Notes and biocontrol insights on the occurrence of leucaena tree and the establishment of leucaena psyllid in Israel

Abstract Leucaena ( Leucaena leucocephala ) is one of about 100 woody plants introduced to Israel for dune stabilization. Today, it is widespread, occasionally planted as an ornamental tree, but primarily regarded as an undesirable invasive weed. In June 2025, a population of the leucaena psyllid, Heteropsylla cubana Crawford (Hemiptera: Psyllidae) was discovered in central Tel Aviv. Based on the extent of damage, it was likely present in the area for at least one year. In early June, three infestation stages of leucaena trees were identified: (i) trees in central Tel Aviv that had almost completely lost their foliage; (ii) trees with healthy foliage but dense psyllid populations (in the Tel Aviv periphery and adjacent areas); and (iii) healthy, non-infested trees in various parts of Israel. By August 2025, trees in central Tel Aviv had regained their foliage. In areas that previously supported high psyllid densities but retained foliage, populations had declined markedly. By mid-August, psyllid populations at all sites consisted mainly of adults and eggs. The observed age structure suggests that vigorous psyllid activity may resume in autumn, when temperatures drop. The extensive use of synthetic herbicides in Israel was once expected to encourage the importation of classical biological control agents against invasive plants. It is hoped that the establishment of the leucaena psyllid in Israel, given its potential to restrain the tree’s growth and limit its spread, will serve as an incentive to consider and implement classical biological control approaches for managing invasive plant species in Israel.