February, '16] headlee: dusts and strawberry weevil 



87 



The tests were made on a variety ("Heritage") growing on a sandy 

 farm near Cologne, New Jersey. Woodlands of mixed pine and oak 

 were located on the southern and western side of the field and that 

 part farthest from them — the southeast corner— was chosen. None of 

 the plots exceeded one eighth of a mile from the woodlands. The infes- 

 tation was rather even with a noticeable increase in numbers of beetles 

 as the woodland to the south was approached. 



We resolved to try contact insecticides, stomach poisons and 

 pure repellents. The contacts chosen were pyrethrum, whale oil 

 soap, tobacco dust, and 40 per cent nicotine. The stomach poisons 

 were arsenate of lead both as a powder and as a spray, a dust of arsenate 

 of lead (1 lb.) and sulphur (1 lb.), a dust of arsenate of lead (1 lb.) and 

 sulphur (5 lbs.), and arsenite of zinc. The pure repellents were Bor- 

 deaux mixture (5-5-50) and hydrated lime. 



The arrangement of the treatments with relation to the field, each 

 other, and the checks is shown in the preceding diagram. The treat- 

 ment began when about 6 per cent of the buds had been cut — a little 

 later than we intended. If the determinations of the buds cut showed 

 little or no protection or that the mixture had burned the plants it was 

 not repeated. The table which follows shows the details. 



Table op Treatments and Results 



