62 
to the flowers, as well as disfiguring the foliage. From time to 
time experiments have been carried out in order to find some 
method of control. During the last two years extensive experi- 
ments, involving particularly the use of the hot water treatment, 
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 Quaran- 
tine, Washington, D.C. The plants have been dug and treated 
at the Botanic Garden. However, in order to carry the experi- 
ments to a successful conclusion, it was necessary to find facilities 
at some distance so that the plants could be grown free from 
further infestation following their treatment. Through the cour- 
tesy of the officials of the State Institute of Applied Agriculture 
at Farmingdale, it was possible to secure the necessary land on 
the Institute grounds. 
In April 1935, an extensive series of varieties was treated, in- 
cluding a large number of Japanese and a smaller number of the 
Siberian, Southern, and Tall Bearded groups. These experiments 
were intended to give preliminary information as to the effective- 
ness of the treatment in killing the thrips organism and determining 
the extent of injury, if any, to the varieties thus treated. In the 
late summer and fall a large number of additional treatments were 
made ; in fact all the plants set out in the newly established Farm- 
ingdale Iris Garden were treated by the hot water methoc 
fad 
Forest PAaTHoLocy 
By ArTHUR HARMOUNT GRAVES 
Chestnut Breeding Work in 1935 
Since there are some to whom this report will come for the first 
time, a restatement of the whole project seems best, in the interest 
of clearness. Our aim is to develop a_tall-growing, disease- 
resistant chestnut tree of a type suitable for timber, to replace the 
valuable native species which has been killed off by the fungus 
Endothia parasitica. To this end we started six years ago to 
cross Japanese chestnuts (comparatively low-growing trees but 
disease-resistant) with the American species (tall-growing but sus- 
