328 



Harr. (oblique-banded leaf-roller), C. {A.) argyrospih, Walk, (fruit-tree 

 leaf-roller), Xylirui spp. (green fruit- worms), Eriocampoides limacnui, 

 L. (pear slug), and Eriophyes pyri, Pgst. (blister mite), the usual 

 controls being mentioned in each case. 



Parrott (P. J.) & HoDGKiss (H. E.). Periodical Cicada in 1916.— 

 New York Agric, Expt. Sta., Geneva, Giro. no. 50, 15th May 1917. 

 4 pp., 2 plates. 



The destructiveness of the periodical cicada [Tibicen septefudecim] 

 is not due to the feeding of the larva, which takes place underground 

 on the sap of the roots of trees, shrubs and vines and is almost 

 negligible in amount owing to the extraordinary slowness of growth 

 and development, extending over a period of 17 years. The adults 

 likewise eat little or nothing, but important injury is caused to trees 

 by the females puncturing the twigs and smaller limbs in order to 

 oviposit, with the result that the limbs are so weakened as to break off 

 with the slightest wand. 



The best method of control is the spraying of the emerging nymphs 

 with home-made or commercial oil emulsion, which is fatal to them. 

 There seems to be no practical method of controlling the adults when 

 occurring in large numbers over wide areas. Trees thoroughly sprayed 

 with Bordeaux mixture or a lime wash are apt to be avoided, especially 

 if there are other trees in the neighbourhood on which the insects can 

 oviposit. Young stock should not be planted in those localities where 

 the insects are known to occur during the two years previous to their 

 expected appearance. 



Parrott (P. J.), HoDGKiss (H. E.) & Lathrop (F. H.). Plant Lice 

 injurious to Apple Orchards. II. Studies on Control of newly 

 hatched Aphides. II. — New York Agric. ExjJt. Sla., Geneva, Bull, 

 no. 431, March 1917, pp. 33-79, 1 fig., 1 plate, 18 tables. 

 [Keceived 30th May 1917. 



This paper deals with the continuation of experimental work on 

 apple Aphids [see this Revieiv, Ser. A, iv, pp. 273-275], with the special 

 object of discovering the effect of the so-called " delayed dormant 

 treatment " in the control of the rosy aphis {Aphis sorhi). 



In 1916 the infestation of orchards in western New York was not 

 severe, and the three species concerned. Aphis sorhi, A. avenae (oat 

 aphis) and A. pomi (green aphis) exhibited the usual seasonal cycle, 

 which is fundamentally constant, but varies slightly from year to 

 year. On 22nd April many oat aphis had hatched, but only a few rosy 

 aphis. By 26th April the rosy aphis had reached their maximum 

 number, being chiefly responsible for the dwarfing of apples, and on the 

 same date the green aphis began to emerge. The egg-distribution of 

 the three species showed marked differences, those of Aphis pomi being 

 in heavy local infestations, while those of A. sorhi and A. avenae were 

 uniformly scattered throughout the orchards, being nowhere very 

 dense. The second generation of A. avenae consisted of winged insects, 

 so that this species had entirely disappeared by the end of June, 

 having done little damage, causing at most only a slight curling of the 

 foliage. From the middle of June until the end of the month A. sorhi 

 was the most abundant, its attack resulting in a severe and characteristic 



