2013 Annual Report
1a.Objectives (from AD-416):
Understanding the ecology of such invasive and high-risk wood-boring insect species in their native ranges is critical to the development of effective and timely management strategies in the United States. Of major importance are the natural enemies involved in regulating the population dynamics of these species in their home countries.
In this research proposal, we will focus on the discovery, identification, and evaluation of key natural enemies in the native range of wood-boring insect species that are already invasive in the U.S. and those considered at high-risk of becoming invasive. This proposed study will be conducted in China, a key U.S. trading partner. Specific Objectives follow:
(1) Discovery and identification of key groups or species of natural enemies that may have the potential for introduction as biological control agents of wood borers invasive in the U.S., such as emerald ash borer, Asian longhorned beetle, and ambrosia beetles. (2) Identification of native (Asian) wood borers that have the potential to infest North American tree species, and discovery of associated natural enemies that may help control those Asian wood borers should they invade the U.S.
1b.Approach (from AD-416):
1. Select one temperate mixed deciduous mesophytic forest in northeast China and one subtropical forest in southwest China with closely related tree species (congeners) native to China and introduced from North America that coexist due to plantings of exotic trees in China during reforestation efforts.
2. Locate and identify three to five pairs of congener species (one Asian, one North American for each genus) of deciduous trees in the general area (~50 km2) of each forest habitat. Likely tree genera to study will be species of ash (Fraxinus), maple (Acer), oak (Quercus), poplar (Populus), and cherry (Prunus).
3. Ten to 15 trees of each species of each pair of trees, as described above at each forest habitat, will be artificially stressed by girdling to attract invading or potentially invading wood borers and their natural enemies.
4. All wood-boring insects infesting these girdled trees will be sampled, collected and identified together with their associated egg and larval parasitoids in the spring or late fall after girdling.
We have conducted the literature search on Chinese wood-boring insects and their food plants (host trees), and identified 15 potentially high-risk species of beetles in three families: Buprestidae (jewel beetles), Cerambycidae (longhorned beetles), and Curculionidae (bark beetles). Those beetles attack not only their native (Asian) trees but also exotic (North American) trees planted in China. Working with our Chinese cooperators, we have located and identified three pairs of the following congener species of deciduous trees in Northeast China:
Pair 1: Fraxinus mandschurica (Chines species) vs. Fraxinus americana, F. velutina, and/or F.pensylvanica (American species).
Pair 2: Populus tomentosa (Chines species) vs. Populus canadensis (American species).
Pair 3: Pinus massaniana (Chinese species) vs. Pinus banksiana (American species). Ten trees of each paired species in the genus Fraxinus (30 trees) and Populus (20 trees) in May of 2013 in Northeastern China (Liaoning and Heilongjiang Provinces). However, appropriate study sites for Pinus species remain to be determined because of constraints of limited resources and lack of detailed information on their distribution. A specific cooperative agreement with the Chinese Academy of Forestry is being formally developed for this project.