Location: Crop Genetics and Breeding ResearchTitle: Parasitism of Melanaphis sacchari (Hemiptera: Aphididae) by Lysiphlebus testaceipes (Hymenoptera: Braconidae) in the greenhouse and field
|LAHIRI, SRIYANKA - University Of Georgia|
|BUNTIN, G. DAVID - University Of Georgia|
|TOEWS, MICHAEL - University Of Georgia|
Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2019
Publication Date: 1/3/2020
Citation: Lahiri, S., Ni, X., Buntin, G., Toews, M.D. 2020. Parasitism of Melanaphis sacchari (Hemiptera: Aphididae) by Lysiphlebus testaceipes (Hymenoptera: Braconidae) in the greenhouse and field. Journal of Entomological Science. 55:14-24.
Interpretive Summary: The sugarcane aphid is a recent invasive pest of sorghum production in southern U.S. states, which causes devastating economic damage on sorghum production. A number of natural enemies of the aphid have been reported in recent years in other states. These beneficial insects include aphid-feeding predators and aphid-parasitizing parasitoid wasps. Compared with a suite of generalist predators, co-evolved parasitoid specialists often have the strongest impact in suppressing pest populations. Therefore, identification of a key parasitoid attacking the sugarcane aphid could lead to improving efficacy of biocontrol programs. The present study was conducted to assess the fecundity of parasitoid wasp on the sugarcane aphid in Georgia. The present study was conducted to assess parasitoid fecundity on the sugarcane aphid in Georgia. The greenhouse experiment showed that the parasitoid can complete its life cycle on the sugarcane aphid in Georgia. However, field sampling showed that the timing and rate of aphid parasitism occurred late, which would not be effective to suppress initial natural aphid infestation and reduce aphid damage on sorghum plants.
Technical Abstract: The sugarcane aphid, Melanaphis sacchari (Zehntner), is an economically important invasive insect pest of sorghum production in the southern USA. The objectives of this study were to: 1) assess the fecundity of Lysiphlebus testaceipes (Cresson) parasitizing M. sacchari in the greenhouse; and 2) examine the temporal synchronization between L. testaceipes and M. sacchari in the field during 2017 and 2018. Results indicate that after 96 h, the number of M. sacchari had increased approximately 90-fold from a single adult in the greenhouse study. The percentage of mummification observed in the greenhouse study was 15.2 ± 3.3. Of those mummies, 88.7 ± 4.4% hatched and 38.6 ± 8.4% of those offspring were males. Field observations showed that L. testaceipes appeared in the sentinel fields in late July to August. The percentage of mummies observed in the June and July planted plots of 2017, and June planted plots of 2018 were 4.5 x 10-4 ± 1.5 x 10-4, 7.4 x 10-4 ± 4.4 x 10-4, and 4.4 x 10-5 ± 1.7 x 10-5 %, respectively. Even though parasitization of M. sacchari by L. testaceipes was observed in both field and greenhouse, the rate of parasitization in the field suggests that this species is not currently synched up with M. sacchari populations and new species of other natural enemies (e.g., other parasitoids, predators, and entomopathogens) or host switching (or expansion) of L. testaceipes will be necessary before this pest can be managed relying solely on biological control agents in Georgia.