556 EXPERIMENT STATION RECORD. 



Some insects and mites attacking the peach in Colorado, G. P. Weldon 

 (Colorado »S7a. Bill. 169, pp. 3-13, pi. 1, fif/f^. 2). — The poach-twig borer (Anur'sia 

 UneatcUa) has been known in Colorado for a number of years, and while 

 not a seriously injurious pest every season, there are seasons when it becomes 

 exceedingly destructive and is responsible for a great financial loss to those 

 peach growers who do not adopt proper methods of control. 



The larvae hibernate in little silk-lined chambers constructed within the bark 

 and very close to its surface. They have been found by the author in Colorado 

 almost entirely in the older crotches, and always, when found there, they 

 have been in the brown portion of the barlv just as close to its surface as 

 the hiberuacula could be constructed. Occasionally the hibernating cells con- 

 taining larvae have been found underneath buds on the new growth of peach 

 trees, but their occurrence in this location does not seem to be at all general. 

 The presence of the larvse during the hibernating period can be detected by the 

 tiny sillven tubes, covered on the outside with bits of bark, which they con- 

 struct at the entrance to their burrows. Frequent reference is made by the 

 author to the bulletins on this insect by Marlatt, of the Bureau of Entomology 

 of this Department (E. S. R., 10, p. 569), and by Clarke, of the California 

 Station (E. S. R., 14, p. 590). 



Although there was a scarcity of the twig borer in 1910, experiments con- 

 ducted show that " Rex " lime and sulphur gave perfect results. " One 

 tree sprayed with black leaf, 1 : 70, was free from wilted tips, and also 2 

 trees sprayed with black leaf ' 40,' 1 : GOO. . . . Black leaf ' 40,' 1 : 600, 

 apparently gave good results. . . . For some unkuowu reason, home-prepared 

 lime and sulphur used at the same time as the ' Rex ' spray, but in another 

 orchard, apparently did little good." However, from experiments conducted in 

 1910 at Clifton, from the experience of many Colorado orchardists who have 

 used lime and sulphur for the control of this pest, and from the apparent 

 success of this spray in California, the author feels justified in recommending 

 its use in sections of Colorado where there is injury from the twig borer. 

 "While arsenate of lead was a total disappointment in this season's test, it 

 has previously been used with good success and is no doubt effective when 

 applied at the proper time." 



The other insects briefly noted are the San Jose and Putnam scales, the peach- 

 borer, the brown mite (Bn/ohia pratensis), and red spider (Tetranychus 

 Mmaciilatus), previously noted (E. S. R., 23, p. 264). 



Two plant lice of the peach, C. P. Gillette and G. P. Weldon (Colorado 

 Sta. Bui. 169, pp. 13-20, flg. 1). — Accounts of the green peach aphis (Myzus 

 persicw and the black peach aphis (Aphis persicce-niger) by the senior author 

 have been previously noted (E. S. R., 20, p. 854). 



The hibernation and spring, summer, and fall habits of the green peach aphis 

 here described are followed by accounts of spraying experiments, the conclu- 

 sions drawn from which are as follows : " Lime and sulphur, both ' Rex ' and 

 home-prepared, black leaf extract, black leaf ' 40,' and soluble oil, may be 

 effectively used for the control of the green peach aphis when applied in the 

 early spring, just as the eggs are hatching. A lime and sulphur spray is not 

 effective when applied 2 weeks or more after the eggs are hatched, for at this 

 time the stem-mothers are mature, or nearly so, and are able to resist the 

 action of this insecticide. Good tobacco preparations may be used with success 

 any time after the aphids hatch ; but it is more diflicult to succeed late in the 

 spring, because it is then more difficult to get the spray on all the lice, on 

 account of the protection of the leaves. The best time to spray for this insect 

 is in the early spring when the eggs are hatching." 



