68 THE EEPORT OF THE No. 36 



MoKTALiTY OF Eggs. The mortality of eggs is considerable. During the 

 latter part of August after the major portion of the egg laying was done, we 

 ejxamined a large number of egg punctures for hatched, healthy and dead eggs. 

 The average per cent, of dead egg& (infertile and diseased) in the September 

 Sweet (autumn variety) was 17.4 per cent.; in the Snow (early winter variety) 

 34.9 per cent.; and in the Northern Spy, 17.1 per cent. 



Mortality of Eggs and Labvae. The mortality of both eggs and larvae 

 was very high in all varieties, as the following table will testify: 



Variety 



Time of Maturing. 



Per Cent, of Mortality of 

 Eggs and Larvae. 



Harvest Summer 



September Sweet Autumn 



Snow lEarly Winter 



Spy Late Winter . . 



77 per cent. 

 88 per cent. 

 97 per cent. 

 98 . 7 per cent. 



Baits and Eepellants. Adults before and during the egg laying period 

 readily lapped up fruit juices and sweetened liquids. We served a varied diet of 

 apple juice, diluted syrup, cut bananas and water to the flies in the cages. In our in- 

 vestigation of remedial measures we made use of this knowledge of the insect's 

 feeding habits. Poisoned molasses was spread on several branches, other branches 

 on other trees were treated in a similar way Avith Tanglefoot. Each Tanglefoot 

 trap was sprayed with a different sweet smelling, attractive liquid. The essence 

 of pear, peach and banana and citronella oil were used. Tin pans containing 

 poisoned cider, essence of pear, citronella oil, and kerosene were also suspended on 

 the branches of badly infested trees. However, the only bait which gave us any 

 results was the kerosene. In seven pans of kerosene we secured at different times 

 twenty males and eight females. 



With the object of repelling egg laying females, nine tin pans containing 

 crude petroleum were hung on a Tolman Sweet. But instead of repelling, the 

 petroleum (or rather rain water with a scum of petroleum) attracted, as vouched 

 for by dead flies in the tins. 



Spraying. We tested two spray mixtures, one composed of arsenate of lead, 

 glycerine and molasses and the other of paris green, glycerine and molasses, but 

 neither yielded satisfactory results. We did not notice any adults feeding on the 

 spray material. If any of them did, not enough died to make the spraying worth 

 the cost. 



Cultural Methods of Control. It does not seem to be possible to prevent 

 the escape of flies from the soil by burying the pupae at a considerable depth with 

 the plough, or by covering them with a baked crust of clay, or with a thick 

 turf. One hundred pupae were placed at a depth of six to seven inches, and 

 another hundred at twelve inches. Forty-one of tlie former and nineteen of the 

 latter emerged. 



Two plots of stiff clay, in each of which one hundred pupae had been buried 

 at a depth of two inches, were watered and then rolled. The sun, as you can 

 imagine, baked the top crust and made it appear as impervious as a flagstone. 

 However, forty adults out of the possible two hundred managed to penetrate 

 through the hard clay. 



