Add spaces: Firstlyisflattened(damaged,weakened)thecropnearesttothepointofintervention,thenother,lessaffectedareas,thetimebetweenlodging(damaging,weakening)ofthefirst,themostaffectedareasandthelast,leastaffectedmayalsovarybyuptoseveralweeks.
Firstly is flattened (damaged, weakened) the crop nearest to the point of intervention, then other, less affected areas, the time between lodging (damaging, weakening) of the first, the most affected areas and the last, least affected may also vary by up to several weeks.