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Herrick (G. W.) & Leiby (R. W.). The Fruit-Tree Leaf-Roller. — 



Cornell Univ. Agric. Expt. Sta., Ithaca, N.Y., Bull. no. 367, 

 December 1915, 32 pp., 17 figs. [Received 18th March 1916.] 



In 1911 the Tortricid, Cacoecia (Archips) argyrospila, Walk, (fruit- 

 tree leaf-roller) suddenly came into prominence in New York State as 

 causing serious injury to apples and minor injury to pears ; during 

 the seasons of 1912, 1913 and 1914 the insect fully maintained its 

 importance as a pest. The first reference to its activity as a pest of 

 economic importance would appear to be one by Packard in 1870, while 

 Lintner reported it in 1889 as a pest in New York State. According 

 to Gillette, it was abundant in Colorado in 1890, if not earlier. In 

 1905 it became very destructive in Missouri and during the past few 

 years it has greatly increased in parts of Colorado and New Mexico, 

 where it has been carefully investigated and experiments have been 

 made on its control by Gill [see this Review, Ser. A, i, p. 225]. 

 C. argyrospila is evidently one of those insects that fluctuate markedly 

 in numbers and destructiveness ; it even appears to migrate from one 

 orchard to another in successive seasons. As the larva of this species 

 is very similar to that of C. rosaceana, the only safe way of determining 

 the host-plant is by breeding the adult. Details are given regarding 

 distribution, food-plants, habits, injuries and life-history. The 

 parasite of this species which was bred in the largest numbers at the 

 Cornell insectary was the Ichneumon, Pimpla conquisitor, which must 

 have destroyed many of the larvae. Other parasites were a species of 

 Amicroplus, twenty-three specimens of which were bred from one 

 larva ; single specimens each of the Ichneumons, Phytodietus 

 vulgaris, Pimpla inquisitor and Glypta simplicipes, which appears 

 to be rather abundant in the field; a specimen of a Chalcid, 

 Sympiesis sp. ; and a single Tachinid, Carcelia nigropalpus. 

 Experiments showed that light traps were not of great efficiency in 

 the control of C. argyrospila, though useful data were obtained by their 

 means. Detailed accounts are given of trials with insecticides. It 

 was found that the eggs of this moth are susceptible to the effect of 

 miscible oils, which, when thoroughly applied, have destroyed from 

 74 to 92 per cent, of them. In Colorado, New Mexico, and Oregon, 

 where these oils have also been used extensively [see this Review, 

 Ser. A, iii, p. 758], an even higher proportion of the eggs has been 

 destroyed. In experiments made during the past three years no 

 injury has resulted from the use of miscible oils. They have been 

 applied in the spring (April) at as near the active growing period of the 

 tree as possible, but always before the buds burst, generally at the; 

 rate of 1 gallon to 15 gallons of water. Only one application should 

 be made, and that on a day when the temperature is above freezing^ 

 In cases of severe infestation the oils should be supplemented by 

 thorough sprayings with arsenate of lead at the rate of 6 lb. to 100 

 U.S. gals, of water or of lime-sulphur solution. At least one application 

 should be made before the blossoms open, and another after the petals 

 fall ; the latter will serve also as the regular spraying for codling moth 

 [Cydia pomonella]. In Hghtly infested orchards spraying with miscible 

 oils may be omitted and reliance placed on thorough applications of 

 lead arsenate or lime-sulphur. One or two applications should be 

 made before the blossoms open and another after the petals fall. 

 A list of 18 works closes this paper. 



