43 
varieties in both 1936 and 1937. Considerable damage was done 
to the planting at the Botanic Garden in 1936, the injury being 
greatly increased in 1937. 
Many experiments were carried out trying to find a preventive 
for this disease, various chemicals being tried. None proved to 
be particularly effective. The most successful procedure seemed 
to be to lift the plants when the soft rot appears, clean them up, 
let them dry for a few days, and then reset in new beds. This 
procedure, however, interferes greatly with the successful estab- 
lishment of the plants and the production of abundant bloom in 
later years. Further experiments are in progress, however, and 
perhaps effective methods may be developed. It may be noted 
that the iris borer, which is so commonly associated with this 
disease, has not appeared in the plantings either at the Institute 
- at the Brooklyn Botanic Garden. 
Iris Thrips Control 
For some years, experiments on the control of the iris thrips 
have been undertaken in cooperation with Dr. C. A. Weigel 
and Dr. Floyd F. Smith of the Division of Truck Crop and 
Garden Insect Investigations, Bureau of Entomology and Plant 
Quarantine, Washington, D. C. Most attention has been given 
to the beardless iris, especially the Japanese varieties, which 
have been severely infested with thrips:in the plantings at the 
Brooklyn Botanic Garden. It has been found that immersion 
in water at 110° F. for thirty minutes was effective in killing the 
thrips. If this is done at the proper time of the year, no serious 
set-back to the iris occurs. Most of the treatments have been 
carried on at the Botanic Garden and the treated plants, for the 
most part, have been taken to the Institute at Farmingdale and 
planted. The results have been written up by Dr. Floyd F. 
Smith and Dr. L. G. Utter, and published as Circular 445 of the 
U.S. Department of Agriculture. 
During the past year, interesting results on the control of 
these insects by spraying have been obtained, and some of the 
promising lines will be followed up the coming season. 
We have had the cordial cooperation of Director H. B. Knapp 
and his associates of the State Institute in providing the land 
and cultivating the iris plantings. 
