The Toothpick Project: Fighting Striga (witchweed) with Smallholder Biotechnology

Summary

Striga hermonthica, a destructive parasitic weed, is one of the leading pest threats to African food security. Striga attacks staple crops on 40 million farms, depleting crop yield by 20-100 per cent. Women are disproportionately affected, as they constitute 70 per cent of maize smallholder farmers. Toothpick Project’s safe, effective bioherbicide, designed by and for smallholders, kills Striga and increases crop yield by 42-56 per cent by using a live inoculum grown from a fungal-coated toothpick.

Challenge/Problem

Striga (witchweed) is an increasingly destructive invasive parasitic weed affecting 40 million farms (about 300 million people) across sub-Saharan Africa. Attacking the roots of maize, sorghum, millet, cowpea and upland rice, it depletes crop yield by 20-100 per cent, resulting in a lack of food and income for farmers. Striga infestations cause over $9 billion in crop loss annually. Striga is one of the leading pest threats to African food security.

Although women are the main food producers in Africa, there is a gender gap in technology adoption. Toothpick’s technology, using a cooked rice substrate, was developed by and with women agronomists, understanding and capitalizing on gendered skills and societal constraints. The Project’s beneficiaries are below the poverty level of $1.90 per person per day.

Some Striga-management technologies exist but haven’t been widely adopted by farmers due to mismatches in technologies, socio-economic conditions, effectiveness, and availability. Weeding occurs too late to reverse damage, and some herbicide-coated maize seeds are toxic, hazardous to other crops, and poorly adopted. Striga-tolerant crop cultivars, push-pull methodology, and improving soil fertility don’t fully restore crop yield. None of these solutions addresses the soil’s Striga seed bank. Costs often exceed farmers’ economic means.

Solution

FoxyT14 (trademarked Kichawi Kill in Kenya) is a biocontrol technology developed to attack Striga hermonthica by using three locally sourced strains of Fusarium oxysporum f.sp. strigae that were selected because they excrete three specific amino acids. The strains are grown onto wooden toothpicks or dowels, dried and stored in a sterile, sealed canister. The village-based producer makes a simple on-farm inoculum by placing the toothpicks in a sterilized container of cooked rice and shaking it twice a day for three days to inoculate all the rice with Kichawi Kill. She then plants 2 grams of inoculated rice with each maize seed. The fungi are host-specific (so they won’t harm other plants), and non-toxic. Five major toxins were not detected in tests at Virginia Polytechnic University and University of Nairobi.

Toothpick has three distribution system developments to implement and test over the next few years: producer distribution, pop-up shops, and NGO integration. The strategy develops micro-agribusinesses, stimulating the local economy.

Toothpick expects that with a conservative estimate of a 25 per cent increase in yield, a farmer should expect to break even in the first year on the US$45 cost of the intervention. Higher yields would mean more food, income, and ability to diversify with more nutritious crops.

Results

In, 2019, Toothpick reached 419 demonstration plots in four counties, with 800 farmers attending organized field days. They also trained 20 village-based inoculum producers, each serving 50 farmers. The number of producers will be increased to 80 for the first year of distribution in 2020.

With an emphasis on women-focused community-based organizations, Toothpick has engaged 20 community partners totalling over 700 members and trained 120 Ministry of Agriculture agents. In addition, 13 scientists from 12 countries have been trained in the virulence-enhancement selection technology, creating a research team to expand use to other crops and geographies.

The required Kenya Pest Control Products Board regulatory trials have been conducted for four years, and registration approval is anticipated by early 2020 in time for the March planting.

Lessons Learned/Potential for replication

The initial plan was to have each farmer make his or her own fresh inoculum. However, in an early trial with FIPS-Africa, there was too much room for contamination error at the farmer level. Therefore, a distribution system was created to reduce contamination risk: certified village-based inoculum producers (trained in sterile-production protocol and microbusiness skills) will use Toothpick’s specially manufactured primary inoculum dispenser and ethanol swabs. This pivot created an agribusiness system, building village economies.

Registration has taken longer than expected, delaying the ability to test Toothpick’s distribution system. In future countries, Toothpick plans to duplicate trials to compensate for unforeseen issues like fall armyworm, flooding and negligent implementers.

Toothpick is also seeking a less expensive substrate for the village-level inoculum. Although rice works perfectly, it is somewhat cost-prohibitive for the farmer. Toothpick is currently testing gritted maize cob as an alternative.

Next Steps

The next steps are to train all 80 selected village-based inoculum producers and outfit them with the required production supplies (such as cookstoves, metallic bowls, forceps and spray ethanol) for the first year of distribution. Each producer will work with approximately 50 farmers in their first year. Demonstration sites in four counties will be created, expanding to eight counties within a few years, and community-based organization partners will also be increased from the current 10.

Internationally, Toothpick’s science team is isolating fungi and selecting virulence-enhanced spores (required in each country individually). These will be put into greenhouse and field trials subject to funding availability.

A social enterprise (Toothpick Company Ltd.) has been created, and Kenya Agriculture and Livestock Research Organisation (KALRO) is registering the product, with registration being co-owned.