Whenever I see photos of the symptoms of Papaya Ringspot Virus (PRSV) up close, I actually think that if it weren’t so destructive, if would be beautiful.
One of the two strains of this Potyvirus, called PRSV-P, infects both Papayas (Carica papaya) and cucurbits (Cucurbitaceae); the plants suffer mosaic (interference with photosynthesis), leaf distortions, patches of necrotic tissue (which invites fungal infection), deformities in the fruit, and greatly-reduced yields. The virus is highly infectious, moving rapidly from plant-to-plant, primarily through aphid predation.
After being introduced to Hawaii in the 1930s, the virus mutated, and by the 1950s had halted 94% of Papaya plantations on Oahu. Production moved to other islands, but the pathogen followed, and also began infecting home gardens in the 1970s. Even with aggressive horticultural and insecticidal management, by the 1990s, the virus infected commercial plantations, and over 50%-80% of the industry was decimated in various global sites of production.
Carica papaya is a rather genetically homogenous tree, so there were few reservoirs of resistance to the virus to be found in feral or wild populations of the plant. As a result, something else needed to be done to save the production of this fruit: in 1998, the answer came in the form of genetic engineering.
One of my many forays into the wonderful world of retail was working at a garden centre, as a “trees and shrub sales associate.” It was a crash course in memorising pertinent information on plants, in order to best advise the customers.
For example, in selling plants in the genus Prunus (plums, cherries, almonds, peaches, nectarines, bird cherries, sloe, and others), this meant closing my eyes and picturing a chart on cross-pollination every time I informed a customer they couldn’t purchase a single tree, and still expect fruit.
Sola dosis facit venenum: The Dose Makes the Poison
In the springtime, a special delicacy to be had is the emerging, curled frond of the fern, called a fiddlehead because of it’s resemblance to the scroll of a fiddle.
Not all fiddleheads are classified as edible: among the most-consumed species are the Vegetable fern (Athyrium esculentum), Ostrich fern (Matteuccia struthiopteris), Royal fern (Osmunda regalis), Bracken (Pteridium aquilinum), Lady fern, (Athyrium filix-femina), and Western sword fern (Polystichum munitum).
While every forest is different, all of them share a few commonalities in the biomass resources they convert into humus and nutrition. The balance between the inputs is what facilitates the growth of mycelial networks, and the long-term retention of nitrogen.
While building a forest ecosystem using permaculture techniques to accelerate succession (sheet mulching, hugelkultür, bioretention swales), these resources need to be thought of as “inputs,” as in, most of your early work in building a functional forest ecosystem will be in adding the materials your soil needs to support a large quantity of plant and animal life.
As habitats of native bees, beetles, and butterflies are sometimes scarce, or in the way of cultivation, it is important to preserve refuges where these creatures can hide, and continue to symbiotically interact with your local ecosystem.
I am in the process of debulking an overgrown Dawn Viburnum: in my zone (8), this beautiful plant produces clusters of pink blossoms as early as December, and flowers right through to February: it provides good forage for non-honeybee pollinators that fly in colder weather. The plant itself is also a great habitat for birds.
Whenever I am doing maintenance on an older shrub like this, it produces a tonne of biomass, so today, I’m going to go over what I do with all of the wood.
Most arbourists these days will tell you that tree topping (the practice of pollarding large trunks and branches on mature trees) is an excessively destructive process: it’s largely been replaced in the trade with spiral thinning.