BUREAU OF ENTOMOLOGY. 253 



native groves satisfactory control is very difficult and insect injury 

 is quite severe; in fact, 90 per cent of the pecan crop here was lost 

 during 1918. Three species of insects are principally involved. 



Insects injurious to walnuts, butternuts, etc., in the North- 

 ern States. This work, especially with the walnut curculio, the 

 hickory curculio, and another speoies that attacks the leaf stems of 

 hickor}^, and with other species as well, has been taken up by the 

 bureau, with headquarters at French Creek, AV. Va. A thorough in- 

 vestigation of insects attacking nuts other than i^ecan throughout the 

 country Avill be carried on. 



cranberry insects. 



In the last annual report the beginning of the work on insects in 

 cranberry bogs in the State of Washington Avas mentioned. This 

 work, in cooperation with the Washington Agricultural Experiment 

 Station, has been continued and important results have been reached. 

 On bogs badly infested by the blackhead fireworm satisfactory re- 

 suits have been secured from three applications at intervals of from 

 17 to 21 days between May 1 and July 1* of nicotine sulplmte con- 

 taining 40 per cent nicotine used at the rate of 1 to 800, with the 

 addition of fish-oil soap at the rate of 2 pounds to each 50 gallons, 

 the spray being applied at the rate of 250 to 550 gallons per acre. 

 Of the spray nozzles tested that known as the Bordeaux appears to 

 be best suited. Growers have generally adopted this treatment and 

 are getting good results. Detailed life-history studies of this insect 

 are nearing completion, as are also studies of the cranberry root 

 weevil. It has been shown of this latter species that it can be con- 

 trolled by spraying the foliage during May and June with 2 pounds 

 of arsenate of lead to 50 gallons of Bordeaux mixture. 



A general survey of insect conditions is being made on cranberry 



bogs on the Pacific coast,, and it is hoped that by the close of the 



season a report can be prepared on the principal cranberry insects 



of that territory. 



peach insects. 



Tests of paradichlorobenzene as a treatment for the peach borer 

 were continued through the growing season of 1018. Experiments 

 with this gas have now been carried on during a period of three 

 years in the peach districts of Maryland, Ohio, Arkansas, Virginia, 

 West Virginia, and Georgia. In some cases blocks of trees have been 

 treated two and three years in succession. It has been found that 

 three-fourths of an ounce or 1 ounce of the chemical per tree applied 

 in the fall after the moths have laid their eggs will result in the 

 destruction of about 95 per cent of the larv99. No injury has re- 

 sulted from this dosage to trees 6 years old and over. Younger 

 trees, on account of their thinner bark, have sometimes been injured. 



Experiments as to the comparative merits of dusting and spray- 

 ing in the control of the plum curculio and certain peach diseases 

 have been continued in cooperation with the Bureau of Plant In- 

 dustry at Fort Valley, Ga., Agricultural College, Miss., and Ben- 

 tonville, Ark. The summer of 1919 has been an unusual one and 

 control measures have been put to a severe test. The dusting method 

 in a general way seems to compare favorably with spraying, even 

 under the worst conditions. 



