THE CRANBERRY ROOTWORM. 7 



New Lisbon, N. J., was the first to introduce this method of preparing 

 arsenite of soda for use in the spraying of New Jersey cranberry bogs. 



In the first two applications arsenic was used at the rate of 1J 

 pounds per acre, the later applications being increased to 2 pounds 

 per acre. Arsenite of lime, prepared and used as just described, is 

 exceedingly cheap compared to arsenate of lead, but the dangers 

 attendant upon its use by inexperienced help, both to human life 

 and from possible injury to the foliage and fruit, are such that it is pre- 

 ferred to recommend arsenate of lead for general use. The latter 

 insecticide is frequently used on cranberry bogs at the strength of 

 3 pounds of paste arsenate of lead to 50 gallons of water or Bordeaux 

 mixture. If arsenite of lime is used as the insecticide, it is very essen- 

 tial that thorough agitation of the spray material be maintained. 

 Some foliage injury, noted on three different bogs, should probably 

 be attributed mainly to a neglect to keep the mixture agitated at all 

 times when spraying. At the conclusion of the second season's obser- 

 vations no new areas on the sprayed bog were found infested and the 

 number of larvae throughout the bog had decreased to a marked degree. 



Having observed on a number of bogs that the injury by the root- 

 worm almost invariably occurs on sandy land and, further, that the 

 root system of the cranberry on such land is exceedingly shallow as 

 compared with that on peat or muck lands, it is fair to conclude 

 that treatment of the bog by fertilizers to stimulate growth will 

 be of great advantage to the cranberry plant in outgrowing the 

 injury of the larva?. 



The New Jersey Experiment Station has amply demonstrated at 

 Whitesbog, N. J., that weak vines on sandy soil can be made to pro- 

 duce an abundance of vines in one season by the application of the 

 proper mixture of chemical fertilizers. It so happens that this land 

 is infested with rootworms, but the extent of the infestation could 

 not be definitely determined without tearing up the fertilizer plats 

 more than is advisable. Some of the plats are known to be infested, 

 but in spite of the presence of the rootworms the vines have made so 

 much growth in two years that pruning would not be inadvisable. 



Sanding infested areas also gives promise of being a satisfactory 

 method of |)i-omoi ing vine growth. Mr. T. B. Gaskill, of New Egypt, 

 X. J., has clearly demonstrated on a small, badly infested area of 

 savanna land thai a L-incb coat of sand will cause the vines to grow 

 vigorously, sending oul runners which cover the bare spaces, and to 



pn-ciif ;i marked contrast to unsanded adjacent vines. 



SUMMARY. 



The cranberry rootworm {Rhahdopterua picipes Oliv.) is the larva 

 of a -mall brown beetle which bas recently been found on a number 

 of cranberry bog in Ne\s Jersey. 



