Adoretus versutus* (Harold, 1869)

Rose beetle

General 

• Polyphagous beetle insect of the Scarab family native to India and Sri Lanka. It has become a pest with its various introductions to the Pacific Islands.
• Adults are approximately 1 cm in length. They are stocky in appearance, brown in color and completely covered with hair.
• Listed on more than 40 plant species: yam,

* Aderotus sinicus is also present in French Polynesia.

• Sensitive botanical family (s)

• Affected production areas :

• Organs attacked

 Symptoms, damage

• Symptoms :
  • Leaves eaten mainly by adults which feed on the blade. This is cut, perforated more or less regularly, the veins sometimes remaining in place and giving the leaves a riddled or lace appearance.
  • Impact on the crop mainly caused by the decrease in the functional leaf area, this is highly damaging for yam production.
• Signs : Presence of adult insects on plants and in the crop (figures).
• Possible confusion :

 Biology

• Development cycle : lasts 80 to 120 days depending on the country. It includes 3 development phases: 3 larval, pupation and adult stages.
  • Larvae developing in the soil on the roots of poaceae.
  • The adults emerge from the ground after pupation for aerial activity. They are rarely observable during the day, they have an essentially nocturnal activity.

 Protection 

• No protection methods are currently available, apart from perhaps installing  canvases  insect-proof in the nursery, on the rows in the open field when planting, and at the openings of shelters when climatic conditions allow it.
• Several alternative solutions are being studied and should provide solutions in the long term:
  • several entomopathogenic agents (viruses, fungi, bacteria and nematodes) in the context of biological control ,
  • biotechnical means ( light and attractive traps ).