June, ’23 
marlatt: plant quarantines 
251 
It seems worth while that we extend every effort in exhausting this 
possibility. 
Mr. D. F. Barnes : The relation of direction of flight to wind direction 
has been brought up. The area to be treated is a fixed factor; the wind 
direction variable, changing from hour to hour. If treatment of an 
area has been undertaken and a certain direction of the lines of flight 
established the only variations possible to compensate for changing 
winds are to vary the distances between the lines of flight or to change 
their direction. In a wooded area, with no distinctive features this is 
difficult. Either of the changes may give unequal distribution but the 
change in direction will, dountless, be more disturbing than the change 
in spacing. We know that the wind may vary as much as 180 degrees 
in an hour but in spite of that we must have even distribution of the 
poison if the insect is to be controlleed. 
JOINT MEETING, AMERICAN PHYTOPATHOLOGICAL SOCIETY 
AND AMERICAN ASSOCIATION OF ECONOMIC 
ENTOMOLOGISTS 
Professor E. C. Stackman, President of the American Phytopatho- 
logical Society, called the meeting to order, and stated that the phyto¬ 
pathologists were very happy to meet again with the entomologists in 
joint session. 
President E. C. Stackman: The first paper on the program will be 
presented by Mr. C. L. Marlatt. 
THE WHEN AND WHY OF PLANT QUARANTINES 
By C. L. Marlatt 
Abstract 
A review was given of important legislation in different countries of 
the world in relation to plant pests. After brief reference to the ex¬ 
istence of ancient legislation, an account was given of the European 
legislation with respect to the Phylloxera, culminating in the Bern 
Convention of 1881, and with respect to the potato beetle, dating from 
1875 when this pest obtained its first foothold in Germany. Other 
European embargoes were also discussed, such as that of Great Britain, 
on account of certain gooseberry and currant diseases. 
