Six Points: How To Properly And Reasonably Use Plant Growth Regulators In The Vegetable Production
Plant growth regulators should be strictly used; otherwise they easily bring losses of vegetable production. So, how to reasonably and properly use plant growth regulators in the right amount in vegetable production?
a. Preparation and use concentration must be accurate
Plant growth regulators require to be used exactly in a low concentration. Regulators with too high concentration may cause crop growth retardation, malformations, flower falling, leaves and roots growth cessation, etc. If these phenomena appear, it is useful to spray crops with a sugar solution in the concentration of 1:125 three times successively. Regulators with low concentration cannot play the due role.
b. To have a good command of processing parts and times
It should be marked to prevent reuse when using plant growth regulators. For example, red and blue ink as well as soil can be marked when the 2,4-D is formulated to prevent spraying shoots and leaves, otherwise it easily causes the deformity. Most plant hormones play roles in certain links of the plant growth, so it should strictly control processing times, which are whether too early or too late to have the desired effect. For example, Naphthylacetate used in young fruit has effect on fruit thinning, while before picking fruits can prevent preharvest fruit drop; gibberellic acid (gibberellin) used for cucumber seedlings can promote staminate flowers growth, while for young cucumber can protect flowers and fruits as well as promote growth; ethephon used in seedling stage can promote staminate flowers growth. The 2,4-D used to treat with tomatoes can play the best role in the flowering period, while has no effect on unopened flowers with green buds and on opened flowers with yellow petals. As for processing parts, they must depend on different plant growth regulators and purposes of use. For example, 2,4-D used for solanaceous plants has to smear pedicels, and PCPA can spray inflorescences. But 2,4-D used for young cucumbers has to smear their bodies except stems and other parts.
c. To control the concentration according to processing circumstances and conditions
Plant growth regulators with high concentration are generally used at low temperatures, vice versa. In addition, they are generally used on a sunny day, because they work slowly in plant body on a cloudy day so as to cause the phytotoxicity easily. If PCPA is applied to treat with tomatoes, its use concentration will vary from temperatures, with 50 milliliters per kilogram below 20°C and 25 milliliters per kilogram at 20~30°C as well as 10 milliliters per kilogram more than 30°C. It must be paid attention to the temperature change after the treatment. If temperature rises sharply after the treatment, plants will be prone to deformity and other negative phenomena. When accelerating the ripening of postharvest tomatoes, it must be ensured that the temperature is up to 20~25°C. It is important to strengthen fertilizer and water management. After treatment with growth regulators, vegetables like cucumbers often grow a great quantity of young fruits or plants accelerate growth, so fertilizer and water management has to keep up with the growth, as well as some deformity fruits should be removed.
d. Small-scale test is required
Use effects of plant hormones are affected by a variety of factors such as climate, product quality and formulation, etc. Crops and their varieties vary from regions to regions, even if the same crop with the same variety will be different for climate and soils. Therefore, before a large area treatment, it must be first taken small-scale trials to determine the appropriate hormone type, concentration, formulation to make sure of scientific and rational use.
e. To achieve an unexpected effect by mixing up with other medicaments
Sometimes, in order to solve several production problems, plant growth regulators should be mixed up to use. And plant growth regulators that are difficult to cause the phytotoxicity and unable to chemically react can be mixed up to use. In addition, whether several plant growth regulators can mix up or mix with other pesticides and fertilizers must depend on a full understanding of enhancements or resistances between mixed pesticides.
f. Be careful of the misuse
The use of hormones should be based on small-scale test results or instructions, not be used indiscriminately. Such as PCPA and 2,4-D are used to prevent flower drop and fruit drop and have a significant effect. But if they are used on pepper and sweet pepper, they will make pepper become deformed fruit and shorter or even flat.
In addition, plant growth regulators are regulating substances in the plant body, but not a substitute for fertilizer and other agricultural practices, so plant growth regulator treatment and cultivation management should be strengthened simultaneously. If you want to control the excessive growth of vegetables, you should use the regulator and simultaneously reduce the amount of water and nitrogen fertilizer as well as increase ventilation; if you want to promote vegetable flower and bear fruit, it is necessary to use regulators and simultaneously improve in the protection of ground temperature as well as reduce air humidity, etc.