1927] 
Control of European Vine-moths 
147 
survey of the country for an infestation where methods of control 
with calcium cyanide could be studied, but without success, for 
the infestations throughout the country had been reduced to 
a minimum. 
European entomologists have uncovered a formidable array 
of natural enemies during their constant studies of these two 
pests. There are recorded some forty hymenopterous parasites 
of the eggs, larvae, and pupae common to both pests. They are 
also frequent victims of several fungi and bacterial diseases. 
The annual loss occasioned by the two pests, despite these natural 
enemies, has always been enormous, for which reason many 
efforts at artificial control have been attempted. 
One of the most promising artificial control measures was 
that attempted on a small scale by Dr. Friedrich Stellwaag of 
Neustadt a/d Haardt, Germany, in 1917-1918. 2 He conceived 
the idea of fumigating the vines with HCN gas by the use of 
sodium cyanide and sulphuric acid under cover, because of the 
success this method had produced in the California citrus groves. 
His preliminary experiments, well planned and thoroughly ex- 
ecuted, were carried on between April 24 and June 12, 1917. In 
April the fumigations were made on the leafless vine stalks 
(winter condition) and in June they were fumigated in their 
summer condition. The results obtained in Dr. Stellwaag’s ex- 
periments may be briefly summarized as follows: 1. Fumigation 
of the plants in their leafy (summer) condition, even when only 
small quantities of the gas are used, cause damage to the foliage 
without completely killing the pests. 2. On the other hand the 
vines in their leafless (winter) condition are able to withstand 
larger quantities of the gas, sufficient (under the conditions of 
the experiment) to kill the cocoons found under the tent* in which 
the fumigation was done. 
The results of his 1918 tests 3 checked substantially with 
those of the previous year, except that more injury to the vines 
was noted due to rapid formation of the gas. Furthermore, Dr. 
Stellwaag believed that this form of fumigation was “too fussy, 
2 “Der Weinbau der Rheinpfalz,” No. 8, August 1917. 
3 “Der Weinbau der Rheinpfalz,” No. 1, January, 1919. 
