September 14. 1907 



HORTICULTURE 



347 



Pear Blight 



rear l)lijrlit lias probably been the cause of more 

 losses to California fruit growers than any other dis- 

 ease. In fact, its ravages have been so uncontrolable 

 that the pear tree in many parts of the state, it a thing 

 of the past. Thousands of dollars have been spent dur- 

 ing the last few years in hopes that this disease would 

 be checked. During the last three years the State Uni- 

 versity has had from four to six men in different parts 

 of the State demonstrating by actual work the meth- 

 ods best adapted for its control. As this disease is also 

 m the east, perhaps a few words upon its history, ap- 

 pearance and treatment will not he out of place. 



Pear blight was first described by the Massachusetts 

 Society for the Promotion of Agriculture in 1792. At 

 this time it was discovered on some apple trees in New 

 York State. Ijater it was found in Long Island, New 

 Jersey and Pennsylvania. Its presence seems to be 

 noticeable in many of the early orchards through the 

 East and Middle West. It is interesting to note that 

 it has never been found in Asia or Europe ; the coun- 

 tries where the pear and apple tree are native. It is to 

 be found not only on them, but also on the quince, haw- 

 thorne and wild plants of the pome family. It was not 

 until 1878 that the cause of the disease was known and 

 this was discovered bj' the pioneer plant pathologist. 

 Professor T. J. Burrill. As new orchards were planted 

 in the Middle West, the blight followed them, but it was 

 not troublesome in California until the last eight or 

 ten years. 'Wlien it did gain entrance it made remark- 

 able headway, due to the favorable climatic conditions 

 for its growth. It is found upon all varieties of pears, 

 but the Bartlett seems to be affected more than the 

 others. 



Pear blight is caused by bacteria (Bacillus amylov- 

 orus.) These microbes are extremely minute and can 

 be seen only through a very high power microscope. 

 They consist of a single elliptical or round like cell and 

 are the smallest living vegetable organism known. So 

 much for the history of pear blight. 



ITS APPEARANCE 



It is first noticeable in the spring of the (year, a 

 month or so after the blossoming period. If you will 

 look at the flower clusters carefully you will observe 

 that where the blight is present, they will look shriv- 

 elled up and those that are affected badly will appear 

 as if dying, and upon these, small globules or drops of 

 gum will bo seen. In a short time you will probably 

 observe the tips of the young shoots or twigs dying. If 

 the weather conditions are favorable for its gro\\i;h, 

 these small twigs will not only die, but also the branches 

 from which they grow. 'Wlien the blight gains en- 

 trance to the larger limbs, it progresses very rapidly. 

 Wlien the bark is scraped off the diseased areas you 

 will notice that the cambium layer, which is normally 

 white, has turned red and where the bark is not too 

 thick, large red drops of gum are exuding, later solidify 

 and turn black. 



As the disease progi'esses, it will not stop in the limbs 

 but will continue to spread in the trunk and roots. The 

 writer has seen the blight kill roots two and sometimes 

 three feet under ground. Not only are the weaker trees 

 affected but many times the best, largest and most 

 healthful trees will siiccumb under its ravages. 



TREATMENT 



The treatment has been discussed before in this 

 paper, so I shall not dwell upon this subject at any 

 length. The only thing to do is to cut it out as fast as 



it appears. If it has gained entrance in the twigs only 

 — cut them off before it runs down into the larger limbs. 

 If it is in the larger branches or trunk, cut out the 

 affected portions. In dealing with this disease, great 

 care should be taken to keep all the instruments well 

 disinfected, as these are a quick way of spreading the 

 blight. Corrosive sublim.ate is the best disinfectant to 

 use. The cuts should also be washed with this material. 

 Conscientious work is the only way of controlling this 

 disease and the lack of it is the cause of many failures. 



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Timely Chrysanthemum Notes 



FEEDING. 



As the plants are now getting to be a good size and 

 llie benches well-filled with roots, they will be in need 

 of liquid feeding to give them the good stout stem, dark 

 foliage and splendid flowers which we all look for with 

 so much anxiety and interest. 



The chrysanthemum grower can not be too careful in 

 this matter, as a little carelessness will spoil a whole sea- 

 son's labor. There are several good chemicals on the 

 market that can be used, but the chemicals in most gen- 

 eral use are nitrate of soda, potash and sulphate of am- 

 monia; if more than one of these are to be used they 

 sliould be used alternately in the following proportion, 

 one four-inch pot of chemical to a 50-gallon barrel of 

 water if applied with an ordinary pump or watering 

 can, but if a Kinney pump is used the amount of chem- 

 ical should be doubled as the chemical is reduced to one- 

 half the strength. This application once a week should 

 be sufficient with a watering of good liquid cow manure 

 given in between. 



The plants should be gone over every two or three 

 days, the side shoots taken off and the suckers cut away 

 from the base of the plants to give the buds and foliage 

 on the main stem all the nourishment possible. 



EUMTGATING. 



The plants should be gotten clear of all insects now 

 if possible, for later on when the buds begin to show 

 color all fumigating will have to be stopped. 



The most effective method we find is to lay papers 

 along the front walk big enough to hold a double hand- 

 ful of tobacco dust, sav ten or twelve to a hundred-foot 

 house making a small hole in the top of the dust and in- 

 serting a short piece of thick twine about an inch long to 

 lie used as a wick. Pour just enough kerosene on the 

 string to ignite the dust, close the house tight letting it 

 remain so until morning. If one fumigating does not 

 destrov the flies this sliould be done two or three nights 

 in succession. In buying the dust the grower should be 

 sure to order the fumigating kind as the others will re- 

 fuse to burn. 



SUPPORTS. 



The supports for the plants should be looked after and 

 put in good shape so that they will be able to hold the 

 flowers in position when they become fully developed, 

 as the weight of a crop of ffowers is far more than one 

 would think. 



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