Silver Bullet for PTA and Kauri Dieback?

Silver Bullet for PTA and Kauri Dieback?










It could be great news for those fighting PTA, the pathogen killing kauri in unprecedented number in Northern bush. Researchers from the University of Florida Institute of Food and Agricultural Sciences and the New Jersey Institute of technology may have discovered a “silver bullet” that will protect the giant trees from this deadly fungus.

PTA (Phytophthera toxa Agathis) is a fungus that attacks the roots of kauri, often leading to the death of the tree, and so far it has proven resistant to all treatments that could sustain kauri for their often 2000 year lifespans. However, the US based team has found a blend of silver nano-particles and wormwood extract can kill several strains of Phytophthera.

“The silver nanoparticles are extremely effective in eliminating the fungus in all stages of its life cycle,” says research team leader, G. Shad Ali. “In addition, it had no adverse effects on plant growth.”

The silver nanoparticles measure 5 to 100 nanometers in diameter (20 nanometers is about the thickness of a cell wall) and are sprayed onto a plant. They then shield the plant from the fungus. Silver nanoparticles are currently being investigated for applications in various industries, including medicine, diagnostics, cosmetics and food processing. They are already used in wound dressings, food packaging and in consumer products like textiles and footwear for fighting odor-causing microorganisms. Since the silver nanoparticles display multiple ways of inhibiting fungus growth, the chances of pathogens developing resistance to them are minimized, Ali said. Because of that, they may be used for controlling fungicide- resistant plant pathogens more effectively.

The team’s work was published this month in the journal Phytopathology. The abstract of their paper is published below

Ali, M., Kim, B., Belfield, K., Norman, David J., Brennan, M., Shad Ali, G., Inhibition of Phytophthora parasitica and P. capsici by silver nanoparticles synthesized using aqueous extract of Artemisia absinthium, in Phytopathology,

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and eco-friendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium L. against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg mL-1 AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50
: 2.1 to 8.3 µg mL-1) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

Budget Hope for Restoring Native Forests?

Budget Hope for Restoring Native Forests?







Will Revived Forest Grant Scheme be Good for Natives?

The revival of the Afforestation Grant Scheme (AGS) announced this week by the associate Primary Industries Minister, Jo Goodhew is unlikely to lead to more planting of native forest, according to Forest Owners Association technical manager, Glen Mackie.

While Mackie acknowledged that the Government’s decision, “ an endorsement of the environmental attributes of forestry and will doubtless make a useful contribution to erosion prevention and the country’s carbon ledger,” this is only the case if the forests are commercial plantation plantings, most likely radiata.

According to Mackie the revived scheme, “…is squarely aimed at pastoral farmers on steep erosion-prone land where the economics of production forestry might be marginal.”

The new version of the scheme will see $22.5 million invested over the next six years to encourage the planting of an expected 15,000 hectares of new forest.

“The new scheme will take up where its highly successful predecessor left off,” Mrs Goodhew says. “Farmers and landowners can again use the AGS to make better use of marginal land and increase farming diversification.”

Successful applicants will receive $1,300 per hectare for new forest planting, with priority given to applications addressing environmental issues such as erosion. However there is no indication in the Government’s release documents of priorities for industrial planting. Those planning rehabilitation of native forest areas should be equally eligible for the grants as other landowners.

Full details of the scheme will be available prior to the due date for applications on 27 May 2015.

Felling Kauri According to the Rules

Felling Kauri According to the Rules












Cutting Down Kauri Was “In the Rules”.

According to a late Auckland City Council report on its granting of consent for a Titirangi developer to cut down a mature kauri, it was all done according to the rules.

In a report delivered yesterday, weeks later than scheduled, the council’s chief planning officer concluded that the consents for the kauri’s felling were “appropriate” and that the commissioners hearing the application were within the rules in not making the felling notifiable.

Popular local action and close media attention saved the tree, while a protestor who remaining up the tree for 3 days in support of its survival has since pleaded guilty to trespass on the Paturoa Road, Titirangi property.