Effects of Helicoverpa armigera egg age on development, reproduction, and life table parameters of Trichogramma euproctidis

Authors: ATASHI, NAZANIN - Shahid Chamran University Of Ahvaz; SHISHEHBOR, PARVIZ - Shahid Chamran University Of Ahvaz; SERAJ, ALI - Shahid Chamran University Of Ahvaz; RASEKH, ARASH - Shahid Chamran University Of Ahvaz; HEMMATI, SEYED - Shahid Chamran University Of Ahvaz; Riddick, Eric

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2021
Publication Date: 6/22/2021
Citation: Atashi, N., Shishehbor, P., Seraj, A.A., Rasekh, A., Hemmati, S.A., Riddick, E.W. 2021. Effects of Helicoverpa armigera egg age on development, reproduction, and life table parameters of Trichogramma euproctidis. Insects. 12:569. https://doi.org/10.3390/insects12070569.
DOI: https://doi.org/10.3390/insects12070569

Interpretive Summary: Helicoverpa armigera is a major pest of crops such as tomato. Because of the potential rapid development of resistance to insecticides by H. armigera and related herbivores, alternative control techniques are necessary. Biological control using natural enemies, e.g., parasitoids, that attack the egg stage of H. armigera could provide a solution. Trichogramma euproctidis is an important egg parasitoid which could be used in augmentative biological control of H. armigera on tomato. This study evaluated the potential of T. euproctidis to parasitize H. armigera eggs of different ages in laboratory arenas. The objective of this research was to determine if young rather than old H. armigera eggs were optimal for T. euproctidis development, reproduction, and life table parameters. Results indicated that T. euproctidis developed faster in 14 h old H. armigera eggs and produced significantly more offspring than in 38 h or 62 h old eggs. This study is important because it provides evidence that T. euproctidis can utilize H. armigera as a rearing host. Using young rather than old host eggs could ensure the persistence of a T. euproctidis mass production system to support augmentative releases.

Technical Abstract: The noctuid Helicoverpa armigera is an economically important pest of agricultural crops in Iran and elsewhere. Research is evaluating the capacity of Trichogramma parasitoids to control H. armigera populations on field crops. The objective of this research was to determine if young rather than old H. armigera eggs were optimal for T. euproctidis development, reproduction, and life table parameters. Bioassays involved exposing T. euproctidis mated females to H. armigera 14, 38, or 62 h old eggs within 24 h in laboratory arenas. Results indicated that the number of host eggs parasitized successfully by T. euproctidis decreased as host egg age increased. Host egg age had no significant effect on T. euproctidis adult emergence. Adults that developed in 14 h old eggs had greater longevity and fecundity than those that developed in 38 h or 62 h old eggs. The intrinsic rate of increase (r) was greatest, and the mean generation time (T) was least for T. euproctidis reared in 14 h old eggs. This study indicates that young H. armigera eggs are more suitable than old ones for T. euproctidis development and reproduction. This study is important because it provides evidence that T. euproctidis can utilize H. armigera as a rearing host. Using young rather than old host eggs could ensure the persistence of a T. euproctidis mass production system to support augmentative releases.