Australian wasp to safeguard SA’s commercial forestsFriday 21 Nov 2014
The tiny wasps and their eggs hijack the trees in order to feed on them. These trees, full of ‘cancerous’ growths, never grow to their full potential, and become like a shrub, or, in some cases, die. As the wasp cannot fly far on its own, it must have entered Israel through plant material, such as timber, nursery stock, and florist industry products. Since 2000 Leptocybe invasa has spread to Eucalyptus plantations across the world, including South Africa, says Slippers. It has managed to close down some forestry sites in a number of countries. (Research since 2000 has shown the wasp infestation to be, in fact, the work of two closely related species). The speed at which the global invasion happened “is unprecedented”, as it used to take decade for pests to travel the world, adds Slippers. “Invasive pests and pathogens have always been a big issue in the industry, but what is changing is the speed at which things are happening. “We knew it was coming to South Africa, we just didn’t know when it would arrive.” The tiny wasp eventually landed in 2007. South Africa has around half-a-million hectares of Eucalyptus plantations, with the wood used for the paper and construction industries. One of the methods to counter the impact and spread of the wasp is the use of biocontrol agents – an enemy to the pest. The use of biocontrol agents for forest insect pests was first introduced in 1910 in South Africa, to counter long-horned eucalyptus borers. Since then biocontrol agents have been introduced another seven times in plantation forests, with research on two other bio-control agents under way. Sourcing the right enemy is the first difficulty, followed by keeping it alive, testing its ‘abilities’, preferences, reproduction cycle and life expectancy in the domestic environment – all under quarantine – and growing the population to the numbers required to counter the problem. All of this takes place at UP’s experimental farm, in Pretoria. The tiny Australian wasp – in fact, 17 000 of them – that has been found to kill the pest wasp, has since 2012 been released on 425 sites in South Africa. FABI is currently testing the efficacy of the introduction. Slippers believes the newcomer will not eradicate the problem completely, but rather bring “down the economic damage to manageable levels”. Source: engineering News | ||
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