|HILTPOLD, IVAN - University Of Missouri|
Submitted to: Journal of Pesticide Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2015
Publication Date: 9/1/2016
Publication URL: https://handle.nal.usda.gov/10113/63121
Citation: Hiltpold, I., Hibbard, B.E. 2016. Neonate larvae of the specialist herbivore Diabrotica virgifera virgifera do not exploit the defensive volatile (E)-ß-caryophyllene in locating maize roots. Journal of Pesticide Science. 89(4):853-858. doi:10.1007/s10340-015-0714-7.
Interpretive Summary: The western corn rootworm is the most economically-damaging insect pest of maize in the Corn Belt of the United States and is also becoming more important in Europe. Insect host-location behavior can often be used in management of major pests. The host-location behavior of newly-hatched western corn rootworm larvae was assessed for reaction a specific compound, (E)-ß-caryophylene (EßC), because this compound is produced by maize roots in response to rootworm feeding and had been found to be attractive to second instar larvae. Under greenhouse conditions, a maize line modified to always release EßC was planted 75 cm apart from an unmodified maize lines that never produce EßC. Western corn rootworm eggs were infested in the center of the plants and the number that went to each plant was recorded after collection. Counts of recovered western corn rootworm larvae did not differ between the two lines, supporting the postulate that carbon dioxide and not EßC is the primary attractant for newly hatched larvae. The chemical ecology of western corn rootworm larvae is discussed and a conceptual model of the foraging behavior of this pest is proposed. Basic knowledge of pest biology is helpful in designing new management strategies.
Technical Abstract: The behavior of the neonate larvae of Diabrotica virgifera virgifera LeConte (western corn rootworm, WCR) was assessed in presence of maize root constitutively emitting (E)-ß-caryophylene (EßC). This root volatile has been shown to attract both second instar WCR and insect-killing nematodes, offering innovative alternatives in controlling this major pest. Under greenhouse conditions, the maize line 201-L1, transformed to constitutively emit EßC, was planted 75 cm apart from its isoline HiII in soil benches. WCR eggs were infested in the center of the benches and neonate attraction toward either root system was recorded by collecting WCR larvae established on both maize lines. Whereas slightly more larvae were found on volatile-emitting plants, counts of recovered WCR neonates did not differ between the two lines. This supports the postulate that CO2 is the primary attractant described for WCR neonates. The chemical ecology of WCR larvae is discussed and a conceptual model of the foraging behavior of this pest is proposed.