THE LIFE HISTORY OF THE STRAWBERRY 



TORTRIX, OXYGRAPHA COMARIANA 



(ZELLER). 



By F. K. PETHERBRIDGE. 



School of Agriculture, Cambridge. 



(With 1 Plate.) 



The first record of serious damage by the caterpillars of this moth was 

 made by Miss Ormerod 1 , from notes sent by Dr Ellis of Liverpool in 

 1883, who in turn recorded them from Mr Richard A. Wrench, of Dee 

 Banks, Chester. The strawberries attacked were in the neighbourhood 

 of Dee Banks. 



The next record is by Theobald 2 who records them as doing serious 

 damage to a field of strawberries belonging to Messrs G. Mount and Sons. 



From 1913-1917 they caused serious damage to strawberries at 

 Terrington St Clements, Walpole and Walton between King's Lynn and 

 Wisbech, and in several cases reduced the crop to about 25 per cent, of a 

 normal one, with the result that many acres of strawberries were ploughed 

 up as being unprofitable. In 1918 they were recorded by Theobald as 

 present in Warwickshire, Somerset and Hertfordshire. 



Life History. The young larvae begin to hatch out at the end of 

 April or early in May. In 1918 they were found on April 21st, but in 

 1917 and 1919 they were not found until the first week in May. As soon 

 as they hatch they begin to feed on the very young folded fan-shaped 

 leaves and to make holes through the successive layers: sometimes they 

 leave the upper epidermis intact. They remain sheltered by the folded 

 leaves so that they are not visible until the leaves are unfolded. After 

 a time some of the larvae begin to feed on the unopened flowers. They 

 bore a hole through the folded calyx and feed on the stamens and 

 developing carpels, with the result that the flowers attacked either do 

 not form fruit or form only distorted ones. 



1 Ormerod, E. A. Handbook of Insects Injurious to Orchard and Bush Fruits, pp. 

 258-260. 



2 The Journal of the South-Eastern Agricultural College, 1911. 



