197 



and provide for indemnity to owners for the destruction of trees when 

 tlie degree of infection is sach as not to threaten the ultimate life of the 

 trees. Expenses for experiments of all kinds and for the watching and 

 care exercised by agents are borne by the State, while the expense for 

 the execution of certain of the regulations are borne one-third by the 

 proprietor and two-thirds by the local society. A fine for disobedience 

 of the regulations is also provided for. The laws, as published, are 

 none too severe considering the urgency of the case, and it is refresh- 

 ing to notice the energy with which the Government has met the threat- 

 ened danger, and at the same time gratifying to note the appreciation 

 shown of our own means and methods. 



USE OF CONTAGIOUS GERMS IIS THE FIELD. 



Most of you are aware that I have not had the greatest faith in the 

 availability of contagious disease germs as a means of battling with in- 

 jurious insects in field, garden, orchard, or forest j there are so many 

 delicate questions involved and so many obstacles in the way of prac- 

 tically carrying out any plan, however plausible theoretically or true in 

 principle. Our ability to contaminate healthy by diseased specimens 

 is but a short step and leaves many important questions, as of rapid 

 dissemination, untouched. The theory is very tempting and has been 

 particularly dwelt upon by some who were essentially closet- workers, 

 having but faint realization of the practical necessities of the case. 

 Theoretically, with those insect diseases of a cryptogamic nature, hav- 

 ing a complex life-history and a resting spore, the difficulties are greater 

 than with those of a bacterial origin, and it is to these last that we should 

 look for important aid if it be available. Yet if the work of Messrs. 

 Lugger and Snow should be fully substantiated, the best results have 

 so far been obtained with the entomophthora of the Chinch Bug. No one 

 will be more pleased to have his doubts dissipated by some tangible 

 evidence of the practicability of this method than myself. Success, if 

 possible, will come only by investigation upon thoroughly careful and 

 scientific lines, such as those begun and still pursued by Professor 

 Forbes. The ease with which he conveyed the Silk Worm pebrine to other 

 larvae ; his conveying the Cabbage Worm Micrococcus to other larv?e, 

 and his carrying this Micrococcus in cultures over winter are promising 

 facts, as is also Professor Osbocn's contaminating cabbage worms in 

 Iowa with specimens brought from Illinois. Congress, having at its 

 last session appropriated $2,500 for some further investigation of the 

 Boll Worm, the possibilities in this direction for this particular insect 

 have caused me to plan investigations having for their object thorough 

 field experiment with some of these disease germs. 



Heliothis armigera is one of those cosmopolitan insects which has be- 

 come more injurious in the United States than in any other part of the 

 world, by virtue of its partiality for green corn, green cotton bolls, and 

 green tomatoes. The polyphagous and partially endophytous habit of 



