Lanyi is a 50% benomyl wettable powder registered for citrus scab, applied as a 500-600 fold dilution spray.
The product performance is described in just one sentence, but three words within it merit careful scrutiny:
A systemic fungicide that possessesProtection, treatment, and eradicationand other effects.
"Protection, cure, and eradication" are the three levels of fungicide action modes; only by understanding their differences can they be applied at the right timing.
1. What are the three levels respectively?
ProtectionThe pathogen has not yet arrived, but the fungicide is applied to cover the plant surface first, preventing spore germination and invasion. It must be applied before disease onset.
TreatmentThe pathogen has already invaded the tissue, and the fungicide enters the plant to inhibit mycelial growth. Application must be made at the early stage of disease development, before the mycelium has extensively spread.
EradicateThe pathogen has already proliferated extensively on the lesions and produced spores; the fungicide suppresses it to reduce the inoculum sources for secondary infection. This typically requires a relatively high concentration and must be applied at the critical stages of disease development.
Benomyl is claimed to combine all three, which is rather uncommon among fungicides. Its foundation comes from two parts:
Benomyl technical materialSystemic, it can be absorbed by plants and then converted in vivo into carbendazim and butyl isocyanate. The butyl isocyanate among the conversion products possesses certain fumigant and eradicant activities.
CarbendazimIt interferes with the formation of the spindle during fungal mitosis—this is the mechanism by which it exerts its protective and curative effects.
II. Key Nodes for Citrus Scab Control
Citrus scab, caused by Elsinoë fawcettii, affects new shoots, young fruit, and tender leaves.
Typical symptomsLesions become suberized and raised, forming scab-like symptoms; leaves are deformed, and the fruit surface becomes rough.
Infection patternsPathogenOnly infects young and tender tissues.Once the tissue has matured (cuticle formation), the pathogen can no longer invade.
Three infection peaks请提供需要翻译的中文段落。
请提供需要翻译的中文段落内容。Spring shoot stage(Bud break to new shoot leaf expansion)
It appears that only "2." was provided, with no Chinese paragraph to translate. Please send the Chinese text you'd like translated into English.Young fruit stage(From petal fall to the early stage of fruit enlargement)
3.Autumn shoot stage
The three stages are young and tender, and highly susceptible. This is the window for control.
What does the "eradication" value of benomyl manifest in?Old lesions on diseased branches and leaves serve as the inoculum source for the next infection. Treating diseased plant residues with higher concentrations before the peak of infection to reduce the inoculum base—this is the significance of eradication.
III. Usage of 500-600 times dilution
Use a 500-fold dilution for severe disease conditions and high inoculum pressure; use a 600-fold dilution for routine prevention.
Calculated for a 30-jin (15 kg) sprayer: 30 g of pesticide for a 500-fold dilution, and 25 g for a 600-fold dilution.
Citrus trees have large canopies, and the actual water consumption should be adjusted according to tree size; the key isAccurate pesticide solution concentration.请提供需要翻译的中文段落内容。
Application siteThe registration explicitly requires that "the fruit, leaf surface, and leaf underside of citrus trees must all be sprayed."
This is particularly important in citrus: the high-humidity environment inside the canopy is a hotspot for scab and anthracnose, and spraying only the outer periphery while neglecting the inner canopy is tantamount to missing the most critical half of the control.
4. 10–15 day interval
Registration: once every 10-15 days.
Why can the spray interval for citrus be extended to 10–15 days?Because the infection window for scab is determined by the growth stages of new shoots and young fruit and is not continuous, the pathogen can no longer invade once the new shoots have matured, so continuous protection is not required during this stage.
Therefore, the 10-15 day interval is actuallyArranged according to the rhythm of shoot growth.During the new shoot emergence stage, intensive protection is applied; after the shoots mature, the application frequency is naturally reduced.
V. Resistance Reminder for Benzimidazoles
Benomyl belongs to the benzimidazole class. The resistance characteristics of this class must be clearly understood:
It exhibits cross-resistance with carbendazim and thiophanate-methyl.All three ultimately act on the same target (spindle formation) in plants. When a pathogen develops resistance to one of them, it is similarly insensitive to the other two.
Changing varieties is not crop rotation.Replacing benomyl with thiophanate-methyl does not solve the resistance problem at all.
True rotation must span across categories.请提供需要翻译的中文段落。
- Triazoles (epoxiconazole, tebuconazole)
- Strobilurin fungicides (pyraclostrobin, azoxystrobin)
- Organic sulfur protective fungicides (mancozeb, metiram)
Copper-based fungicides (copper hydroxide)
Treating the benzimidazole class (benomyl, carbendazim, thiophanate-methyl) as a single "use pool" and controlling the total number of applications from this pool within a season is the key to effective resistance management.
6. Mixing Restrictions
Do not mix with strongly alkaline pesticides or copper-containing formulations.Benomyl decomposes and loses efficacy under alkaline conditions.
Compatibility with copper-based formulations should be kept separate.Copper-based fungicides (such as copper hydroxide) are commonly used on citrus (for the control of scab and citrus canker), but they must not be tank-mixed with benomyl and should be applied separately.
Secondary dilution for pesticide preparationWettable powders should first be dissolved to form a mother liquor.
7. A noteworthy point
Benomyl is converted in plants to carbendazim and butyl isocyanate, which means thatIts actual active substance is identical to that of carbendazim.请提供需要翻译的中文段落。
From the perspective of pesticide cost: if the goal is solely to control scab, benomyl and carbendazim have similar efficacy; the "eradicant" activity of benomyl is relevant in scenarios where inoculum sources need to be suppressed (e.g., orchard sanitation, disposal of diseased plant debris), and it is not necessarily the preferred choice for routine protective applications.