Characteristics of the cuscuta campestris
The cuscuta is a unique plant: it has no roots and is almost completely free of leaves. It develops mostly from seed: from this, under favorable conditions at first emitted very small leaves and for a short time we have the photosynthesis of chlorophyll. At the same time, the stem develops and begins to “turn” on itself until it is able to cling to the host plant. Studies have established that each cuscuta is guided to the one it prefers by capturing specific volatile organic compounds.
Once reached, small suckers are produced, called austors: they penetrate inside the tissues and begin to suck the sap. From that moment on, the diffusion on the plot continues, taking the classic colouring from yellow to reddish. Then it will produce the flowers (white, bell-shaped) and then also the seeds, very fine, white or black.
On which crops does it grow? Why does it damage them so badly?
The cuscuta campestris grows particularly on sugar beets and potatoes. This species and the others widespread in our territory, however, also parasitize many other plants including alfalfa, flax, chrysanthemums, dahlias, hypomea, helenium, echinacea and ivy. We specify, however, that, in the absence of these, it adapts to live also on many other essences.
It is particularly harmful for various reasons: first of all, as it develops, it covers a good part of the foliage of the host, reducing its insolation and consequently its development.
Among its many capabilities there is also that of influencing the growth of the parasitized plant: at the arrival of high temperatures stimulates the production of flowers and fruits, but then steals the sap that would be used to feed them using it, instead, to grow his own. There is therefore a sharp reduction in yield in the plots concerned. In addition, a high percentage of cushion in the forage can be harmful to the animals that feed on it.
How to prevent it from reaching our land
There are many strategies to be implemented.
For the seed industry, the cuscuta has long been an almost insurmountable obstacle. It was not uncommon for the seeds to be contaminated by the very small seeds of this parasite, which contributed to its further spread and cast shadows on the seriousness of the producers. Today, various techniques have been used to remedy the problem: the most common is to mix iron filings with it.
This is inserted in the tegument of the cuscuma (more porous than that of alfalfa) allowing magnets to separate it from the “good” product: in this respect we can therefore be much quieter.
However, we must pay attention to irrigation water: it must always be clean and not come into contact with other plots of land. Let us also avoid using unsterilised soils. It is also necessary to be very careful with manure: although less rich, cattle manure is safer, thanks to the double digestion that inactivates many seeds. Even better is the pelleted one.
What if there is already?
Unfortunately, getting rid of it definitively is not easy, but one can, however, year after year, limit its spread a lot.
If you are growing in a vegetable garden or on a farm plot, you should first spray several times with an anti-gemination product. Ideally, however, you should use a total herbicide and then switch to a weed control device, stopping for a long time so that the heat does not remain only on the surface. Alternatively, or in combination, very deep ploughing by turning at least 50 cm of soil is also quite effective.
Unfortunately, the seeds are very resistant: the cold is not a problem for them and they keep a good germinability for at least 10 years: only after this period of time, leaving the plot free from crops, you can be sure that the cuscuta is completely eradicated.