369 



Garman (P.). The Oriental Peach Fest— Mar ijland Agric. Expt. Sta., 

 College Park, Bull. no. 209, December 1917, 16 pp., 25 figs. 

 [Received 17th June 1918.] 



Cgdia {Laspegresia) molesta, Busck (Oriental peach motli) has 

 appeared in the District of Columbia and the adjacent counties of 

 Maryland, injuring peach trees by feeding on the terminal buds of 

 the twigs, of which as many as 90-100 per cent, may be killed, though 

 the normal number is from 50 to 70 per cent. When the fruit begins to 

 ripen, the larva frequently leaves the twig and enters the peach near 

 the stem, infesting 5 to 15 per cent, of the fruits. The insect also 

 infests the fruits of aj)ple and quince and the twigs of plum and 

 apricot. 



The egg is always laid on the under-side of a leaf, usually at a 

 considerable distance from the initial feeding point of the larva, which 

 often has to travel 6 inches or more to reach suitable food. The 

 incubation period varies from 4 or 5 days at midsummer to 7 days 

 in cool weather. The young larva bores down the core of the twig 

 for an inch or more from the tip, the attack resulting in gummosis, 

 the destruction of the leaves, and the splitting of the twig. The 

 average length of the larval stage is 11 days. When full growTi, 

 the larva leaves the twig or fruit and constructs an inconspicuous 

 cocoon, which in summer is found well out on the t^vigs ; the pupal 

 period has an average length of 10 days. The larvae of eggs laid 

 later than 25th August make cocoons hidden in c^e^^ces of the bark 

 or in similar places, in which they hibernate, pupating in the spring. 

 The adult is crepuscular, the eggs being usually laid singly during 

 the evening or night, usually only one on a leaf, but often on several 

 different leaves of the same t^\^g. 



Since the life-cycle thus occupies about 26 days, it follows that a 

 monthly recurrence of the larval infestation of twigs may occur, and 

 since the earliest noted date of infestation is 22nd May, there is a 

 possibility of 4 broods during the season, provided that a warm 

 September is experienced. 



It is supposed that this Tortricid was introduced into the United 

 States through the port of New York about three years previously 

 on flowering cherry, and its dispersal has been caused by the shipment 

 of infested peaches and nursery stock. 



Two Hymenopterous parasites attack this pest, the most important 

 of which is the egg-parasite, Trichogramma minutum, Riley ; the 

 value of tliis Chalcid lies in the variety of its hosts, which include 

 several common Lepidoptera. In 1917 a count of the eggs of 

 C. moksta in the field showed 80 per cent, to be parasitised by 

 T. mimitum. A second parasite, Macrocentrus sp., has been reared 

 from the larva, but only in small numbers. 



As regards remedial measures, the most vulnerable stages are those 

 of the egg and early larva, and though it is impossible to keep the 

 young twigs coated with arsenical poison, the young larvae can be 

 prevented from entering the fruit by a thorough application. The 

 pupa cannot be effectively destroyed owing to the character of the 

 cocoon, and the adult apparently cannot be reached by any measure 

 known at the present time. General recommendations for control 

 include the winter application of concentrated lime-sulphur, and 

 (C496) Wt.P2/137. 1,500 9(18. B.&F.,Ltd. Gp. 11/3. a 



