42 DEPARTMENT REPORTS. 



on the opening buds in large numbers. Over fifty lice in one case were- 

 counted on a single bud. T?ro days after the application the trees were 

 again visited, when scarcely a live louse could be found. In a count of two 

 hundred specimens only one live individual was fouud. 



Whale-Oil Soap. Several experiments were made with this soap, which 

 proved it to be nearly or quite equal to the kerosene emulsion for the destruc- 

 tion of the aphides. The strength used was one-half pound of the soap to 

 four gallons of water. 



Soft Soap. Common soft soap reduced in four parts of water was also- 

 found very eflficient for the destruction of the plant lice. 



CABBAGE MAGGOT (AI^THOMYIA BRASSIC^). 



Kerosene emulsion, strong soap-suds and Loudon purple, in the wet way, 

 were freely applied on Tuesdays, Thursdays and Saturdays of each week,, 

 beginning May 5, about the roots of early cabbages for the destruction of the 

 cabbage maggot. This was continued until the flies had stopped their work 

 of egg-laying. An examination of the plants at this time showed them to 

 be nearly as badly infested with maggots as were the untreated rows. This 

 does not prove that the substances had no effect to diminish the attack of 

 the maggots. There was a red mite very numerous in the garden, and which 

 ate great numbers of the eggs about untreated plants. It proves that the 

 benefit of the insecticides did not much exceed the benefit of these little 

 mites. Three of the mites were taken into the laboratory and fed upon fresh 

 eggs to note their rations. Several days' feeding proved that these little 

 mites would suck not less than fifteen eggs each every day. As it was com- 

 mon to find four or five of these little friends about a single plant, it can be 

 readily seen that they were very helpful in lessening the number of maggots 

 about the plants. In another patch kerosene emulsion, whale-oil soap, Lon- 

 don purple and pyrethrum water were used as above, treatment beginning 

 May 21, three days after the plants were set out. The kerosene emulsion was 

 too strong and did the plants more harm than good. The rows treated with 

 London purple and whale-oil soap did not lose quite as many plants as the 

 untreated rows. The pyrethrum seemed to have no effect whatever. 



ONION MAGGOT (ANTHOMYIA CEPARUM). 



Rows of onions were also treated with insecticides as were the cabbages, 

 but received more harm than good. 



RADISH MAGGOT (aNTHOMYIA RAPHANI). 



Kerosene emulsion, whale-oil soap, common soft soap, a strong tobacco 

 decoction, and powdered charcoal were faithfully used about radish plants 

 for the destruction of the radish maggots, but all to no effect. Not a bunch 

 of marketable radishes was taken from the treated or untreated rows in the 

 eniire bed. We do not at present know of any application that is practicable 

 for the destruction of the radish maggot. The location of the bed must be 

 changed each season or else the flies must be shut out by means of gauze. 



PARIS GREEN AND LONDON PURPLE VS. FOLIAGE. 



These two arsenites, in the proportion of one pound to fifty gallons of water. 



