Natural Perspectives

Remember when Professor Harold Hill sang “Trouble” in the “Music Man?”

That’s the song about the danger of playing pool in River City. If that

song were being sung in Huntington Beach, it would go something like

this.

“Well, ya got trouble, folks, right here in Surf City. With a capital

T, that rhymes with P and that stands for psyllids.”

Psyllids (pronounced sill-ids), properly called red gum lerp psyllids,

are the nasty little insects that are destroying our eucalyptus trees in

Central Park.

Lerp, which rhymes with twerp, is an Australian aboriginal name that

means house. The lerp is the hard little cover, or case, that the psyllid

nymph makes to protect itself. These cases are the bumps covering the

eucalyptus leaves. The psyllids also secrete sticky honeydew, which

promotes the growth of black mold. Add these things up and you’ve got

trouble. Big trouble. With a capital T that rhymes with P, which in

psyllid is silent.

We’ve got lerp psyllids all over town. If you’ve walked in Central

Park lately, or sat through one of the lovely Sunday evening band

concerts in the park, you must have noticed how bare the eucalyptus trees

look. Those poor trees have almost no leaves. The few leaves that remain

are covered with sticky, bumpy lerps.

Red gum lerp psyllids came from Australia and were first reported in

this country in 1998. They spread from Los Angeles County to 37 other

California counties, including Orange County. In fact, we’re almost at

ground zero.

Eucalyptus trees in Southern California were imported from Australia

in the 1800s to provide railroad ties and firewood. For the past century,

they’ve flourished. Hawks nest in their branches and hummingbirds feed on

their flowers. Warblers and flycatchers feed on insects they find among

the leaves. Some birds, such as bushtits, like to eat the psyllids and

will do their part to help keep the population in check. While the

eucalyptus may not provide a habitat as good as native trees, they do

have biological value, as well as beauty and fragrance.

The trees in Huntington Beach Central Park were planted about 40 years

ago when the park was created. Some of them may not live much longer

because the lerp psyllids are sucking the life right out of them.

However, the trees aren’t quite dead yet. Experts say that although

the trees may look like they’re nearly dead during the summer, eucalyptus

are remarkably resilient. They generally make a comeback in fall,

responding with new growth. Fortunately, help is on the way in the form

of biological control. We may be able to save our trees if they can hang

on until the cavalry arrives. Or until Professor Hill comes marching in

with his 76 trombones.

The Center for Biological Control at the University of California at

Berkeley has declared war on lerp psyllids. Scientists there brought back

a number of parasites from Australia in 1999. These parasites attack lerp

psyllids. The scientists studied several of them and selected a

parasitoid wasp, pyllaephagus bliteus, as the most likely candidate to

combat the psyllid infestation here. The Center for Biological Control is

now raising quantities of these tiny wasps, but they can’t produce enough

to keep up with demand. The wasps will infect and kill off, or at least

greatly reduce, the population of lerp psyllids. But it will take time

for scientists at Berkeley to raise enough parasites to distribute

throughout the infected zone, and then it will take even more time for

the biological control to have an effect.

Parasitoid wasps were released initially at several sites during the

summer and fall of 2000, and again this summer. Central Park received 15

of them last December. We were selected as the release site for Orange

County because we have a relatively healthy population of red gum

eucalyptus compared to drier areas such as Tustin, and because prevailing

winds should carry the wasps inland once they reproduce.

The wasps are expected to spread naturally, preying upon the lerp

psyllids as they multiply. While there is evidence that the wasps are

reproducing in San Diego, there is no evidence so far that they have

reproduced here. That doesn’t mean that they haven’t, however. There are

still too few of them to monitor adequately.

It may be several seasons before we see an effect, but eventually our

eucalyptus trees should recover. By using biological control, we can feel

good knowing that we didn’t resort to massive spraying of expensive

noxious chemicals, which aren’t known to be effective against the

psyllids anyway.

Meanwhile, don’t worry about our fine old trees in Central Park being

cut down. They look like they’re dying, but they have a good chance for

recovery. It just won’t be soon. Jim Conklin, supervisor of tees,

landscapes and chemicals in Public Works says they won’t cut them down

unless they’re stone dead and the bark has peeled off. The city is going

to give the parasitoid wasps a chance to save the trees.

As Professor Hill said, “May I have your attention, please? Your

attention, please. I can deal with this trouble, friends, with the wave

of my hand.”

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at o7 [email protected] .