471 



The foliage of cowpeas, both in a fresh and a decaying condition was 

 found to be very attractive to the larvae. Tests were therefore made 

 to determine whether this attractiveness was maintained in the 

 presence of arsenicals, and whether the latter were effective in destroy- 

 ing the grubs. Cowpea foliage, which had been previously sprayed 

 with molasses (1 pt. to 3 pts. water) and dusted with Paris green (100 

 per cent.), was buried to a depth of 2 inches in soil containing a number 

 of larvae. Subsequent examination showed that a quantity of the 

 fohage had been eaten and the mortality among the larvae amounted 

 to 90 per cent, in 16 days. Decaying leaves treated as above caused a 

 mortaUty of 100 per cent, and remained palatable for at least 27 days. 

 When mixed with three times its weight of flour, Paris green proved 

 fatal to 100 per cent, of larvae in 25 days. Leaves treated with white 

 arsenic (100 per cent.) retained their efficiency for at least a month and 

 destroyed 100 per cent, of larvae. When diluted with flour, as in the 

 previous experiment, the resulting mortality did not exceed 33 "S per 

 cent. White arsenic, although much less efficient in the diluted form, 

 has the advantage of being about one-sixth of the cost of Paris green. 

 The total cost of labour and undiluted white arsenic for use on a large 

 scale would not exceed 12s. 6d. per acre. In the field, cowpeas should 

 be sown about three weeks after the first appearance of the adult 

 beetles. The plants would then be ready to spray, dust and plough in, 

 about four weeks later. It is proposed to carry out field investigations 

 in connection with this method of control during the next season. 



Jarvis (E.). a New Insect Pest of Sugar-Cane. — Queensland Agric. 

 JL, Brisbane, vi, no. 2, August 1916, pp. 102-103. 



Melanitis leda, L., was found in small numbers in plantations of young 

 canes in the neighbourhood of Gordonvale. This butterfly is widely 

 distributed in Australia and also occurs in New Guinea. Egg-masses, 

 containing from three to eight eggs, are found on the under side of the 

 leaves, the larvae feeding on the foliage of sugar-cane and grass. The 

 pupae were attacked by a disease, possibly of a bacterial nature. 

 Parnara maihias appeared to be widely distributed. The eggs of this 

 butterfly are laid singly on the upper side of cane leaves. The larvae 

 are attacked by a Braconid and a Tachinid parasite. Telicota 

 angias hreffti was aho found during the month. 



Smoking out Rutherglen Bug. — Agric. Gaz. N.S.W., Sydney, xxvii, 

 no. 7, July 1916, p. 488. 



In 1914 the Rutherglen bug [Nysius vinitor] was so numerous in an 

 orchard that the owner only obtained 100 boxes of apricots. In the 

 following year sheep manure was deposited in heaps on the south-west 

 side of the orchard, from which quarter there was a night breeze in the 

 early summer. Sulphur was mixed with these heaps, and when they 

 were burnt, the fumes were so strong that it was not possible to cross 

 the orchard in the early morning. The resulting crop comprised more 

 than 3,000 boxes of apricots and no traces of the bug could be detected. 

 It is considered probable that any material giving rise to a dense 

 smoke would be effective in driving these insects out. 



