19 



better enable them to stand the sun when transplanted. It was 

 observed that while the plants in the shaded portion of the beds 

 came up earlier and looked healthier during the first three weeks, 

 after that time those without shade looked the better and were 

 finally more vigorous and larger. 



The advantage of the shade is in reducing evaporation and thus 

 enabling the seeds to germinate quicker and more perfectly, and also 

 that it protects the beds from washing by heavy rains. It often hap- 

 pens, as it did in 1903, that many seed beds are entirely destroyed by 

 heavy rains, either by washing away the seeds before they germi- 

 nated or by washing out the plants when quite small. 



Cloth shade was also tried, and seemed to serve better than the 

 straw (PI. I, figs. 3 and 4). The cloth shade was less dense than 

 that of straw, and, while it allowed most of the rain to pass through, 

 it served as a regulator by breaking the fall of the rain and thus 

 preventing washing. 



It is believed that straw shading offers sufficient protection against 

 washing of the seed beds alone to justify its construction, and that 

 in practice it would be well to dispense with it as soon as the plants 

 are well established and all danger from washing is past. 



Another seed bed was divided into five plats and each covered with 

 a different colored cloth, the colors being white, green, blue, yellow, 

 and red. Experiments in France on lettuce and other plants, when 

 growing under different colored glass, have shown that plants develop 

 very differently as a result of such treatment, and it was thought that 

 this experiment might indicate something of value in relation to the 

 growing of wrapper leaf under cloth. Unfortunately the seed used 

 on these plats was poor, being imported Cuban seed, which seems to 

 be very unreliable if bought in the open market, and only a few 

 plants were secured, so that no data of any importance were obtained. 



Soon after the tobacco plants in the seed beds had come up numer- 

 ous burrows were noticed, which indicated the presence of " changas." 

 These galleries or burrows were treated with a solution consisting of 

 1 part of kerosene to 14 parts of water. Openings were made in the 

 burrows at frequent intervals and a small amount of the solution put 

 in. This treatment was repeated two days later, after which no 

 plants were destroyed. 



The plants also appeared to be suffering from some disease and 

 were therefore spraj 7 ed with a dilute solution of Bordeaux mixture. 

 This treatment seemed to be very beneficial, and after a few days no 

 more diseased plants appeared. Bordeaux mixture is especially valu- 

 able as a seed-bed spray because it is a remedy for many diseases that 

 occur on young tobacco plants. a When the plants turn yellow in 



«A description of the flea beetle, tobacco worm, leaf miner, cutworm, and other 

 insects affecting tobacco, together with remedies for their extermination, is given 

 in Farmers' Bulletin No. 120. U. S. Department of Agriculture. See also, Porto 

 Rico Sta. Bui. 2 on the Changa or Mole Cricket. 



