NINETEENTH EEPORT OF STATE ENTOMOLOGIST 17 



The addition of sweet substances, such as syrup and molasses, was 

 not found to increase the effectiveness of the arsenical sufficiently^ to 

 warrant the added expense. 



A very reassuring feature concerning the outbreak was the dis- 

 covery of as high as 30 per cent reduction of the infestation through 

 the beneficial work of the parasites, which are in no way injured by 

 the artificial control measures. While this degree of parasitism is 

 insufficient at present to materially reduce the numbers in the most 

 heavily infested districts, it augers well for a natural control within 

 a few years, inasmuch as the parasitism over this same area a year 

 previous amounted to less than 10 per cent. The fruit growers are 

 generally encouraged with the present outlook and are planning more 

 •extensive and thorough control measures for the coming year. 



BLISTER MITE 



This tiny form which attacks both foliage and fruit of the apple 

 probably caused more injury and financial loss to the fruit growers 

 of the Bitter Root Valley in 1921 than any other orchard pest. In 

 fact, it is questionable whether in the aggregate the loss in culls and 

 "C" grade fruit due to injury by the blister mite was not as great 

 -as that caused by all the other orchard pests combined. While this 

 injury was more or less noticeable over the valley as a whole, especially 

 to Wealthy, Rome Beauty, Mcintosh, and Winter Banana, it was par 

 ticularly severe in some of the orchards about Darby, in which the 

 •dormant or late dormant spraying with lime-sulphur had been omitted 

 for some years. 



The blister mite is not a difficult pest to control. Either lime- 

 ■sulphur or miscible oil, carefully and timely applied, should give 

 satisfactory results. On the whole, lime-sulphur is to be preferred, 

 TDeing less expensive and thoroughly dependable for this purpose. 

 On account of the more general use of control measures against this 

 pest in 1922, much less damage resulted than in the previous year. 



THE GRANARY WEEVIL 



Reports which came to us in September, 1921, regarding the serious 

 losses due to the granary weevil (Calendra granaria L.) in south- 

 western Minnesota and South Dakota, where in some instances losses 

 ranging up to one hundred and twenty-five dollars on a carload of 

 ■wheat were experienced, caused us to make an investigation concerning 

 this insect in Montana. Letters were sent to eight hundred grain 



