30% Mancozeb SC, registered for tomato early blight, 240-320 mL/mu, spray.
In the product performance section, there are two statements that are quite rare among fungicides:
1. This product is of low toxicity, and its fungicidal mechanism is a unique multi-site action.No resistance, can be used continuously.请提供需要翻译的中文段落。
2. It is readily degradable in natural environments, which is beneficial to environmental protection.
The phrase "can be used continuously" is worth elaborating on.
I. What are multi-site modes of action?
Mancozeb is a protective fungicide belonging to the organic sulfur group. Its mode of action differs from that of most modern fungicides:
Most fungicides are single-site.— Acting on a specific enzyme or receptor of the pathogen. A single mutation at this site in the pathogen may confer resistance. This is why many fungicides become ineffective after only a few years of use.
Mancozeb is a multi-site— Simultaneously interfering with multiple sulfhydryl enzyme systems of the pathogen. For the pathogen to develop resistance, multiple gene mutations would need to occur simultaneously, which is highly improbable.
This is the origin of "no drug resistance."Strictly speaking, it is not that resistance is absolutely impossible, but rather that the probability of resistance developing is so low that it does not constitute a problem in practical agricultural production.
II. What does "continuous use" mean?
This has special value in resistance management:
When the varieties of highly effective systemic agents are limited and resistance pressure is high,Mancozeb can be used as a "buffer agent" in alternation.It can effectively reduce the application frequency of systemic agents without introducing new resistance risks.
Practical approach: Divide the application timings within a season into "protective nodes" and "curative nodes." Protective nodes are assigned to mancozeb, while systemic agents are deployed only at curative nodes. This approach is both economical and helps extend the service life of systemic agents.
III. The protective agent has only one window of action.
This is the most important point to understand when using mancozeb:
Disease infection has two stages:Surface germination(spores land on the leaf surface, germinate, form germ tubes, and penetrate the epidermis) andOrganizational expansion(Mycelium spreads between cells.)
Protectants can only act on the first stage.Once the germ tube penetrates the epidermis, protectant fungicides are no longer effective.
This is why protectants mustApply before rainfall.Rainfall is the trigger for spore release and germination; the fungicide film must cover the leaf surface before the spores arrive in order to form an effective barrier. Post-rain respraying is often too late, as infection may already have occurred.
IV. Characteristics of Tomato Early Blight
SymptomsConcentric ring-shaped lesions appear on the leaves (hence the name "ring spot"), spreading upward from the lower older leaves. Stems and fruits may also be affected.
Occurrence conditionsHigh temperature and high humidity. 25–28°C combined with high humidity leads to rapid disease development.
Sources of infectionThe pathogen overwinters in diseased plant residues and soil, and spreads via rain, wind, and irrigation water.
Key points for prevention and control请提供需要翻译的中文段落。
Start from the lower old leaves; when conducting field scouting, be sure to turn over and examine the lower leaves.
Intervene at the early stage of disease onset; do not wait until the upper leaves are also affected.
Remove lower diseased leaves to reduce inoculum sources.
V. Regulation at 240-320 mL/mu
Lower limit 240 mLPrevention-oriented, under dry weather conditions and low disease pressure.
Maximum 320 mlDuring the rainy season, the period of disease increase, and when plant density is high.
Mancozeb isSuspension concentrate (SC)Milliliter measurement is more precise and more convenient for field portioning than powder formulations.
VI. Practical Significance of "Easily Degradable in Natural Environment"
This statement is not merely an environmental slogan; it carries practical safety implications:
Mancozeb degrades relatively rapidly in soil and on plant surfaces.The residual risk is relatively low.This is important for continuously harvested vegetables (such as tomatoes) — the pre-harvest interval can be relatively short.
However, it should be noted that rapid degradation also means thatShort residual efficacy.During the rainy season, the application interval should be shortened.
7. The 10-day interval and application quality
Registration: once every 10 days.
As a protectant,Coverage quality determines control efficacy.请提供需要翻译的中文段落。
Spray evenly and thoroughly, especially on the underside of leaves (spore germination does not occur only on the upper leaf surface).
The older leaves at the lower part of the plant are the key focus (diseases typically start from the lower part).
Do not apply pesticide on windy days or when rain is expected within 1 hour.
8. Precautions for Use
Do not mix with alkaline pesticides or copper-containing formulations.
Some crops are sensitive to manganese.Some pear and persimmon cultivars are relatively sensitive to mancozeb during the young fruit stage, and fruit surface spotting may occur. Tomato is relatively tolerant, but observation is still recommended for the first application.
Preparation of pesticide solutionShake the suspension concentrate well before use. Dilute it into a mother liquor first, then add water to the required volume.
Nozzle selection: Medium droplets to avoid excessive drift.
9. Tomato: 15-day interval, 3 times per season
Pre-harvest interval: 15 days; maximum 3 applications per season.
Continuous harvesting of tomatoes means that a 15-day interval requires a 15-day pre-harvest interval after application before picking can resume — an obvious time cost during the peak fruiting period.
This is the characteristic of a "protectant."Good safety profile (low toxicity, readily degradable), but the pre-harvest interval is not short, as it needs to provide protection over a relatively long period.
3 applicationsApply one basal application before the rainy season and two maintenance applications during the rainy season.
10. Toxic to fish.
Precautions: "This product is toxic to fish. Do not allow the spray solution to contaminate water sources."
Mancozeb is toxic to aquatic organisms.Washing of application equipment in water bodies such as rivers, ponds, and ditches is prohibited.The remaining pesticide solution must not be poured into water.
This is particularly important to note for plots around rice fields and near fish ponds.
11. One week interval after copper-based fungicide application
This product must not be mixed with copper-based or strongly alkaline pesticides. If copper, mercury, or alkaline agents have been applied, an interval of one week is required before applying this product.
Copper-based fungicides are commonly used for the control of bacterial diseases in tomatoes. A one-week interval must be observed after the application of copper-based fungicides.
12. Why "Alternating Use Is Recommended"
"As a measure to delay resistance development, alternating use with pesticides of different modes of action is recommended."
This may appear to contradict "no resistance," but in fact it does not:
Mancozeb itself hardly develops resistance.
However, long-term single use willScreen out the microbial populations that are also resistant to other fungicides.(Because only highly resistant strains can survive.)
Alternating the use of different agents helps maintain the sensitivity of the microbial population to multiple pesticides.
13. Other Safety Precautions
Wear protective clothing, protective boots, a mask, and gloves.
Do not smoke, eat, or drink while spraying. After work, wash hands and exposed skin.
The packaging materials shall be incinerated or deeply buried and must not be used for other purposes.
Pregnant and lactating women must avoid contact.