Millions of insects zapped with gamma-rays and let loose into the wild to destroy their mates.
The very thought is enough to make any self-respecting greenie choke on his tofu. Actually, the sterile insect technique (SIT) is as environmentally friendly as it gets, and forms a major part of “integrated pest management” as mainstream farmers move away from spraying poisons.
On the unassuming Nietvoorbij campus of the Agricultural Research Council (ARC) in Stellenbosch, a small private company called SIT Africa irradiates some 7-million male Mediterranean fruit fly pupae per week with gamma-rays emanating from a nugget of radioactive cobalt. This renders the emerging insects sterile. They are shipped by the million to fruit farms in the Western Cape, where they mate with “wild” females, making the latter sterile in turn.
In the tiny Limpopo town of Letsitele near Tzaneen, a small company, Du Roi IPM, breeds millions of ladybirds and wasps on cultures of the mealy bug and red scale pests, grown on a substrate of butternut. The predators and parasites are harvested, packed and sold to citrus and grape farmers throughout the country.
The South African bug industry, only just emerging from its chrysalis, is tiny compared to its counterparts elsewhere in the world. In Guatemala, the largest sterile insect factory in the world produces 2,8-billion fruit flies per week. The largest mass producer of predator insects is the Netherlands-based Koppert, which delivers â,¬52-million worth of insects to European tunnel farmers a year.
Nor is the technology used in South Africa unique. It is largely imported, and only slightly adapted to local conditions. But what is amazing about the local industry is that it has managed to take hold with no government support apart from a R1,5-million grant some years ago from the Western Cape government and salaries paid to researchers of the ARC.
Developing an industry around environmentally friendly pest control is pre-eminently a government-driven project. It requires long-term thinking and a culture change, with farmers’ objections ranging from superstition to real concerns about higher costs and lower efficiencies. Integrated pest management only really starts working if most farmers in an area act together to suppress a pest, and total eradication requires the cooperation of the local non-farming communities as well. The technology is new and risky, and the mass production of insects is difficult and capital-intensive. An insectary’s temperature, humidity and sanitation has to be managed precisely. With SIT, the radiation requires even more capital and controls. If ever there was a case for government leadership and support, this is it.
The Stellenbosch SIT project is the only one in the world with no sustained government backing, and is also the smallest of such undertakings. But this is about to change. Anton Rabe, SIT Africa chair and CE of the Deciduous Fruit Producers Trust (DFPT), says a memorandum of understanding was signed this month with the department of agriculture for a national roll-out of an integrated pest management programme, with SIT as a central component. Costs will be shared between government and the industry on a 50-50 basis. The cooperation will include extending SIT production facilities, the dissemination of sterile insects and monitoring.
Rabe expects a national rollout to cost about R20-million a year.
The fact that an industry has taken hold at all — a new SIT radiation plant is being built in Citrusdal for the fight against the false coddling moth — is an interesting measure of how strong an economic force environmentally friendly farming methods have become. There seem to be two forces at work.
The one is pressure from export markets to move away from chemicals. Fruit imported into first-world markets are scanned for the residues of unregistered chemicals. The list of these chemicals is growing, as a process of re-registration for agricultural chemicals is under way in the US. It costs millions to re-register a chemical, and in many cases the cost is not worth the effort for chemical companies. So farmers have fewer and fewer kosher chemicals to choose from.
The second force is resistance of the pests to chemicals, which is not simply a theoretical risk. Since the 1970s, farmers have had bad experiences with resistant pests. Increasing the concentration of poison and the frequency of spraying, as well as using new chemicals helps only for a while.
The varied methods of integrated pest management seem to be the answer, and farmers are adopting them fast, with or without government support. But the problem is cash and credibility. When the chemicals are cheaper, it is hard to convince a cash-strapped farmer to think medium-term. “The fruit industry has gone through very tough times. The last five to eight years have probably been one of the worst times to introduce the SIT programme,” says Barnes.
About four years ago, two of South Africa’s four commercial insectaries collapsed because of the strengthening rand, which made imported chemicals so cheap that breeders of predator insects could not compete. To make matters worse, the patent rights of some chemicals lapsed, and generics were imported at a tenth of the price.
Du Roi IPM general manager Felix Hacker says they had to drop their prices by about 45%. His partner, marketing manager Clive Pountney, says they survived the crunch because they diversified, breeding and selling two types of ladybird and two kinds of wasp. Also, with the help of a small Western Cape agricultural services company, Erichem, they managed to break into the table-grape market. Previously, they only sold to citrus farmers.
Apart from rands and cents, there is the problem of credibility of integrated methods. If you have your life savings tied up in the next harvest, as farmers continually do, the temptation to reach for the tried and tested can of poison is too much. Experimenting with integrated methods is simply postponed to better years.
The result is a limited yet growing application of bio-friendly pest control. Du Roi IPM’s insects are released on less than a tenth of South Africa’s 60Â 000 hectares under citrus cultivation. SIT Africa’s sterile fruit flies cover 14Â 000 of the country’s 74Â 000ha of deciduous fruit.
Du Roi’s Hacker expects an “exponential” growth in uptake among farmers as predator insects gain credibility and knowledge of their application spreads.
Rabe pins his hopes on a faster method: statutory levies, forcing farmers to buy the service. The advantage is that it will provide the kind of blanket coverage needed to forge a reputation for South Africa as an area of low pest prevalence. The prize is unprecedented access to export markets.
Doomed in SA
Will bio-friendly pest control ever reach the stage where ordinary home-owners can go down to their local nursery, buy a handful of ladybirds and release them in their suburban gardens?
Yes, says Felix Hacker, the owner of Du Roi IPM, a small Limpopo insectary that breeds predator insects for farmers. The practice has already taken hold in the US.
But it is early days in South Africa, says Hacker, who investigated the possibility with Johannesburg nurseries. At present, too much education of the public will be needed to make it viable. Release times and methods require knowledge of the insects, as does the monitoring of their efficiency.