Global Farmer Field School Platform

The mechanical control intervention against the Fall Armyworm – The case of Embu county pilot project







The mechanical control intervention against the Fall Armyworm - The case of Embu county pilot project 

An update on the FAW response programme


The situation

The FAO SFE Global Fall Army Worm (FAW) (Spodoptera frugiperda) Emergency response programme has just finalized a mechanical control intervention of the FAW in Embu County of Kenya. In October –November 2017, this was one of the few smallholder-farming areas with a standing crop of maize.  The farmers have also been growing tomatoes, French beans and other horticultural products. The use of chemical pesticides is an institutionalized practice, and virtually every household owns a knapsack sprayer. The reliance and dependency on chemical pesticides proved futile against the FAW threat. This pilot project therefore presented an alternative option to pesticides control by way of utilizing the large unemployed youth talent in the county. The six-week pilot intervention project aimed at generating lessons learned for the region in view of the forthcoming main cropping season in March-June 2018.

Proposed Solution

The key purpose of the pilot was to define and test a system of incentive-based FAW mechanical control that is sustainable in nature, cost effective and sufficiently generic in model for wide application at scale across a range of contexts and countries. In this pilot, 50 field scouts, 8 supervisors, 5 data entry clerks, 1 lead trainer and 1 County Programme Officer formed the implementation team. The target beneficiaries were 300 households, with over 380.5 Ha of land under maize mechanically cleaned for FAW continuously for six weeks. Each household was visited twice a week by the Field scouts. One county sensitization for over 40 frontline extension workers was undertaken. One community FAW awareness and sensitization event was conducted as a transparent means of selecting the 300 pilot farmers and 50 field scouts. A two day technical the field Scouts (57% female, 43% male) were taught how to scout for FAW egg masses and how to crush them. The procedure at every scouting visit was as follows:

  • Start scouting for egg masses at crop emergence together with the host farmer and members of his family.
  • Examine plants for cream or grey egg masses on the underside of leaves especially near the stem
  • Fold the healthy part of the leaf against the eggs and press firmly back and forth by hand
  • Ensure all eggs have been crushed before moving to the next plant
  • Record the number of egg masses crushed
  • For caterpillars (larvae) and pupae, collect them into a plastic container, record their numbers and destroy them out of the crop area.


Prior to the mechanical control, a baseline survey of the 300 farmers was carried out using epicollect sytem on phone tablets.  Every scouting visit culminated in a daily FAW record documentation that were verified by the supervisors and keyed in by data entry clerks. In summary the number of larvae collected in the field significantly dropped over time. Fewer and fewer larvae were there to be collected. The vertical lines above show the range of the average number of larvae collected e.g. in first week approximately (18-100) while on 12th week (5-32). Additionnaly, more crops survived over the six week pilot period 


Mr. Aaron Njagi – a farmer in Maangia Village and the field scout (Catherine Wanja) have been working together since the inception of this project. The farmer reported that in one portion of the farm, he sprayed seven times but the infestation remained prevalent. When compared to Catherine’s work for two weeks he noticed that the larvae had greatly reduced. Mr. Njagi also reported that neighbouring farmers came to witness the mechanical destruction of the FAW on his farm and they later went to replicate the same on their farms.

Mrs. Agnes Waithera Mureithi, from Kanduri village accepted to be part of the target farmers. She was introduced to a field scout called Ms. Jane Wanja. The field scout started the mechanical control alone. What provoked Agnes is that her husband had sprayed the crop at least three times but with no success. After watching what Jane was doing, Agnes became convinced that mechanical control was working. Agnes then trained her husband, her two children and later on to her parents in law. After continuous mechanical control, Agnes is proud to have harvested from the two plots. The parent-in-laws have also appreciated her work.  As her resolution, she may have to focus more on her compound but if she gets more money, she may hire extra labour for FAW mechanical control. She is convinced that if the entire village could work communally on mechanical control, then the FAW menace will be history.

Mrs. Anastacia Wawira Karuri from Kathamba village is a perfect exemplification of team work. She was introduced to the mechanical control approach by a field scout called Stella Kagendo Ireri. This field scout was also assisted by Ms. Sicily Muthoni and Ms. Lydia Mombasa. She involved her husband and everybody else in the neighborhood. Anastacia argues that even if the method is tedious, it is much better than waiting for her husband to bring home yet another ineffective pesticide spray.

The way forward

The pilot project has proved that FAW management is proving sustainability. Plans are underway to roll out an expanded phase in Embu and Bungoma counties targeting at least 900 farming households. Ten existing Field Schools in each county will be introduced to the newly designed FAO FAW curriculum for adaptive and comparative farmer experimentation.