1488 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



malin, one part of the reagent to 10,000 

 parts of water may be employed, or one 

 pint to 1,250 gallons has heen sufficient to 

 check infection. Permanganate of potash 

 is rather a mild disinfectant as compared 

 with formalin and it is necessary to use 

 one pound to 625 gallons of water. A 

 stronger concentration discolors slightly 

 and the former strength is advised. Cop- 

 per sulphate, which is both a cheap and 

 effective disinfectant, may be used, of 

 about the same strength as the perman- 

 ganate of potash. Care should be taken 

 that this is not employed in very much 

 more concentrated form, one pound to 250 

 gallons, for instance, resulting in injury 

 in the form of a burn. Unfortunately, how- 

 ever, this substance attacks the arm of 

 the tank and is therefore less desirable 

 than those previously referred to. A 

 higher concentration of blue stone is 

 needed on account of the alkalinity of the 

 water used. In distilled water, one part 

 of blue stone to 1,000,000 will be effective. 



Brown Spot 



A serious trouble in some localities, 

 characterized by the development of dark 

 brown, sunken, dead spots of considerable 

 size on the rind, appearing from five to 

 ten days after the fruit is picked. Not 

 visible on the tree. Apparently due to 

 climatic or other local conditions rather 

 than to any parasite. 



It would appear that in the physiologi- 

 cal processes which go on in the rind dur- 

 ing its development and ripening, some 

 substance or principle is present in cer- 

 tain areas which inhibits these normal 

 processes. When the orange is picked 

 early in the season it appears that this 

 inhibiting substance is in an active condi- 

 tion and causes the area of tissue where 

 it is present to begin to die as soon as 

 the fruit leaves the tree. If the orange 

 stays on the tree until later in the sea- 

 son the injurioxxs substance seems to dis- 

 appear or be removed in some manner, 

 leaving the rind in a normal condition. 



Chlorosis 



This term applies to eases where the 

 leaves become yellow and pale, lacking 

 the normal green color. No definite dis- 

 ease is indicated by these symptoms, 



more than that the trees are in distress 

 of some sort. The cause of the trouble is 

 usually to be found in some unfavorable 

 soil condition. 



Damping Off 

 Khi^octonia fmarium 

 Causes the loss of great quantities of 

 orange seedlings in the seed beds. The 

 plants begin to die in spots which gradu- 

 ally extend, finally involving large areas 

 if not checked. Two distinct forms of 

 the disease are recognizable, one caused 

 by the first-named fungus above, produc- 

 ing a decay of the stem just above ground, 

 while the other shows itself in dead spots 

 on the stem at any point. 



These troubles can only be controlled 

 by strict attention to proper methods of 

 planting and watering. The seed bed 

 should be constructed with an inch of 

 clean, fresh sand on top, with heavier 

 soil beneath. For the inexperienced grow- 

 er, particularly, it is better to make fur- 

 rows six inches deep and about a foot 

 apart, planting the seed broadcast on the 

 ridges between. The water may then be 

 run in these furrows and allowed to soak 

 into the ground laterally, rather than be- 

 ing sprinkled on the surface. Where the 

 seed is sown broadcast all over the sur- 

 face of the bed and the water applied by 

 sprinkling, watering should always be 

 done in the morning and no oftener than 

 is absolutely necessary. In many cases a 

 good watering once a week is sufficient to 

 keep the soil under the sand wet enough 

 and twice a week is almost always suffi- 

 cient until the plants get quite large. It 

 is better to give the bed a good soaking 

 at long intei*vals rather than to keep 

 sprinkling on a little water frequently. 

 One should keep the surface as dry as 

 possible and after the plants get well 

 started determine the need of water by 

 digging down into the soil beneath rather 

 than wetting the bed as soon as the sur- 

 face sand gets dry. 



Die Back 



This general tei-m denotes cases where 

 the branches die back from the tips. It 

 is not a specific disease, but as in the 

 case of mottled leaf, indicates that some- 

 thing is wrong with the tree. The trouble 



