Synergistic effects of Aphidius colemani (Hymenoptera: Aphidiidae) and Coccinella undecimpunctata (Coleoptera: Coccinellidae) releases for the biological control of Diuraphis noxia in wheat fields

ABSTRACTThe Russian wheat aphid, Diuraphis noxia, is a significant pest for grain crops worldwide. Bioagents such as the parasitoid, Aphidius colemani and the predator, Coccinella undecimpunctata have been shown to be effective against many aphid species. This study aimed to investigate the combined effect of releasing these two bioagents on controlling D. noxia without using pesticides. To achieve this, three systems of release were evaluated in the field: (1) the parasitoid A. colemani at rate of 4 mummies/m2, (2) the predator C. undecimpunctata at rate of 10 individuals (3rd larval instar)/m2, and (3) A. colemani (4 mummies/m2) + C. undecimpunctata (10 individuals/m2) and control. After four releases, the combination of A. colemani and C. undecimpunctata resulted in the highest percentage of reduction in aphid population, with a reduction of 95.58, 95.53% in 2020 and 2021, followed by 86.94, 83.92% in A. colemani plots and the lowest reduction percentage in C. undecimpunctata plots, with 65.1, 68.92%, in 2020 and 2021, respectively. Based on these results, it is recommended to use the combination of the two bioagents, A. colemani and C. undecimpunctata for controlling D. noxia in a wheat field. Therefore, the use of a combination of natural enemies, carefully timed and repeated releases, and consideration of intraguild predation dynamics can help to achieve effective biological control of aphids in wheat crops. The use of natural enemies such as A. colemani and C. undecimpunctata can reduce the application of pesticides and promote sustainable pest management practices.KEYWORDS: Aphidparasitoidpredatorcombinationrelease Disclosure statementNo potential conflict of interest was reported by the authors.