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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #349913
Research Project: New Technologies and Strategies to Manage the Changing Pest Complex on Temperate Fruit Trees

Location: Temperate Tree Fruit and Vegetable Research

Title: Caterpillar-induced plant volatiles attract adult herbivores and generalist predator

Author
item EL-SAYED, ASHRAF - NEW ZEALAND INSTITUTE OF PLANT & FOOD RESEARCH
item KNIGHT, ALAN
item BASOALTO, ESTEBAN - UNIVERSIDAD DE CHILE
item SUCKLING, DAVID - UNIVERSITY OF AUCKLAND

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary: Effective, low-cost monitoring of tree fruit pests is an important component of developing integrated programs which can minimize the use of insecticides. Researchers at the USDA, ARS, Temperate Tree Fruit and Vegetable Research Unit, Wapato, WA in collaboration with researchers at the New Zealand Institute for Plant & Food Research, Lincoln, New Zealand and Universidad Austral de Chile, Valdivia, Chile evaluated whether a new lure developed with volatiles released by apple foliage injured by insect feeding would be effective for the key leaf-feeding moth pest of apple and for a key insect predator, lacewing adults. It was determined that the new lure was effective and caught both sexes of two moth species and lacewings. Information from this research supports the continued effort to develop even more effective lures that can be used in trap-based monitoring program for important moth pests in fruit crops.

Technical Abstract: Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered to be an indirect plant defence against herbivores. On the other hand, the caterpillar-induced plant volatiles have been reported either to repel or attract conspecific adult herbivores. This work was undertaken to investigate the response of both herbivores and natural enemies to caterpillar-induced plant volatiles in apple orchards. We sampled volatile compounds emitted from uninfested apple trees, and apple trees infested with generalist herbivore the pandemis leafroller moth, Pandemis pyrusana (Lepidoptera, Tortricidae) larvae using headspace collection and analyzed by gas chromatography/mass spectrometry. Infested apple trees uniquely release six compounds (benzyl alcohol, phenylacetonitrile, phenylacetaldehyde, 2-phenylethanol, indole, and (E)-nerolidol). In field tests, binary blends of phenylacetonitrile + acetic acid or 2-phenylethanol + acetic acid attracted a large number of conspecific male and female adult herbivores. The response of herbivores to herbivore-induced plant volatile (HIPVs) was so pronounced that over one thousand and seven hundred conspecific male and female adult herbivores were caught in traps baited with HIPVs in three days trapping period. In addition, significant number of male and female obliquebanded leafroller were caught in traps baited with 2-phenylethanol + acetic acid or phenylacetonitrile + acetic acid or a ternary blend contains 2-phenylethanol + phenylacetonitrile + acetic acid. This result challenges the current paradigm hypothesised that HIPVs repel herbivores and question the indirect defensive function proposed for these compounds. On the other hand, a ternary blend of phenylacetonitrile + 2-phenylethanol + acetic acid attracted the largest numbers of the general predator, the common green lacewing, Chrysoperla carnea. To our knowledge, this is the first record of the direct attraction of conspecific adult herbivores as well as predators to the shared caterpillar-induced plant volatile in the field.