Biological control of pests is a growing market in the world. It is expected that the use entomopathogenic fungi to control pests will take an important share of this market. Most fungal products in the world are based on aerial conidia produced by solid fermentation using cereal grains. An alternative for aerial conidia is the use of blastospores, yeast-like hydrophilic cells that can be produced in large amounts by liquid fermentation in a short time (<4 days), in a small space and with low hand labor compared to the solid fermentation method. Therefore, the main objectives of the present studies were first to optimize a liquid culture medium for low cost production of Metarhizium blastopores; second: to assess the bioactivity of air-dried blastospores against the cattle-tick Rhipicephalus microplus and the corn-leafhopper Dalbulus maidis; third: to develop an air-dried and spray-dried Metarhizium blastospore formulation with bioactivity against the corn-leafhopper D. maidis; fourth: to improve the shelf-life of the best air-dried and spray-dried formulations stored in refrigerated (± 4°C) and in ambient conditions (28°C) using oxygen and moistures absorbrs or vacuum and fifth: to use comparative genome-wide transcriptome analyses to determine changes in gene expression between the filamentous and blastospore growth phases in vitro to characterize physiological changes and metabolic signatures associated with M. anisopliae and M. rileyi dimorphism. We showed that blastospore production of Metarhizium is isolate- and species-dependent.Glucose-enriched cultures inoculated with pre-cultures improved yields reaching optimal growth for Metarhizium robertsii ESALQ1426 (5.9 × 108 blastospores/mL) within 2 d. We argue that both osmotic pressure, induced by high glucose titers, and isolate selection are critical to produce high yields of blastospores. Fermentation experiments based on growth kinetics defined a low-cost medium using 80 g/L corn steep liquor as the most suitable nitrogen source for inducing blastospore growth in M. robertsii (4.7 × 108 cells/mL) in only 2 days of cultivation at a total cost of $0.30 USD per L. Resultant airdried blastospores of ESALQ1426 were proved to quickly kill R. micropulus larvae and D. maidis adults with an efficiency comparable to that of conidia. Co-formulants were selected to compose formulations that allowed to keep M. roberstii blastospore viability after drying. The addition of oxygen-moisture absorbers into sealed packages increased from three to four-fold the half-life times of air-dried and spray-dried formulations stored either refrigerated (4 °C) or ambient temperature (28 °C) compared to the respective controls. However, the values obtained for half-life using modified atmosphere were less than 3 months. The most promising resulting spray-dried and air-dried were as infective as fresh blastopores to D. maidis inducing mortality rates ranging from 60.3 to 78.2% after spraying with 5 × 107 blastospores/mL. The median lethal concentration (LC50) was significantly higher for air-dried formulation (2.42 × 107 than for the spray-dried formulation (4.65 × 1 06), suggesting a possible detrimental effect of the former technology in fungal virulence. Comparative genome-wide transcriptomes of M. anisopliae and M. rileyi showed a clear molecular distinction between the blastospore and mycelial phases. The main physiological processes associated with up-regulated gene content in M. anisopliae blastospores during liquid fermentation were oxidative stress, amino acid metabolism, respiration processes,transmembrane transport and production of secondary metabolites. In contrast, the u pregulated gene content in hyphae was associated with increased growth metabolismand cell wall re-organization, which underlines the specific functions and altered growth morphology of M. anisopliae blastospores and hyphae, respectively. Conversely, it was observed that the M. rileyi yeast-like cells produced in liquid medium activated a series of specific genes related to signal transduction, and specific membrane transporters related to iron acquisition which was not observed in hyphae. Oxidative stress and activation of specific heat shock proteins were key factors involved in formation of yeast-like cells. On the other hand the yeast-like phase grown in solid medium activates a set of unique genes, not found in other Metarhizium spp., specific membrane proteins and several virulence factors. Significant transcriptomic differences between the metabolism of blastospores and of hyphae were demonstrated. These findings illustrate important aspects of fungal morphogenesis in M. anisopliae and M. rileyi and highlight the main metabolic activities of each propagule under in vitro growth conditions. The genomic studies laid the foundation for understanding the main metabolism required for blastospores growth in liquid medium and identified candidate genes that will serve as a basis for future research on optimizing M. anisopliae and M. rileyi blastospore production.