parte 1 82 Difesa: colture erbacee in pieno campo Perfecting your English FOCUS ON - Herbaceous crops in open fields Despite the fact they belong to different species and orders, herbaceous crops in open fields show some common features in the plant disease management which are strictly linked to the geopedological and agro-meteorological knowledge and to the farming practices employed. The farming practices, in association with the agronomic, genetic, chemical and microbiological defense strategies, can guarantee quality production and environmental conservation. A few simple prophylactic measures are basic operating procedures and really effective against some pathogens infesting any kind of soil. They are the seed treatment, a wise choice of crop rotation, the rejection of sod-seeding and green manure (in the presence of strong infections), the removal and burning of infected residues. Such procedures apply independently of the phyto-pathological tests on the crop examined. According to the final usage of the different produce, the extensive herbaceous crops are divided into plants grown for food and plants grown for industrial and processing purposes. Cereals belong to the first group: crops which have always been staple food in the human diet and they still play a primary role in many peoples nutrition. Wheat, rice and maize are the most widely grown. Wheat is mainly widespread in Europe, rice in Asia and maize in America. Several adversities (viroses, pathogens, pests) have developed over time evolving with the crop little by little, while farming practices were turning increasingly intensive. Nowadays, risks, both for humans and animals, derived from the potential danger of food contami- nation caused by toxins of fungal derivation (ochratoxins, aflatoxins, fumonisins, ergosterols) can be avoided by employing suitable farming practices together with a rational use of agrochemicals. Industrial crops belong to different botanical species, but they are classified according to their usage and industrial processing of the main product. Therefore we have oil producing plants (soyabean, sunflower, rape), sacchariferous plants (sugarbeet), textile fibers plants (cotton, hemp, flax), biomass and fodder plants. The crops aiming at obtaining natural fibers (not so widespread in Italy if not for research purposes) are meeting increasing interest among the no-food or not-onlyfood produce. Today, in Italy, tobacco, fodder and meadow plants on the one hand, aromatic and medicinal plants on the other, are increasingly relevant respectively for the invested land surface and for the specific properties. As far as pest management is concerned, pesticides are applied in open fields more frequently with industrial crops . Protection against adversities is basic and irreplaceable for these crops (e.g. the seed treatment) in order to preserve the quantitative and qualitative integrity of the produce (quantity: e.g. rhizomania for the beet; quality: fiber integrity for the textile plants). Pesticides application with fodder plants may be considered an unusual practice. On the other hand, with medicinal plants the application of suitable farming practices (sometimes integrated by copper and sulphur treatments and insecticides spread on the soil) is usually enough to guarantee a good output. 1. Operative sheet - The seed treatment The seed treatment is a process which is regarded today as a highly qualified, rational and evolving procedure among the farming practices, being an alternative means to the use of phytochemicals to protect crops against pests in the open fields. In the past pesticides used to be spread over the whole crop in the fields; afterwards, with the advent of soil pesticides, phytochemicals were distributed over the ground along the seed rows. Finally, today the seed treatment further reduces the soil surface in contact with the chemical substance. This technique consists in an even, precise and localized application over the seed of specific products against fungal diseases and pests, with possible addition of nutritional elements suited to improve the plantlet germination and growth. The main advantages of seed treatment are: Protection of the crop in the early stages of development; Reduction of active substances spread over the ground; Targeted application of phytochemicals; Simpler operations in the elds compared to the treatments with micro-granulates or with additional spreading tools. This allows to preserve the seed value to the advantage of the crop productivity and quality.
Difesa delle colture