In many countries, economic considerations are an important factor in government decision making on the introduction of genetically modified (GM) products. However, reliable information on their actual or likely economic impact is often lacking. This brief illustrates the use of a methodological framework to assess the potential economic impact of introducing genetically modified tomatoes in Ghana. The framework consists of four interrelated levels of analysis, corresponding to four sets of actors in the economy: (1) farm (smallholder producers); (2) market (processors, traders); (3) the pertinent industry or sector of the national economy (consumers and producers, linked by markets); and (4) international trade.
TOMATOES AND TOMATO YELLOW LEAF CURL VIRUS:
Tomatoes are a popular food item in Ghana. A main source of vitamins A and C, they are consumed on a daily basis in many households. Moreover, tomato production is an important source of income for smallholder farmers. While domestic tomato production has intensified across the country in recent years, it still does not meet the high demand, so tomatoes are imported from Burkina Faso five to six months of the year. This situation is attributed to a number of constraints in the production and marketing chain. One such constraint is a virus, transmitted by the white fly (Bemisia tabaci). If the fly is not controlled at the early stages of tomato cultivation, it can cause tomato yellow leaf curl virus (TYLCV), a disease that devastates crop yields and critically affects farmers’ livelihoods. Farmers often use pesticides to control the white fly, but they may be ineffective if the plant is already infested. Also, the use of clean new seed is strongly recommended to help control the disease, but seed recycling is common practice. Unfortunately, this further reduces the genetic diversity among tomato varieties making crops more susceptible to pests and diseases and farmers more vulnerable to disastrous yield losses.
CONSTRAINTS TO TOMATO PRODUCTION:
Several factors affect tomato production and ultimately the cost of tomato cultivation. For one, farmers obtain seed either from their own fields, from neighbors and friends, or from women’s groups that maintain and distribute varieties that are in high demand in the marketplace. This recycling drives down seed price, but has a negative effect on seed quality. Also, most tomato varieties used in commercial production are introduced varieties, which are not well adapted to local conditions in Ghana. This, along with the seasonality of tomato production, creates periods of abundance and scarcity, which dramatically affect market prices. On average, labor (land preparation, transplanting and harvesting) represents more than 50 percent of total production costs, but farmers who use family labor are hardly aware of this. Services and equipment costs together account for only 6 percent of the total expenses incurred by a tomato producer. Manure is often used as fertilizer by producers across the region. During the rainy season, fungal diseases and pests are common. Because synthetic insecticides and fungicides are generally too expensive for the average farmer to use, such expenses represent on average only 2 percent of the total costs. Access to irrigation facilities also conditions production. Still, despite these constraints, farmers consider tomato production to be a profitable activity.