ee ee ee Se ee rc crrrrS—™CTC 
« 
38 BULLETIN 1357, U. S. DEPARTMENT OF AGRICULTURE 
ticed by keeping the beds free from dried leaves and applying no 
mulch. In the spring of 1922, despite a continued and careful § 
search, only a few scattered beetles were found and the greenhouse # 
was practically free from infestation. Undoubtedly the constant 
hand picking had resulted in a great decrease in the numbers of 
beetles of the overwintering brood. 
In one instance a modification of the hand-picking method was 
advised, which resulted in a greater efficiency because of the greatly 
reduced labor required. It is customary among rose growers to 
water the plants so heavily every three or four days that the water 
collects in puddles or pools on the surface of the bed, from which it 
gradually drains off. Where heavy infestations exist the beetles are @ 
dislodged and thrown to the ground during the syringing and water- 
ing, and on landing in the water they make vigorous efforts to reach. 
the nearest plant or other object on which to make their escape. Va- 
rious growers took advantage of this habit by having the gardeners © | 
follow the man who watered the plants to collect all floating or § 
swimming beetles possible. In a very short time as many as 1,000 
beetles were gathered from three beds of roses. 
Although this method of warfare is crude and only partially effec- 
tive, it appealed to the florists, and for this reason efforts were di- 
rected toward improving the practice by “ filming” the surface of § 
the flood water with a contact insecticide, such as kerosene nicotine 
oleate.® 
Spraying the insects on the plants with the same solution proved 
ineffective, because of their hard wing covers and body. The success 
of this treatment therefore depended on the beetles swimming 
through the poison so that it came in direct contact with the softer 
body ‘parts under the wing covers. Preliminary tests were made 
with one-half pint of kerosene nicotine oleate stock solution diluted 
with 4 gallons of water. This solution was applied over about 6 
square feet of surface by means of a sprinkling can, and the results 
were promising. Applied in this manner the insecticide was greatly 
diluted by filming and spreading over the water surface; neverthe- 
less its effect on the beetles was apparent almost immediately aiter 
they came in contact with it. 
Fourteen beetles were collected and held for observation. Seven of 
them had been subjected to this treatment, whereas the others had 
merely been washed from the plants by the force of the water. Two 
days later the treated specimens were dead and the “checks” were 
still alive. Three days after the preliminary test 7,000 plants in one 
large range were treated. Specimens of the treated beetles kept 
8 Kerosene nicotine oleate stock solution is prepared as follows and is a slight modifica- 
tion of William Moore’s original formula. 
Stock solution: 
Solution 1— 
BCOTOSONG a ac 2a a al ee ee 8 parts or 1 gallon. 
Oleic: geid (2 ees 2 ee es oe eee es 1 part or 1 pint. 
Solution 2— 
a LEY ri Pewee cP Uy EL Ys Weenie Pi Be ly oA ot SR a ll tly Ld 3 2 parts or 2 pints. 
Waters S50 fia 2s ops fr bee Ree ch eee, Se eS, 8 parts or 1 gallon. 
Solution 1 is prepared by slowly pouring the oleic acid into the kerosene, stirring con- 
stantly. In another vessel solution 2 is made up by adding the volatile nicotine to the 
water. The stock solution is then prepared by stirring solution 1 into solution 2 and 
bringing the mixture to a creamy consistency by churning it rapidly for several minutes, 
pouring from one vessel to the other, or pumping the liquid back upon itself through a 
bucket pump. 
eee 
