Analysis on the phytotoxicity symptoms appeared on 11 kinds of commonly used plant growth regulators
Phytotoxicity symptoms will vary in different kinds of plant growth regulators products. Below are the methods from pesticide manufacturer to distinguish the phytotoxicity symptoms appeared on the commonly used plant growth regulators.
Phytotoxicity symptoms of paclobutrazol: plant will dwarf, root tuber and tuber will become small and deformed, leaves will become curl, old leaves in the stem base will fall off ahead of time as well as young leaves will shrivel. Regarding cottons, in which the plant will seriously dwarf, fruit branches cannot stretch, leaves will become deformed, redundant vegetative shoots will cluster as well as the buds and bolls will shed. Peanut, of which the blade and fruit will become small, the plant growth will be inhibited and plant will have premature senility. As the pesticide effect of paclobutrazol will last for a long time, it will also have phytotoxicity on the next stubble crops which will have the phytotoxicity symptoms such as no emergence, late emergence, low emergence rate, deformed seedling and so on.
Phytotoxicity symptoms of mepiquat chloride: blade will become small and thick, internode will become dense, redundant vegetative shoots will cluster and plant will grow unevenly, thus a large number of buds and bolls will fall off, besides, cotton will become mature late in the late growing period of cotton. Mepiquat chloride will have little phytotoxicity on gramineae plants, of which the dose range is rather wide. Besides, it will not have phytotoxicity on the next stubble plants.
Phytotoxicity symptoms of compound sodium nitrophenolate: when the phytotoxicity is slight, the plant growth will be inhibited and the development of young fruit will be retarded; when the phytotoxicity is severe, plant will wilt, yellowing and die eventually. Compound sodium nitrophenolate is less likely to have phytotoxicity which often occurs on peach tree, watermelon and other sensitive crops and can lead to blossom drop, fruit drop, hollow fruit and other phenomenon.
Phytotoxicity symptoms of ethephon: when the phytotoxicity is slight, the top of plant will wilt, leaves, flowers and young fruits of the lower part of plant will gradually yellowing and drop, besides, the residual fruits will become mature ahead of time. When the phytotoxicity is severe, the whole plant leaves will become yellow and drop rapidly, fruits will become mature and drop rapidly, which will lead to the death of whole plant. According to the reports of Chinese Pesticide Net, the excessive using or improper using of ethephon can both lead to phytotoxicity. However, ethephon will not have phytotoxicity on the next stubble plants.
Phytotoxicity symptoms of 1-naphthylacetic acid: when the phytotoxicity is slight, it will defoliate the flowers and young fruit, but it has little effect on the plant growth. When the phytotoxicity is severe, blade will wilt, petiole will flip, blade will drop, and eventually the fruit will become mature rapidly and drop. Regarding the phytotoxicity occurred in the seeds soaking process, of which the slight effect reflects in the small root quantity and deformed root, while the severe effect will lead to no rooting and no emergence. Most of 1-naphthylacetic acid will not have phytotoxicity on the next stubble plants except for part of them.
Phytotoxicity symptoms of DA-6 (diethyl aminoethyl hexanoate): spots will appear on the blades and gradually expand from light yellow to dark brown and eventually becomes transparent. Currently the phytotoxicity of DA-6 (diethyl aminoethyl hexanoate) has not been found in other crops except for the peach trees.
Phytotoxicity symptoms of triacontanol: when triacontanol is used excessively or has low purity, which will lead to bend sheath in the seedling stage and deformed root, while used on the mature plants, the young leaves will become curl.
Phytotoxicity symptoms of brassinolide: overgrowth of plant, small fruit quantity and form mummified fruits in the late growing period.
Phytotoxicity symptoms of gibberellin: fruits will become stiff and crack, ripe fruits will taste bitter, and plants will become mature late.
Phytotoxicity symptoms of chlormequat chloride: plants will dwarf seriously, fruit branches cannot stretch, blade will become deformed, redundant vegetative shoots will cluster, internode distance will shorten, branches and leaves will become friable and easy to broken. Phytotoxicity of seeds soaking, in which the root will become bend, growth of young leaves will be seriously inhibited, the emergence will be postponed in 7 days and will appear to be distorted deformity after emerging. Chlormequat chloride will easily have phytotoxicity on dicotyledon, but will not on monocotyledon. Besides, it will not have phytotoxicity on the next stubble crops.
Phytotoxicity symptoms of 2,4-D: when the phytotoxicity is slight, the petiole will become soft and bend, blade will become sag, leaves at the top of plants will turnup, blade will become deformed, fruits will become deformed, ripe fruits will be changed into hollow fruits and dehiscent fruits. When the phytotoxicity is severe, most of the blade will become sag, the leaves will seriously turnup and become deformed and shrink, plant growth point will shrink and become necrotizing, thus the whole plant will gradually wilt and die. Therefore, if 2,4-D is used improperly, it will kill the plants like herbicide. It will have severe phytotoxicity on dicotyledon and light phytotoxicity on monocotyledon.
Above are the phytotoxicity symptoms appeared on commonly used growth regulators in plants, which should be found and remedied in time so as to avoid the economic losses that caused by it.