Endophytic colonization of plants by the fungus Akanthomyces muscarius and its effect on the peach aphid Myzus persicae
Keywords:
entomopathogenic fungi, phytoregulatory activity, broad beans, tomatoes, peach aphidAbstract
The ability of three strains of entomopathogenic fungus Akanthomyces muscarius to endophytic colonization was studied in beans, tomato and acanthus. In beans, phytoregulatory activity of the fungus was revealed. Watering soil with spore suspensions of strains Vl 21 and Vl 61 resulted in increase of green mass, plant length, and root mass (for Vl 61). Strain G-033 VIZR colonized beans most effectively when sprayed on leaves, occurrence in leaves and stems was 66 % and 40 %, respectively. Occurrence of Vl 61 in leaves and stems was 11–16 %. It was also found in roots and leaves after seed soaking in spore suspension, unlike other strains, which only colonized stems. The occurrence of Vl 21 was highest in leaves when sprayed (15 %). Colonization of beans with A. muscarius negatively influenced aphids feeding on these plants. On Vl 21-colonized plants, aphid fecundity was 26 % lower than in control and mortality reached 19 %. Vl 61 showed a fecundity decreasing trend and 50 % mortality of aphids. Strain G-033 VIZR didn’t affect aphid fecundity but caused 57 % mortality. Occasional aphid specimens displayed cases of mycoses. When the soil under tomato plants was watered with fungal spore suspension, the isolates predominately colonized the tomato stems, while colonization rate of leaves and roots did not exceed 8 %. The ability of green fluorescent protein-labeled strains Vl 61* and Vl 72* to colonize perennial acanthus plants was shown. Both strains were isolated from all parts of the acanthus, most frequently from leaves and stems.
