Stem Gall Wasp

Notification

New State and World Record

An undescribed stem gall wasp on Chinese Banyan

Prepared by:

Bernarr Kumashiro, Hawaii Dept. of Agriculture Insect Taxonomist and WPDN PI Bernarr.R.Kumashiro@ hawaii.gov

October 30, 2012

 

 

 

 

 

Galled stem with          Defoliated trees  Adult wasp

Exit holes

Photos by HDOA staff

 

On July 13, 2012, an arborist caring for the grounds at East-West Center submitted to the Hawaii Dept. of Agriculture Taxonomy Lab, samples of infested stems of Chinese banyan, Ficus microcarpa. The arborist noted that the leaves were sparse on the terminal stems and the affected trees generally appeared unhealthy. Insect Taxonomist Bernarr Kumashiro noticed that there were many galls formed on the stems, besides the common galls on the leaves formed by the agaonid wasp, Josephiella microcarpae (first found in Hawaii in 1989). Galls on the stems were not observed or recorded previously in Hawaii. Kumashiro also noticed that there were emergence holes on the galls. Upon dissecting some galls, he found some un-emerged adults, which appeared to be agaonid gall wasps.

The leaves were stripped from stems by technician Janis Garcia and the material was held

in a jar for wasp emergences. A few days later, adult wasps began emerging and these were mounted for closer observation. They appeared to be in the same family as the leaf gall wasp and appeared a bit larger. Kumashiro emailed a colleague in Australia who studies gall wasp for more information, and was referred to a specialist in France (Jean­ Yves Rasplus), who is familiar with gall wasps on banyan. Rasplus was a co-author of

the description of Josephiella microcarpae (mentioned above) in 2001. Kumashiro asked

Rasplus if he had heard of any gall wasps attacking stems of F. microcarpa and Rasplus replied negative. He offered to look at actual specimens and these were sent to him. On October 6, 2012, Rasplus replied that clearly it is a new undescribed species of Josephiella. He offered to describe it, along with Kumashiro, and it may be awhile before we obtain a name.

 

Branch entomologists collected more material from the grounds of East-West Center and Nuuanu and held the material for emergences. Along with the stem gall wasp, four other species of wasps emerged, believed to be hyperparasitoids or inquilines. These were low in numbers and were also sent to Rasplus for identification. We are currently gathering information on the distribution of the stem gall wasp throughout the state and if it is attacking other species of Ficus. It is believed to be widespread on Oahu, and is present at Kahului on Maui, and Hila on the Big Island.