ANNUAL REPORT, 1933 



23 



hundreds of acres were dusted commercially. In both the research and commer- 

 cial dusting, all the dusts used were mixtures of fine ground pyrethrum flowers 

 and 300-mesh gypsum. Following is a summary of the results of the season's 

 experience with these dusts (the pyrethrum dust used in the mixtures having 

 a 1 per cent p\rethrin content in all cases). 



Insect 



Gypsy Moth 



{Porthetria dispar L.) 



Cranberry Spittle Insect 

 {Clastoptera vittata Ball) 



Cranberry Black Bug 



{Plagiognathus repelitus Knight) 



False Army Worm 



{Xylena nupera Lint.) 



Brown Cranberry Spanworm 

 {Ematurgia amitaria Gn.) 



Blackheaded Fireworm 



(Rhopobola vacciniana Pack.) 



Cranberry Girdler 



{Crambus hortuellus Hubner) 



Green Cranberry Spanworm 

 (Itame sulphurea Pack.) 



Blunt-nosed Leafhopper 

 (Ophiola slriatula Fall.) 



Cranberry Weevil 



{Anthonomus musculus Say) 



*Since this mixture is strong enough to materially reduce infestations of several other important 

 bog pests, its use is perhaps advisable in spite of the cost. The last week in June is probably the 

 best time to treat this leafhopper, all things considered. 



Work with Chemical Weed Killers. (W. H. Sawyer.) In preliminary tests from 

 July 28 to August 29, 1932, to find out the effects of weed killers on cranberry 

 weeds and cranberry vines, the following chemicals were tried in different strengths 

 of solution and sometimes in combination with one another: Sodium chlorate, iron 

 sulfate, copper sulfate, sodium arsenite, sodium arsenate, sodium chloride, calcium 

 chloride, ammonium chloride, sodium hydroxide, sodium bisulfate, calcium hypo- 

 chlorite, zinc chloride. Of these twelve chemicals, sodium arsenate seemed to 

 promise best results. Sodium arsenite and sodium chlorate proved to be excellent 

 killers for cranberry weeds, but in concentrations effective on weeds also killed 

 cranberry vines equally well. The highest differential between injury to weeds 

 and injury to cranberry plants was secured with weak solutions of sodium arsenate. 

 As low a concentration as 10 pounds per acre in 550 gallons of water, applied as 

 a spray, was found to effect a complete kill of the aerial portion of wild bean 

 {Apios tuberosa) with no noticeable injury to cranberry vines. Brambles and 

 some of the lesser weeds were also killed, but on poison ivy the sodium arsenate 

 was ineffective in concentrations low enough not to injure cranberry vines. 



