The Mena weekly star., 1921-05-05
CONTROLLING
 COTTON DISEASES
Practice Crop Rotation and Plant Di- sease-Free Seed or Disease Resist ant Varieties to Prevent Loss, Is
 Advice of Dept, of Agriculture.

In certain sections of the South cot ton diseases are so prevalent and severe that portable crops cannot be grown by the methods usually em- ployed. There are, however, control measures which can be depended upon to greatly reduce losses from many of the diseases which cause greatest damage. These diseases, with meth ods of control, are described in Farm ers' Bulletin llS1 "Cotton Diseases and Their Control" recently issued by the United States Department of Agriculture.
 Wilt, or black root, according to the bulletin, causes the greatest losses to the cotton crop. Affected plants first wilt, and then die. The roots of diseased plants turn black, and from this fact comes the name black root" The disease Is widely dis tributed turnout the sandy soils of the cotton belt, from Virginia to Tex as, and spreads each year to new lo- calities. In severe cases the yields are reduced as much as 75 to 90 per cent.
 The planting of wilt-resistant var ieties of cotton, combined with the use of proper rotations, is the only eff fective method now known of con- trolling the disease.
 The presence of another disease, root-knot, in many sandy soils, makes the wilt more severe and it is, there fore, essential that infested lands be planted for one or more years to crops which resist root-knot before wilt-resistant cotton is grown. The first wilt-resistant variety, Dillon, was bred by cotton specialists of the department, who also developed Dixie, a productive medium early variety, the Dixie-Triumph, and Dixie-Cook. Both of the latter are early varieties.
 Root-knot is next in importance to wilt from the standpoint of money losses to the cotton crop. It is found chiefly on the same types of soil, but as it is more widespread in it occur renee and as it attacks other crops, 1t causes a greater loss to farmers. The balls produced on the roots of the cot ton plants cause them to become stunted. Root-knot can be controlled by using crop rotations in which root-knot-immune crops are planted on diseased fields for two or three years previous to planting cotton. Among such crops are barley, velvet beans, corn, several varieties of cow peas, Bermuda grass, millet, oats, rye, peanuts sorghum and wheat.
 Cotton anthracnose is often more widespread than wilt, since it is known to occur in most of the cotton growing sections. 1t annually causes losses which range from slight to as high as 80 or 90 per cent of the crop. Losses may be largely reduced by giving careful attention to seed selec- tion and crop rotation. Seed for planting should be secured only from fields free from disease or be selected from healthy plants at some distance from any which have diseased bolls. Some varieties of cotton seem more resistant to this than others. The TooIe, Triumph, King, Dillon, Cleveland and Russell cottons are Tn general fairly free from anthracnose.
 Bacterial blight, disease which causes large money losses, attacks the cotton bolls, leaves and stems. The first signs of the disease are dark green, water-soaked spots on leaves and bells which spread and later be- come dark brown to black. The best method on control is to plant only di- sease-free seed, and to practice crop rotation.
 Shedding the premature dropping of the squares or young bolls. can be lessened, according to the bulletin by increasing the supply of humus in the soil and by late shallow cultiva- tion to conserve soil moisture.
 Measures recommended for the con- trol of rust are the addition of humus to the soil, the use of potash con taining fertilizer, and drainage if the land is wet.
 No satisfactory method of controll- ing Texas root rot is available, but deep faii blowing and crop rotation are recommended as the best known measures for reducing losses from this disease.
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