10 Life History of the Strawberry Tortrix 



Arsenite respectively. These sprays did not succeed in reducing the 

 caterpillars to any extent, probably due to mechanical difficulty of 

 reaching with the spray the young folded leaves on which the young 

 caterpillars feed. 



Many of the growers who sprayed with Lead Arsenate were pleased 

 with the results, but they were then probably not aware that, thanks 

 to the energies of the chalcid parasites, the caterpillars had almost dis- 

 appeared from strawberries which were not sprayed. 



Apart from parasites, the best means of reducing this pest seems to 

 be to run a mowing machine over the crop so as to cut off the tops as 

 close to the crown as possible when the pest is in the second pupal stage, 

 viz. at the beginning of September. (It is a common practice with many 

 growers to cut off the tops during the autumn.) The tops must then be 

 raked up and burnt or buried before the moths come out, i.e. the middle 

 of September. I tried this on one field but unfortunately the grower 

 waited too long before destroying the tops. (Note: the eggs are laid 

 too low down to be cut off in this manner.) 



Old strawberry beds destined to be ploughed up should be ploughed 

 after the eggs are laid in November, as by ploughing earlier than this 

 the moths will probably lay their eggs on neighbouring crops of straw- 

 berries, or on wild plants of Fragaria and Comarum near. 



