VEGETABLE GROWING IN NEW SOUTH WALES. 123 



vessel, and into this pour some bi-sulphide of carbon, and close the door 

 tightly. This liquid becomes a gas when exposed to the air, and, being 

 heavier than air, the fumes diffuse among the potatoes and destroy any moths 

 and larvae. This should be repeated every ten to fourteen days, in order to 

 kill any larva; or moths that might emerge from the egg stage. Four or five 

 charges should be sufficient. About 5 Ib. of liquid bi-sulphide of carbon to 

 every 1,000 cubic feet of space should be used. As the gas is highly 

 inflammable, the greatest care should be exercised. No lights of any kind 

 should be near, or disastrous results will follow. 



Of course it is recognised that many growers may not, perhaps, be in a 

 position to provide themselves with a suitable airtight room, but every effort 

 should be made to do so, and to adopt the treatment recommended It 

 will be found that the potatoes free from infestation will realise better 

 prices, and the trouble and expense will be warranted. In the absence of 

 such a store-room, the potatoes should be drawn into a heap, a saucer 

 containing carbon bi-sulphide placed on top, and the whole covered closely 

 with a cloth. 



Covering with grass or hay from some place remote from the potato crop, 

 and occasionally sprinkling with water, is a primitive method, but is found 

 to keep the attack in check. 



On small areas the moth may also be captured by use of lantern traps (see 

 page 132). 



Pseudo-looper or Silvery Plusia Moth (Plusia Argentifera). 



The green caterpillar of this species of moth commonly feeds on the 

 foliage of beans, creepers, and potatoes. They pupate in loose, silken cocoons, 

 which they spin on the foliage or stalks and sometimes on the ground. 



Brushing into a tray of oil and water, as is described on page 132, is 

 recommended as a means of control, while spi-aying with arsenate of lead (see 

 page 129), is also advantageous where the foliage is not too dense. 



Rutherglen Bug (Nysius vinitor). , 



This little plant-bug is a tiny brown insect with silvery-grey wings, and 

 measures about one-sixth of an inch in length. They suck up the sap with 

 their beaks, and, where numerous, soon cause the plants to shrivel. They 

 appear in summer from eggs that have been deposited on the grass and 

 weeds by the autumn brood of the previous season, and are particularly fond 

 of potato and tomato plants, although they infest many other plants and 

 trees. They fly very well, and in the warmer part of the day are very active. 

 For this reason, and because they shelter on the under-surfaces of the foliage, 

 it is difficult to destroy them with a contact spray. The best method of 

 destroying them is to use a shallow tray containing a mixture of water and 

 kerosene, as described on page 130. 



