Insect Pests’ Resistance to Bt Crops: Its Implication on FAW Management

Prof. Huang interacting with one of the participants during the seminar

Prof. Huang (Left) interacting with one of the participants during the seminar

The use of single-gene Bt plants is one of the factors contributing to the rapid development of Bt resistance in the invasive fall armyworm(FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), a new pest species which has the potential to devastate maize production in Kenya with implications on food security.

This was revealed by Prof. Fangneng Huang, an entomologist from Louisiana State University, USA, in a presentation on the threats of insect resistance to Bt crops and the subsequent Integrated Resistance Management (IRM) strategies, during a seminar organized by the Department of Horticulture to highlight long-term strategies in the management of the invasive fall armyworm, Wednesday, April, 26, 2017.

Fall armyworm frass and damage on maize - PICTURE COURTESY

Fall armyworm frass and damage on maize – Picture Courtesy

The seminar discussion comes in the wake of the fall armyworm which has caused damage to the maize crop in the recent past.  Although the worm is believed to have invaded Kenya during the last few months of 2016, it was first reported by farmers as nuisance caterpillars towards the end of December the same year. The presence of the fall army worm in Kenya was confirmed in March 2017 through the Ministry of Agriculture, Livestock and Fisheries.

The participants explored the various Integrated Pest Management options that farmers should be encouraged to adopt for sustainable management of the FAW and other invasive pests. The seminar offered Prof. Huang an opportunity to share his work with the academic fraternity, with participants drawn from the teaching staff and postgraduate students in  the Department of Horticulture and the Institute of Biotechnology as well as representatives from Monsanto Kenya Limited.

The seminar acknowledged that knowledge gained from the 20 years of Bt crop use in the world could also be valuable for fall armyworm management in Africa.

Seminar participants pose for a group picture with Prof Huang after the Seminar

Seminar participants pose for a group picture with Prof Huang after the Seminar

The fall armyworm caterpillars are green, brown or black in colour depending on development stage. A mature caterpillar has a distinct white line between the eyes, which form an inverted “Y” pattern on the face (this is seen when the worm is placed facing you). In addition, there are pronounced four black spots aligned in a square on the top of the 8th segment near the back end of the caterpillar.

Fall armyworm is a ferocious feeder which upon invasion quickly destroys maize crop. After feeding, FAW caterpillars leave behind large amounts of moist sawdust-like frass near the whorl and upper leaves. The adult moth has capacity to fly over 30 km in one night drifting through air current. The female lays 1500- 2000 eggs in her life time, enabling the pest to quickly establish in new areas. Attack on maize at early vegetative stage can result into 100% crop loss if no control measures are taken.