Erythrina Gall Wasp Larvae

gall wasp larvae 1gall wasp larvae

Quadrastichus erythrinae,  erythrina gall wasp larvae, very very small. Found on one of my house wiliwili trees. I dissected a galling leaf stem about 1/2″ long and there were about 5 to ten larvae inside. Only manage to save one to photograph.

it lives

The cutting of a wiliwili tree branch from an old tree lives on. My successful experiment with propagation of an older  wiliwili branch validates the resiliency of this species. In my previous post “Downed Wiliwili Branch Lives On”,  the span between the downing of that large branch sometime prior to 2011.11.09 until 2012.3.5, when the  5 inch diameter branch cutting was made, is over five months.  After eight months in a pot, small nodes of leaves started to show on that branch. The cutting’s size ,old age  and  its long period of survival after being severed from the main tree are significant details.  We now know that severed large branches can survive without a source of water for up to six months. Smaller branches up to 5 inches in diameter can be regrown. If we can get to a downed branch in the wild and cover its broken end in dirt or  seal it from the open air, perhaps we can save that branch or regrow it into a new tree.

waiakamali gulch wiliwili trees

Trees in this gulch and adjacent Luahina Gulch has been surveyed and located. This is my second visit to these trees, first time was September 2010 . Both of these gulches are in the Kohala Watershed Partnership Pelekane Bay Restoration Project just north of Pu’u Kawaiwai. The trees are in a fenced area so they will have a better chance of producing offsprings. At this time 17 September 2012, the trees are starting to leaf and some are still flowering. We have had some rain in the area so the gulches are green with grown grass and vegetation.


Trees at the upper part of the Waiakamali gulch which are deeper inside of the gulch are heavily infected by gall wasps. Some are 80-90% infected. Young leaves and leave stems and even seed pods are galled. I think that the wasps have recently include seed pods as host to lay eggs, either that or the larvae expand their appetite for seed pods. By contrast group of trees 50 yards away further down the gulch are fairing much better with minor galling and healthy seed pods. Seeds are also infected by bruchid beetle (Specularis impressithorax). Group of trees in more exposed areas are fairing much better with minor galling. I have a theory that due to high winds in more exposed areas trees out in the open are less frequented by gall wasps.

Forty seven trees were counted. excluding very young plants planted by KWP. Oldest trees are 20-22″ diameter. Youngest are as small as 3″ diameter.

wiliwili seeds galled

downed wiliwili branch lives on

This photo was taken 2011.11.09 showing an older lone tree with a large branch damaged and downed by wind. This must have occurred sometime during 2011. When visited again on 2012.03.5, branches are still alive as evident by their greenish color. Cut samples show bark and cross-section of some branches are still moist and green.  Branches of varied size and thickness were carried out for replanting  in pots at Kawaihae.  I hope these branches will take root and continue living ( cuttings of wiliwili branches will form roots studies showed). The larger branches in pots are showing signs of withering on some smaller branches, however the bark and remaining smaller branches showed no signs of withering into the end of April.

As observed,  a 1.5 foot diameter broken branch will stay alive well over six months, so how does this translate to the amount of time it took for a mature 100-200 years old tree to die?  A tree seen alive in one year then fell down with dried withered branches all the way to its extremities a year later may have started to die at least six months prior. Wiliwili trees are drought resistance so they could stay dormant up to three years. This complicates our understanding of why some trees that live for hundreds of years start to die recently. Gall wasps may be one of the culprits, but certainly not the main cause.