West Sussex County Council said work is ongoing to remove Ash trees which could pose a risk to road users because of Ash Dieback infection and the potential for branches to fall into the road.
A spokesman added: “Ash Dieback is a highly destructive disease which, sadly, is predicted to kill up to 95 per cent of Ash trees in this county.
“To keep the road network safe, the County Council needs to fell severely infected trees. Their removal will open the area to light and allow natural regeneration of trees from the existing seed source.”
Felling works have been ongoing on sections of the A24, with new dates now scheduled. Dates have also been programmed for works on the A286 and A29, all subject to factors such as severe weather.
Nighttime closures will be in place for sections of the road as follows with signed diversions:
April 19 to 21: A24 Southbound from Washington Roundabout
April 22 to 23: A24 Northbound, Glaseby Lane to Washington Roundabout
April 26 to 30: A24 Northbound from Hop Oast Roundabout
May 4 to 5: A286 Binderton Lane to Church Lane, West Dean
May 6 to 7: A29 Fairmile Bottom at Madehurst
On May 10 to 11, a lane will be closed and temporary traffic lights in place for work on the A29 Northbound at Slindon.
An ornithologist will carry out a survey of each site before work starts to ensure no nesting birds are disturbed, the council said.