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NouGARET (R. L.). The Achemon Sphinx Moth {Pholus achemon, 

 Drury). — Mthly. Bull. Cal. Deft. Agric. Sacramento, viii, no. 10, 

 October 1919, pp. 560-584, 17 figs. 



Pholus achemon, Drury (grape-vine sphinx moth) occurs in all 

 parts of the United States and Canada where grapes are grown, but 

 outbreaks of tliis pest have not been reported outside California, 

 Several cases of sudden severe infestations are described, in which 

 grape-vines were completely defoliated. During these attacks 

 attention Was entirely given to controlling the pest until the larv^ae 

 were completely killed off, so that there was little possibility of 

 investigations into the life-history. It is now known that the eggs 

 are deposited singly on the upper surface of fully-developed leaves, 

 never on the tender growing leaves of the shoots. The number 

 of eggs laid by one female and the period of incubation have not been 

 discovered. There are three larval stages, lasting on an average 

 7| days, 7 days and 9 days respectively. During the whole larval 

 period feeding continues voraciously, the leaves being entirely skele- 

 tonised. The vine frequently puts forth a fresh growth of leaves 

 within about a week or 10 days, and this new growth can be hastened 

 by irrigation, but in the meantime the development of the fruit has 

 been arrested and the berries may shrivel and drop so that the crop 

 is a total loss, and in any case they do not attain perfect maturity. 

 When the larva is fully grown, it ceases feeding and drops or descends 

 to the ground. It then buriows into the soil and after 5 or 6 days 

 of this pre-pupal period, pupation begins. Apparently some moths 

 emergj about one month later, but the majority remain in the 

 gro. nd until the following spring. There is therefore only one real 

 generation in a year with a partial second. It also seems probable 

 that a partial generation may precede the true one, from a few over- 

 wintering pupae. The larvae are of two distinct colours, and examina- 

 tion indicates that reddish-tinted larvae develop into male moths, 

 while green ones give rise to females ; this point requires further 

 investigation. 



Many of the larvae are attacked by disease in the pre-pupal period 

 and shrivel up. Many others are parasitised by a Tachinid, Sturmia 

 distirivta, Wied., which oviposits on them. Severe infestations occur 

 so suddenly that time is an essential factor in successful control. 

 An efiective remedy devised by the author consists of 11 lb. lead 

 arsenate paste, with 24 lb. atomic sulphur, 1 lb. ground glue, 1| U.S. 

 pints Black-leaf 40 and 200 U.S. gals, of water. This is most efiective 

 if applied a few days before the larvae are fully grown. The spray 

 should be applied with a spray gun. In one severely infested vine- 

 yard, the treatment of which is described, an average of five outfits 

 of two spray guns each were kept working for 17 days from 23rd May 

 to 9th June, during which time 165,000 U.S. gallons of the spray were 

 used. The cost of the materiah, apparatus and labour amounted to 

 about £2,200. As the crop saved was estimated by the owner to 

 be worth about £60,000, the control work cost less than 4 per cent, 

 of the net returns. Caterpillars of the first and second instars were 

 very susceptible to the spray and died almost immediately after 

 contact. After 48 hours all individuals on the vines were either 

 dead or dying. 



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