The red palm weevil (Rhynchophorus ferrugineus), also known as palm weevil, Asian palm weevil or Sago Palm Weevil originates from tropical Asia, but has spread to Africa and Europe with distribution through the Mediterranean since the 1980s.
Life cycle and appearance of Red palm weevil
The adults of the red palm weevil (Rhynchophorus ferrugineus) are typical weevils: the head extends with a long thin rostrum that holds the antennae and tiny mandibles. The size and colour of adult weevils greatly varies. Most individuals in the Mediterranean area are about 30 mm long, with females 10 to 15% larger than males. This makes them the largest weevil of Europe and North Africa. Their colour ranges from entirely orange-red to all black with all intermediates, depending on the number and size of black marks.
Eggs are creamy white, shiny and oblong. Larvae are creamy white, legless, pyriform with a brown head and body comprised of 13 segments. Fully grown larvae migrate to the periphery of the palms to build a solid elongated cocoon made of rolled-up palm fibres. After the cocoon is formed the larva enters a pre-pupal stage, its body contracts and it does not crawl any more. The future adult organs are well visible on the pupa.
It is very difficult to recognize the first signs of red palm weevil (Rhynchophorus ferrugineus) presence and only later stages of attack are conspicuous. However, the damage done before these later stages when detection becomes easier, can suffice for palms to die.
Females lay eggs individually into soft tissues mainly at the base of living fronds. Larvae are present and feed in the softest and most humid living tissues (growth areas) with a low to moderate proportion of fibres. Their feeding causes deterioration of this tissue, making it easier for adult weevils to lay eggs deeper into the tissue. Additionally, this provides entry points for microbial agents that can further destroy living tissue. Due to the specific morphology of the palms, direct or indirect destruction of the apical bud will lead to the death of the plant, which makes the red palm weevil (Rhynchophorus ferrugineus) a very harmful insect.