One of the most important means of preventing the development of diseases and pests is to put all the necessary effort and means into ensuring the vigorous growth of vegetable plants, since weak or rickety plants are easily contaminated and constitute sources of infection that can spread to the whole crop.
On the other hand, it is necessary to apply general hygienic measures consisting of uprooting the first contaminated plants and burning them or making them disappear from the orchard, as well as the leaves and the remains left in the soil after harvesting.
Like vegetables, weeds provide a favourable environment for the development of parasites which can subsequently contaminate the cultivated plants, and it is therefore advisable to remove any weeds which may develop. Even if the plants are of good quality and vigorous and hygiene measures are respected, the danger of diseases and pests is a constant threat that, if it occurs, requires the use of chemical control. It is well understood that the regulations on the subject and the instructions given by the manufacturers of anti-parasite specialities must be scrupulously respected, especially by keeping the concentrated products in a locked cabinet, out of the reach of children and never near the food.
Great care must also be taken in the preparation and use of crop spray mixtures. Pesticides act by direct contact or after absorption by the plant, which transports them with the sap to the different organs, where they neutralize the parasite. The application of treatments by means of powders is more effective in the morning, when the vegetables are still covered with dew, which allows the best adherence of the powder on the leaves and stems. It is advisable to comply with the time limit prescribed for each insecticide product, before harvesting, to avoid the arrival of crops with excessive residues, which are harmful to health.
Certain specific products can be incorporated into the soil to destroy soil diseases or parasites. In any case, do not use more than the necessary quantities of pesticides, because here, excess is a recognized defect. The repeated and too frequent application of the same insecticide can lead to the appearance of insect breeds resistant to this product; thus, the judicious and moderate use of varied pesticide products is the best way to ensure the good health of the crops, avoiding the possibility of the appearance of resistant breeds.
In contrast to the chemical control that so few people like, there is the biological control, based on fighting a pest or a disease by means of natural predators, either by attracting them or by carrying out releases so that they manage to control the population of the pest.