] 1 ANNUAL BEPOBTS OF DEPARTMENT OP AGRICULTURE, 1 
Comparative tests wore conducted under controlled conditions with many 
materials as substitutes for lead arsenate in soil for the control of the 1: 
Some of these materials were equally as effective iii destroying the 
but are either costly or injurious to plants, it was found that the effectivi 
of add lead arsenate in killing the larvi •• Is modified by the type of boIL This 
difference was not correlate. l with the total salts present or the pll i I 
SOIL The amounts of soluble ammonia, phosphorus, ami magnesium were the 
most important factors influencing the Insecticidal action under favorable 
conditions, tin- effectiveness being increased in Boils containing nigh concen- 
trations of water-soluble ammonia or phosphates and decreased with the 
Increase of soluble magnesium salts in the soil. 
The adult beetle causes considerable damage to roses in commercial green- 
houses by emerging during the winter months and feeding on blooms. Tests 
during the season indicate that this damage can be prevented without injury 
to the plants by treating the beds with lead arsenate. Preliminary data indi- 
cate that ortho-chloro-phenol, cresol, limpid oil, and carbasota may be of con- 
siderable value as repellents for the Japanese beetle and thus afford protection 
to flowering shrubs in home gardens against injury by the beetle. 
In further study of the geraniol bait as an attractant for the Japanese beetle, 
it was found that none of the constituents of geraniol is more than GO percent 
as attractive as the recommended combination of geraniol and eugenol. Phenyl 
ethyl alcohol added to the standard bait increased the attraction, but the in- 
crease in the cost of the bait for a comparatively small gain in the number of 
beetles caught does not appear to be warranted under general conditions. These 
studies have made it possible to prepare and recommend specifications for a 
cheaper grade of geraniol for use in attracting the Japanese beetle. It has 
been definitely established that traps painted green and white are superior to 
traps painted with other colors. Public-service patents covering two types of 
Japanese beetle traps have been granted to F. W. Metzger. 
Derris is a weak stomach poison but has a definite repellency for the adult 
Japanese beetle, the repellent action appearing to be due to the rotenone and 
deguelin content. Exposure to light decreased the effectiveness of derris and 
the material was readily washed from foliage by rain. Several materials have 
been tested as stickers and as means to prevent the decomposition of derris 
in the field. Oils, while very effective stickers, have been found to accelerate 
the decomposition of derris when spread in a thin layer on the surface of the 
leaf. The emulsified residue from rosin stills lias been found to be the cheapest 
and most effective sticker that does not accelerate the decomposition. The 
addition of magnesium silicate to the spray increased the period that the 
material is effective as a repellent Derris without a sticker appeared to be of 
little value in the protection of early ripening apples from attack by the beetle. 
Derris with the sticker has given promising results. The derris spray has a 
disadvantage in that it is necessary to repeat the application every week to 
maintain good control. 
It lias been known for several years that the application of hydrated lime 
afforded considerable protection to foliage from injury by the beetle, but the 
material was limited in its usefulness on account of its poor adhesiveness. 
The addition of aluminum sulphate to the lime spray produced a residue on 
the foliage which lasted through the summer. The use of this cheap, nontoxic 
r<pei lent spray offers considerable promise in commercial orchards and on 
ornamental trees and shrubs. 
investigation to develop methods for treating agricultural commodity 
prevenl artificial dispersion of the insect by human :m«ii«-ies BUggeStS that 
fumigation with hydrocyanic add carbon dlsulphide, or ethylene oxide, now 
■fled for the treatment of small fruits ami bananas, might be extended to In- 
clude potatoes, <>ni<iis. cabbage, peaches, apples, and certain other farm product- 
The lead arsenate treatment of nursery stock in the field has been very satis- 
factory and has made it poSSibe to eliminate -rubs in the soil about the 
roots of large quantities of stork. The major weakness of the treatment is 
in the lack of a uniform distribution in the commercial nurseries. In tests. 
uniform distribution was obtained by applying lead arsenate over the whole 
area of ground on which plants wore standing and working it into the soil. 
The application of the head arsenate only to the area between rows of plants 
did not. b reSUll in a uniform distribution. RnCOUTaging results have 
with paradichlorobensene for the treatment of certain varieties 
Bales I potted plants to destroy larvae in the i" 
