Emerald ash borer (Agrilus planipennis
Fairmaire), an Asian species was discovered attacking ash trees (Fraxinus spp.)
in 2002. EAB is established throughout
much of the Midwestern and eastern United States. In North America,
the emerald ash borer (EAB) attacks only native ash species. To date, none have been observed to be
objectives of this study were to determine:
relative suitability and preference of Asian and European ash (Fraxinus spp.) biotypes for the emerald
ash borer, Agrilus planipennis
Asian and European ash (Fraxinus
spp.) biotpyes are suitable for future ash breeding programs
in the 2009 and continuing through the 2013 field season, a series of studies
were conducted to evaluate Asian and European ash (Fraxinus spp.) biotypes for preference and suitability for the
emerald ash borer (EAB). Laboratory
no-choice adult feeding studies were used to test for feeding preference and
suitability. Adult beetles were reared from
infested logs and two to three adult female beetles were placed in clear
plastic cylinders with candidate ash foliage and allowed to feed. Feeding cylinders were held in a rearing cage
at approximately 75oF and 60-70 relative humidity, with a 16:8 photoperiod. The beetles were monitored daily for evidence
of feeding and mortality and records kept.
from the no-choice feeding studies on Asian and European ash biotypes indicate
that adult EAB beetles lived the longest (mean=14 days) on F. pennslyvanica (preferred host) compared to the Asian and
European species tested. Several beetles
lived several months on F. pennsylvanica. Adult beetles lived the second longest period
(mean=8 days) on Fraxinus angustifolia
var. australis and consumed
approximately 22% of the leaf tissue.
The mean # of fecal pellets (275) was second only to F. pennsylvanica with a mean of 326
fecal pellets. Beetles feeding on the
remaining Asian and European ash biotypes (F. angustifolia var. pannonica,
F. excelsior, F. ornus)all removed an average of 3% of the leave tissue, lived less
than six days, and had a mean of <100 fecal pellets.
Additional Asian no-choice laboratory feeding bioassays
have revealed adult beetles feeding on F. chinensis ssp. rhynchophylla,
and F. longicuspis var. siebolidiana removed <8% of leaf
tissue. Biotypes with medium
susceptibility included F. bungeana, F. chinensis, F.
platypoda and F. mandshurica var. japonica with 10-15% of the foliage consumed. Highly susceptible species (24-32% foliage
consumed) included F apertisquamifera,
F. insularis, F. paxiana, F. stylosa and F. pennsylvanica (highly
Mortality rate were higher on less suitable hosts
and lower on more suitable hosts. Biotypes
with low susceptibility consisted of F.
angustifolia var. pannonica, F. apertisquamifera, F. chinensis,
F. chinensis ssp. rhychophylla, F. mandshurica, F. mandshurica var. japonica
and F. syriaca. Highly
susceptible biotypes included F.
angustifolia var. austalis and F. longicuspis var. siebolidiana.
These preliminary results indicate:
, F. chinensis, F. angustifolia var. austalis
appear to be more suitable for adult EAB feeding and may not be good
candidates for inclusion in ash tree breeding programs.
, F. insularis, F.
languinos, F. oxycarpa var. tamariscifolia, F. pallisae and
F. syriaca appear to be less suitable for adult EAB feeding and may show
promise for inclusion in future ash breeding programs.