Do herbicides used in orchards affect fruit trees?
Herbicides do affect fruit trees, but as long as the application method is mastered properly, the effect is not significant. Generally, before using herbicides, you can spray some limewater, Bihu (a plant growth regulator), film-forming agents, etc. onto the trees, which can effectively reduce the impact of herbicides on fruit trees.
Which herbicides do not harm fruit trees?
1. Foliage-applied herbicides
After weeds emerge, chemicals applied directly to weed stems and leaves to kill the weeds are called foliage-applied herbicides, such as glyphosate, 2,4-D butyl ester, dicamba, bentazone, etc. Foliage application means diluting the herbicide in a certain amount of water and spraying it on weed seedlings, eliminating weeds through the absorption and translocation of the chemical by the weed stems and leaves. The control effect of foliage-applied herbicides is closely related to temperature, light, and the wetting condition of the herbicide on the plant surface.
2. Soil-sealing herbicides
These involve spreading the herbicide on the soil surface or mixing it into the soil through cultivation to establish a herbicide sealing layer that kills germinating weeds. This type of herbicide can be absorbed by weed roots, coleoptiles, or the upper and lower hypocotyls to take effect. Isoproturon, acetochlor, chlorotoluron, and others all belong to this category. By application time, these herbicides can be divided into pre-sowing treatment and post-sowing pre-emergence treatment. The former refers to sealing the soil before sowing flower and nursery stock seeds, so that it can be absorbed by weed rootlets and sprouts and to prevent or reduce volatilization and photodegradation losses of the herbicide. The latter involves soil treatment after sowing but before emergence; this method is mainly used for herbicides that are easily absorbed by weed coleoptiles and young leaves and translocated upward, and is safe and harmless to the young sprouts of nursery stock.
3. Selective herbicides
Herbicides that can kill weeds without harming crops are called selective herbicides. Such herbicides sometimes can only kill one species or one category of plants among the weeds in a field, while having relatively little effect on the plants deliberately planted in the field or nursery. For example, when haloxyfop or quizalofop is applied in nurseries, it can only kill monocotyledonous weeds, mainly Alopecurus aequalis (shortawn foxtail), without harming the nursery stock. Metolachlor and quizalofop-P can be applied during the weed seedling stage; as long as the concentration is appropriate, they are relatively safe for crops such as nursery stock. Of course, the selectivity of herbicides is relative. Selective herbicides can also be used as non-selective herbicides when the dosage, application period, and application method are changed; non-selective herbicides can also be safely used during the growth period of nursery crops through “time-difference selection” and “position-difference selection.”
4. Non-selective herbicides
Non-selective herbicides, also called broad-spectrum herbicides, cause indiscriminate damage to plants, making no distinction between weeds and crops, and can kill both weeds and crops at the same time. Glyphosate, Gramoxone, Nongminle, and others all belong to this category. These herbicides are mostly used to control weeds in economic crops such as tea, mulberry, orchards, coffee, and rubber. Glyphosate and Gramoxone are broad-spectrum non-selective herbicides that can rapidly destroy green plant tissues but have no killing effect on non-green parts such as tree trunks and stems. Nongminle is a newly developed non-selective herbicide with strong efficacy and no residue, and can be applied directly to water surfaces such as ponds and lakes to control various weeds and hygrophilous weeds. It is used in various orchards, mulberry fields, tea gardens, and can also be used for weed control in industrial and mining areas, warehouses, highways, and urban and rural environmental sanitation. It can also be applied by smearing to remove non-ornamental weeds in lawns and landscape areas. Contact herbicides: After these herbicides contact plants, they are difficult to translocate within the plant or have poor mobility, and their damage is limited to the site of contact with the chemical. This localized contact-killing action is sufficient to cause weed death. Herbicides such as nitrofen, paraquat, and propanil belong to the contact type. When applying these herbicides, spraying must be uniform, and controlling perennial rhizomatous weeds requires multiple applications before they can be killed.
5. Systemic herbicides
This type of herbicide can be absorbed by plant roots, stems, leaves, coleoptiles, and other parts, and can be translocated within the plant body. Therefore, systemic herbicides are also called internally absorbed herbicides. For example, glyphosate, 2,4-D, MCPA, chlorsulfuron, and other herbicides all belong to this category. Glyphosate can control weeds because the solution is absorbed through the leaf surface and then translocated to the roots, causing the weeds to slowly die.
The above is the relevant introduction on whether herbicides affect fruit trees. We hope it is helpful to everyone.