About the project

Improved insect resistance

Project members: Prof. Christer Björkman

Associated to the project: Dr. Adriana Puentes, Dr. Johan Stenberg, Karin Eklund, Dr Anna Lehrman, Dr. Mikaela Torp

The main insect pest in willow plantations have so far been the leaf beetle Phratora vulgatissima. Both adult beetles and larvae feed on the leaves of willows and can reduce growth by up to 40 %. The population dynamics of leaf beetles, and hence risk for outbreaks, is to a large extent affected by natural enemies. Two of the most important natural enemies can feed both on the willows and on the eggs and larvae of the leaf beetle. In addition, both of these predatory bugs (mirids and anthocorids) lay their eggs in the stems and in the leaves of willows. This intimate connection to the willow and their role in beetle dynamics makes it natural to include them in our studies. Based on results from our studies, mainly involving three clones of Salix viminalis (“susceptible”) and three clones of S. dasyclados (“resistant”), we have been able to develop a reliable protocol for determining resistance. The willow defenses act both directly (negative effects on beetles) and indirectly (positive effects on natural enemies).
A most interesting result is also that S. dasyclados plants fed upon by leaf beetles send out signals in other parts of the same plant that attract their “body guards” (anthocorid bugs). In the future, we aim at identifying genetic markers of leaf beetle resistance by studying a cross between S. viminalis and S. dasyclados.
Download (printable): pdf Leef beetles on Salix

Updated 2016-11-29 |Berit Samils