What precautions should be taken when using herbicides on nursery flowers?
Using herbicides on nursery flowers requires caution. When choosing a herbicide, note that many herbicides are not suitable for use in gardens, flower nurseries and lawns. The details are as follows:
1. Post-emergence herbicides for controlling broadleaf weeds——bentazone, dicamba, fluroxypyr, chlorimuron, clopyralid, haloxyfop, MCPA and others must not be used in nurseries, gardens or dichondra lawns.
2. Post-emergence herbicides for controlling grass weeds——post-emergence herbicides for controlling grass weeds such as haloxyfop-R-methyl, fluazifop-P-butyl, quizalofop-P-ethyl, sethoxydim, clethodim, fenoxaprop-P-ethyl and others are not suitable for use on grass lawns, because while controlling grass weeds these herbicides also damage the lawn.
3. Herbicides with a long residual life——sulfonylurea herbicides such as chlorsulfuron, metsulfuron-methyl, bensulfuron-methyl, pyrazosulfuron-ethyl, chlorimuron-ethyl, tribenuron-methyl, nicosulfuron and others; imidazolinone herbicides such as imazethapyr and others; heterocyclic herbicides such as quinclorac, clomazone and others.
These herbicides have too long a residual life in the soil. In nurseries where these herbicides have been used, flower seedlings planted even 3 years later may be harmed. Metsulfuron-methyl can cause spray damage to tall fescue lawns, causing tall fescue to turn yellow and die. Clomazone can cause lawn plants to turn white.
4. Herbicides with toxic effects on the soil——some herbicides of the amide, urea and triazine classes, as well as alachlor, acetochlor, fluometuron, metribuzin, simazine, atrazine, prometryn, monuron and others.
If these herbicides are applied to a lawn, then under waterlogged conditions they affect the root system of the lawn plants, which in turn affects the development of the lawn plants; where they are applied continuously, they cause the soil structure to deteriorate and become compacted, affecting the aeration of the soil around the roots of the lawn plants and thereby causing the lawn plants to turn yellow.
5. Highly toxic or carcinogenic herbicides——sodium pentachlorophenate and paraquat are highly toxic and are absolutely prohibited in nurseries and lawns. Nitrofen has been banned in many countries because of its carcinogenicity, and our country has banned it since 2000. Lasso (alachlor) has carcinogenic effects on animals and is also unsuitable for use. Trifluralin has been banned in Europe because of its carcinogenicity.
6. Herbicides with drift contamination——dicamba, molinate and others have relatively serious drift contamination problems. Generally there are flowers and seedlings around a lawn, and spraying drift-prone herbicides such as dicamba and molinate on the lawn will affect the growth of the surrounding flowers and seedlings.
7. Herbicides with an unpleasant odour——for example, the odour of MCPA is irritating to people, and after inhalation it affects people's stomachs and also causes phytotoxicity to seedlings, so it is unsuitable for use.
8. Non-selective herbicides——such as glyphosate (Roundup), paraquat (Gramoxone) and others. Although some seedlings have a certain tolerance to low doses of glyphosate, sometimes the damage glyphosate causes to seedlings is difficult to judge clearly by visual inspection, and sometimes this damage is slow, and in addition drift is unavoidable when spraying glyphosate, which will cause damage to surrounding sensitive flowers and seedlings.
In short, when choosing a herbicide, in addition to considering the prevention of direct damage to flowers, seedlings and lawns, it is also necessary to prevent some potential, possible and hidden damage, so as not to cause irreparable damage to the yield and quality of flowers, seedlings and lawns and to the surrounding environment. When using them, attention should be paid to selecting, according to different needs, varieties and periods, herbicides with a broad weed-killing spectrum, a moderate effective period, a good eradication effect and no pollution.