Biochar alters maize growth, mycorrhizal associations and fall armyworm performance

Biochar is a carbon source employed to improve soil properties, promoting plant health and nutrition in agroecosystems. Root associated microorganisms such as arbuscular mycorrhizal fungi (AMF) are also used as bioinoculants in combination with biochar to provide eco-friendly alternatives for crop production under unfavorable growth conditions. However, information on the effects of biochar on multitrophic interactions of plants with herbivorous insects is limited. Therefore, the objective of this work was to evaluate the effect of biochar and arbuscular mycorrhizae on plants and herbivorous insects.

We established a multifactorial experiment with maize plants, AMF (two strains, Rizhophagus irregularis and a native consortium) and the Fall Armyworm Spodoptera frugiperda with and without soil application of biochar. Variables of biomass, plant nutrition, mycorrhizal colonization and performance of herbivorous insects were measured.

We found that biochar reduced insect herbivory and promoted mycorrhizal association in maize. However, plant growth was reduced. Additionally, AMF increased the weight of fall armyworm larvae.

Our results show that biochar influences maize plant development, AMF, and fall armyworm performance, but did not affect interactions between these below- and above ground components.