In reviewing the possible methods of artificial control of the drill., T. C . 

 Nelson (1922) lists poisoning, trapping, dredging, transplanting, and breeding of 

 resistant oysters. Of these he considers poisoning impractical; and trapping not 

 yet successful; but urges the development of poisoned baits. Since 1922 some 

 progress has been accomplished in all of Nelson's suggestions except breeding of 

 resistant oysters In a recent personal communication he corroborates the wnter.'s 

 conviction that the evidence for drill dissemination by man is outstanding and con- 

 clusive and he suggests accordingly that the first procedure in oyster culture to 

 ur.dergo thorough overhauling is transplantation of oysters. 



Fedenghi (1930b, 1931c) and Galtsoff et al (1937) resolve the control of 

 'he drill into two distinct problems: the prevention of the migration and dissemina- 

 tion of the drill over new areas and its removal and destruction from infested 

 bottoms Drill control in oyster cultural practices according to Galtsoff etal. falls 

 roughly into mechanical and biological methods; the latter utilize knowledge of the 

 life history and habits of the animal , Fedenghi emphasizes the fact that preventing 

 'he distribution of the drill to new areas is somewhat easier than eradicating it once 

 it has become established 



Stauber (1943) believes that drill control must be a continuous process by 

 which Urosalpinx can be kept constantly in check . Thus large costs relative to a 

 full scale program of drill control should drills become numerous, may be pre- 

 vented. He also states that no one aspect of drill control should be stressed at the 

 expense of another, and that drill control should be carried out on grounds regard- 

 ess of the lack of control of drills on adjacent bottom since mass migrations from 

 ground to ground do not best explain the existing data on the distribution of drill 

 populations. He also italicizes the important statement, which the writer would 

 Like her emphasize, that m order to adequately determine the need for the 



appli( ation of control measures proper quantitative sampling of drills on grounds 

 is m i : 



Summarized in a general way Stauber s recommendations for drill control 

 ware Bay may be abridged as follows: (1) before seed oysters are planted on 

 a ground, resident drills should be removed; (2) if high drill concentrations appear 

 i seed oysters are planted oyster drrll trapping should be employed from ear Ly 

 April (to take advantage of the preoviposition period) to late October; (3) m replant- 

 ing seed and adult oysters efforts should be made to remove accompanying drills; 

 (4) if such tiansplantation is performed in May-July when oyster drill oviposition 

 is at its height egg cases should be destroyed possibly by dipping or spraying with a 



tivc toxic chemical; (5) when oysters are being dredged for market all accompany- 

 ing drills should be segregated to reduce the need for subsequent drill removal from 

 these grounds 



104 



