ORIGINAL RESEARCH article
Front. Agron.
Sec. Agroecological Cropping Systems
This article is part of the Research TopicRegenerative Agriculture for Soil Health, Greenhouse Gas Mitigation, and Climate ActionView all 19 articles
Do rates matter? Validation of insect frass fertilizer rates in a vegetable intensified push-pull technology for optimal sustainable production
Provisionally accepted
Priscilla Mwikali Kimuli1
Dennis Beesigamukama1
Judy Wambua2
Bonoukpoe Sokame1
CHRYSANTUS MBI TANGA1
Frank Chidawanyika1
Sevgan Subramanian1
Daniel Munyao Mutyambai1*- 1International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
- 2South Eastern Kenya University, Kitui, Kenya
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Push–pull system intensification with vegetables (VIPPT) has contributed significantly in maintaining good control of lepidopteran pests and parasitic weeds with additional food and nutritional security benefits. However, the impact of integration of different rates of black soldier fly frass fertilizer (BSFFF) in the VIPPT to enhance productivity, has not been explored. This study investigated the effects of different BSFFF application rates on growth performance, pest infestation severity, diversity of natural enemies and yield of kale (Brassica oleracea L. var. acephala) grown underVIPPT in two agroecological zones. Plants were grown in soils amended with five different levels of BSFFF (0, 50, 100, 150 and 200) kg N ha-1), blends with inorganic fertilizers, (Di-ammonium phosphate (DAP) and Nitrogen, Phosphorous and Potassium (NPK)), and unfertilized soil (control). Across the two sites, plants treated with 200 BSFFF exhibited faster growth and higher yield (by 7% and 82%) compared to 150BSFFF and 0BSFFF, respectively. Similarly, aphid infestation was lower in the 200BSFFF treatment (by 64% and 1 %) compared to inorganic fertilizer and 0BSFFF. Additionally, natural enemies such as Coleoptera (35% and 97%), Hemiptera (17% and 97%) and Diptera (100% and 44%) were more abundant in 200BSFFF than 0BSFFF and inorganic fertilizer treatments, respectively. Our findings demonstrate that integration of VIPPT and BSFFF at an application rate of 200 Kg N ha-1 BSFFF significantly improves growth and yield of kales while reducing the severity of pest infestation and conserves natural enemies of key cruciferous pests. The synergistic effects of these technologies hold great promise towards sustainable vegetable production, environmental and biodiversity conservation.
Keywords: agrobiodiversity, Hermetia illucens, Kale, pest management, regenerativeagriculture
Received: 30 Sep 2025; Accepted: 21 Nov 2025.
Copyright: © 2025 Kimuli, Beesigamukama, Wambua, Sokame, TANGA, Chidawanyika, Subramanian and Mutyambai. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Daniel Munyao Mutyambai, dmutyamba@yahoo.com
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