Relative susceptibility of Salix clones to chrysomelid beetles: evidence from the Stott willow collection at Ness

Abstract

Willow species and hybrids growing in the Stott willow collection at Ness, UK, differed markedly in their susceptibility to leaf damage by inseets, predominantly ehrysomelid beetles, with the rank order of suseeptibility remaining relatively constant over 2 years. Some species displayed a wide range of variation in susceptibility amongst clones; others very little. The range of susceptibilities of hybrids tended to mirror those of the parent species, with the hybrid usually sustaining leaf damage levels intermediate between those of the parents. Leaf damage in most species was higher on the lower leaf surface up to mid-season, beyond which leaf perforation damage beeame prevalent. Damage levels did not appear related to leaf toughness. Apparent levels of leaf damage were lower in October versus ]uly/August samples across nearly all species. Heavy leaf damage in one year did not appear to induce the production of leaves that were more resistant to inseet attaek in the following year.

The susceptibility of herbal willow to Melampsora rust and herbivores

“…3a, b). Differences in beetle feeding amongst the clones, however, support the earlier findings that willow susceptibility to leaf beetles is strongly controlled by genetics (Hodkinson et al 1998;Glynn et al 2004). There was no clear relationship between growth and insect feeding at both sites.…”

A Genetic Study of a Salix Germplasm Resource Reveals New Insights into Relationships Among Subgenera, Sections and Species

“…There are some 30-40 species of Melampsora on Salix, each occurring on a specific range of willows. Except for M. amygdalinae, all willow rusts having five-spore stages require taxonomically very different plants (alternate hosts) to complete their lifecycle [18]; (4) Several authors have reported that S. triandra differs from most other willow species in its low content of glycosides and extremely low content of tannins (in laboratory-grown plants), although both secondary compounds are common in Salix [35]; (5) S. triandra also contains the highest concentration of salidroside, which is apparently a very rare glycoside in European willow species [59], and it has been argued that the rather high resistance of S. triandra to insects [25,61] may be attributed to this trait [24,28,41,56,61].…”

Variable responses of natural enemies to Salix triandra phenotypes with different secondary chemistry

“…In the former case, it can lead to premature leaf‐abscission and in the latter to total defoliation of S. triandra ramets. Rust infection as well as leaf beetle damage and attacks by galling sawflies have been documented to affect growth and survival of willows (Bach 1994, Hodkinson et al 1998, Kendall and Wiltshire 1998, Hakkarainen et al 2005). We have not estimated the effect of our natural enemies on clone fitness and we are therefore unable to determine the strength of selection on specific plant traits.…”