The occurrence and prevention of strawberry plant growth regulator phytotoxicity
In strawberry protected cultivation, by spraying excessive gibberellin, it may lead to the excessive growth of stipe especially scape, thus flowers and fruits will become small as well as it will seriously impact output. By spraying excessive triazole pesticides, such as paclobutrazol, plants will dwarf.
Gibberellin can promote plant cell division and elongation. However, if the concentration is too high or it is used too much, it will lead to plant flourish. Besides, the stipe and peduncle will become long as well as most of nutrition will be used in plant elongation growth, thus it will limit the growth of fruit, will lead to long ears and small fruits as well as will seriously reduce output.
Ethephon is a kind of plant growth regulator that can promote ripening, can adjust plant growth, development, metabolism and other physiological functions, can promote fruit ripening, leaf drop and fruit drop as well as can dwarf plant. Ethephon is easy to absorb by plant, which will gradually release ethene in plant body, will increase the peroxidase activity of plant and will reduce apical dominance. However, if it is used too much or too early, it will reduce fruit output, will inhibit plant growth and plant will become withered.
Paclobutrazol is a kind of temporary plant growth retardant, which can inhibit the synthesis of gibberellin in plant body, can control stalk elongation, can inhibit terminal bud growth, can promote lateral bud germination and the formation of flower bud, can increase alabastrum number, can improve fruit setting rate as well as can improve fruit quality and cold resistance. However, when the concentration is higher than 500mg/l, it will dwarf plant and will reduce output due to the strong inhibiting effect.
As swelling agent has fast stimulation, the growth speed and elongation speed of young fruit pulp cell will become fast as well as the expansion speed will exceed growth speed, thus it will lead to void fruit and malformed fruit.
The prevention methods of strawberry plant growth regulator phytotoxicity are as follows: strictly control the use age, use concentration, dosage and use frequency of plant growth regulator. As gibberellin powder is insoluble in water, it should be dissolved with a small amount of 95 percent of ethanol solution and should be diluted with water before using. Besides, as the water solution is easy to lose effect, it should be prepared and used at the same time. It should not be mixed with alkaline pesticide or fertilizer. Regarding ethephon, it should be sprayed on fruit under the concentration of 1000ml/l when the fruit is about to become mature. Besides, it also should not be mixed with alkaline pesticide. In order to prevent strawberry stolon, 250mg/l paclobutrazol can be sprayed twice respectively in the mid third of June and the first third of July, but the concentration should not exceed 500mg/l. For the concentration of swelling agent, it should be well controlled so as to avoid overspeed fruit expansion and fruit cracking.