Natural remedies against whiteflies
The fight against these white flies or white butterflies is not a simple thing because often we start from incorrect vegetational conditions (excessive specialization, use of inappropriate nitrates, incorrect pruning, etc.). These insects belonging to the family of aleirodidi (Aleyrodidae WESTWOOD, 1840), are responsible for damages of different entities to vegetables, fruit and citrus. These small white insects (the most common of which belong to the species Trialeurodes vaporariorum) usually lurk on the lower page of the leaves, feeding on the sap and thus debilitating the plant. This also causes yellowing, defoliation and, in case of serious attacks, until the death of the plant. Being insects that may have many generations during the year, the preventive rather than healing aspect is important, also through the preventive elimination of the eggs.
The most important preventive aspect is not to bring the plants to excessive vegetation both for irrigation in excess and for the contribution of nitrates (which in general should be banned from agricultural production). If we are dealing with trees (citrus, fruit trees, etc.) we must ensure that the interior of the foliage receives a certain brightness and, above all, the plant is always kept clean enough even with only water washes (to which you can add marseille soap); the jet is directed from the bottom to the top. Fighting with insects that parasitize (parasitoids) aleudrodids can be adopted. Among these we mention the Encarsia formosa or the Cales noacki (on which I have personally done several researches with the CNR). But this must be done in the presence of an agronomist and never in an unguided manner.
Among the natural insecticides, the macerates and the garlic-based solutions can be considered an excellent natural remedy against these infestations; but here it depends on the extent of the attack and the ability to prepare it for you (or to get it on the market).
If cultivation is in a greenhouse, the speech is more delicate. Before a new cultivation you must carefully clean the greenhouse from all vegetation and destroy all the solanaceous plants (especially the spontaneous ones) in the vicinity (these insects live mainly there).
Finally, the need to never specialize crops; this is a distortion (which has no basis of agro ecology) of modern agriculture. The more we specialize, the more we diminish the energy system of our crops: therefore, to associate, alternate rows, plants that repel insects (Nasturtium, Tansy, etc.) and fertilization only with organic substances.