Diseases of Cereal Grains

Ergot Symptoms: The most common sign if a dark purple to black body (sclerotia) found replacing the grain in heads of the plants just prior to harvest. Prior to Development of the sclerotia bodies in the grain head, the fungus develops a stage in the open floret and form droplets that are sticky and yellowish on the infected flower parts. Favorable Conditions: Wet weather and wet soils. Cool weather during flowering is when plants are most susceptible Effects of Ergot Causes a loss of yield Affects Grain grade Toxic to Animals Control of Ergot Rotation with nonsusceptible crops Deep-plow fields to bury ergot spores Plant ergot free seed.

Frost Damage Symptoms Cause Effects Plants tend to shrivel and curl up. Within a couple of days damaged foliage looses color. After 3-5 days if plants have survived they will begin showing new tissue expansion. Cause Lethal frost damage occurs at temperatures below 28 degrees F. Effects Causes a loss of yield of both hay and grain plants Reduces the qualities of grains and hays.

Loose Smut Symptoms Disease Cycle Effects of Loose Smut Control As the plant emerges from boot stage a diseased head appears. Kernels and glumes have been converted to masses of black spores. Later these spores will be blown away leaving the rachis of the head bare. Disease Cycle Plants are infected only during flowering by wind blown spores. Rain and insects may also disseminate spores When infected kernels begin to germinate the hibernating fungus becomes active as well. By heading time the entire contents of the head become transformed into a mass of black teliospores. Effects of Loose Smut Greatly reduces grain yields Affects Grain Grade Control Resistant Varieties are available Plant disease-free seed. Seed treatment is very effective and also an inexpensive way to control loose smut.

Stripe Mosaic Symptoms Transmission Control At an early stage yellow stripes are produced along leaf veins. Severity of damage varies greatly with the strain of the virus. Transmission The virus is transmitted by seed in over 90% of cases. By pollen to the pollinated plant Mechanical inoculation Control Seed sample should be tested for infection before sowing. Some strains of barley have exhibited signs of resistance No treatment will kill the virus without killing the seed.

Stripe Rust Symptoms Disease Cycle Control The fist sign is the appearance of small, yellow, elongated pustules in rows on the leaf. After pustules mature they burst releasing a mass of spores. Plants with have a scorched droughty appearance. Disease Cycle Typically wet cool weather favors the development of the fungus. Many disease cycles take place in one growing season. Temperatures above 59 degrees prevents formation of pustules. Control Application o fungicides can interrupt epidemic outbreaks. Use of resistant plants has been a major means of controlling stripe rust.

Common Rust Symptoms Favorable conditions Transmission Control Reddish-brown oblong pustules on leaves Rust colored spores that will rub off Favorable conditions Cool temperatures with high humidity. Transmission Spores are blown by wind into previously uninfected areas. Cycle completes every 7 to 14 days and will spread again. Control Resistant hybrids Fungicides are not economical High temperatures will prevent rust

Drought Symptoms Preventative measures Initially the foliage wilts and the the leaf stomates close. Roots will loose tiny fibers and plant will begin to die. Edges of leaves and new growth will appear dry and shriveled. Preventative measures Plant varieties that are resistant to drought or that are most suited for growth in your climate. Irrigation systems.

Ear Rot Symptoms Disease Cycle Effects Control Most ear rot varieties exhibit a mold of various color depending on the type on the caps of kernels usually towards the base or head of the ear. Kernels may become discolored and are easily broken into pieces. Disease Cycle The spores are spread by air currents and other mechanical means. Crops residues also spread the funguses Effects Reduce yield, quality, and feed value of the grain. Control Grown resistant varieties Control of earworms and corn borers that are carriers Harvest corn as soon as possible Store grain free of plant debris and at the recommended moisture levels

Iron Deficiency Symptoms Causes Loss of intense green color as chlorophyll production is decreased The plant will yellow between the veins on the leaves. In severe cases the entire leaf may be white Causes Very often develops in acidic soils. High accumulation of other heavy metals relative to the amount of iron present.

Nitrogen Deficiency Symptoms Plants are stunted and show a general yellowing of foliage. Symptoms are first evident in older leaves. Young leaves will remain green for longer periods of time but eventually the whole plant will be affected.

Stalk rot Symptoms Causes Control The fungus typically invades the base of the corn stalk. First symptoms usually appear as an onset of grayish-green color of the leaves. The lower stalk turns from dark green to a tan and becomes soft. When diseased stalks are split the pith usually has a reddish of pinkish discoloration. Causes Plants that undergo stress are more susceptible to stalk rots. The fungus survives year to year on infested corn stalks and roots left in the field. Control Hybrids will good stability and that are resistant to common stress factors in your area. Control of Insects that cause stress. Rotate crops Harvest early to avoid lost ears in the field

Phosphorous Deficiency Symptoms The first symptom is a loss of sheen of the older leaves, that may appear darker green. Next the veins on the underside of leaves with exhibit red, blue or yellow discoloration. Plants become stunted and new leaves are reduced in size.

Copper Deficiency Symptoms Plants suffering from copper deficiency are severely stunted with small terminal leaves. Terminal leaves eventually die. As terminal leaves die multiple buds will appear on below each leaf giving the plant a “witches broom” appearance.

Grain Weevil Effects Prevention Methods Direct feeding damage results in the reductions in weight, nutritional value, germination, and market value. Contamination of grain. Prevention Methods Don’t store new grain in a bin with older grain. Clean and spray bins before adding new grain. Inspect grain regularly Fumigate already infested grain.

Grasshopper Damage

Potassium Deficiency Symptoms Exhibited in older leaves first. A browning occurs along the leaf margins. May cause a reduction in plant size.

Wireworm Damage

Yellow Mosaic