Skies start to darken: Swarms of the biblical bugs have arrived due to unusual heavy rain
Darkened skies and layers upon layers of the insects were discovered on trees as masses of the bugs arrived along the Red Sea and invaded the country from Sudan and Eritrea.
Egypt has also been struck by large numbers of locusts, with 80 million in a swarm there could be devastating consequences for food supplies.
Experts have warned crops will be put at risk from the legions of bugs flooding Najran at the weekend.
Unusually heavy rainfall in the region led to the deluge of biblical bugs arriving in the country in mid-January with even more coming in a week later.
Worshippers in the Holy City of Mecca were covered in the bugs when they first started to arrive leading cleaners to have to fumigate the Great Mosque.
Specialist teams also had to be drafted in to tackle the bug infestation.
With a small swarm capable of chomping its way through the same amount of food in one day as 35,000 people, UN experts warned about the level of creatures arriving in Saudi.
Fruits, crops and vegetation are all at risk of being eaten through.
'Good rains along the Red Sea coastal plains in Eritrea and Sudan have allowed two generations of breeding since October, leading to a substantial increase in locust populations and the formation of highly mobile swarms,' the U.N. Food and Agriculture Organisation warned.
R.C.