Israelis like to think they’re sweet and soft inside with a tough and spiky exterior, which is why the national symbol and name for native Israelis is sabra, named for the sabra cactus whose fruit, once past the prickly and tough rind, is noted for its sweet flavor. That symbol is under threat however from an invasion of aphids, parasitic insects against which the cactus has no natural defenses. The aphids could conceivably become a problem all over the country, which is why efforts by the Ministry of Agriculture, in partnership with the Jewish National Fund and the Volcani Center in Beit Dagan, are seeking ways to fight them off before they become an intractable problem.
“The aphids first were noticed by a local farmer from the Hula Valley [in northern Israel],” said David Brand, chief forester and head of the Forestry Department of KKL-JNF. “The specific aphid can cause severe damages to our local Sabra compared to other insects that attack the Sabra but cause local and minor damages.”
The Sabra plant has a long history in the Middle East, dating back approximately two centuries when it was imported specifically so insects that feed on the plant could be harvested to make dyes. Additionally, the plants were also used as fences for livestock and property borders.
“It is already a part from our natural and national landscape,” Brand said.
Unlike the dye-producing insects, however, the aphids are a real problem.
“This aphid probably inserts toxins to the leaf tissue of the plant and eventually the leaf and the plant collapse,” Brand said.
As for how the pests arrived, the current theory is that someone illegally imported a Central American cactus, some of which have narcotic properties.
“We presume that someone that visited in Central America would like to introduce to Israel this plant in order to grow such plant in his private garden for local consumption,” Brand said.
Aphids that managed to hitch a ride on the illegal import then made their way into the Sabra cacti population.
Aphids are a common enough agricultural problem in the Americas, but natural predators like ladybugs can be used by farmers to keep crop failure to a minimum. Unfortunately, there is no natural aphid predator in Israel.
Other cacti might suffer from the aphid infestation but luckily for now the threat to Israeli wildlife is limited to just one species and just the one valley. To combat the bugs, Brand said there are both short and long-term plans.
“We consider in the short term to eradicate the aphids by mechanical mean or by chemical spray. For the long term, we would like to introduce the natural enemy to the aphid,” he said.
Although the general prognosis for the Sabra plant is positive, the infestation is a reminder of how devastating accidental species importation can be to an ecosystem, as sometimes even a sharp and tough outside isn’t enough to keep a species safe.
“This is a real threat on the Sabra. We must take all measures to combat the aphids.”