(Black Soldier Fly Production Workshop, 2013 Carolina Farm Stewardship Association Sustainable Agriculture Conference, Durham, North Carolina; 16 November)
Saturday morning found the CFSA Outdoor Workshop Space writhing with maggots—the high protein, high fat larvae of the Black Soldier Fly (Hermtia Illuscens). It is a bit errant to claim that these larvae were actively writhing, as most were moving a bit more slowly than usual due to the cooler late autumn temperature.Some, in fact, were not moving at all, having been frozen and then carefully dried for preservation.
This workshop was group taught in the truest sense, with Patryk Battle of Living Web Farms and Dave Lamie, Wallace Campbell, David Thornton, and Ben Case, all of Clemson University, hosting the workshop; their friends Dr. McBug (Richard McDonald) and Karl of ProtoCulture assisted.
The basics were covered right away. Black Soldier Fly Larvae (BSFL) are utilized to great success in other parts of the world as a waste management tool, feed for livestock, and in the production of biofuels. BSFL encompass an impressive combination of protein, lipid (fat), and nutrients (omega 3, omega 6, and calcium to name a few). This species exists in 80% of the world and is not considered to be a house or crop pest as the adult Black Soldier Flies prefer to hang out in trees and have no mouths.
The adult Black Soldier Fly will only live between three and five days. BSFL take in all of the food they need while still within the larvae stage; after becoming an adult fly, their agenda is to lay eggs and then die. In nature, BSFL eat manure, rotting plant matter, and dead animals—which, it was mentioned, makes them perfectly suited to disposing of food waste within a farm, school, or urban system.
A variety of methods for BSFL habitat creation were exhibited and explained. Pat Battle’s DIY method (pictured above) involves a 55-gallon barrel with lid, cinder blocks, shade, and low bins such as restaurant bus tubs. Another option was put forth by Karl from ProtoCulture (image below), who boasted a bioconversion rate of 20 pounds of BSFL for every 100 pounds of waste input with use of his system. This open-top white plastic vessel must have drainage holes drilled in the bottom, be protected from rain and sun, and be situated upon an absorbent mulch such as chopped bark, which can then be reintroduced to the system as a nitrogen- and phosphorous-rich soil amendment.
In terms of the efficiency of the BSFL colony as a waste management option, they need to be fed every couple of days at most—so their environment does not become anaerobic—as they will devour whatever food waste they are given very quickly. BSFL love fermentation waste (leavings from cider pressing, breweries) because the yeast it helps them to accumulate protein more efficiently. BSFL can be fed animal processing waste, but concerns about survival of pathogens suggests that care should be taken when the larvae are also intended for use as feed. The same is true is using BSFL to mitigate human sewage, a system the Gates Foundation is supporting overseas. BSFL provide a solution for those who have animals invading their compost bins, as when the leavings from the colony are used for compost, not even scavenging animals will try to get into the compost to eat it.
When BSFL are ready to pupate, they will crawl out of the bin at a twenty degree angle and ‘harvest themselves,’ so some livestock producers situate their colonies so the larvae can just crawl right into the chicken pens. In Hawaii, where BSFL are being leveraged in small- and large-scale systems for their many functions, hog producers feed 30% BSFL directly to the hogs and supplement with a cheap, low-protein grain. In terms of storage, the larvae can be kept in the freezer for one week and, when dehydrated, will keep for up to six months.
The oil that is created as a by-product of pressing BSFL into livestock-ready edible pellets is a pharmaceutical-grade oil similar to that used to treat burn victims. This flexible oil can also be utilized within a biofuel production system. David and Ben, of Clemson University, demonstrated this process for the participants. Dried BSFL (protein and lipid) were combined with South Carolina-grown Black Oil Sunflower Seeds (the husk contributes fiber) in a 70:30 percentage ratio, which produces a stellar poultry pellet with high nutrient value. David and Ben used a press dedicated to this purpose, but suggested that any oil press would work—even a KitchenAid with a suitable attachment will do the job.
Participants of this workshop who arrived thirsty for information about efficient management of food and other farm wastes, economical high-protein feed options for a variety of livestock, and sustainable on-farm fuel production systems left satiated, with any concerns or questions resolved over the course of this comprehensive team-taught lesson.
QuincyGray McMichael Lewis
Greenbrier Valley Local Foods Initiative (WV) www.greenbriervalley.org