Preliminary investigation into impact of Sitona lepidus adults on white clover seed production

A small plot trial was undertaken in the Waikato to determine the potential impact of Sitona lepidus adults on white clover seed production. Five densities of adult weevil were caged on 1 m2 plots from the time of peak adult emergence in November 1998 until harvest in late January 1999. In the laboratory, weevil adults were found to severely damage clover inflorescences when no leaves were present. Although feeding damage on leaves was highly visible in the field plots, with over 80% of the leaflets damaged at the highest density of 600 adults/m2, weevil adults were found to have no effect on flowering or seed production.

Pasture tolerance to the herbicide metsulfuron-methyl

Trials were carried out in spring and autumn at two locations in New Zealand to measure the effects of metsulfuron-methyl on pasture production and composition. Metsulfuron-methyl at 3-12 g/ha resulted in 20-45% loss of herbage production. This was particularly evident for two months after spraying, with no significant reduction in dry matter yield 3 months after treatment in spring. The effect on pasture composition was more persistent. Metsulfuron-methyl, along with clopyralid and picloram + 2,4-D completely removed the clover for the three month duration of the trial. The consequences of broadcast application of these herbicides in pasture need to be considered in the context of the overall farming system.