20 BULLETIN 78, IT. B. DEPARTMENT OF AGRICULTURE. 



Pupation takes place at an average depth of 1£ inches. The pupal 

 cells are fragile and easily broken up by plowing or disking. Many 

 of the pupae are deeply buried by plowing and the moths are unable 

 to reach the surface. 



The satisfactory results following summer treatment of land, 

 whether or not cowpeas or other similar crops are grown, are mainly 

 due to the fact that conditions are made unfavorable for the deposi- 

 tion of eggs by the moths and for the growth of newly hatched larvae. 



FALL AND WINTER TREATMENT OF LAND. 



During September, 1909, two cultural experiments were begun in 

 Appomattox, Va., to ascertain the effect of fall and winder treatment 

 of land already infested with Crambus larvae. 



The field selected on the J. F. Purdum farm contained five plats 

 of one-half acre each. In this experiment (experiment A) fall and 

 winter preparation of the tobacco land gave decidedly beneficial 

 results. The field had been in pasture previous to plowing, but the 

 growth of weeds was not so rank as on the land used in experiment B. 

 The following were the results obtained in each of the plats: 



Plat No. 1. — Ground plowed during second week in December, 1909. Thoroughly 

 disked during first week in January, 1910. Tobacco planted during last week in May. 

 Number of plants, 2,200. Number replanted, 89. Per cent injured, 4+. 



Plat No. 2.— Land plowed during first week in January, 1910. Disked during 

 second week in February. Tobacco planted during last week in May. Number of 

 plants, 2,350. Number of plants reset, 165. Per cent injured, 7+. 



Plat No. 3. — Land plowed during last week in February, 1910. Disked during third 

 week in March. Tobacco planted during last week in May. Number of plants, 2,280. 

 Number of plants reset, 138. Per cent injured, 6+. 



Plat No. 4- — Land plowed during third week in March, 1910. Disked during third 

 week in April. Tobacco planted during last week in May. Number of plants, 2,214. 

 Number of plants reset, 251. Per cent injured, 11 + . 



Plat No. .5 {check plat). — Land plowed during third week in April. Prepared for 

 planting during last week in May. Tobacco planted during last week in May. Num- 

 ber of plants, 2,225. Number reset, 375. Per cent injured, 17 + . 



Tobacco in all plats was replanted twice. A good stand of plants 

 (about 98 per cent) was secured by July 4. After July 4 there was 

 but slight injury from the worms. The land had been heavily 

 fertilized, and the tobacco made a fine growth. 



The second tobacco cultural experiment was conducted on the farm 

 of Mr. J. R. Horsley (experiment B), in Appomattox County, Va. 

 Four plats, each containing 1 acre, were included in the experiment. 

 Two check plats, one at each end of the experimental plats, were 

 used. Each of these contained 1 acre. The growth of weeds was 

 heavy, stickweed, daisy, and buckhorn plantain being abundant. 



\\i this test beneficial results from fall and winter plowing were not 

 so conclusive as in the experiment on the Purdum farm (experiment 



