-4- 



Most of the preliminary results have been favorable, and a 

 dosage of 1 pound of DDT in 100 gallons of spray is generally accepted as 

 most desirable on fruit trees. At this rate, outstanding control of codling 

 moth, leafhopper and Japanese beetle has been obtained. DDT appears to be 

 exceptionally compatible with other insecticides and fungicides and promises 

 to provide many desirable combinations. Preliminary experiments indicate 

 satisfactory compatibility v;ith Fermate or Puratized for scab and other di- 

 seases; with DN for red mite; v/ith nicotine for aphids; and with lead arsen- 

 ate for plum curculio. It is safe' on peaches and we expect to develop a 

 satisfactory schedule against the Oriental fruit moth. 



Some reports show a lack of uniformity in the manufacture of 

 DDT, and chemists have found the presence of isomers which are chemical mix- 

 tures containing identical elements in similar proportions but in different 

 arrangement and varying in their action. 



DDT has already been micronized, fused vrith sulfur, dissolved 

 in paint, and sprayed onto carrier particles to form a dust. Many other 

 formulae, processes and combinations will be made before the most satisfactory 

 form for each purpose is established. 



The effect of DDT on other animal life is being thoroughly 

 studied. Some birds are killed by eating poisoned insects or by drinking im- 

 pregnated water. Many native pollinating insects will be killed, especially 

 where flov.'ering cover crops are grovni in the orchard. 



We are confident that a practical and profitable schedule for 

 using DDT in orchards can be worked out. But, please, be patient. Give us 

 time, 



— Yf, D. ?/hitcomb 



OYSTER SHELL SCALE A PROBLEM IN MAKJE APPLE ORCHARDS 



During the past four or five years oyster shell scale has 

 been on the increase in a number of Maine apple orchards. At present the 

 scale presents a real challenge in some of the infested orchards. Although 

 the problem appears to bo most severe in Maine orchards, there are several 

 aspects of the situation that are of interest to apple growers throuj^h a much 

 wider section of Hev;^ England, 



Destructive Hpbits of the Scales. As the name implies, infested apple 

 twigs appear as thougli encrusted with minute oyster shells. At first only 

 a few scales may be present, and as they are about the same color as the 

 apple bark J they are easily ovetlook^d. As the infestation increases the 

 smaller twigs become heavily encrusted, and a fovi of the scales settle on the 

 growing apples. Finally the whole tree^ in^iluding the tru:il: and large limbs, 

 as well as the tv;igs, may become heavily infested by the scales. As the in- 

 festation gr'T.vs, the tree becomes weakened; small tvdgs bo^in to die, and 

 later larg:jr limbs are killed by the scales. In some orchards only a few 

 scattered trees are severely infested by the scales. In other orchards, in- 

 festation is widespread. 



