Bt maize targets pests, not people, expert tells Kisumu Court

The adoption of Bt maize by Kenyans farmers will help address the issue of food security as well as pest control which affects the plant in the country, a maize breeder expert has told the High Court.

Appearing before Kisumu High Court Judge Justice, Dr. Stephen Mugo urged the Court To dismiss the case filed by activists to oppose open field cultivation, and placing on the market of genetically modified maize (Zea mays) commonly known as Bt maize (MON 89034).

Dr. Mugo observed that currently used chemical control methods pose problems of high pesticide costs and application risks, direct and indirect damage to human and livestock health, damage to the environment, and development of resistance to the pesticides.

“Approved genetically modified maize varieties offer safe and cost-effective alternatives for pest and weed control, and eliminate damage to human and livestock health, and damage to the environment. These alternatives include insect-protection traits (classically exemplified by Bt maize) among other traits developed using genetic engineering techniques,” said Dr. Mugo during the cross examination by the petitioners’ lawyers.

The Bt maize which was approved by the National Biosafety Authority in 2025 was developed using modern biotechnology methods to protect itself against specific pests such as the maize stem borers and fall armyworms, which are devastating pests in maize fields.

National Biosafety Authority is mandated to exercise general supervision and control over the transfer, handling and use of Genetically Modified Organisms (GMOs) with a view to ensuring safety of human and animal health and provision of adequate protection of the environment.

 As a result, farmers were to expect less damage to their maize crop, leading to increased harvests and better-quality grains. This could also lower production costs and reduce risks to health and the environment by using fewer insecticides used for pest management.

Dr. Mugo Mugo told the Court that in Kenya, more than 400,000 metric tonnes (MT) of maize worth over USD 90 million is lost annually to stem borer pests

“The impact of insect-pests on crop production has worsened with the arrival of the invasive new pest – the fall armyworm (FAW) in Africa, including Kenya, in 2016. Fall armyworm poses a significant risk for about 10 million maize-producing smallholder farmers in Africa. A recent report indicates that a quarter of the 2.9 million hectares of maize land was infested by the pest in 2017, causing a loss of over 134,000 MT of maize worth more than USD 30 million,” added the expert.

He noted that therefore, there is an urgent need to address the menace of the fall armyworm in different parts of Africa because of its threat to maize production and food security.

Dr. Mugo explained that Bt maize does not contain bacteria as alleged. Rather, certain GM maize varieties contain one or more genes from soil bacteria (for example Bt or CP4) that enable the plant to produce specific proteins adding that these proteins have defined biochemical activities relevant to insect pests or herbicide metabolism and are not active against the human and livestock digestive systems.

“Like all GMO foods, Bt is extensively tested more than conventional foods as it is regulated during development, testing, release, and even during open commercialization, thus ensuring that it is safe. Further, regulatory bodies such as the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) have repeatedly found Bt crops to pose no risks to human health and herbicide-tolerant events authorised by competent regulators,” he added.

Dr. Mugo went on : “On this basis, the evidence does not support the assertion that Bt maize threatens the right to health or quality food.”

The expert told the Court that Bt maize targets insect pests and has no effect on weeds; it therefore cannot, by its nature, create “super-weeds.”

“The issue of herbicide resistance arises only in herbicide-tolerant crops, such as “RoundUp Ready” varieties, which are distinct from Bt maize. Even then, the risk of herbicide-resistant weeds is effectively managed through integrated weed management and proper stewardship practices, both of which are standard requirements in responsible agricultural systems,” said the expert.

He further told the Court that Bt maize improves the quality of maize grain and also reduces aflatoxin contamination, lowers pesticide use, reduces production costs, and enhances food security.

“Rather than undermining the right to food, Bt maize will, in fact, strengthen its production and resistance to diseases,” explained Dr. Mugo.

He added that the adoption of genetically modified maize is entirely voluntary as farmers will retain full freedom to choose between GM, hybrid, improved, or indigenous seed varieties.

“ In fact many farmers customarily enhance indigenous varieties through natural crosspollination. Cross-pollination with Bt maize does not eliminate indigenous varieties; rather, it may introduce beneficial traits such as pest resistance. The evidence therefore does not support claims of inevitable monopolization or arbitrary deprivation of property rights. This is further demonstrated by Kenya’s

experience with Bt cotton, introduced over five years ago, where there has been neither monopolization by trait or variety owners nor any disputes arising from pollen flow among farmers,” added Dr. Mugo.

He went on: I wish to state that maize contains no Bt bacterium, it contains plant-expressed proteins encoded by introduced genes. Bacillus thuringiensis is itself a naturally occurring soil bacterium long coexisting with humans and livestock without demonstrated systemic adverse effects. Even assuming that the endotoxin was there, it does not adversely affect humans or livestock. Bt is widely used as a biological pesticide in organic farming, considered safe for humans, livestock, and aquatic organisms.”

Dr. Mugo added that from scientific and regulatory evidence, approved GM maize varieties, including Bt maize, does not contain whole bacteria, does not inherently endanger the human health, and have been cultivated and consumed worldwide for nearly three decades without demonstrated population-level harm to human health.

“GM maize offers significant benefits in reducing crop loss, pesticide use, and aflatoxin contamination, thereby enhancing food security, protecting the environment, and supporting public health, provided stewardship and regulatory conditions are observed,” he explained to the Court.

Bt maize application, was jointly submitted by the Kenya Agricultural and Livestock Research Organization (KALRO) and the African Agricultural Technology Foundation (AATF) to the National Biosafety Authority.

The hearing of the case continues from 2nd to 3rd June 2026.