TOBACCO WILDFIRE IN 1922. 25 



reported good control. This year several growers of sun as well as shade 

 grown tobacco spraj-ed plants in the field from one to six times, until the 

 plants were too large to permit of further treatment, but the resuLts have 

 not been eneoiu'aging in the case of sim-growai tobacco. While the treat- 

 ment seemed to check the disease for a time, later in the season after the 

 plants had gro\vn too large to continue the treatment, wildfire spread 

 rather rapidly, and at harvesting little difference could be observed be- 

 tween the sprayed and unsprayed areas in the same field. In the case 

 of one grower who had a rather bad field infection when the plants were 

 small, the use of a Bordeaux mixture applied twice on part of the field 

 when the plants were small checked for a long time any further spread 

 of the disease, and at harvesting time the part of the field sprayed twice 

 showed much less wildfire than the unsprayed part of the field. 



Bordeaux mixtures are cheaper and under field conditions remain on 

 the leaves a longer time, which is of course desirable from the infection 

 protection stand])oint, but a disadvantage when the plants are more than 

 half-grown, as it remains on the leaves and the blue color is undesirable 

 after the cure. 



Another factor operating against the efficiency of dusts or sprays in the 

 field is that after the plants are about half-gro\ni it is a practical im- 

 possibility to operate a duster or sprayer to advantage, and one is obliged 

 to stop the treatment at what might be termed the critical period, as it 

 is well kno\ni that there is often a heavj' wildfire infection just prior to 

 maturity. 



It is believed, however, that some benefit might be obtained from dust- 

 hig or spraying when the plants are small and until the}^ are about a foot 

 high, particularly if spraying or dusting were combined with picking off 

 diseased leaves, and the spraying or dusting repeated at very close inter- 

 vals, say two or three times a week for a period of two weeks or so. 



It is believed that the application of dusts or sprays to tobacco in the 

 lield is worthy of further consideration both by the growers and the 

 station, and next season more detailed experiments along this line will be 

 •carried on. 



At present, however, the evidence at hand is not very favorable for this 

 method of control. 



THE OUTLOOK FOR 1923. 



The cjuestion now most frequently asked by the grower is: What can 

 we expect from wildfire in 1923 and in the following years? Will it con- 

 tinue as prevalent and troublesome as it has been in 1922? Will it be- 

 come worse after our land is thoroughly infested with the germ? Or will 

 it gradually disai)pear? Frequently tobacco growers have told the writers 

 that they would stop raising tobacco if they thought the disease would 

 continue to be as serious as it has been during 1922. No man can predict 

 its future behavior with certainty or anything which approaches cer- 

 tainty, but we can base some judgment on (1) what we know about its 



