Abstract. Wairimu WJ, Kimenjul JW, Muiru WM, Wachira PM. 2022. Interactions between soil additives and a variety of naturally occurring nematode-demolishing fungi in banana fields of Meru and Embu Counties, Kenya. Cell Biol Dev 6: 82-93. Plant-parasitic nematodes pose a significant danger to banana production, as they reduce the productivity, quality, and lifetime of banana orchards. This study aimed to evaluate the diversity, quantity, and occurrence of nematode-demolishing fungi in banana production farms to use them to manage plant-parasitic nematodes. Also examined was the impact of organic and inorganic soil additives on nematode-demolishing fungi. The study region was divided into three agroecological zones: UM3 (Low), UM2 (Middle), and UM 1 (Upper). Ten farms were chosen randomly for a soil sample in each zone to determine the diversity and abundance of nematode-demolishing fungi. One farm was chosen randomly for soil additive treatments in each zone. The gathered soil samples were used to isolate and identify nematode-demolishing fungi at the species level. The diversity of nematode-demolishing fungi varied significantly between zones, with the highest variety and number of fungi found in the highest zone. Arthrobotrys, Monacrosporium, Nematoctonus, Harposporium, and Paecilomyces were the identified genera. Arthrobotrys was the most often isolated genus, with a frequency of 45%, followed by Harposporium, with a frequency of 18%. The remaining three genera each had a frequency of 9%. The A. dactyloides, A. oligospora, A. robusta, A. longispora, A. superba, H. anguillulae, H. crassum, Meria coniospora, Monacrosporium cionopagum, N. leiosporus, and P. lilacinus were among the species identified. The A. oligospora had captured and destroyed 98 plant parasite nematodes, whereas M. cionopagum and Dactyllela phymatopaga had eliminated 88 and 76 plant parasitic nematodes, respectively, within the same time frame. The amount of nematode-demolishing fungi was significantly different between the various soil additives, with chicken dung having the greatest number of 74 isolates, followed by cow manure, goat manure, the control treatment, and inorganic additive with 71, 69, 54, and 39 isolates, respectively. The amount of isolated nematode-demolishing fungi fluctuated throughout time, from 89 pre-treatment isolates to 122 after three months and 96 after six months. The variation of nematode-demolishing fungi over time was significantly different, demonstrating the impact of diverse soil additives on their existence. Arthrobotrys spp. is a suitable option for field efficacy studies since it was the most diversified, had the highest demolishing rate, and the organic additives facilitated its dispersion in banana plantations.