(1) Hail insurance on all insured crops is in force for the full growing season with the following provisions:
(a) there will be no liability on grain until 75% of the plants are plainly jointed;
(b) no liability is assumed on beans and peas until they show a practical stand;
(c) no liability is assumed on any crops for loss or damage to blooms, leaves, or stems unless such loss or damage plainly reduces the quality or quantity of the production;
(d) when loss or damage is sustained on immature crops the adjustment may be delayed until the extent of the damage may be more accurately determined; and
(e) no liability is assumed on mustard or flax until 75% of the plants are four inches tall, and on sugar beets until 75% of the plants have 12 or more leaves.