Mr. Lawrence Ouma Onyango has a Master of Science degree in Crop Protection attained at the University of Nairobi in 2023. He holds a first-class honours degree in Agriculture and Human Ecology Extension from Egerton University. Lawrence conducted his MSc. Research at the International Centre of Insect Physiology and Ecology (icipe) under the Dissertation Research Internship Programme (DRIP). He completed a comprehensive survey about the occurrence and management of soil-dwelling pests of vegetables in Kenya and evaluated the potential of insect-composed fertilizer in controlling onion flies/maggots and yield promotion. Over the research period, Lawrence attended several trainings in morphological and molecular insect identification, bioassay studies, crop nutrition, data analysis, GIS and remote sensing and scientific writing. Lawrence is intensely interested in crop protection, plant-insect interaction, insect ecology, integrated pest management, edible insects and insect-pathogen interaction. Lawrence is a member of the Horticultural Association of Kenya (HAK) and participated in an oral presentation at the 22nd workshop held at Jomo Kenyatta University of Agriculture and Technology (JKUAT). Results from his research have also been published in high-impact journals.
Abstract
Soil-dwelling insect pests constitute a significant challenge to vegetable production in Kenya, but their monitoring and management is constrained by soil heterogeneity and overreliance on pesticide. A field survey was conducted to assess the occurrence and management of soil-borne pests of cabbage and onions in the major growing counties and the insects were collected for morphological and molecular characterization. Laboratory bioassays and a field study were conducted to evaluate the effect of fortified black soldier fly (BSF) frass fertilizer on onion flies and onion yield. Results from the field survey give the first report of onion fly (Antherigona orientalis) as a significant pest of onions and cabbage root fly/seed-corn fly (Delia platura) as a potential pest of cabbage in Kenya. Other soil-borne pests identified across different agroecological zones were white grubs (Maladera sp.), wireworms (Agriotes sp.), and sap beetles (Urophorus humeralis), with incidences ranging from 6.7–11.2%. Over 95% of farmers in the survey region relied on broad-spectrum pesticides to control soil-dwelling pests, which pose significant risks to human health and biodiversity. The study demonstrated that BSF liquid fertilizer amended with 20–100% pupae exuviae has the potential to manage onion fly with 65.0% and 31.2% egg and larval mortality. Soil amendment with 120 kg N ha-1 BSF frass fertilizer and 1–8% chitin can also increase the marketable yield of the onion by 24.0–49.6%, compared to 32.9% by commercial fertilizers. The study recommends sustainable management of onion flies and enhancement of onion yield using fortified BSF frass fertilizer.
Important Links
https://scholar.google.com/citations?user=byMGyqAAAAAJ&hl=en&authuser=1
Research Supervisors
Prof. James W. Muthomi
Prof. John W. Kimenju
Dr. Chrysantus M. Tanga
