154 



solutions, kerosene emulsions, or even dilute preparations 

 of some of the commercial petroleum compounds, now on 

 the market under various trade names, has been demon- 

 strated. 



Tobacco preparations have long been used for the de- 

 struction of plantlice, though some experience is necessary 

 to secure the proper dilution, owing to the variability of 

 waste tobacco products from which decoctions are usually 

 prepared. There are noAv on the market a number of ready- 

 made tobacco extracts. A most promising one is known as 

 black leaf extract. It has given very good results in an ex- 

 perimental way, even when diluted with 60 parts of water. 

 Some of our New York State fruit growers are using a di- 

 lute lime-sulfur wash in place of Bordeaux mixture, and 

 after adding poison thereto find this preparation a very 

 efficient fungicide and effective in controlling codling moth 

 and of great A^alue in destroying plantlice when the appli- 

 cation is made at the usual time we spray for codling moth. 

 Several of the standard commercial lime-sulfur washes, di- 

 luted with 40 parts of water, have been used in this way. 

 It is possible that this combination or some modification may 

 ultimately take the place of the poisoned Bordeaux mixture 

 and solve for all time the problem of controlling plantlice 

 outbreaks, since one thorough spraying just after the blos- 

 soms fall would probably obviate the necessity of further 

 treatment of plantlice, particularly if this was an annual 

 practice. 



The essential in all these cases, so far as plantlice are 

 concerned, is to maKe the application before the foliage has 

 become badly curled. The need of special treatment for 

 aphis outbreaks must of necessity depend upon several fac- 

 tors, namely, favorable weather conditions and the relative 

 abundance of natural enemies. It has been shown that ab- 

 normally cool weather in the spring and early summer is 

 likely to ])e folloAved by aphis injury, owing to the fact that 

 plantlice reproduce readily under such conditions, while the 

 activities of their natural enemies are seriously hindered. 

 Consequently, an incipient attack by aphids, accompanied 

 by a scarcity of natural enemies and the probability of con- 

 tinued cool weather, should serve as a warning to the fruit 

 •grower, and result in immediate spraying. 



