The quest for enhancing agricultural yields due to increased pressure on food production has inevitably led to the indiscriminate use of chemical fertilizers and other agrochemicals. Biofertilizers are emerging as a suitable alternative to counteract the adverse environmental impacts exerted by synthetic agrochemicals. Biofertilizers facilitate the overall growth and yield of crops in an eco-friendly manner. They contain living or dormant microbes, which are applied to the soil or used for treating crop seeds. One of the foremost candidates in this respect is rhizobacteria. Plant growth promoting rhizobacteria (PGPR) are an important cluster of beneficial, root-colonizing bacteria thriving in the plant rhizosphere and bulk soil. They exhibit synergistic and antagonistic interactions with the soil microbiota and engage in an array of activities of ecological significance. They promote plant growth by facilitating biotic and abiotic stress tolerance and support the nutrition of host plants. Due to their active growth endorsing activities, PGPRs are considered an eco-friendly alternative to hazardous chemical fertilizers. The use of PGPRs as biofertilizers is a biological approach toward the sustainable intensification of agriculture. However, their application for increasing agricultural yields has several pros and cons. Application of potential biofertilizers that perform well in the laboratory and greenhouse conditions often fails to deliver the expected effects on plant development in field settings. Here we review the different types of PGPR-based biofertilizers, discuss the challenges faced in the widespread adoption of biofertilizers, and deliberate the prospects of using biofertilizers to promote sustainable agriculture.

Biological control is a relatively cheap and most feasible long-term approach for controlling deadly weeds. Parthenium hysterophorus L. is a pernicious weed, imposing deleterious economic effects on humans and livestock. Microbial products thus offer a non-chemical alternative for controlling a noxious, invasive and pernicious weed like Parthenium. Phoma is a well-known phytopathogen responsible for many diseases in plants and is known to produce an array of bioactive extracellular toxic compounds, i.e. agribiologicals. Before application these have to be effectively formulated to enhance their absorption and translocation within the foliar tissues. Adjuvants are formulatives of microbial bioherbicides which ensure maximum herbicidal performance. Research on adjuvant and formulation technology for ecofriendly agrochemicals has advanced rapidly in recent years. Phytotoxins from Phoma sp. FGCC#18 have been tested for their compatibility with different formulants. Phytotoxicity damage was studied by seedling and detached leaf bioassays after different hours post-treatment. Tween 80 at 0.5% was found to be the best formulant, while the combination of Tween 80 and coconut oil at 0.5% exhibited maximum damage to Parthenium seedlings and detached leaves.