18 replies to this topic

[happ]

http://www.latimes.com/news....et=true

According to this article in today's LA Times, a tiny but nasty predatory wasp from Africa is devastating the native Hawaiian coral tree [E. sandwicensis] or Wiliwili tree.

Anyone familiar with this situation, esp you gardeners in Hawaii? Could the wasp also attack other types of erythrina trees?

It sounds serious  

[fastfeat]

It's actually the one-year anniversary today this pest was discovered at Miami Metrozoo.

http://www.doacs.sta...o/gallwasp.html

It has devastated many E. variegata (the primary species in SoFla) in Dade Co; I'm sure it will spread northward. I saw evidence of it on my container-grown E. flabelliformis, E. coralloides, and E. speciosa in Miami Springs. So far, I haven't seen them in Palm Beach Co on these species, but the tip-borer devastates them anyway.

I don't know if the gall wasp will survive in a Mediterranean climate or not. If the pest does thrive in such areas, I predict it will blaze through CA corals like red gum lerp psyllid did on Euc. camaldulensis.

[Dave-Vero]

It's reached Ft. Lauderdale  http://www.doacs.sta...iology/4603.pdf  (pdf file)

[happ]

fastfeat & Dave
Thanks for the info [is there a link to botany section?

Have not read of any infestation of E. caffra/lysistemon [probably the most popular in Cali

[LJG]

Happ, the story requires a login. Can you post the text? I am curious about this. How does the wasp cause the damage?

[fastfeat]

Happ--

I'm not sure about the link to the botany section where Dave's article came from.

E. caffra and E. lysistemon are basically non-existent here (aside from a few E. caffra 'Flavescens'  I'm struggling to keep the tip-borers out of). They don't do well with our summer rains/dry winters.

[happ]

Seems the first place for new bugs is thru Florida [no offense.  The tiny size of these wasps may create detection problems.  

Here's the entire article Len:  

Tiny wasp brings a big problem for crops in Hawaii

An insect with African origins is killing off the wiliwili tree, which is a windbreak of major agricultural importance.

By Tomas Alex Tizon, Los Angeles Times Staff Writer
October 15, 2007

HONOLULU — The wiliwili trees began dying in the summer of 2005. Since then, wiliwili groves on all the Hawaiian islands have been devastated, leaving barren plains in their stead.

For each tree, it was the same process: First, gnarled lumps would appear on the leaves. Then the leaves and branches would turn brown. Within months, the tree would be dead.

Scientists determined that the culprit was a tiny predatory wasp from Africa, only recently discovered by science. Botanists named it the erythrina gall wasp: erythrina for the type of tree it attacks, and gall for the tumors it creates in leaves. An adult gall wasp is one-third the size of a typical mosquito.

"It's tiny, like dust, but the damage it causes is unbelievable," said Mohsen Ramadan, a state entomologist who characterized the epidemic as one of the worst problems ever caused in Hawaii by an invasive species. Trees killed by the gall wasp number in the thousands, from inner-city neighborhoods in Honolulu to rural farms on Molokai and desert-like plateaus on Kauai and the Big Island -- all in a short period.

Now, state officials hope to introduce a predator from Tanzania, the eurytoma wasp, as the last best hope to save the wiliwili trees. Officials must first prove the new insect will not harm any other species. The approval process, according to Ramadan's boss, Neil Reimer of the state Department of Agriculture, could take three months or three years. The state is also seeking comments from the public.

Introducing new species as a biological-control agent has always been a tricky proposition in Hawaii, where nonnative plants and animals have wreaked havoc on native species. The best known biological-control failure involved the mongoose.

The sugar industry brought them to Hawaii to control the rat population (believed to have been brought by ancient Polynesians). But the mongooses, active chiefly in the daytime, did not prey on nocturnal rats. Instead, they went after the islands' native birds. Mongooses continue to menace bird populations on the islands.

"We're going to win some, we're going to lose some," said Art Medeiros, a biologist on Maui. Medeiros is collecting and preserving the seeds of native wiliwilis in case the trees are wiped out by the gall wasps. He said if native wiliwilis died off, vast stretches of land on Maui would become deserts.

Native wiliwilis have orange or red bark with green leaves divided into three parts and colorful red flowers. They can grow to more than 30 feet in height and three feet in diameter at the trunk.

The type of wiliwili most affected by the gall wasp is sometimes referred to as a coral tree. It is tall and thin, with branches and green leaves that begin from the ground up.

Coral trees have been used for years as windbreaks. Planted in a line, they form living green walls. According to Christy Martin of the state Coordinating Group on Alien Pest Species, on Molokai, farmers who shielded crops and fields with coral trees have struggled against wind damage since the gall wasp nearly wiped out the island's coral-tree population.

Martin said that a large wiliwili tree that "provided shade for half a block" outside her office at the University of Hawaii-Manoa campus succumbed to the gall wasp. It had to be cut down before it simply fell over.

Honolulu city workers have cut down more than a thousand dead or dying wiliwilis in parks and medians.

Martin explains that the wasps inject their eggs into leaves, and its larvae form galls where the wasp matures. The galls deform the leaves and interfere with the plant's ability to take in water and light, eventually causing the tree's death.

A female gall wasp, whose life only lasts two to three weeks, can produce as many as 150 wasps.

Beginning last year, Ramadan took two extended trips to Africa to research the wasp and, most important, to find a remedy. During his travels in Africa, Ramadan noted that although gall wasps could be found, they did not seem to devastate tree populations as in Hawaii.

The reason, he said, was the presence of natural predators that kept the gall wasp population in check. One was the eurytoma wasp, which looks similar but is black. The gall wasp is mostly orange.

The eurytoma wasp kills its cousin by inserting its eggs into galls containing gall-wasp larvae. The eurytoma wasp, which matures faster, hatches and eats the gall-wasp larvae.

Ramadan said there was no way to know for sure how the gall wasps made their way to Hawaii, although they probably hitchhiked on luggage or cargo transported by plane. Some of the highest concentrations of infested wiliwili trees are found at or around the state's airports.

"They're so small they could be transported easily without being seen," he said of the wasps.

Ramadan said he believes the wasp species traveled from Africa across the Indian Ocean to China and Taiwan and then across the Pacific to Hawaii.

The wasp was first described as a new species in a 2004 scientific journal that studied samples from Singapore and East Africa.

tomas.alex.tizon@latimes.com

[Dave-Vero]

http://www.doacs.sta...tany/index.html

Sorry to not have provided the link.  Florida is quite good at spotting new arrivals.  Climate and extensive international commerce ensure that there will continue to be more.  Just this week there was a news story of giant lizards running amuck in a town unaccustomed to such insults.

[Wai`anae Steve]

I have two erythrina from Australia that have survived so far.  One is in my green house the other in the ground and about 6 feet tall but very skinny.

I think Daryl sent me the seeds many years ago.

[JasonD]

Good news about wiliwili. Researchers have had quick success in biocontrol with a parasitic wasp that's getting the pest under control. Here's an heartening story on Youtube about replanting Erythrina sandwicensis at Mo'omomi on Moloka'i. Now they're trying to recreate a lost forest type - lowland dry forest. When the trees are big enough, they'll be able to harvest wood for surfboards.

[fastfeat]

Good news about wiliwili. Researchers have had quick success in biocontrol with a parasitic wasp that's getting the pest under control. Here's an heartening story on Youtube about replanting Erythrina sandwicensis at Mo'omomi on Moloka'i. Now they're trying to recreate a lost forest type - lowland dry forest. When the trees are big enough, they'll be able to harvest wood for surfboards.

Thanks Jason. I hope they are successful.

Sadly, E. sandwiciensis, like E. variegata, does not survive for long in Mediterranean climates.

[Palms1984]

There's a Wiliwili in Balboa Park which is in full bloom now. It blooms and grows well here in San Diego.

Here's a photo which was taken on March 7, 2012

Attached Thumbnails

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[Palms1984]

Here's a close up of the flowers

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Edited by Palms1984, 10 March 2012 - 08:57 PM.

[Palms1984]

Here's another closer view of the previously posted tree.

Edited by Palms1984, 10 March 2012 - 08:55 PM.

[JasonD]

Glad to see a thriving specimen in San Diego. Having seen the species growing as high as 3000 feet above sea level on leeward Kohala, I'd expected it would grow in SD.

[fastfeat]

There's a Wiliwili in Balboa Park which is in full bloom now. It blooms and grows well here in San Diego.

Here's a photo which was taken on March 7, 2012

Is this tree tagged as E. sandwiciensis? It looks identical to one in the parking lot at Quail BG that I believe was tagged as E. caffra 'Flava' (or maybe I presumed it was?).

[Palms1984]

There's a Wiliwili in Balboa Park which is in full bloom now. It blooms and grows well here in San Diego.

Here's a photo which was taken on March 7, 2012

Is this tree tagged as E. sandwiciensis? It looks identical to one in the parking lot at Quail BG that I believe was tagged as E. caffra 'Flava' (or maybe I presumed it was?).

Pretty sure it's E. sandwiciensis. Being from Hawai'i I've seen many of these trees in bloom. I looked on the internet for E. caffra 'Flava' could not find any information or pics.

[Palms1984]

Glad to see a thriving specimen in San Diego. Having seen the species growing as high as 3000 feet above sea level on leeward Kohala, I'd expected it would grow in SD.

Yes, San Diego has the perfect climate for this tree, especially since it's native to the higher elevations of the Hawaiian Islands.

It's very sad that the Erythrina trees have been decimated! When I went back to Hawaii for my family reunion I didn't notice very many Coral trees around.

[DoomsDave]

E. sandwichensis rocks the house in So-Cal, no problem.

I had a few babies that morphed into these mini-Incredible Hulks that busted loose from their pots, put on ragged shorts and tried to destroy EVERYTHING.

I ended up giving them away to a guy that had a few acres, since they get much too big for my place.

But!

That story shows that there might well be a semi-happy ending to the saga of . . .

The RED PALM WEEVIL (of doom).