soluble salts are too high or plant suffers root system damage. Have soil tested by your County Extension Agent. Use soil insecticides, fungicides. Select resistant varieties.
Poor drainage and aeration: Use organic matter or sand in soil.
Insect or nematode damage: Use recommended varieties and soil insecticides or nematocides.
Tall, spindly, and unproductive plants: A sign of excessive shade. Relocate to sunny area. Keep weeds down.
Blossom drop (tomatoes): For hot dry periods, use mulch and water. Plant heat-tolerant varieties.
Fruit fails to set (vine crops): Poor pollination. Avoid spraying when bees are present.
Blossom end rot, causing leathery, dry, brown blemishes on blossom end (tomatoes, peppers, watermelons): Maintain a uniform soil moisture. Avoid over-watering and excessive nitrogen.