Some soil fungi are natural born killers and the Institute of Sustainable Horticulture at Kwantlen University plans to put that talent to work for agriculture.
Institute director Deborah Henderson has been identifying, isolating and assessing the functions of soil fungi in her Langley campus lab and has a few particularly cold-blooded candidates identified.
Beneficial organisms native to local soils have potential to control pests, prevent blights that afflict tomato vines and attack root-rotting fungi that affect blueberries and raspberries. Henderson’s lab recently received a $122,000 Growing Forward 2 grant to develop three new biological pesticides.
Henderson went looking for candidates in undisturbed soils such as forests that have more beneficial fungi than soils where pesticides and fungicides are used.
Beneficial fungi sometimes attack other fungi that are harmful to plants, while others kill insects, such as chafer beetle. The lab tested each type of fungi by infecting insects with it in a series of “murder trials.”
“The ones that killed the insects were successful, now we are taking the next step to see if we can develop them into products,” she said. Other fungi were tested in petri dishes to see if they would knock off the fungi that promote root rot and other problems for crops.
Henderson hopes to create soil treatments that will protect plants without chemicals and the endless cycle of interventions that are inevitably required when natural soil ecosystems are damaged.
“When we use chemicals to kill the harmful fungi [in agricultural soils], we kill all the fungi, some that were probably helpful, and then we inherit their jobs if they were helping keep things in balance,” she said. “It’s like Murphy’s Law: a chemical treatment will usually kill all the beneficials, but it never seems to kill all your pests and you will always have a resurgence in your pests to deal with.”
Each fungi has to pass a series of tests, starting in the petri dish and ending with real-world field trials. That is, if it can even be cultured in sufficient quantity to apply on a commercial scale, over hundreds of hectares.
“OK, if you can kill in a petri dish, can you kill it in a field, can you kill it on a plant?” she asked. “Can it survive in the soil or on a plant long enough to kill an insect?”
Promising fungi are grown in a feeding solution, then transferred to grow on grain such as barley or rice. When the food resources are exhausted, the fungi produce spores. Spores mixed with water can be sprayed onto crops at a measurable rate, which is essential to assess their effectiveness.
“Spores are the active ingredient and they can be distributed easily in the environment where they will grow and hopefully attack insects or other fungus,” she explained.
The insecticidal fungi bore right through the insect’s protective armour, feed on the insect and multiply, releasing a new wave of spores as a kind of insect carcass fungi bomb. Recent trials of the fungi trycloderma on sick soil at a nursery in Abbotsford and on fields in Delta have provided encouraging results.
Henderson is preparing a new application to the Natural Sciences and Engineering Research Council of Canada for a three-year product development project in partnership with the nursery.
“It’s never a short road, but if you don’t start you never get there,” said Henderson.
Author: Randy Shore, Vancouver Sun