Pollination system and hybridisation of Tabernanthe iboga: successful crossing of two forms with different fruit morphology.
Tabernanthe iboga (family Apocynaceae) is native to Western Africa; Angola, Cabinda, Cameroon, Central African Republic,…
I know the title of this post sounds like a medieval book but I feel it is something we need to have a chat about! In many other aspects of our lives, hygiene has certainly evolved over human history and has resulted in the decreased incidence of certain illnesses and deaths from related diseases. From the simple act of hand-washing to prevent the spread of influenza and colds (edit: and now novel coronavirus which has brought this topic to the fore of society again), to the sterilisation of medical tools and surfaces to stop post surgical infections. It could also be argued that over-sterility/hygiene is now resulting in its own problems and chronic diseases due to a decrease in beneficial symbiotic organisms, both on our skin and within our bodies. What we need to achieve is a balance between the two, as humans are social creatures who now have the ability to spread disease far and wide, with the rapid ways in which we can travel and cross the paths of 100-1000’s of other humans each day.
In the same way that the role of hygiene has played in our lives, I believe hygiene processes can play a huge role in the incidence and reduction of disease within columnar cacti populations in cultivation. For example, I used to have small outbreaks of witches broom (a phytoplasma which causes mutated growth), but have virtually eliminated this through removal of the growth and sterilisation of knives and secateurs to stop the spread through dirty tools. So two simple hygiene factors; removal of infective material and sterilisation. How many people growing cacti do you know that have a great big old dirty knife they use to take cuttings and that they rarely or never clean?! Its like the reuse of syringes in early days that allowed the spread of diseases like HIV and Hepatitis B/C. Simple sterilisation of knives between cutting different cacti for propagation will stop/limit the spread of bacterial, fungal and viral diseases of cacti.
Some of the simple yet effective ways to increase health of your cuttings (Trichocereus, Cereus, Myrtillocactus are all columnar cacti) are listed below.
Reusing pots for plants has been mentioned as a possible transmission vector for disease, but I can’t say I’ve had issues and neither have several other serious cacti growers I have talked to. Diseases such as anthracnose are highly prevalent especially in the subtropics and I think you’e more likely to pick those up with water splash or airborne than through pots. It is always good practice to clean out used pots (I do this within a few hours as soil washes out easier before it fully dries) with a stiff spray nozzle on a hose. You could also use a 70% alcohol spray or bleach bath to give a final clean.
Hygiene, whilst super important, doesn’t stand alone however and other factors such as the health and nutrient status of the cactus and the microclimate it is growing in (humidity, daily temperature ranges, airflow, hours of sunlight etc) are all considerations for the keen cactus grower outside of their natural range.