You can hide some of the axis labels by wiring to the chart's BeforeLayout event like this:
void radChart_BeforeLayout(object sender, EventArgs e)
foreach (var item in radChart.PlotArea.XAxis.Items)
if ((double)item.Value > new DateTime(2009, 8, 1, 0, 0, 0).ToOADate())
item.TextBlock.Text = " ";
The code above will hide all XAxis labels with date value bigger than 2009/08/01.
Regarding your other questions about hiding some of the major ticks, there is no way to loop through MajorTicks of the axes which means that you can either make all of them invisible or nor of them.
the Telerik team
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