18() Biology and Economic Significance of Tipula paludosa 



period ranged from 16 to 21 days. There was one case in which, 

 owing to severe drought, it lasted six weeks. The actual proportions 

 of crop failure were stated thus: 



Period between sowing 



and germination . Proportion of crop lost 



16 days one-fourth of whole crop 

 6 weeks one-third of whole crop 



17 days one-tenth of whole crop 



3 weeks loss incurred ; proportion not estimated 



16-18 days almost one acre destroyed 



3 weeks one-third of crop 



3 weeks one-third of crop; it recovered later 



On this account early sowing, especially in our north-eastern 

 climate, is attended with a certain amount of risk. The same risk 

 would apply to all late districts in seasons when fine weather early in 

 spring tempts the farmer to sow early. 



Tipula and Oat Varieties. 



The question of the relative resisting or recovery power of different 

 oat varieties in relation to Tipula attack has been investigated both 

 in the field and in plot experiment. The experience of the farming 

 community within the College area has been obtained and discussed, 

 and the general view is given below. There exists some opinion that 

 the larva exercises a selective capacity and prefers some varieties to 

 others, as is evidenced by the following statements: 



"They (i.e., the Tipula larvae) like Potato oats better than Sandy." 

 "Potato oats are more liable to attack than Red Oats or Sandwich." 

 "They are more fond of 'Potato' varieties." 

 "Waverley suffers from attack more than Potato or Sandy." 

 "'Banner' oats suffer more than Potato." 



All the evidence, however, goes to show that this is not the correct 

 interpretation. It is not the larvae which "prefer" particular varieties, 

 but particular varieties which show better power of recovery from 

 their attack. Some of the writers expressed their experiences more 

 carefully : 



" Of the ' Waverley ' and ' Hamilton ' oats which were sown side by side, the 

 'Waverley' had to be resown; 'Hamilton' oats were only shghtly thinned." 

 " The ' Red Oats ' resisted poorly, ' Providence ' and ' Potato ' did better." 



Taken collectively the views of over a hundred farmers who have 

 had experience of Tipula attack is contradictory with regard to the 



