Prof. Zvi Mendel isn’t a particular fan of the prickly pear (aka “sabra”) cactus. “I like the fruit but I’m not crazy about it; one at a time is enough for me,” he admits.

But that hasn’t stopped this entomologist from the Volcani Center Agricultural Research Organization from devoting the last 11 years to saving the plant from an aggressive species of parasitic scale insect that began sweeping through Israel from Lebanon in the north in 2013.

If you want to know how bad it could have been if Mendel hadn’t stepped in, you only need to look at Morocco, which used to grow a lot of sabras.

So far, Morocco has lost around 150,000 hectares of prickly pear to the bug — called false carmine cochineal or Dactylopius opuntiae — and some 30,000 people have lost their jobs. Two factories producing seeds oils from the cacti were forced to close.

The sabra, of course, has an extra poignancy in Israel. Though the plant is actually an import originally from Mexico, it has come to be regarded as a metaphor for Israelis themselves – prickly and difficult on the outside, soft and sweet inside. The extinction of the plant here would have been a sorry blow to Israel’s vision of itself.

It’s more than that, though. The prickly pear cactus is an important cash crop cultivated and sold all over the world. It is high in fiber and antioxidants and is known to assist in diabetes and cholesterol control.

The sabra is also used as animal feed and is a good raw material for many other products.

“It’s an excellent and versatile plant,” says Mendel. “It can tolerate extreme temperatures and live on low-quality water. It’s a very successful industrial plant.”

Oops, wrong purchase

So, what happened?

Well, and this bit is not exactly official — the story is pieced together from the Lebanese press – in 2012, a Lebanese farmer decided to buy some cochineal scale for his sabra plants as they have been used for a couple of centuries to make red dye. But instead of buying cochineal, he mistakenly bought the false cochineal and the result was devastating.

The pests from his plants began to spread like wildfire across southern Lebanon, spreading – mostly through migrating birds – into Syria, Jordan and Cyprus, causing severe damage. Cacti infected by the scale insects whiten, dry up, and eventually die.

The first sighting in Israel was in the Upper Galilee in 2013. From there it gradually began to move down through the country as birds unwittingly picked up the scale insects on their legs and deposited them wherever they stopped to rest.

When Mendel and his team understood what was beginning to happen in Israel, they joined forces with the forestry department of environmental organization Keren Kayemeth LeIsrael-Jewish National Fund (KKL-JNF) to look for an answer.

Spraying the cacti, they quickly discovered, didn’t help. Moreover, it was bad for the environment. They needed a more effective solution.

“In its native climates, the cactus does not need to protect itself against pests like the scale because someone else is doing the job – other types of insects. If it is brought to new climates, like Israel, then the plant does not develop the necessary means to cope with the pest, so becomes very susceptible,” explains Mendel.

The best solution, he realized, was to find the natural predator to the scale bugs in Mexico and bring them to Israel.

With the help of KKL-JNF, Mendel began work with KKL Mexico. A Mexican scientist collected a small ladybeetle, belonging to the genus Hyperaspis trifurcata, that fed on the cochineal, and sent it to Israel to be reared.

Asking the public for help

The first ladybeetles were introduced to Israel in 2016, but initial attempts were not always successful. Often by the time KKL-JNF foresters could release the beetle onto the infected plants, it was already too late — the plants couldn’t be saved and the beetles, without a source of food, also died.

At this point, Mendel’s team enlisted the help of the public, publishing articles and brochures in Hebrew, Arabic and English, asking for help collecting the natural enemies in the northern areas and introducing them quickly to new infestations farther south.

Around 300 to 400 people got involved in the initiative, helping accelerate the spread of the beetle and quickly identifying new hotspots as they developed.

By 2019, to get ahead of the spread, much like a fire brigade setting small deliberate fires to stop a massive blaze, the team also began a new method of bringing infected cactus plants where both cochineal and beetle were already slugging it out to new uninfected areas, so that both populations could establish themselves quickly.

“We worked with local people to keep track of the areas and make sure we were not creating an outbreak, or that something would go wrong, but these balanced islands worked wonderfully,” says Mendel.

Sharing the success

The tide began to turn, and the work in Israel positively impacted neighboring Lebanon, Syria and Jordan. “We first released the beetle in the Galilee and of course it spread in all directions. It doesn’t recognize international borders,” Mendel tells ISRAEL21c.

Another deliberate policy was to bring beetle populations to areas near Gaza to stop the spread of the infection into sabras in the enclave.

“The idea was that if we can establish natural beetle populations not far from the border with the Gaza Strip, then we can prevent the destruction of the cactus tree in Gaza,” he says.

As the environmentalists constantly refined their tactics, Mendel shared the growing Israeli knowledge and experience with the rest of the world.

“We translated everything into Arabic, English and French,” he explains. “We supplied all the protocols on how to do it properly, how to rear the beetle, release it, spread it, etc. The information flew very quickly. Other countries have definitely learned how to cope with this problem from the Israeli experience.”

He also shared the information with Morocco and offered to send beetles produced in Israel. Official attempts were rebuffed, but eventually as Morocco began suffering heavier losses, a private company from Agadir approached Mendel and asked him to send the beetles for them to rear.

“I told them that I don’t mind if they don’t want to say the scale came from Israel, but my one condition was that they send the beetles free of charge,” he says.

“Morocco probably will manage to reduce their losses, but they did it very late. The damage is unbelievable.”

Though Israel’s outbreak is now under control even as it continues to spread south, other countries are increasingly at risk, including Spain, Algeria and Tunisia.  Mendel is also in contact with colleagues in Italy and France.

Mendel believes it’s only a matter of time before Sicily is also impacted.

“The major risk now is Sicily. It’s the major supplier of the prickly pear fruits to Italy and beyond. The scale has already spread to Algeria and Tunisia, and Tunisia and Sicily are on one of the major migratory routes for birds from Africa to Europe,” Mendel explains.

Libya is also likely to be in danger, and possibly Egypt too.

Eucalyptus trees saved by wasps

The sabra is not the only tree that Mendel, through his long career, has helped save.

Israel’s eucalyptus trees were also under threat from a pest, and nobody knew which insect could control the problem.

In the end, with advice from an Australian researcher, Mendel flew to the Australian outback and spent long days searching snake-infested riverbeds before he finally found the answer – a small parasitic wasp that looked very much like 30 or so other parasitic wasps also found on the eucalyptus.

He brought it back to Israel, reared it successfully and released the offspring into the wild, sending others to any countries that requested help.

Mendel retired nine years ago, but at 76 he’s still the main address for anyone looking for help fighting a sabra plant infection.

In Israel, many people contact him to ask where they can find active spots to pick up the beetle, and researchers and growers worldwide are still in contact seeking advice and support.

It’s all very hands on. Mendel requests photographs of outbreaks and analyzes them to see if any beetles are already there with the cochineal. He also sends photographs of the beetles, so people can identify them.

If the beetle isn’t readily available, he says the first step for anyone with the problem is to wash the cochineal off the plants. “This isn’t a control,” he says. “They will soon return, but if you release pressure from the plant it restrains the cochineal, and gives it time for natural enemies to build up.”

A predatory fly

In the last year, Mendel’s team also discovered and imported a predatory fly from Mexico that kills the cochineal and is more aggressive than the beetle.

By now, the scale bug in Israel has spread to the Dead Sea shore in the east, and to Beersheva in the west. “It will continue to spread,” Mendel confirms, “But it is now under control.”

Thanks to that better control, the chance of migratory birds spreading the infection has fallen.

“I do feel proud of what we’ve managed to achieve,” says Mendel. “I was the leader, but this is a team effort. There are other people who helped me do the job. I couldn’t have done it alone.”

He notes that KKL-JNF arranged free courses for growers all over the world on how to combat the pest.

“We have helped so many people in a short time, and people appreciated what Israel could do to help.”

Originally posted at israel21c.org