Healthier trees, thanks to pest-control partners

Wood is a precious renewable useful resource that’s used broadly throughout numerous sectors, from the paper, textile and bioelectronic industries to building and mining. When plantations are harvested sustainably for his or her assets, they supply financial, environmental, cultural and human-health advantages.

Pest-control methods kind an important a part of sustainable forest administration. South Africa is a world chief on this regard, with 80% of the nation’s timber plantations licensed by the worldwide Forest Stewardship Council.

Compared with standard agriculture, South African forestry makes use of minimal portions of pesticide, relying as a substitute on cultural practices and organic management, in addition to breeding resistant bushes and pheromones.

This has been achieved largely via shut partnership between forest entomologists on the University of Pretoria (UP) and foresters within the trade.

The forestry trade is a significant contributor to South Africa’s financial system, because it produces about 18,2 million cubic metres of wooden yearly with an estimated worth of R40 billion.

Commercial forest plantations in South Africa consist primarily of Eucalyptus, pine and wattle.

Unfortunately, these extremely productive tree species are susceptible to assault by indigenous and launched insect pests.

Biological management
One of essentially the most sustainable and environmentally pleasant methods of controlling an insect pest is to introduce its pure enemies into the realm. These can embrace insect ailments, predators and parasites, which might considerably cut back the pest inhabitants.

Approximately 20 years in the past, forestry firms teamed up with forest pathologists and entomologists at UP to determine environmentally pleasant pest-control methods for forest plantations. This partnership has led to vital adjustments to how pests are managed.

Researchers at UP have recognized biocontrol brokers for a lot of the vital plantation pests in South Africa. These brokers are studied in quarantine laboratories earlier than being launched into the sector to guarantee they do no hurt to native bugs. After their security has been established, they’re mass-reared within the laboratory, then launched in timber plantations the place excessive ranges of the pest bugs happen.

In some circumstances, resembling with Selitrichodes neseri, the parasitic wasp of the bluegum chalcid, just a few releases in 2012 had been enough for the wasp to set up in some Eucalyptus-growing areas.

This offered efficient management of the pest in subsequent years. In different circumstances, resembling with Deladenus siricidicola, the parasitic nematode of the Eurasian woodwasp, common releases of the biocontrol agent had been required. For this motive, rearing amenities, which offer enough nematodes every year for environment friendly management of this insect pest, had been established at UP.

UP forest entomologists usually journey to the native lands of insect pests to discover new biocontrol brokers which have higher survival traits. The subsequent expedition will go to Southeast Asia to determine biocontrol brokers that may be deployed towards the polyphagous shothole borer, which is killing native and indigenous bushes in cities and landscapes all through South Africa.

Volatile indicators
Insects talk with one another by scent. The unstable chemical substances launched by bugs to entice a mate or sign concern or different vital data are generally known as pheromones.
Pheromones can be used to confuse bugs and disrupt their mating behaviour, and are an vital method to handle pests in plantations.

Researchers at UP not too long ago recognized the mating pheromone of the Eucalyptus cossid moth, which is indigenous to South Africa however has switched its host and is now a significant pest of cold-tolerant Eucalyptus species. The pheromone is utilized by the forestry trade for monitoring the pest in plantations and for mass trapping.

UP scientists are producing the pheromones, designing dispensers to launch the pheromone in a managed method, and figuring out the optimum placement of traps to maximise insect seize.

Tree breeding for resistance
Plants have advanced methods to beat back insect feeding by producing protecting measures resembling scales, thorns, resin or noxious chemical substances. During the previous 100 years, tree breeders have targeted primarily on enhancing productiveness and wooden high quality, and uncared for defences towards insect assault.

This is why many tree varieties grown in South Africa are significantly inclined to insect injury. In response, forest entomologists at UP have began screening tree varieties for his or her resistance to insect feeding and have recognized quite a few chemical traits.

The Eucalyptus snout beetle (Gonipterus scutellatus), for instance, which is a significant pest in Eucalyptus plantations worldwide, prefers to feed on leaves with a excessive sugar and low fats content material.

Tree breeders at the moment are utilizing this data to choose new varieties with low sugar and high-fat content material to develop planting inventory for future plantations. A brand new greenhouse facility has additionally been constructed at UP to decide the resistance of tree varieties and the explanations for this resistance.

Knowledge change
An in depth partnership between the trade and researchers has sped up investigation into economically related trade issues in addition to the implementation of recent administration methods within the discipline. The shut connection between UP and South Africa’s forestry trade is fostered by entomologists working within the plantations and alluring foresters for analysis days on the college.

UP’s partnership has additionally created alternatives for the employment of entomology college students, and for them to study from the trade and make an impression via their analysis tasks.

Email Liesel Swart at [email protected].