Professor Zvika Mendel
, an entomologist from the Volcani Agricultural Research Center, is leading the search for natural enemies of the cochineal scale insect, with the help of KKL-JNF and its Friends in Mexico.
“This fly will help to bolster our biological control campaign against the pest,” explained Prof. Zvika Mendel. “As it develops very quickly, producing a new generation within about six weeks, we hope that we shall soon be seeing it everywhere in nature.”
Prickly pear cacti afflicted by the cochineal scale insect become covered in what appears to be a white powder, then dry up and die. This phenomenon has been increasingly observed in northern Israel
in recent years, and there are fears that it will spread throughout the country and destroy its prickly pears, which, although they arrived originally from Mexico, are regarded as an ultimate symbol of Israeliness.
The cochineal scale, the rapacious aphid that is attacking the cacti, is also Mexican in origin. Will the predatory Mexican fly prove capable of saving the situation? As it feeds exclusively on the troublesome aphids, there would certainly seem to be reason for optimism.
Professor Mendel explains that, as competition between the fly and the beetle is not too fierce, he believes that the two insects will be able to coexist and work together against the aphid. “The fly lays its eggs inside the cochineal scale colonies, and the larvae that hatch feed on the aphid during all the different stages of its development,” he said.
About three years ago an unsuccessful attempt was made in Israel to control the cochineal scale insect biologically with the help of an Australian beetle
. The next stage was the use of a Mexican beetle
belonging to the genus Hyperaspis
, a natural enemy of the cochineal that was then released at different locations throughout northern Israel.
And, indeed, the Mexican beetle appears to be doing a good job. Dr. Alex Protasov
, a researcher in the Volcani Agricultural Research Center’s entomology department, told us:
“We’ve seen a significant improvement in the prickly-pear cacti that have been treated with the beetles. In Moshav Amirim, for example, we recently revisited one of the affected plants and found it to be completely free of the pest.”
Only the remnants of the beetles’ pupae on this cactus at Amirim bear witness to the fierce battle waged there in recent months, with a most satisfactory outcome. The hope now is that the beetles will move on to other affected cacti and continue the biological warfare on their own.
In view of these positive results, the experiment has been extended to include another natural enemy imported from Mexico – a small fly from the Chamaemyiidae family called Leucopis bellula
. On its arrival in Israel nine months ago it was placed in quarantine to ensure that it would not prove harmful to local fauna, and only after it had received full official authorization was it allowed to become operational.
An initial dose of almost two hundred flies has been released into Klil and Rakefet, two communities in northern Israel, and thousands more are due to be set free soon at different locations throughout the north.