Lettuce Pest Management Guidelines
UC agricultural management guidelines for control of lettuce pests. Relative Toxicities of Insecticides and Miticides Used in Lettuce to Natural Enemies and Honey Bees (8/07) Lettuce Weed Photo Gallery, with Common and Scientific Names ... [... more]
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Lettuce Drop
Two species of Sclerotinia infect lettuce in California and cause a disease known as lettuce drop: in coastal growing areas Sclerotinia minor is the primary species of importance, while in other areas S. sclerotiorum is more prevalent. ... [... more]
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Lettuce Mosaic
Symptoms of lettuce mosaic vary greatly. Leaves of plants that are infected at a young stage are stunted, deformed, and (in some varieties) show a mosaic or mottling pattern. Such plants rarely grow to full size; head lettuce varieties infected ... [... more]
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Scientific Name: Spodoptera exigua
Beet armyworms lay their eggs in distinctive cottony masses on leaf surfaces. Newly hatched beet armyworms are small green worms that often feed in groups. Older beet armyworms vary in color, but usually have many fine, wavy, light-colored ... [... more]
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Stunt nematode: Merlinius sp.
Root knot nematodes are known to cause economic damage in most areas of California. The needle nematode has been reported only from the Imperial Valley where it can cause serious damage. Damage to plantings can delay maturity and reduce head ... [... more]
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Serpentine leafminer: L. trifolii
Begin checking young seedlings for leafmines. Most mines occur on cotyledons and the first true leaves, and damage is worse in older leaves, which can be stripped in the field at harvest. Some mines are most obvious from the underside of the ... [... more]
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Scientific Name: Pseudaletia unipuncta
Armyworms can damage lettuce seedlings by feeding in the crown and chewing away the midrib and growing point. Once heads form, these caterpillars can bore into them, making the heads unmarketable. COMMENTS: Do not use if leafminers are a problem. ... [... more]
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Relative Toxicities of Insecticides and Miticides Used ...
Selectivity: Broad means it affects most Groups of insects and mites; narrow means it affects only a few specific Groups. Generally, toxicities are to western predatory mite, Galendromus occidentalis. Acute toxicity low but reproductive capacity ... [... more]
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Beet Yellow Stunt
Beet yellow stunt causes pronounced yellowing of older leaves; later, infected plants collapse prematurely and die. Internally, the phloem tissue of the stem and crown is brown and necrotic. General weed control, especially of Sonchus spp., ... [... more]
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Susceptibility of Weeds of Lettuce to Herbicide Control
Weed management for organice lettuce production BEN = benefin (Balan) PRO = pronamide* (Kerb) W. E. Bendixen, UC Cooperative Extension, Santa Barbara Co. BSL = bensulide (Prefar) Integrated weed management fiddleneck swinecress, creeping MET = ... [... more]
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Pathogen: Bremia lactucae
Downy mildew causes light green to yellow angular spots on the upper surfaces of leaves. White fluffy growth of the fungus develops on the lower sides of these spots. With time these lesions turn brown and dry up. Older leaves are attacked first. ... [... more]
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Foxglove Aphid
Foxglove aphid is usually light green with darker green spots at the base of the cornicles but has several color forms, ranging from green to orange to pink. Some of the wingless aphids have many black markings on the top of the abdomen as well. ... [... more]
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