Evening Republican, Volume 16, Number 210, Rensselaer, Jasper County, 2 September 1912 — FIRE BLIGHT [ARTICLE+ILLUSTRATION]

FIRE BLIGHT

By M. W. Richards,

Assistant Hortl-

culturist, Purdue Experiment Station. Purdue University Agricultural Extension.

Fire blight has caused more damage to the Indiana apple crop this season than all other diseases combined. It is safe to say that at least 85 per cent of the fruit Bpurs were killed by blossom blight this spring. Since that time numerous apples have been •truck by the fruit blight and practically every apple and pear tree in the stMe has been covered with twig blight. Fire blight is a strictly American disease. It has been known ever since the early days of horticulture,

Body blight caused from infected pruning saw. When this canker was small it Should have been thoroughly cleaned—disinfected and painted. The top of the tree oould then have been saved. but Its true nature was not known until 1881, when Professor T. J. Burrill of Illinois showed, beyond a shadow of doubt, that It was caused by a specific bacterial organism. The disease manifests itself In several ways and has several names. In the early spring it attacks the blossoms when It is knpwn as blossom blight; later on It may affect the fruit, when It Is called fruit "blight. Throughout the growing season the disease works on the rapidly growing new shoots and causes the tpyical fire or twig blight. The disease spends the winter in the bodies of the trees in the canker form. In the spring the bacteria start to reproduce and from these cankered areas arise the organisms which are responsible for the new infections. As the organisms in the canker reproduce, a slimy ooze is discharged from the wound. This ooze is teeming with bacteria. Bees visit this semi-sweet, slimy fluid and carry the bacteria to the flowers—a blossom

Characteristic "fire-blight." Works in hew growth. Twig, killed from A. Should b« cut at B and burned. blight results. Aphids and treehoppers also feed on this liquid. They then migrate to the tender shoots of the newer growths, insert their

beeks covered with myriads of ba» teria and the twig blight is started. Borers and bark beetles also carry the disease on their bodies and when tunneling into the tree bodies cause cankers to be formed. Cankers are also formed by the bacteria gaining entrance through blighted water sprouts. The disease/can only gain an entrance into the tree by way of natural openings or wounds. Once there it works in the sap wood of the tree. The fact that it works in the interior portions of the tree and that it does not trust to be spread by "means of spores renders it almost immune from our standard sprays. The only satisfactory remedy so far advanced for this most pernicious pest is that of cutting out all diseased tissue and burning it. All wounds made should be thoroughly Bterillzed so as to prevent renewed infection. Spasmodic removal of blighted wood is a waste of time. If the blight is to be controlled, a systematic effort must be made. Cut out all blighted wood at once. Make the cut at least six inches below the dead portion of the twig. Sterilize the stub. This can easily be accomplished by using a solution of corrosive sublimate made up at the fate of one part to 1,000 parts of water. This solution is most readily made by obtaining the corrosive sublimate from the druggist in tablet form. These tablets are known as antiseptic tablets and when one is dissolved in one pint of water a 1 to 1,000 solution of corrosive sublimate is obtained. Place the antiseptic, solution in a bottle with a sponge over the mouth. This bottle can then be tied on the pole shear just below the blade and used to disinfect the stub. In handshear work the bottle may be swung from the belt in a burlap bag which encases the body of the bottle, but leaves the neck exposed. If the blight is to be eradicated from an orchard, treatment for its control should be begun in the winter time. Give each tree a careful examination

Fasten an old bottle near the blade of the pole shear. This Is easily dons by means -of a burlap band. Wire Sponge over bottle mouth. The bottle is filled with disinfectant. The constant motion of the pole keeps sponge saturated. This is then swabbed over each wound, thoroughly disinfecting it. for body cankers. Thoroughly cleau each canker, taking pains to remove all infected wood. Scrape the wound well, disinfect it and then paint with whitedead paint. Just as soon as the trees blossom, visit each tree at least once a, week and break out all blighted spurs. Rub off all water sprouts as they appear. These wounds will not to be disinfected. Throughout the growing season keep the twlgbligbt cut out by systematic use of the pole shear. Rigorous orchard sanitation should also be practiced as anything which tends to control insect pests also tends to the control of the blight. This outline of treatment may seem expensive and severe, but remember that a body canker may kill the tree outright—blossom blight greatly.reduces the crop and twig blight so Injures the tree as to Impair Its fruiting ability. By beginning early, blight should be controlled for not more than |2.00 per acre per season.

Body Blight.

Twig Blight.

Pole Shear Fitted for Blight Work.