eng Enviro Research Publishers Current Agriculture Research Journal 2347-4688 2321-9971 2026-05-11 14 1 119 133 26906 article Milka Mbithe Kananda 1 Joseph Juma Mafurah 2 Miriam Karwitha Charimbu 2 Department of Plant Variety Testing and Protection Kenya Plant Health Inspectorate Service, Nakuru, Kenya Department of Crops, Horticulture and Soils Egerton University, Njoro, Kenya Potato (Solanum tuberosum L.) is a valuable and nutritious staple food crop, driving both food security   and economic growth globally. However, potato production has been limited by infection of potato cyst nematodes (PCN) causing significant yield losses. This study evaluated the efficacy of five biocontrol agents and botanical extracts in the management of PCN within production systems. Potatoes were grown in pots containing sterile soil in a screenhouse arranged in a Complete Block Design for two consecutive cycles. The pots were treated with biocontrol agents; Nemguard (Paecilomyces lilacinus), Trichoderma viride and botanical extract; Maytech (polysulphides),   Pesticide (Nimbecidine), and a negative control that was not treated.The pots were then inoculated with PCN cysts. Data on cyst count, tuber yield and plant vigor were collected and analyzed using analysis of variance (ANOVA). The results indicate that Cyst reproduction index was significantly reduced in Pesticide, Trichoderma and Maytech treated pots. This was quantified as   0.83% (Maytech), 2% (Nemguard), 0.33% Pesticide and 0.83% in Trichoderma, as compared to negative control. Treatment and Cycle × Treatment were significantly differently for PCN juveniles (p≤0.05);4.95,5.5; and  final potato cyst nematodes (FPCN)/ 200g of soil (p≤0.001).; 254.58, 50.55. All the biocontrols had significantly higher plant vigor than control. The Pesticide and Trichoderma treated pots resulted in high total number of marketable tubers, weight of marketable tubers, low number of final potato cyst nematode per 200g of soil and PCN juveniles. The reproductive index (r=-0.68) and FPCN/200g of soil (r=-0.28) had a negative correlation with weight of total tubers. The number of PCN juveniles increased with a decrease in weight of total tubers at the rate of 6.23 (counts). These results show the effectiveness of biocontrol and their potential in management of PCN and therefore recommend testing of Pesticide and Trichoderma under field conditions. http://www.agriculturejournal.org/volume14number1/efficacy-of-microbial-and-biochemical-biopesticides-against-potato-cyst-nematodes-globodera-rostochiensis-and-globodera-pallida-in-kenya/ Biocontrol; Cyst; Juveniles; Marketable tubers; Nematode; Potato