Taiwan Forestry Research InstituteTaiwan Forestry Research Institute

Erythrinae Eulophid Wasp (Quadrastichus erythrinae Kim) is a gall-making herbivorous wasp from Africa. It was firstly recorded in 2004, but it has cause huge damages on coral trees in many countries. It belongs to Eulophidae, Hymenoptera and only occurs on Erythrina trees. Its spreading speed is scaring fast. There are lots of infection records of side-walk trees and garden coral trees around Taiwan. The infected tissue will produce covering galls. They usually occur in clusters on new shoots, twigs, petioles, leaf midrib and even on leaf tissue. Trees with serious infection are vulnerable to other insects or disease and thus cause the trees die back.

Infection Stage

According to the number of galls on a leaf, the infection level can be divided into 4 stage
1st Stage:
less than 15 galls, at this time leaf and stem remains its original shape.

2nd stage:
Galls around 16-30, galls gathered and even cause leaf curling.

3rd Stage:
Enlarged galls on leaves and stems and gathered as a bump. Leaf shape cannot be identified and the twig shoots are withered.

4th Stage:
The leaves fall out totally, and stinky tissue fluid comes out from the phloem tissues. The hosts die back gradually.

Suggestion of integrated pest control
Take proper actions according to different infection stage:
Stage 1st : Be Cautious (Plantation Management)

1. Stop planting new Erythrina trees to avoid pest outbreak.
2. Destroy the serious infected seedlings.
3. Strengthen the tree health by proper fertilization and irrigation

Stage 2nd : Handle It (Visual Attraction)

1. burn out the infected leaves to avoid pest expansion.
2. Hang the yellow wasp sticker (550-600 nm) under the tree crown twigs and replace it periodically.

Stage 3rd : First Aid (Chemical Treatment)

1. Conduct pruning management. The tools should be sterilized and the litter should be burned.
2. After the raining season, start to apply systematic pesticides, but don’t apply before heavy rain.
3. Workers need to wear protection gear. Pesticides should be applied at upwind position and done before 9:00 in the morning.

Stage 4th : Clean Out (Field Management)
Remove the dead infected trees. Clean out the standing death to avoid the further infection or other pest occurrence.