THE SO-CALLED TOBACCO WIREWORM IN VIRGINIA. 



21 



A). On plat No. 1 the effect of mowing and burning the weeds after 

 the eggs had hatched was noted. 



Plat No. 1. — Weeds mowed and burned during third week in September, 1909. 

 The land was not disturbed until the ground was prepared for planting, during the 

 third week in May. Number of plants in plat, 4,400. Number of plants reset, 610. 

 Per cent injured, 13. 8+. Tobacco replanted twice. 



Plat No. 2. — Ground plowed during last week in September, 1909. In March, 

 April, and May it was disked and harrowed at frequent intervals, no vegetation being 

 allowed to grow before the tobacco was planted, in order, if possible, to starve out the 

 hibernating larvse. Number of plants, 4,400. Number replanted, 415. Per cent 

 injured, 9.44-. 



Plat No. 3. — Land plowed during second week in March and not disturbed until 

 just before planting. Number of plants, 4.400. Number of plants reset, 410. Per 

 cent injured, 9.3-4-. 



Plat No. 4. — Land plowed during third week in December, 1909. Nothing further 

 done to it until prepared for planting during last week in May, 1910. Number of 

 plants, 4,400. Number replanted, 540. Per cent injured, 12. 2+. 



The results of these experiments are shown also in Table IX. 

 All plats were replanted twice. A good stand of 98 per cent was 

 secured by July 5. 



Table IX.- 



-Effects of fall and winter treatment on injury by the tobacco Crambus 

 in 1909 and 1910. 



Exper- 

 iment 

 No. 



A2 



A3 



A4 



A 5 

 Bl 



B2 

 B3 

 B4 

 B5 



Preliminary treat- 

 ment. 



Time of treatment. 



Plowed 



....do 



do 



do 



....do 



Weeds mowed and 

 burned. 



Plowed 



....do 



....do 



Second week of December, 1909. 



First week of January, 1910 



Last week of February 



Third week of March ' 



Third week of April 



Third week of September, 1909. 



Later treatment. 



Thoroughly disked. 



Disked 



do 



do 



Disked and har- 

 Last week of September j. rowed at f re- 

 Second week of March quent intervals. 



Third week of December j 



First week of April Disked 



First week of 



January, 



1910. 

 Second week of 



February. 

 Third wee'k of 



March. 

 Third week of 



April. 



March, April, 

 May. 



First week of 

 May. 



Exper- 

 iment 

 No. 



Planted tobacco. 



Number 

 ofplants. 



Number 

 reset. 



Per cent 

 injury. , 



Al 





2,200 

 2, 350 

 2,280 

 2,214 

 2, 225 

 4,400 

 4,400 

 4,400 

 4,400 

 8,800 



89 

 165 

 138 

 251 

 375 

 610 

 415 

 410 

 540 

 1,218 



4 



A2 



do 





A3 



do 



6 



A4 



do 



11 



A5 



do :. 



17 



Bl 





13.8 



B2 



do 



9.4 



B3 



do 



9.3 



B4 



do 



12.2 



Bo 



do 



13.9 









In the season of 1910-11 another series of cultural experiments was 

 conducted on the J. F. Purdum farm, in Appomattox County, Va 

 The land previous to preparation for tobacco was in meadow 



