The use of chemicals during plant vegetation
In addition to the previously mentioned protection methods, mainly consisting in the prevention of the development of diseases and pests, the use of chemicals during plant growth is of great importance. Among the treatments associated with it, we will most often deal with dusting, spraying, aerosolization and gassing.
Pollination, i.e.. sprinkling very fine, with a dry preparation, is a very easy and quick procedure. The technique of its carrying out is thoroughly discussed in textbooks of vegetable and horticulture.
Spraying was also discussed during lectures on vegetable and horticulture. As a reminder, here are some, that in the case of spraying plants with leaves covered with a waxy coating (among the ornamental ones they will be. in. palm trees, cloves, tulips) an agent should be added to the liquid to make it settle better on the plants, e.g. gray soap in the amount 1 kg in 100 1 liquid or a special preparation Netzmittel-Wolfen.
Dusting and spraying are used both in greenhouse cultivation, and the ground. Preparations for spraying or dusting are given in the descriptions of individual diseases and pests.
Aerosolization is a procedure similar to spraying, from which it differs in this, that the droplets of the solution are much finer; the splashed liquid turns into a mist. For this treatment you need special devices - aerosol generators. Currently, preparations are produced in special metal containers, self-atomising when pressing the appropriate canister device.
The "Greenhouse Spray" preparation for pest control is available on the market.
Gassing is of great use when grown in greenhouses. It is relatively easy to make, effective, harmless to plants and inexpensive.
A treatment that has been used for a long time, especially when combating powdery mildew, is the so-called. gassing with sulfur vapor. For this purpose, the sulfur in powder or in pieces is heated to a temperature above 460 degrees C. At such a temperature, sulfur turns into dense steam and settles on plants, killing pathogenic fungi. The sulfur is heated in special apparatuses called sulfurators; the sulfurator consists of a charcoal firebox and a sulfur tank placed on top of it. Electric sulfurators are even easier to handle. On 1 m2 of the room is consumed from 0,5 do 0,75 g of sulfur.
When combating many pests (m. in. aphids and whitefly) Cyanofum gas is used. For this purpose, on dry greenhouse pavements, cyanofum is spread on paper supports, using - depending on, pest species - from 20 do 60 g preparation on 100 m3 of the room. The calcium cyanide contained in the preparation decomposes in the presence of water vapor in the air, emitting a highly poisonous gas - hydrogen cyanide. So that the decomposition does not happen too quickly, on 24 hours before gassing, watering and spraying of plants is stopped, and covers the water tanks. The temperature in the room should not be lower than 13 ° or higher than 22 °, as the plants could be damaged. Gassing should be carried out at night, leaving Cyanofum for 8-10 hours (when growing young or particularly delicate plants - for 4-5 hours). After this time, the remnants of the preparation should be removed, and the greenhouses should be thoroughly ventilated. By 5 hours after gassing, the plants must not be watered, in the case of strong sunlight, the greenhouse must be shaded. Because the hydrogen cyanide released from the preparation is highly poisonous to humans, the preparation must be disassembled in a mask and protective clothing, and after unfolding, leave the greenhouse immediately. Before entering the greenhouse to ventilate it, also wear a mask and protective clothing.