570 IOWA DEPARTMENT OF AGRICULTURE 



Those ranchers who give normal cultivation to their orchards do not 

 worry much ahout this weed. To a certain extent they consider it an 

 advantage, since it springs up after cultivation stops and makes a good 

 winter cover crop. But in cases where orchards receive insufficient cul- 

 tivation the weed is a more or less serious injury to the trees, especially 

 to young trees. Bindweed is a greater nuisance in vineyards than in 

 orchards on account of the lack of shade and the greater difficulty in the 

 v.-eed knife. 



(4) The presence of wild morning-glory vines, although it injures 

 the market value of hay, protjably does not materially affect its feeding 

 value. In the case of alfalfa, clover, cowpeas, and other hay crops that 

 produce a shading effect, the bindweed is a neglible factor. 



DISTRIBUTION. 



Bindweed is found in most sections of the United States and southern 

 Canada. Although it sometimes occurs on upland soils, it is found more 

 often on deep bottom lands and on rich prairie soils. The weed is there- 

 fore at its worst on the most productive and most valuable land. It 

 grows on the valley lands of New England, the middle Atlantic states, 

 and to a lesser extent in the Southern states; also in the entire area of 

 the Corn Belt and on the valley lands of the West. East of the one hun- 

 dredth meridian the native hedge bindweed is the most common species, 

 although the field bindweed is also widely scattered. West of that point 

 the field bindweed is probably the most common species, the hedge bind- 

 weed occurring to some extent in California. The trailing form with 

 downy leaves {Convolvulus sepium repens) has been reported as a weed 

 from central-western Kansas only, in which locality it has become a most 

 serious menace to the wheat growers. The fourth species of importance 

 as a weed is the California form (Convolvulus caJi/oi'mcHs), which occurs 

 only in central-western California, for the most part on hill lands. 



Although bindweed usually occurs distributed generally over the land, 

 it is sometimes confined to well-defined patches. It is not an uncommon 

 sight to see one or more of these patches in a field, each of a more or less 

 circular outline, indicating that the weed is spreading by its underground 

 growth from a central point of infection. Where the land has been infested 

 for some time and careless cultivation has been given, the weed becomes 

 scattered over the land. 



Another interesting point which has been disclosed by a study of this 

 weed under field conditions is that the underground parts rarely penetrate 

 the subsoil. This depends, however, somewhat on its character, since a 

 subsoil that resembles the surface soil in texture and fertility admits the 

 roots and rootstocks to a certain extent. In all cases where the subsoil 

 is of an impervious or clayey nature the underground parts of the plant 

 are confined to the soil stratum entirely. 



METHOD OF ERADICATION. 



From the facts stated it is evident that the only successful methods for 

 the eradication of bindweed must be based on the suppression of all top 



