BLODGETT: WEATHER AND CROP DISEASES IN TEXAS 77 
commonly invaded by the rust-parasite Tuberculina in so far as the 
leaves still attached to the plants were concerned. These were, 
however, far fewer in number than those affected earlier, as shown 
by the dry leaves under the plants in the rows, which were shed 
by the plants before becoming parasitized. 
The disease was noted almost simultaneously by Dr. Morton 
of Mercedes and County Agent Miller of Edinburg, from both of 
whom specimens were sent to the Experiment Station. Field 
inspections and interviews four weeks later showed the epidemic 
to be past, and no fresh areas developing. It was learned that 
about two weeks previous to the observed outbreak of the disease 
about a week of showers and cloudy weather had occurred, this 
being distinctly unusual in that section. After making allowance 
for possible inaccuracy of statement, it seems probable that the 
disease was present in cotton fields on the Mexican side of the Rio 
Grande, as Dr. Morton learned of ‘yellow leaves" occurring in 
that locality. Southwest winds prevail during much of the season 
in that part of Texas, and invasion of spores from the alternate 
host (as yet unknown) or possibly viable sporidia from germinating 
teleutospores might be carried over the half mile of river between 
the Mexican and American fields. According to Dr. Morton, the 
trouble spread northeasterly from Rio Grande City or Sam For- 
dyce to Edinburg and Donna, making a total travel of 25 or 30 
miles in a couple of weeks or less, according to his observations and 
conversations with farmers. 
An interesting ecological detail was learned during a personal 
inspection of the fields, namely, that those fields suffered most 
Which were nearly ready to show first blooms. Fields either older 
or younger were less seriously injured. This was shown in the 
fields showing effects of serious damage by the presence of bolls 
with the involucral bract and calyx carrying aecidial sori; fallen 
leaves with the rust areas in abundance were numerous under such 
plants. 
There may be some close relation between the date of appli- 
cation of irrigation water to the field and the appearance therein 
of the rust. This point did not come to mind in time to receive 
attention while in the field, but may have an important bearing 
through the use of the Rio Grande water as a vehicle of transport 
