INTERACTIONS BETWEEN AMBROSIA BEETLES AND THEIR FUNGAL SYMBIONTS
Biological Integrated Pest Management Unit
2013 Annual Report
1a.Objectives (from AD-416):
The goal of this project is to isolate and characterize strains of fungi (Ambrosiella spp.) associated with ambrosia beetles. Objectives include.
1)Identify and assess genetic diversity among strains isolated from Xylosandrus crassiusculus and X. germanus and.
2)Determine impact of fungal diversity on beetle development within various hosts and substrates.
1b.Approach (from AD-416):
Ambrosia beetles (Xylosandrus spp. and others) are pests of a wide array of woody plants used in the nursery industry. They depend, for their survival, on their own cultivation of a fungus (Ambrosiella spp. and others). Fungal strains isolated from Xylosandrus spp. will be identified and assessed through sequencing of 18S, 28S and ITS regions of ribosomal DNA from X. crassiusculus and X. germanus. Brood development and symbiont growth will be evaluated for each fungal genotype on representative hosts or diet substrates. Fecundity of beetles within galleries will be evaluated.
A total of 129 isolates from X. germanus and 88 from X. crassiusculus, from 4 and 6 states, respectively, are now in culture and undergoing further analysis. Preliminary data indicate that at least two genotypes of the symbiotic Ambrosiella fungus are associated with X. germanus. Only one genotype was observed among Ambrosiella isolates associated with X. crassiusculus.