Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae <i>(Hermetia illucens) </i>Frass on Farming of Kales <i>(Brassica oleracea</i>)

Clinton Ochieng Otieno; Evans Nyakeri; Regina Nyunja

doi:doi:10.11648/j.aje.20250903.11

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Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea)

Clinton Ochieng Otieno^*

, Evans Nyakeri

, Regina Nyunja

Published in American Journal of Entomology (Volume 9, Issue 3)

Received: 9 June 2025 Accepted: 7 July 2025 Published: 25 August 2025

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Abstract

Farming of edible insects is on the increase globally because it can promote circular economy. However, the resultant frass is a potential environmental pollutant, despite its high content of valuable nutrients and bioactive compounds. This research investigated application of black soldier fly frass as both biofertilizer and biocontrol agent on kales (Brassica oleracea). The study specifically investigated effect of black soldier fly frass on growth performance, assessed its pesticide activity; and determined effect of fermentation on frass efficiency as a pesticide. The study used a randomized complete block design to arrange the experimental plots. Three frass types were applied on kales a rate of 50 grams per plant in potted pots in a field and performance assessed by counting number of leaves in a plant and measuring leaf surface area. Frass mixed with water at a ratio of 1:1 was filtered to make frass tea and applied on kales at a weekly rate of 100 ml per plant for 4 weeks. Performance was evaluated by counting the number of pest spot attacks on the vegetables and counting number of insect larvae collected per plant. Lastly, frass from the most potent substrate was selected, and fermented for 2 and 4 days respectively to produce “frass tea” and used as above. The results were analyzed in SPSS using ANOVA and presented in graphs and tables. Results showed that kales grown on frass from chicken+fruit+brewery waste treatment had superior growth with mean value of 1.01±0.8 for number of leaves and 2.15±0.02 for leaf surface area respectively, compared to 0.47±0.1 and 1.16±0.10 respectively for the control. Secondly, frass tea from chicken+brewery waste was more effective as it recorded mean values 0.16±0.10 and 0.06±0.06 respectively for pest bites and number of larvae collected respectively, compared to 0.87±0.09 and 0.42±0.17 respectively for the control. Thirdly, fermentation had no effect on frass performance as a biopesticide as results from 2- and 4-day fermentations showed no significant differences. In conclusion, frass can be used as both an effective biofertilizer and biocontrol agent to replace conventional chemicals.

Published in	American Journal of Entomology (Volume 9, Issue 3)
DOI	10.11648/j.aje.20250903.11
Page(s)	100-106
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Black Soldier Fly, Biofertilizer, Biopesticide, Kales

1. Introduction

The farming of edible insects has been popularized by the Food and Agriculture Organization (FAO) of the United Nations under the policy of feeding people with alternative food sources

[1].

The popularity can be attributed to several factors. One, insect farming contributes to the production of a protein rich biomass to mitigate protein insecurity among humans and domesticated livestock. Two, use of organic waste for insect production contributes to the circular economy concept of reducing wastage, reusing resources and recycling nutrients

[2].

Third, the technology restores a popular delicacy in most traditional communities that had become infamous by a combination of scarcity and westernization

[3].

In addition, edible insects can be consumed both directly as human food and indirectly as feed for edible livestock such as pigs, fish, chicken etc. Indirect consumption has gone a long way in promoting consumption among the youth and those with low regard for direct entomophagy

[4].

Lastly, the practice has potential for mitigating negative climate change effects as it utilizes limited resources such as water, and land, and contributes little greenhouse gases

[5].

A number of insects are reared in different geographical locations of the world both for food and feed, depending on nativity of the insect, familiarity and traditional culture. Examples include the Black Soldier Fly (BSF), crickets, mealworms, cockroaches, the common housefly, locusts, longhorn grasshoppers, edible stink bugs, caterpillars, beetles and honey bees among others. The mass breeding of insects for feed and food is in full industrial development for the production of animal protein. In Africa, there are more than 2,300 insect-based enterprises highlighting the immense business potential of this emerging industry

[6].

The industrial scale farming yields large quantities of frass as one of the main outputs. The production of a tonne of edible insects generates between 2 to 4 tons of frass

[7, 8].

It is actually estimated that by 2025, production of insect manure could reach 1.5 million tonnes per year

[9].

Despite the high ratio of frass production per tonne of edible insects harvested, little attention has been given to this side product of insect feeding

[10].

There is therefore need to find value-added opportunities for the frass side product.

Frass is rich in plant nutrients and its constant production in large amounts makes its usage as an organic fertilizer viable to replace agrochemicals and promote sustainable agriculture and circularity

[11, 12].

However, frass has been poorly explored in comparison to the larval biomass obtained in the same process, and there are numerous knowledge gaps related to its usage in agriculture.

Nutrients found in frass include macronutrients and micronutrients readily available to crops, chitin rich exuviate that increases resistance to pests, growth hormones, and beneficial microbes that enhance plant growth and root elongation

[13-16]

. This makes it a potent biofertilizer, biopesticide, or animal feed ingredient

[17].

Again, chemical pesticides have negative environmental impacts, therefore careful management strategies should be put into place to mitigate concerns on human, animal and environmental safety

[18].

Frass usage will be an alternative user- and eco-friendly management strategy.

Previous studies have evaluated the use of synthetic chitin and chitin of crustaceans in crop pest and disease management. For instance,

[19]

studied its effect on seed germination and shoot weight of crookneck squash.

[20]

reported significant improvements in growth, yield and postharvest quality of lettuce grown in soil amended with shrimp shell chitin powder and fermented chitinous material. Application is however hindered by the high cost of synthetic chitin and limited availability of crustacean chitin respectively.

Among the farmed insects for animal feed production, the Black Soldier Fly (BSF) has emerged as a first among equals. The insect has a high reproductive capacity, is cosmopolitan in nature with a wide geographical distribution, and has no pest or vector status. Its larvae have a veracious appetite of consuming organic wastes and byproducts easily available in nature to produce biomass with both high crude protein content and a balanced amino acid composition

[21].

As they feed, a BSF larva undergoes multiple developmental stages, passing through six larval instars, the last of which is prepupa

[22]

leaving behind a mass of excreta, unconsumed organic matter, and shaded chitinous exuvia, collectively referred to as frass, which contains a substantial amount of nutrients

[23].

The chitin of BSF larvae contains antimicrobial peptides against pathogenic bacteria, such as Salmonella enterica and Escherichia coli

[24].

Whereas the chitin can boost the immune system of broilers,

[25]

demonstrated the role of chitin in promoting the growth of juvenile turbots. However, despite these beneficial effects of BSF chitin in animals, its role has not been evaluated in the cultivation of vegetables challenged by fungal, bacterial and nematode diseases, and pests such as aphids and cutworms

[26-28].

This study sought to investigate the efficacy of chitin containing BSF frass on kale growth and yield and pest control, to generate information necessary for their use as an alternative eco-friendly alternative. The study’s specific objectives were to investigate the effect of BSFL frass on growth performance of kales, assess the pesticidal activity of BSFL frass from different feeding substrates on kales, and determine the effect of fermentation on frass efficiency as a pesticide.

2. Materials and Methods

2.1. Study Area

The study was done at Jaramogi Oginga Odinga University of Science and Technology main Campus insect farm in Bondo. The farm is located at latitude 0° 14' 19.00" N and Longitude 34° 16' 9.98" E. Bondo is characterized by generally high temperature ranges with mean minimum and maximum temperatures of 15°C and 30°C respectively, a mean annual temperature of 22°C, and an altitude of approximately 1250 m above sea level. The area receives an annual rainfall amount that ranges from 800 to 1600 mm per annum in two rainy seasons. It has high relative humidity with mean evaporations being between 1800 to 2000 mm in a year courtesy of the nearby Lake Victoria

[29].

2.2. Source of BSF Frass

BSF frass was obtained from the JOOUST BSF colony that has been in existence since 2015. The colony was established by BSF attraction form the wild

[30].

The larvae in the colony are regularly fed on assorted fruit wastes (overripe bananas, mangos, pineapples and avocadoes), vegetable waste (kales, amaranths, spinach etc.), poultry waste, food remains, and brewery waste. The fruit wastes are collected from Bondo open air market, poultry faeces from the University chicken farm, while the food remains are collected from the JOOUST student and staff messes. Brewer’s waste is obtained from a local brewery located in Kisumu city, a distance of 60 km from JOOUST.

2.3. Larvae Feeding

The different sets of BSFL were separately fed the following groups of substrates in triplicates to produce the desired frass: Group 1: fruit waste (ripe avocado, pineapple, mangos and bananas) and brewer’s waste in a ratio of 1: 1; Group 2: animal manure (poultry) and brewery waste in a ratio of 1: 1; and group 3: chicken manure, fruit wastes and brewery waste in a ratio of 1: 1: 1. The larvae were reared according to a standard protocol as per

[30]

3. Study Design

The study used an experimental randomized complete block design to arrange the experimental plots of kales. However, the study had different experimental procedures corresponding to the study objectives. Each experimental plot measured 3 m by 3 m and the kales were planted at the recommended distance of 0.6 m by 0.6 m producing a total of 16 kales per plot, as they were planted 0.3 m from the edges. Inter-plot and inter- block distances were 1 m wide to act as a buffer.

3.1. Assessment of Frass as a Biofertilizer

The three frass types were randomly allocated to the experimental plots of kales, with one control with all the treatments being replicated three times. Frass of about 50 grams was applied per seedling in the plot except for the control treatments as per

[31]

. All regular recommended cultural practices, including weeding and watering were carried out similarly in each treatment and control plot. Every week, the number of leaves emerged and leaf surface area were measured per plant.

3.2. Effects of Frass as a Biocontrol Agent

Frass from different treatments was collected and 500 grams of the frass was mixed with 2 litres of water to make frass tea, which was filtered using a sieve. The frass tea was applied using a manually operated knapsack sprayer (volume: 20 L, Farmguard (R) at rate of 100 ml per plant, at an interval of 7 days, in the evening at 4 pm

[32].

The sprayer was thoroughly being washed using soap and well rinsed with water prior to application of each bio pesticide type. Every week, the plants in a plot (except those at the borderline) were visually examined for signs of pest attack in the leaves, with a damaged leaf being recognized by the presence of larva exit hole or “leaf bites”

[33]

and by counting the number of cutworm larvae found on the leaves to determine infestation levels. The assessment of the infestation level was done during the first two harvesting times of kales at the 10^th and 12^th week after transplanting and recorded in a table.

3.3. Effects of Fermentation on Frass Efficiency

Frass from all treatments was collected, mixed to form a common mixture. 1 kg of the mixed frass was mixed with 5 litres of water and allowed to ferment for either two or four days. After sieving, the frass was applied as earlier described. Every week, the plants in a plot (except those at the borderline) were visually examined for signs of pest attack in the leaves, with a damaged leaf being recognized by the presence of larva exit hole or “leaf bites”

[33]

4. Data Analysis

Data collected was analyzed using SPSS and Microsoft Excel software 2013. The means obtained were compared using ANOVA and the results presented in graphs and tables. General linear Model (GLM) was used to test the interaction between experimental period.

5. Results

5.1. Growth Effect of Frass as a Biofertilizer on Kales (Brassica Oleracea)

In this study, frass from all the three treatments produced more leaves per plot than the control treatment (Table 1). Again, there were significant differences among the three in terms of number of leaves produced. In terms of surface area, the treatments significantly outperformed the control. There were significant differences among them as shown in Table 1. Among the treatments, treatment three produced kales with the largest surface are followed by two and lastly treatment one (Figure 1).

Table 1. Growth effect of frass as biofertilizer.

Parameter	CW+BW	Control	FW+BW	CW+FW	F-value	P-value
No of leaves	0.83±0.06^a	0.47±0.03^b	0.85±0.07^a	1.01±0.08^a	8.04	0.0001
Leaf surface. Area	1.54±0.16^a	1.16±0.10^b	1.81±0.12^c	2.15±0.02^d	6.39	0.0001

Key: Values with the same letter in a row indicate no significant differences

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Figure 1. Effect of frass on kale leaf surface area.

5.2. Pesticide Activity of BSFL Frass of Different Feeding Substrates on Kales (Brassica Oleracea) Vegetable

Leaf bite numbers were significantly high in the control compared to all the frass treatments. However, the results also varied with treatment two being the lowest performer while treatment three and one respectively had no significant difference in the number of leaf bites recorded. Cut worm larvae abundance followed the same trend, as the control had the highest number compared to the three treatments. However, there was no significant difference between treatments three and two though treatment one recorded the lowest number of cutworm larvae (Table 2).

Table 2. Performance of frass tea as a biocontrol agent.

Parameter	CW+BW	Control	FW+BW	CW+FW+BW	F-value	P-value
Bites (No)	0.16±0.10^a	0.87±0.09^b	0.43±0.15^c	0.26±0.16^a	4.29	0.001
Cutworm larvae abundance	0.06±0.06^a	0.42±0.17^b	0.26±0.16^c	0.26±0.13^c	1.25	0.123

Key: Values with the same letter in a row indicate no significant differences.

5.3. The Effect of Fermentation on Frass Efficiency as a Pesticide on Kales (Brassica Oleracea)

Fermented frass had no significant difference compared to the control treatment. Consequently, there was no significant difference between frass fermented for two days and that fermented for four days. The same applies to the number of cutworm larvae detected in the different treatments which was not significantly different (Table 3).

Table 3. Effect of fermentation on frass bio-pesticidal efficiency.

Parameter	Control	Frass_F2	Frass_F4	F-value	P-value
Bites (No)	0.87±0.09^b	0.69±0.10^b	0.71±0.14^b	6.39	0.003
Cutworm larvae abundance	0.42±0.17^b	0.50±0.14^b	0.56±0.15^b	1.75	0.163

Key: Values with the same letter in a row indicate no significant differences.

6. Discussion

6.1. Effect of Frass on Kale Growth Parameters

In this study, all the frass treatments had significantly higher growth effect compared to the control, showing that the BSF larvae frass probably supplied important growth nutrients to the kales and that the frass is not a waste product per se, but an input for another cycle. Though no characterization of mineral content was done on the frass, a previous study also reported enhanced potato growth and yield grown using BSF frass, and attributed this to higher nutrient availability and synchrony for plant growth associated with BSF frass fertilizer

[34, 35].

Another study reported a similar performance of BSF frass to commercial fertilizers in increasing maize production, and chili pepper

[27]

. As in this study, the performance of frass varied with the number of substrates used. This shows that the more substrates frass is derived from, the superior the performance of that frass probably due to more nutrient composition. The better performance of treatment three compared to two and one respectively is probably due to this.

Besides superior nutrient content, frass better performance compared to the control has also been previously attributed to the chitin component. The chitin in BSFL frass is thought to increase soil fertility by inducing improvements in the soil microbiome. The frass stimulates the proliferation of beneficial microorganisms and plant defenses that help promote plant development

[27].

This is because BSFL Frass is the plant-digestible form of chitin, and when under environmental stress, the chitin naturally produces antimicrobial peptides that serve as a defense barrier that reduces pathogenic bacteria, such as Salmonella enterica and Escherichia coli, during the treatment process, thereby reducing the pressure on the plant

[36].

A study that amended soil with chitin also reported that the chitin enhances plant growth by improving the accessibility of nutrients, especially nitrogen

[8].

6.2. The Effect of Frass as a Biopesticide

This study reported fewer pest leaf bites in the crops treated with frass tea compared to those in the control treatment. This is consistent with previous studies that reported that BSF frass significantly contributes to the suppression of soil-borne plant pathogens and pests

[37, 38, 27, 16].

The suppression activity is attributed to the chitin content of frass that under environmental stress, naturally produces antimicrobial peptides that serve as a defense barrier against pathogenic bacteria. Another study also reported the effectiveness of BSF frass as a biopesticide that is an eco-friendly substitute for synthetic pesticides in crop production

[39].

The chitin in frass is also reported to suppress soil borne plant-parasitic fungi

[40]

and nematodes

[41].

6.3. Effect of Fermentation on Frass Biopesticide Efficiency

The current study reports that fermentation had no effect on the efficiency of BSF frass tea as a biopesticide. Consequently, there was no significant difference in both the number of leaf bites or cutworms collected from plants subjected to frass fermented for two days and that fermented for four days or even the control. This shows that the active components in frass against pathogenic microbes are not affected by fermentation process. Unfortunately, no previous study has investigated the effect of fermentation on frass efficacy to enable valid comparison to be made.

7. Conclusions and Recommendations

Frass obtained from BSFL feeding activity is an effective biofertilizer of kales as exhibited by both fast growth effect and large surface area of kale leaves. Again, fresh BSFL frass tea is an effective biocontrol agent of pests on kales as evidenced by both the significantly reduced pest leaf bites and low number of cutworm larvae collected from kales subjected to the frass treatments. Lastly, frass is a potential multipurpose product with the benefits of improving crop growth performance and suppressing pests and plant pathogens. Therefore, the study recommends BSFL frass as an eco-friendly replacement for both mineral fertilizer and chemical pesticides. Though this study did not include pupa casings, as black soldier fly mass production systems produce huge amounts of these shells/exuviate, the study recommends that pesticidal activity of these pupal casings be too investigated. Consequently, BSFL frass is recommended for use as both a source of nutrients and as biological control agent of pest and pathogens

[26].

Acknowledgments

I would wish to acknowledge JOOUST University for allowing me to carry out this study within the University farm.

Conflicts of Interest

The authors declare no conflicts of interest.

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Otieno, C. O., Nyakeri, E., Nyunja, R. (2025). Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). American Journal of Entomology, 9(3), 100-106. https://doi.org/10.11648/j.aje.20250903.11

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Otieno, C. O.; Nyakeri, E.; Nyunja, R. Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). Am. J. Entomol. 2025, 9(3), 100-106. doi: 10.11648/j.aje.20250903.11

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Otieno CO, Nyakeri E, Nyunja R. Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). Am J Entomol. 2025;9(3):100-106. doi: 10.11648/j.aje.20250903.11

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@article{10.11648/j.aje.20250903.11,
  author = {Clinton Ochieng Otieno and Evans Nyakeri and Regina Nyunja},
  title = {Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea)
},
  journal = {American Journal of Entomology},
  volume = {9},
  number = {3},
  pages = {100-106},
  doi = {10.11648/j.aje.20250903.11},
  url = {https://doi.org/10.11648/j.aje.20250903.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.aje.20250903.11},
  abstract = {Farming of edible insects is on the increase globally because it can promote circular economy. However, the resultant frass is a potential environmental pollutant, despite its high content of valuable nutrients and bioactive compounds. This research investigated application of black soldier fly frass as both biofertilizer and biocontrol agent on kales (Brassica oleracea). The study specifically investigated effect of black soldier fly frass on growth performance, assessed its pesticide activity; and determined effect of fermentation on frass efficiency as a pesticide. The study used a randomized complete block design to arrange the experimental plots. Three frass types were applied on kales a rate of 50 grams per plant in potted pots in a field and performance assessed by counting number of leaves in a plant and measuring leaf surface area. Frass mixed with water at a ratio of 1:1 was filtered to make frass tea and applied on kales at a weekly rate of 100 ml per plant for 4 weeks. Performance was evaluated by counting the number of pest spot attacks on the vegetables and counting number of insect larvae collected per plant. Lastly, frass from the most potent substrate was selected, and fermented for 2 and 4 days respectively to produce “frass tea” and used as above. The results were analyzed in SPSS using ANOVA and presented in graphs and tables. Results showed that kales grown on frass from chicken+fruit+brewery waste treatment had superior growth with mean value of 1.01±0.8 for number of leaves and 2.15±0.02 for leaf surface area respectively, compared to 0.47±0.1 and 1.16±0.10 respectively for the control. Secondly, frass tea from chicken+brewery waste was more effective as it recorded mean values 0.16±0.10 and 0.06±0.06 respectively for pest bites and number of larvae collected respectively, compared to 0.87±0.09 and 0.42±0.17 respectively for the control. Thirdly, fermentation had no effect on frass performance as a biopesticide as results from 2- and 4-day fermentations showed no significant differences. In conclusion, frass can be used as both an effective biofertilizer and biocontrol agent to replace conventional chemicals.},
 year = {2025}
}

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TY - JOUR
T1 - Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea)

AU - Clinton Ochieng Otieno
AU - Evans Nyakeri
AU - Regina Nyunja
Y1 - 2025/08/25
PY - 2025
N1 - https://doi.org/10.11648/j.aje.20250903.11
DO - 10.11648/j.aje.20250903.11
T2 - American Journal of Entomology
JF - American Journal of Entomology
JO - American Journal of Entomology
SP - 100
EP - 106
PB - Science Publishing Group
SN - 2640-0537
UR - https://doi.org/10.11648/j.aje.20250903.11
AB - Farming of edible insects is on the increase globally because it can promote circular economy. However, the resultant frass is a potential environmental pollutant, despite its high content of valuable nutrients and bioactive compounds. This research investigated application of black soldier fly frass as both biofertilizer and biocontrol agent on kales (Brassica oleracea). The study specifically investigated effect of black soldier fly frass on growth performance, assessed its pesticide activity; and determined effect of fermentation on frass efficiency as a pesticide. The study used a randomized complete block design to arrange the experimental plots. Three frass types were applied on kales a rate of 50 grams per plant in potted pots in a field and performance assessed by counting number of leaves in a plant and measuring leaf surface area. Frass mixed with water at a ratio of 1:1 was filtered to make frass tea and applied on kales at a weekly rate of 100 ml per plant for 4 weeks. Performance was evaluated by counting the number of pest spot attacks on the vegetables and counting number of insect larvae collected per plant. Lastly, frass from the most potent substrate was selected, and fermented for 2 and 4 days respectively to produce “frass tea” and used as above. The results were analyzed in SPSS using ANOVA and presented in graphs and tables. Results showed that kales grown on frass from chicken+fruit+brewery waste treatment had superior growth with mean value of 1.01±0.8 for number of leaves and 2.15±0.02 for leaf surface area respectively, compared to 0.47±0.1 and 1.16±0.10 respectively for the control. Secondly, frass tea from chicken+brewery waste was more effective as it recorded mean values 0.16±0.10 and 0.06±0.06 respectively for pest bites and number of larvae collected respectively, compared to 0.87±0.09 and 0.42±0.17 respectively for the control. Thirdly, fermentation had no effect on frass performance as a biopesticide as results from 2- and 4-day fermentations showed no significant differences. In conclusion, frass can be used as both an effective biofertilizer and biocontrol agent to replace conventional chemicals.
VL - 9
IS - 3
ER -

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Clinton Ochieng Otieno

Department of Biological Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya

Contact Email

http://orcid.org/0009-0000-6918-685X
Evans Nyakeri

Department of Biological Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya

http://orcid.org/0000-0001-8034-6922
Regina Nyunja

Department of Biological Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya

http://orcid.org/0009-0007-2072-0856

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Figure 1

Figure 1. Effect of frass on kale leaf surface area.

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APA Style

Otieno, C. O., Nyakeri, E., Nyunja, R. (2025). Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). American Journal of Entomology, 9(3), 100-106. https://doi.org/10.11648/j.aje.20250903.11

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ACS Style

Otieno, C. O.; Nyakeri, E.; Nyunja, R. Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). Am. J. Entomol. 2025, 9(3), 100-106. doi: 10.11648/j.aje.20250903.11

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AMA Style

Otieno CO, Nyakeri E, Nyunja R. Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea). Am J Entomol. 2025;9(3):100-106. doi: 10.11648/j.aje.20250903.11

Copy | Download

@article{10.11648/j.aje.20250903.11,
  author = {Clinton Ochieng Otieno and Evans Nyakeri and Regina Nyunja},
  title = {Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea)
},
  journal = {American Journal of Entomology},
  volume = {9},
  number = {3},
  pages = {100-106},
  doi = {10.11648/j.aje.20250903.11},
  url = {https://doi.org/10.11648/j.aje.20250903.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.aje.20250903.11},
  abstract = {Farming of edible insects is on the increase globally because it can promote circular economy. However, the resultant frass is a potential environmental pollutant, despite its high content of valuable nutrients and bioactive compounds. This research investigated application of black soldier fly frass as both biofertilizer and biocontrol agent on kales (Brassica oleracea). The study specifically investigated effect of black soldier fly frass on growth performance, assessed its pesticide activity; and determined effect of fermentation on frass efficiency as a pesticide. The study used a randomized complete block design to arrange the experimental plots. Three frass types were applied on kales a rate of 50 grams per plant in potted pots in a field and performance assessed by counting number of leaves in a plant and measuring leaf surface area. Frass mixed with water at a ratio of 1:1 was filtered to make frass tea and applied on kales at a weekly rate of 100 ml per plant for 4 weeks. Performance was evaluated by counting the number of pest spot attacks on the vegetables and counting number of insect larvae collected per plant. Lastly, frass from the most potent substrate was selected, and fermented for 2 and 4 days respectively to produce “frass tea” and used as above. The results were analyzed in SPSS using ANOVA and presented in graphs and tables. Results showed that kales grown on frass from chicken+fruit+brewery waste treatment had superior growth with mean value of 1.01±0.8 for number of leaves and 2.15±0.02 for leaf surface area respectively, compared to 0.47±0.1 and 1.16±0.10 respectively for the control. Secondly, frass tea from chicken+brewery waste was more effective as it recorded mean values 0.16±0.10 and 0.06±0.06 respectively for pest bites and number of larvae collected respectively, compared to 0.87±0.09 and 0.42±0.17 respectively for the control. Thirdly, fermentation had no effect on frass performance as a biopesticide as results from 2- and 4-day fermentations showed no significant differences. In conclusion, frass can be used as both an effective biofertilizer and biocontrol agent to replace conventional chemicals.},
 year = {2025}
}

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TY - JOUR
T1 - Evaluation of Biofertilizer and Pesticide Performance of Black Soldier Fly Larvae (Hermetia illucens) Frass on Farming of Kales (Brassica oleracea)

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