ARE YOU "S'ilECTIir- FOR RESISTANCE?" 



Reports of recent USDA research enphasize that the ability to "resist" the 

 effects of a ndticide is inherited by nites. "Resistance" or the ability to 

 withstand the poisonous effects of pesticides on the part of insects and aites 

 is not neviT, Horrever, the development of strains tolerant of pesticides never 

 occurred so fast as it has since the introduction of many of our present-day 

 insecticides and niticides. It is cause for thought and planning, 



Nov, research shov;s plainly that the ability of mites to ivithstand the toxic 

 effects of most niticides developed vdthin the last few years is an inherited 

 trait. Furthermore, once a resistant strain is developed, the ability of that 

 strain to vrlthstand the effects of miticides is not likely to be lost. Once a 

 resistant strain of a mite or an insect is developed in an orchard, a potato or 

 vegetable farm, or a greenhouse, the ovmer has to depend upon biological and cll.i- 

 atological factors or wait until a ne\i and superior insecticide or niticide cones 

 along. 



For orchardists this report on the inheritance of resistance can be a warning, 

 with strains of nites strongly resistant to phosphates and codling moth strains 

 very resistant to DDT already v:ell established in New York State, it would seen 

 wise for Massachusetts rrowers to attempt a "delaying action". 



For mites this could be usine an oil at least once every three years so as 

 to kill red mite in an entirely different way, as ccrapared to the action of the 

 summer or foliage-type miticides. VJhen it comes to fighting yellov: mite or 

 2-spotted iTiite, do not depend upon phosphates alone. Use phosphates when it is 

 _ logical to do so because of the presence of aphids or other insects you wish to 

 control. T/hen only mites are the troublesome pests, svrltch to one or more of the 

 non-phosphate materials and do a "clean-up" job, 



"i^en it cones to codling moth, don't be too hasty in your decision to leave 

 lead arsenate out of all the Cover Sprays Important for codling moth control. 

 And there may be good reasons for suggesting the use of phosphates against cod- 

 ling moth rather than to depend entirely upon DDT year after year, 



E. H. Vlheeler 



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CURING j'AGNESIUI'J DEFICIENCY IN CULTIVATED BLUEBERRIES 



Magnesium deficiency has not been a common trouble with blueberries in Mass- 

 achusetts. Since it is not uncommon on other fruits, it would not be surprising 

 if magnesium deficiency occurred more frequently in the future . Experience iirith 

 blueberries, as vrell as with other fruits, has shovm that heavy applications of 

 potash could bring about roagnesium deficiency. As the amount of potash contain- 

 ing fertilizer is increased it v;ould be vri.se to be on the lookout for tliis trouble. 



