Endophytic colonization of Vicia faba and Phaseolus vulgaris (Fabaceae) by fungal pathogens and their effects on the lifehistory parameters of Liriomyza huidobrensis (Diptera: Agromyzidae)

Abstract

Ten fungal isolates belonging to the genera Beauveria (3), Hypocrea (1), Gibberella (1), Metarhizium (2), Trichoderma (1) and Fusarium (2) were evaluated in the laboratory to determine whether they could become endophytic in two pea leafminer (Liriomyza huidobrensis) host plants (Vicia faba and Phaseolus vulgaris), and to assess their possible negative effects on leafminers. Beauveria (ICIPE279), Hypocrea, Gibberella, Fusarium and Trichoderma isolates colonized roots, stems and leaves of both host plant species. Beauveria isolates G1LU3 and S4SU1 colonized roots, stems, and leaves of P. vulgaris but only the root and stem of V. faba. Isolates of Metarhizium failed to colonize the two host plants. The effects of endophytically colonized fungal pathogens on mortality, oviposition, emergence and longevity of L. huidobrensis were investigated after endophytic colonization of V. faba plants. All the fungal isolates that succeeded in colonizing the host plant were pathogenic to L. huidobrensis, causing 100 % mortality within 13.2 ± 0.7–15.0 ± 0.6 d. However, Hypocrea outperformed the other isolates (p < 0.0 001) in reducing longevity of the progeny (11.2 ± 1.0 vs. 17.8 ± 1.4 d in the control), the number of pupae (80.0 ± 6.7 vs. 387.0 ± 21.7 pupae in the control), and adult longevity (3.8 ± 1.0 vs. 9.9 ± 1.8 d in the control). Adult emergence was significantly reduced (p < 0.0 001) in Hypocrea (21.4 %) and Beauveria (38.0 %) treatments compared to the control (82.9 %).