158 EXPERIMENT STATION EECORD. 



tender leaves, riaaiiiig tlieui with suiall holes. Infested trees present a tied-up 

 iuid scraggly appearance where the leaf-folders become very numerous. The 

 leaves in which the folder works turn brown as the result of the feeding, and a 

 badly Infested block of apple stock may have the appearance of having been 

 swept by fire. 



The leaf-folder itself is a greenish-yellow worm, about i in. long when it is 

 full grown. It is slightly hairy, but these hairs or setse are hardly noticeable. 

 There are two different forms of the moths, an orange-colored form which 

 appears in the late spring and in the summer, and a slate-colored form which 

 appears in the fall. The leaf-folders appear three times during the season : 

 First, as soon as the leaves are out on the trees; second, about the middle of 

 June; and third, early in August. They remain on the trees from 4 to 6 weeks 

 before they become mature. 



Where there is only a small area infested much benefit can be obtained by 

 picking or pinching the infested leaves. From the experiments here recorded 

 it is concluded that in order to be effective spraying must be done when the 

 leaf-folders are very young or while they are still iu the egg stage. A home- 

 made arsenate of lead applied when the folders were iu the egg stage gave good 

 results. The 1* strength composed of arsenate of soda 6 oz., acetate of lead 

 18 oz., and water 50 gal., is recommended. The natural enemies of this pest are 

 said to play an important part in regulating its abundance. Two species of 

 tachinids determined as belonging to the genera Nemorilla and Bactromyia were 

 bred by the author from these folders. The ichneumonid, Chorincaus cari- 

 natiis, was bred from the pupal stage. The braconid, CUnocentrus americanus, 

 is said to have been the most common parasite. Chalcis ovata, and several new 

 chalcids, were also reai*ed. The synonymy and life history are considered, in 

 addition to which technical descriptions of the stages, and a bibliography of the 

 more important references are given. 



Wormy apples and how to prevent them. Results of spraying' for codling' 

 moth in 1908, J. E. Buck iMrgiiiiu Sta. Bill. /,Si. />/j. ,i-l.i, fif/s:. 0). — Follow- 

 ing an account of the life history of the codling moth, spraying experiments are 

 reported, the details of which with the results obtained are presented in tabular 

 form. The results of spraying by several practical fruit growers are also given. 

 The more important points brought out have been summarized by the author as 

 follows : 



" There are two broods of codling moth in Virginia. 



" Temperature conditions governing the blooming of the apple trees seem to 

 determine also the appearance of the first moths in the spring. 



" The spraying right after the petals fall from the bloom is most important, 

 it being possible to kill over 97 per cent of the worms l)y one thorough drench- 

 ing application of arsenate of lead at this time. 



" Both Paris green and arsenate of lead, when thoroughly applied, will pro- 

 duce a high percentage of worm-free fruit. A pressure of at least 00 to 80 lbs. 

 is necessary to produce a good spi'ay with Bordeaux caps. 



"Arsenate of lead has proved superior to Paris green in all our tests this 

 season. It adheres better, and can be applied simply in water without any 

 danger to fruit or foliage. One and one-fourth pounds in a drench spray, and 

 2 lbs. in mist sprays to each .50 gaj. of spray, have given good results, the re- 

 sults being slightly in favor of the mist spray, whei'e two sprayings were given. 



" Spraying IS to 20 days after the petals fell from the bloom this season gave 

 very good results, and indicates that it may be worth while to make the appli- 

 cations this late if for any reason the spraying has not been done at the proper 

 time. No one, however, should neglect the earlier spraying with this iu view, 

 as it may not prove true for every year. 



