Blue willow beetle

The blue willow beetle is found on willow (Salix) species, whose leaves contain low levels of salicylates[5][6] in fens, carrs and on river banks, but also often in willow short rotation coppice and other agricultural landscapes.[7] It often aggregates on host plants.[8] On Salix cinerea, it prefers and is more common on female than male trees despite higher egg predation exerted by the common flowerbug Anthocoris nemorum on female trees.[9] It is univoltine in Sweden[2] but can produce multiple generations per year in other parts of its distribution range.[10] Proliferation of larvae and egg production varies with vegetation.[11] It overwinters under lichens on trees and under tree bark.[12] Predators of blue willow beetle eggs include A. nemorum and Orthotylus marginalis. Larval predators include A. nemorum, the bug Rhacognathus punctatus,[10] a syrphid fly (possibly Parasyrphus nigritarsis)[13] and the wasp Symmorphus bifasciatus.[14] Adult beetles are parasitized by the wasp Perilitus brevicollis[15] and consumed by R. punctatus.[13]

In Europe, the blue willow beetle can become a severe herbivore pest on willows.[16] For plantations of common osier (Salix viminalis), herbivory reducing biomass production by up to 40% has been estimated .[17] It is susceptible to Bacillus thuringiensis tenebrionis and also Spinosad when treatment is applied to affected plants[18].