238 



Hecke (G. H.). The Grasshopper Outlook for 1920.— Mthly. Bull. 

 Cal. State Dept. Agric, Sncraniento, ix, no. 3, iMarch 1920, pp. 

 53-54. 



Severe infestations of grasshoppers are expected in California in 

 1920 owing to the exceptional numbers of adults that were known to 

 deposit eggs in the late summer of 1919 ; the mild and dry winter 

 encouraged their development, and the shortage of spring rains will 

 probably force them to migrate to irrigated lands and seek food in the 

 green fields and orchards. A State-wide grasshopper campaign is 

 beintr undertaken. 



QuAYLE (H. J.). The Codling Moth in Walnuts. A Partial Report of 

 Investigations for 1919. -Mthly. Bull. Cal. State Dept. Agric., 

 Sacramento, ix, no. 3, March 1920, pp. 6-4-69, 2 figs. 



The codhng moth, Cydia (Laspeyresia) pomonella, has been known in 

 California as a pest of walnuts, as well as of apples, since 1909. Recent 

 experiments have proved that the insect can be transferred from one 

 food-plant to another without affecting its development. Under field 

 conditions, however, when walnut and apple foliage are interwoven, 

 90 per cent, of the apples may be infested and not more than 1 per 

 cent, of the walnuts, while outside the area of walnut infestation, the 

 nuts will remain immune though apples growing in contact with them 

 are infested. Until recently it was thought that the later broods only 

 attacked walnuts, but it is now known that the hfe-history of the 

 moth is practically identical on both food-plants within the same 

 locality. 



Most of the larvae appearing in early spring enter the nuts at the 

 calyx end, causing them to fall to the ground without attaining 

 maturity. When the nuts have grown large enough to come more or 

 less in contact, the larvae frequently enter at the point where two 

 nuts touch each other. From mid-July onw^ards the nuts are harder 

 and the larvae can only enter at the suture at the base, or, if they 

 fail to find this, they may complete development in the husk of the 

 nut. 



The control of C. 'pomonella in walnuts should follow, in general 

 outline, the methods adopted in the case of apples, but the large size 

 of walnut trees presents a difficulty in reaching all parts ; it is also 

 difficult to get the poison to where two nuts are in contact, and there is 

 no calyx cup to fill. An average-sized walnut tree requires 25 U.S. 

 gals, of spray to cover it thoroughly, a larger one, 35 U.S. gals., while 

 an apple tree requires 8 or 10 U.S. gals., but reckoned on acreage 

 there is not much difEerence, there being fewer walnut-trees than 

 apple-trees to the acre. Burlap bands round the trunk are a valuable 

 accessory measure. Dusting with lead arsenate powder was tried 

 extensively in 1919, and gave considerable success both with walnuts 

 and apples. To avoid injury to the tree, basic or neutral lead 

 arsenate should be used rather than the standard or acid variety. 

 Applications should be made just previous to the time when the 

 maximum number of larvae of the two important generations enter 

 the nuts, the dates diii'ering with different counties. It has been 



