Journal of Economic Entomology (2018) 111, 1587-1594

Allan Mweke, Christian Ulrichs, Paulin Nana, Komivi Senyo Akutse, Komi Kouma Mokpokpo Fiaboe, Nguya Kalemba Maniania and Sunday Ekesi (2018)
Evaluation of the entomopathogenic fungi Metarhizium anisopliae, Beauveria bassiana and Isaria sp. for the management of Aphis craccivora (Hemiptera: Aphididdae)
Journal of Economic Entomology 111 (4), 1587-1594
Abstract: Cowpea, Vigna unguiculata ((L.) Walp; Fabales: Fabaceae), is an important indigenous vegetable and grain legume in the tropics where it represents a major diet component. Cowpea aphid, Aphis craccivora (Koch; Hemiptera: Aphididdae) is a major pest causing up to 100% yield losses. Aiming at establishing alternative approach to synthetic insecticides, we evaluated the pathogenicity of 23 fungal isolates including Metarhizium anisopliae ((Metschn.) Sorokin; Hypocreales: Clavicipitaceae), Beauveria bassiana ((Bals.) Vuill.; Hypocreales: Cordycipitaceae), and Isaria sp. (Hypocreales: Cordycipitaceae) against adult A. craccivora in the laboratory. Adult apterous aphids were sprayed with conidial suspensions titred at 1 × 10⁸ conidia ml^-1 for pathogenicity tests while 1 × 10⁴, 1 × 10⁵, 1 × 10⁶, 1 × 10⁷ and 1 × 10⁸ conidia ml^-1 were used in dose response bioassays. All the fungal isolates were found pathogenic to A. craccivora, causing mortality of between 34.5 and 90%. The lethal 50% mortality time (LT₅₀) values varied between 3.3 and 6.3 d, with the best isolates being ICIPE 62, ICIPE 41 and ICIPE 644. The lethal concentration mortality (LC₅₀) values were 2.3 × 10⁶, 1.3 × 10⁸ and 1.3 × 10⁹ for ICIPE 62, ICIPE 41, and ICIPE 644, respectively. M. anisopliae isolate ICIPE 62 produced more conidia on aphid cadavers (4.5 × 10⁷) than ICIPE 41 (2.7 × 10⁷) and ICIPE 644 (2.1 × 10⁷) 6 d post-treatment. Relative potency comparison showed that ICIPE 62 was more potent than the other two isolates. In the screenhouse, conidia of ICIPE 62 significantly reduced A. craccivora population compared to control but there was no significant difference between emulsifiable and aqueous formulations. Small-holder leafy vegetable producers could gain more profits using fungal-based biopesticides in Aphid-IPM strategies, leading to reduction of pre-harvest intervals after their application compared to synthetic insecticides.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Komi K.M. Fiaboe, Sunday Ekesi, Christian Ulrichs, Nguya K. Maniania

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aphis craccivora	Cowpea and relatives (Vigna)
Beauveria bassiana (entomopathogen)	Aphis craccivora	Cowpea and relatives (Vigna)
Metarhizium anisopliae (entomopathogen)	Aphis craccivora	Cowpea and relatives (Vigna)