96 Habits of the Tomato Moth 



houses. The plants had not been sprayed and no organised hand-picking 

 had been practised. The first brood of larvae was at its maximum about 

 the last week in May, and the second about the third week in July. 

 It was then the most heavily infested of the 12 blocks in the nursery. 

 The foreman in charge thought that it would be necessary to put all 

 the hands available at the work of hand picking the larvae in order to 

 save the crop. Experimental trapping with various baits had been 

 commenced in June on a small scale, and at the beginning of July three 

 traps baited with ale and treacle were placed in each house, one at each 

 end and one in the middle, suspended from the wires near the gutters. 

 This system of trapping was continued to the end of the season, with 

 the exception of a fortnight at the beginning of August when all but 

 four of the jars were removed and replaced by 72 pieces of muslin 

 soaked in the bait to which 1 per cent, sodium fluoride was added. This 

 method was considered unsatisfactory as, though the initial outlay is 

 less, the attention required by them is greater than in the case of the 

 jars, and as shown above a poisoned moth may lay a few eggs. Also 

 no dead moths could be found, and it was thought that the growers 

 would have more confidence in a method, the results of which were 

 evident. When the full quota of jars were replaced on August 14 the 

 poison was added to the bait. 



At first the moths were caught at the rate of 80 a night, and the 

 numbers steadily decreased to the end of July when 8 a night were being 

 captured. The third flight of moths commenced while the exposed baits 

 were out, and were caught at the rate of 175 a night when jars were 

 replaced, and the nightly catch declined till, from September 16 onwards, 

 it only averaged 2. A total of 1057 were taken in the second flight, 

 and 1968 in the third flight, while an unknown number were poisoned. 

 Of these 3023 moths approximately 71 per cent, were females, many of 

 them distended with eggs. In order to estimate the effects of this trapping 

 counts of the large conspicuous larvae were made occasionally in one 

 of the end houses, each examination occupying about two hours. On 

 July 23, before the trapping could have affected the numbers of these, 

 351 were seen, and a week later 150 (reference to Diagram III will show 

 that this reduction was quite abnormal and could not have been obtained 

 by hand-picking). On August 11, 65 were found, and on September 10, 

 16 only. The larvae following on the large third flight of moths were 

 therefore very few, though in neighbouring blocks where early spraying 

 had been done, those of the third brood could be collected by the 

 thousand in September. 



