Abstract
Optimum time for glyphosate application, to achieve both a good control of horsenettle and better conditions for pasture renovation by sod-seeding, was determined during the period 1983 to 1984. Three application times were evaluated in plants subjected to treading and those without treading.
The results obtained were as follows:
1) The best control of horsenettle was obtained by the application of glyphosate on August 30, when the plants were at the late bloom or fruiting stage. Glyphosate was more effective in uninjured plants than in those damaged by treading (Fig. 2, Table 1).
2) For pasture renovation with sod-seeding orchardgrass, the application of glyphosate on August 30 was also superior to the other treatments. Though there remained two weeks till sod-seeding time, glyphosate applied at a rate of 4.1kg/ha could well suppress the vegetation including horsenettle and contribute to the increase of productivity of forage (Table 2).
3) These results suggest that late August application is the most suitable for the use of glyphosate for sod-seeding renovation of pasture heavily infested with horsenettle.
