Hi gore The large hole in the leaf doesn't appear to be related to insect damage - it looks like mechanical damage from another source. The 'burned' edge on the leaf looks like it could be caterpillar damage.
There are small green insects on the underside of the leaf that are aphids, which pierce the leaf surface and suck sap, causing white marks.
A natural insecticide like pyrethrum or Neem oil should help get rid of them. These products are 'contact' insecticides - the pests are killed only when directly hit by the spray - so you may need to apply every week to 10 days to gain reasonable control. Aphids have a very short life cycle so you'll need to keep on top of the spraying to disrupt it.
If the leaf edge damage is from caterpillars or some other chewing pest, then the treatment suggested above will be effective against them too.