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SECOND REPORT ON ECONOMIC BIOLOGY. 



C. In this case the grapes were about the size of peas, and the 

 fumigation was carried out in very sultry weather about 3 a.m. 

 Grapes browned and killed, the entire crop was lost, but the foliage 

 remained uninjured, and the Mealy Bug was destroyed. A few 

 appeared in October and were destroyed by a second fumigation. 



The next two cases were a conservatory and a greenhouse, the 

 figures for which were as follows : 



In the first case the report is " Complete success. No injury to 

 maidenhair ferns, or any plants under treatment." The pests were 

 Aphis and Mealy Bug. In the last case, the house contained 

 chrysanthemums in full bloom, severely infested with green fly. 

 " Result. Every aphis killed, also slugs, flies, wasps, butterflies. 

 A toad was uninjured. Not a petal or leaf was injured." 



PI ere again I have given in the fifth column the proportions that 

 would have been used had Mr. Froggatt's formula been followed. 



I think it is quite evident from the above five experiments, all 

 repeated, that, provided the foliage is dry, and given a temperature 

 of 5o-52 F., and the absence of a strong light, excellent results may 

 be obtained. 



My first experiment was to test the effect of the quantities men- 

 tioned by Mr. Froggatt. For this purpose a small conservatory of 

 1,000 cubic feet, containing many flowers and blooms, ferns, etc., 

 was used. The temperature was 50 F., after sunset, and the time 

 allowed was half-an-hour. The following quantities w r ere used : 

 10 cy., 10 ac. , 30 water. 



Result : The majority of the plants were killed. Maidenhair 

 fern w r as burnt and dead. Primulas of various kinds were flagging 

 and scorched. All the pests aphids, flies, wasps, etc., were dead. 



The same house was partly re-stocked and again fumigated, 

 using 2, 4, 8, and proved perfectly satisfactory, the pests being 

 destroyed and the plants uninjured. 



