The fungal species Metarhizium novozealandicum, that occurs only in New Zealand and Australia has been poorly studied. In this work, a new strain of M. novozealandicum isolated from a larva of Wiseana sp. is described based on morphology, genomic multilocus (ITS, EF-1α and β-tubulin) phylogeny, growth in different culture media and insecticidal activity. The isolate AgR-F177 was clustered in the same clade with M. novozealandicum. AgR-F177 colonies developed faster on Sabouraud Dextrose Agar (SDA) than on Potato Dextrose Agar (PDA) when incubated at 25℃, with no growth observed at 30℃ on either media. Conidia yield on an oat-based medium in semisolid fermentation was 7.41 x 10⁸conidia/g of substrate and a higher yield of 1.68 x 10⁹conidia/g of substrate was obtained using solid fermentation on cooked rice. AgR-F177 formed microsclerotia (MS) in liquid fermentation after 7 days reaching the maximum yield of 3.3 × 10³ MS/mL after 10 days. AgR-F177 caused mortality in Wiseana copularis, Costelytra giveni and Plutella xylostella larvae with efficacies up to 100%, 69.2%, and 45.7%, respectively. The ease of production of AgR-F177 with different fermentation systems and its pathogenicity against different insect pests reveal its potential as a new biopesticide.

Beauveria pseudobassiana formed three-dimensional aggregates of cells (CAs) in liquid culture. CAs were formed mainly by blastospores and conidia, distinct from microsclerotia formed through adhesion of hyphae. The formation, germination and sporulation of CAs were studied, as well as the pathogenicity of conidia produced from them against adults of black beetle. After 4 days of culture, CAs were formed, becoming compact and melanised after 10 days of incubation. Electron microscopy showed three-dimensional CAs averaging 431.65 µm in length with irregular shapes and rough surfaces, where cells were trapped within an extracellular matrix. CAs germinated after 2 days of incubation on agar-plates producing hyphae and forming phialides and conidia after 4 days. Produced conidia caused 45% mortality of black beetle adults. CAs germination and sporulation on soil were directly correlated with soil moisture, reaching 80% and 100% germination on the surface of soil with 17% and 30% moisture, respectively. CAs maintained 100% germination after 2 years of storage under refrigeration. These CAs could have a similar function as microsclerotia in nature, acting as resistant structures able to protect internal cells and their ability to sporulate producing infective conidia, suggesting their potential to be used as bioinsecticides to control soil-dwelling insects.