Crops
Elytroteinus geophilus Lucas (1861)
Yam weevil
General
- Insect belonging to the order Coleoptera and the family Curculionidae. Its English name is fijian ginger weevil.
- Found in the Asia-Pacific region on ginger, tarot and copra crops.
- Causes significant damage to yam tubers in the production areas of Poindimié and Ponérihouen in New Caledonia, elsewhere its impact is minor.
- Damage observed during harvest; they are caused by larvae and adults.
- Sensitive botanical family (s)
| Dioscoreaceaes |
- Affected production areas :
| New Caledonia |
- Organs attacked
|
Roots |
Tubers |
Symptoms, damage
- Symptoms :
- presence of perforations (3 to 5 mm in diameter) and galleries in the tubers
- The impact on the harvest is very low, even if the presence of the pest in the field can be important in certain geographical areas.
- Signs : Presence of larvae on plants and in the culture (figures).
- Possible confusion :
Biology
- Development cycle : The biology of this pest is poorly understood, it is difficult to observe adults in the field. However, this pest has a biological cycle common to the order of Coleoptera with 3 stages of development: larval stage, pupation and adult.
- The larvae develop in the tubers and continue their cycle, with adult hatching in the fields or during crop storage. They are larger than adults and are 1.2 cm long. Cream-colored, they have a brown head that is half the width of their body.
- The adults, measuring 5-8 mm, are brown in color, with light cream-colored patterns, especially on their elytra.
Protection
- Sort and control the sanitary quality of future plants at harvest and during storage in order to limit the spread of the pest.
- If seed tubers are purchased outside a pest free farm, check the quality of the tubers purchased.
- Fragment the seeds when planting in order to more easily detect the presence of galleries and larvae and thus limit the introduction of the pest into the new plots.
- Avoid late harvests in the fields.
- Clean the room dedicated to the storage of tubers and carry out a crawl space for 4 to 6 months.