Alfalfa Field Manuals

Phosphorus Deficiency
Phosphorus deficiency usually does not produce a definite symptom, only a…
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Potassium Deficiency
Symptoms show up first as white spots around the outer edges of the upper…
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Sulfur Deficiency
Like phosphorus, sulfur deficiency produces stunting, the degree varying…
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Boron Deficiency
Boron-deficient alfalfa is sometimes called "yellow top." The symptoms are…
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Calcium (Lime) Deficiency
Alfalfa will not grow well on acid soils. Where lime shortages are a…
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Iron Deficiency
The upper leaves are a bleached yellow color. Iron deficiency usually…
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Frost Heaving
Heaving usually occurs on heavy soils high in moisture. Alternate freezing…
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Air Pollutant Damage
Alfalfa is sensitive to high concentrations of smog, sulfur dioxide or…
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Bacterial Wilt
First symptoms are a yellowish-brown discoloration in the woody cylinder…
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Phytophthora Root Rot
Phytophthora root rot occurs in wet, poorly drained soils during extended…
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Fusarium Wilt
Stems on one side of the plant wilt and die, and later the entire plant…
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Fusarium Root and Crown Rot
External symptoms are evident first in the leaves which curl at the edges,…
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Sclerotinia Crown and Stem Rot
The first symptoms occur in the fall as small brown spots on leaves and…
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Anthracnose
Diamond shaped lesions with dark borders appear on the lower portions of…
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Rhizoctonia Stem Blight
Dark, sunken cankers form near the base of the stem. The lesions often…
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Common Leaf Spot
Small, circular, brown to black spots appear on the leaflets. As the spots…
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Lepto Leaf Spot
Small brown spots on the leaflets, surrounded by a halo, enlarge and…
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Stemphylium Leaf Spot
Spots on the leaflets are oval or irregular and appear sunken. Usually…
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Spring Black Stem
Dark spots with irregular borders appear on the leaves. They enlarge and…
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Summer Black Stem
Large, usually circular, light gray to black spots appear on the leaves…
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Bacterial Leaf Spot
Small water-soaked spots on the leaves enlarge, become brown to black, and…
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Downy Mildew
Light green to yellow blotches appear on the leaves. Terminal portions of…
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Alfalfa Mosaic Virus
Symptoms of alfalfa mosaic are yellow streaks between the leaf veins or…
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Stem Nematode
Frequently appears in moist field conditions, normally early in the spring…
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Alfalfa Weevil
Damage usually starts in early spring when the larvae emerge. The young…
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Clover Root Curculio
The adult clover root curculio is a small, slender, dark-gray snout beetle…
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Potato Leaf Hopper
This tiny light green insect which jumps when disturbed is a common cause…
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Pea Aphid
This large bright green aphid is common on alfalfa. It builds up huge…
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Spotted Alfalfa Aphid
This tiny aphid is light yellowish green or straw colored with rows of…
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Meadow Spittlebug
The meadow spittlebug is an early spring pest. The most characteristic…
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Variegated Cutworm
This cutworm can cause extensive damage to alfalfa during warm, wet…
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Differential Grasshopper
The differential grasshopper is only one of several species of…
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Lygus Bug (Several species)
There are several species of Lygus bugs which are common in alfalfa…
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