The Pulaskian., 1917-10-19


 son clover. There is good evidence tending to show that cotton also is not affected by tobacco wilt, and there is no reason for supposing that oats are affected
 The wilt germ attacks number of plants other than tobacco, and these plants must be kept off the land if tine rotation is to be effective. These plants include tomatoes, Irish pota- toes, and peanuts.
 RagwGed, which is very common fin the flue-cured district also is attacked: it is important that this weed be kept down.
 It appears from the test that on badly infested land the growing of crops not attacked by wilt for four or live years will give better results than only three years of such cropping. The three-year period greatly reduced the amount of wilt, however. It is be- lieved that on badly infested soils a crop of tobacco should not be grown oftener than once in every five years. 1 but after the disease has been brought under control tobacco probably may be grown safely every fourth year. Un- der no circumstances should two crops of tobacco be grown in succession on infested soil.
 l Prevent Spread of Disease.
 Although the rotation of crops makes it possible to grow tobacco on land infested with wilt, those farms In the wilt area that are still free from the disease command a consider able premium, because a larger acre age of tobacco can be grown on them. It is clearly to the interest of the owner to use every possible means of keeping his farm free from the to- bacco wilt. Thorough burning of to- bacco seed beds will destroy the wilt parasite, but the seed bed may be- come reinfested if diseased soil from surrounding fields, even in very small 1 quantities, is allowed to reach the bed after it has been sterilized. The seed bed, as well as the field, also may be- come infested Icy surface drainage from infested fields This explains
 
 that wilt may appear in the first crop of tobacco grown on freshly cleared lands, a fact which should serve as a warning of what may be expected if the surface drainage from neighboring wilt-infested farms Is allowed to reach noninfested tobacco lands. For the above reasons tobacco growers are ad- vised to avoid setting in fields free from infestation plants obtained from seed beds which may be infested. A half dozen infested plants may easily be the means of establishing the wilt permanently on q plantation
 Source of Disease.
 There is no reason for supposing that the disease is carried over in the seed, and there is no doubt that the two principal sources from which healthy fields receive the disease are CD soil from infested fields and (2l diseased tobacco plants, either living plants or the dead material of leaf stem, stalk, or root. Infested soil car ried on a blow borrowed from neigh hor or on the feet of an animal or of man may serve to introduce the dIs- ease. In the process of flue curing If might be expected that the compara- lively high temperatures used toward the end os the curing would be suf- feient to kill the parasitic organism. I but cases have been observed in Gran vile county in which it is highly prob able that the wilt was introduced on tobacco farms through the use of stems as q fertilizer It is not advis- able to use tobacco stalks or stems from diseased fields on lands not al- ready infested with wilt, since the eur ing process cannot be relied upon in all cases to sterilize these materials. Finally. tobacco growers are advised to practice rotation of crops on their tobacco lands as a means of prevent ing the wilt, for if the soil is exposed to infestation the disease is less rkely to become established when a system atic rotation of crops is followed.
 Cover Crops Benefit.