72 HATCH EXPERIMENT STATION. [Jan. 



however, as we have stated, not borne out by our observa- 

 tions ; on the other hand, the reverse is true. In general, 

 elevation is connected with dew only in a relative sense, 

 inasmuch as a location 300 feet above the sea may be subject 

 to less dew than one 600 feet in height. And it is not to 

 be presumed, as one writer has inferred, that the elevation 

 above the sea level necessarily indicates in every instance 

 the amount of dew which ought to be present there ; in other 

 words, local conditions affect the amount of dew. On Long 

 Island it is reported that the lower beds rust first, and then 

 those on higher elevations. It may be perfectly true that 

 this takes place in that region and on those soils, although 

 no such instance has come to our knowledge in this State. 

 When plants are not resistant enough to stand uredo spore 

 infection it is not difficult to understand how this might take 

 place ; but the presence of any amount of dew fails to infect 

 some beds in this State. The principal bed on the college 

 grounds is located near a pond, and only a few feet above 

 it. If the effect of dew constitutes an important factor for 

 uredo spore infection, then it would seem as if this bed 

 ought to show it, but fortunately it never has. 



There is evidence, however, that dew plays an important 

 part in asparagus rust infection in those regions where all 

 of the conditions are favorable for uredo spore outbreak ; 

 or, in other words, there are local conditions that exert an 

 influence ; but it appears to exert no such influence so far 

 in those beds which show resistance enough to overcome the 

 uredo stage. We have repeatedly seen plants grown under 

 trees, or in any place where they were shaded by some cov- 

 ering, that scarcely showed the rust, whereas those plants 

 just outside of the covering of the limbs, etc., might be 

 badly affected. Our attention has been repeatedly called to 

 this peculiarity by correspondence with asparagus growers, 

 and this freedom from susceptibility in such local instances 

 is undoubtedly caused by the absence of dew. These facts 

 suggest a possible remedy for the rust, — at least in the 

 starting of young plants. The young plants rust much 

 more easily than the old ones ; they are much more severely 

 injured, and are a constant source of contamination. If 



