TABLE 4.4 Productivity of Different African Palm Weevil Farming Systems Production system
Quantity of raffia used
Productivity
Traditional gathering
1 raffia stem of 2 to 3 meters
35 larvae
Semi-farming
1 raffia stem of 2 to 4 meters
50 larvae
Farming
Less than ¼ stem
69 larvae
Source: Muafor et al. 2015.
BSFL convert a significant amount of substrate and are not considered pests. The BSFL feed on most organic substrates, including fruits, vegetables, cereals, tubers, and legumes. But they can also feed on organic wastes, such as animal manure (Li et al. 2011; van Huis 2019; Sheppard 1983) and fecal sludge (Lalander et al. 2013). The potential of using BSFL to break down organic waste has been explored for decades (Sheppard 1983). Only the BSFL feed; the adult BSF does not have a mouth, and so it does not feed or bite. As such, the BSF is not considered a pest. BSFL production is also used for waste management in many parts of the world. BSFL can convert organic waste into different end products, such as oil, protein, and biofertilizer. In Australia, Korea, and Malaysia, industrial-scale BSFL are used to reduce urban wastes. The success of these operations depends on the safe and efficient handling of large volumes of waste. In China, Kenya, and South Africa, BSFL are used to reduce manure from large-scale livestock production and fecal sludge from cities. In Europe, the main concern with producing BSFL feed from manure is making sure the feed meets safety requirements (EFSA 2015), while in Asia, the concern is converting large amounts of organic wastes from crowded urban settlements (Wang and Shelomi 2017). Consequently, facilities in the European Union and North America are designed to have BSFL digest preconsumer food waste and market the resulting larvae for poultry or aquaculture feed, while facilities in Asia are designed to convert large volumes of mixed wastes into insect biomass. For example, over a 15-year period, China developed industrial-scale BSFL plants with the capacity to convert more than 100 tons of organic waste per day. Table 4.5 shows the estimated values from BSFL converting fecal sludge into protein, biofuel, and biofertilizer in three African cities (Diener et al. 2014). BSFL grow quickly, building up fat, protein, and chitin. The BSFL’s growth period is only two weeks from hatching to harvest. During this two-week period, a larva weighing less than 1 milligram grows to 180 milligrams or more. This growth rate is almost two times faster than the average growth rate of a broiler chicken. This would correspond to a chicken weighing 40 grams when it hatches and growing to more than 700 grams in two weeks. The BSFL’s growth varies with the substrate it is fed and the abiotic environment 140
Insect and Hydroponic Farming in Africa
