Mechanism of Action of Endophytic Fungi Hypocrea lixii and Beauveria bassiana in Phaseolus vulgaris as Biopesticides against Pea Leafminer and Fall Armyworm

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.

Endophytic fungi protect tomato and nightshade plants against Tuta absoluta (Lepidoptera: Gelechiidae) through a hidden friendship and cryptic battle

Endophytic fungi live within plant tissues without causing any harm to the host, promote its growth, and induce systemic resistance against pests and diseases. To mitigate the challenging concealed feeding behavior of immature stages of Tuta absoluta in both tomato (Solanum lycopersicum) and nightshade (Solanum scabrum) host plants, 15 fungal isolates were assessed for their endophytic and insecticidal properties. Twelve isolates were endophytic to both host plants with varied colonization rates. Host plants endophytically-colonized by Trichoderma asperellum M2RT4, Beauveria bassiana ICIPE 706 and Hypocrea lixii F3ST1 outperformed all the other isolates in reducing significantly the number of eggs laid, mines developed, pupae formed and adults emerged. Furthermore, the survival of exposed adults and F1 progeny was significantly reduced by Trichoderma sp. F2L41 and B. bassiana isolates ICIPE 35(4) and ICIPE 35(15) compared to other isolates. The results indicate that T. asperellum M2RT4, B. bassiana ICIPE 706 and H. lixii F3ST1 have high potential to be developed as endophytic-fungal-based biopesticide for the management of T. absoluta.

Entomopathogenic Fungi as Endophytes for Biological Control of Subterranean Termite Pests Attacking Cocoa Seedlings

This study was conducted in the scope of developing a sustainable effective approach against subterranean termite pests using entomopathogenic and endophytic fungus-based biopesticides. Termites, Odontotermes spp. workers, were tested for their susceptibility to 15 entomopathogenic fungal isolates through the direct spraying of conidia suspensions at 1 × 108 conidia/mL. In general, all the isolates screened were pathogenic, with 100% mortality 4–7 days post-inoculation. However, the most virulent isolates were Metarhizium brunneum Cb15-III; the M. anisopliae isolates ICIPE 30 and ICIPE 60; Hypocrea lixii F3ST1; and the Beauveria bassiana isolates ICIPE 279, ICIPE 706 and ICIPE 662. These isolates were further tested for their endophytic colonization of cocoa seedlings using seed soaking, soil drench and foliar spray at 1 × 108 conidia/mL. The colonization of the plant tissues by the fungi was determined using a culture-based technique. Only the B. bassiana isolates ICIPE 706 and ICIPE 279, and H. lixii F3ST1 colonized the cocoa seedlings, with varied colonization rates among isolates and inoculation methods. Three naturally occurring endophytes—Trichoderma asperellum, Fusarium solani and F. redolens—were also isolated from the cocoa seedling tissues. These findings suggest that cocoa seedlings are conducive to endophytic fungal growth either occurring naturally or from artificial inoculation Our findings could possibly lead to an innovative approach to the management of herbivory and subterranean termite pests in cocoa agroforests.

Morphology characterization and in vitro study of bio agents, plant extracts and chemicals against Pestalotiopsis mangiferae in Manipur

A study was conducted in vitro condition to analyse the morphology and efficacy of bio agent, plant extract and some chemical against P. mangiferae which was collected from different districts of Manipur. The morphological characters under study consist of colony and conidial characteristics such as colour, shape, size and appendages. The cultural growth colour of P. mangiferae on PDA varied from concolour to versicolour fuliginous. The conidial shape varied from oval and spherical to elliptical with prominent appendages. The conidial length and widths were 22.9 and 5.7 μm respectively. The diseased sample which was collected from different district of Manipur consists of three septation and the number of conidial appendages was found 2-3 numbers. Among seven antagonists namely Penicillium citrinum, Trichoderma atroviride, T. ovalisporum, Hypocrea lixii, T. harzianum (69 and 131) and T. asperellum evaluatedin vitro, T. asperellum showed the best in inhibiting the growth of the fungus (85.8%). Among three plant extracts viz. garlic, neem and sweet flag evaluated in vitro, garlic extract (3.0%) showed the best result (100.0%). Among the seven chemicals viz. carbendazim, thiophenate methyl, mancozeb, imidacloprid, fipronil, profenophos and thiomethoxam evaluated in vitro, thiophenate methyl (0.05%) and carbendazim (0.05%) showed the best result with 100.0 percent inhibition in fungal growth.

Caracterización morfológica y molecular de cepas nativas de Trichoderma y su potencial de biocontrol sobre Phytophthora infestans

El presente trabajo muestra la caracterización morfológica y molecular de 10 cepas nativas de <em>Trichoderma</em> (TL2, TL4, TL5, TL6, TX7, TX8, TT6, TF8, TF10 y TJ6) y su relación filogenética, así como su capacidad de biocontrol contra <em>Phytophthora infestans</em>. Los resultados de la caracterización molecular al amplificar la región ITS1-ITS4 del ADN ribosómico nuclear y un fragmento del gen <em>tef1α</em> mostraron que de las 10 cepas, seis corresponden a <em>Trichoderma asperellum</em> (TL2, TL4, TX7, TX8, TT6 y TF8) y cuatro a <em>T. harzianum</em>/<em>Hypocrea lixii</em> (TL5, TL6, TF10 y TJ6). El análisis filogenético por máxima parsimonia demostró que existe una estrecha relación entre las cepas de estos dos grupos. Las pruebas <em>in vitro</em> de biocontrol entre el antagonista y el patógeno indicaron diferencias significativas (p&lt;0.05). La cepa TX8 registró el mayor porcentaje (98 %) de inhibición, mientras que TL4 fue la de menor porcentaje (49 %). Las cuatro cepas de <em>H. lixii</em> (TL5, TL6, TF10 y TJ6) presentaron capacidad de inhibición media (55-66 %).