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Residual amounts of diamide insecticides in Belarusian crop production

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Residual amounts of diamide insecticides in Belarusian crop production

How diamides work and why they are replacing former insecticides

Pest control is complicated by the fact that pests quickly adapt to traditional preparations. Insecticides from the diamide group solve this problem thanks to a completely different mechanism of action. According to the IRAC classification, they belong to group 28 — modulators of insect ryanodine receptors. Today, diamides are among the top five best-selling insecticides in the world, actively displacing outdated and toxic organophosphorus compounds and carbamates.

In the Republic of Belarus, three active ingredients from this group are registered: chlorantraniliprole, tetraniliprole, and cyantraniliprole. Preparations based on chlorantraniliprole are effective against the Colorado potato beetle, European corn borer, diamondback moth and cabbage moth, small white butterfly, codling moth, and leafroller. Tetraniliprole protects winter and spring rapeseed from the cabbage seed weevil, cabbage stem weevil, brassica pod midge, and diamondback moth, and corn and cabbage from the European corn borer, western corn rootworm, diamondback moth, and cabbage moth.

  • Efficacy against Lepidoptera — up to 100%
  • Protective action period — up to 28 days
  • Water solubility of cyantraniliprole — 14.2 mg/L
  • Water solubility of chlorantraniliprole — 0.88 mg/L

Pay attention to the application method: cyantraniliprole is registered in Belarus for thrips control strictly for root application via drip irrigation.

Product safety: results of residual amount analyses

In experiments to study biological efficacy, specialists verified the safety of the harvested potato, corn, white cabbage, winter rapeseed, apple crops, as well as greenhouse tomatoes and cucumbers (grown on mineral wool). Sampling was carried out according to GOST 34668-2020 within the timeframes stipulated by state registration rules. The analysis was performed using liquid chromatography on a Hewlett Packard 1100 instrument with a diode-array detector, using analytical standards with a purity of more than 95%.

The main result of the analyses: in none of the samples were residual amounts of active ingredients detected. This confirms that when application regulations are followed, preparations of this group are safe for the consumer. All indicators fall within hygienic standards, and the sensitivity limit of the instruments in many cases proved to be significantly lower than the maximum residue limits (MRL).

For crops where domestic MRL standards have not yet been established in Belarus and Russia (for example, for rapeseed), safety was assessed according to the international standards of the Codex Alimentarius.

Active ingredient Crop and produce Analysis time after application, days Substance recovery during analysis, % Residue content and standards (MRL)
Chlorantraniliprole Potato (tubers) 20 and 39 (with double application at 12 g/ha);
30 (with single application)		 73.0–79.2 Not detected. Lower limit of determination is significantly below MRL.
Corn (green mass, grain, oil) 60 (with single application) 78.2–97.0 Not detected. Limit of determination is at or below MRL level.
White cabbage (heads) — 71.7–95.4 Not detected. Lower limit of determination is significantly below MRL.
Winter rapeseed (seed, oil, straw) 60 above 80.0 Not detected. Limit of determination is no higher than 0.064 mg/kg. MRL in RB and RF not established. MRL according to Codex Alimentarius: seed — 2.0 mg/kg, straw — 30 mg/kg.
Apple (apples) 20 (with double application) 97.7–104.0 Not detected. Limit of determination is below MRL.
Tetraniliprole Corn (green mass, grain) 60 above 80.0 Not detected. Limit of determination: 0.008–0.080 mg/kg (for green mass — 0.212–0.470 mg/kg). MRL not established.
Rapeseed (seed, oil, straw) 20 above 80.0 Not detected. Limit of determination: 0.008–0.080 mg/kg (for straw — 0.212–0.470 mg/kg). MRL not established.
White cabbage (heads) 20 above 80.0 Not detected. Limit of determination: 0.008–0.080 mg/kg.

Decomposition of chlorantraniliprole and tetraniliprole in field crops

Tests show that insecticides from the diamide group do not accumulate in open-ground produce by the time of harvesting. Active ingredients chlorantraniliprole and tetraniliprole decompose completely in plants during the growing season. Based on data on their decomposition dynamics, safe pre-harvest intervals have been determined for each crop, which are included in the application regulations for the preparations.

  • Maximum application rate of chlorantraniliprole — 12–60 g a.i./ha
  • Maximum application rate of tetraniliprole — 50 g a.i./ha
  • Maximum application rate of cyantraniliprole — 100 g a.i./ha
  • Completeness of diamide recovery during analysis — 71.7–104.0 %

When analyzing samples of potatoes, corn, cabbage, rapeseed, and apples, residual amounts of chlorantraniliprole were not detected in any of the experiment variants. The completeness of recovery of this substance from plant matrices ranged from 71.7 to 104.0%, and the lower limits of its quantitative determination correspond to established hygienic standards. This confirms the accuracy of the analyses and guarantees the purity of the harvested harvest.

Tetraniliprole also showed complete safety when treating corn, rapeseed, and cabbage. No traces of the insecticide were detected in grain, green mass, seeds, or oil. The extraction efficiency of tetraniliprole from plant samples ranged from 80.6% to 93.9%, and its lower limit of quantification is significantly below the permissible thresholds.

Detailed results of the monitoring of residual amounts of active ingredients of diamide insecticides in samples of plant products are presented in the table:

Active ingredient (AI) Crop Maximum application rate, g a.i./ha Number of applications Days after treatment Analyzed sample Extraction, % LOQ, mg/kg MRL, mg/kg Result, mg/kg
Chlorantraniliprole Potato 12 1 30 tubers 73.0 0.043 1.0 not detected
2 20 tubers 78.8 0.024 1.0 not detected
2 39 tubers 79.2 0.024 1.0 not detected
Corn 40 1 60 green mass 86.0 0.060 not regulated not detected
1 60 green mass 78.2 0.075 not regulated not detected
1 60 grain 81.6 0.010 0.02 not detected
1 60 grain 97.0 0.020 0.02 not detected
1 60 oil 90.2 0.016 not established not detected
Cabbage 40 2 30 heads 71.7 0.049 20.0 not detected
2 60 heads 72.4 0.058 20.0 not detected
2 63 heads 95.4 0.011 20.0 not detected
Rapeseed 40 2 60 seeds 87.8 0.064 not established not detected
2 60 oil 86.9 0.064 not established not detected
2 60 straw 81.4 0.062 not regulated not detected
Apple 60 2 20 apples 104.0 0.005 0.5 not detected
2 20 apples 97.7 0.005 0.5 not detected
Tetraniliprole Corn 50 1 60 grain 80.6 0.008 not established not detected
1 60 green mass 81.0 0.470 not established not detected
Rapeseed 50 2 20 seeds 91.9 0.076 not established not detected
2 20 oil 92.4 0.071 not established not detected
2 20 straw 93.9 0.212 not regulated not detected
Cabbage 50 2 20 heads 84.4 0.080 not established not detected
Cyantraniliprole Cucumber (protected soil) 100 4 1 cucumbers 76.0 0.009 not established not detected
4 3 cucumbers 76.0 0.009 not established 0.023
4 5 cucumbers 75.7 0.009 not established 0.014
Tomato (protected soil) 100 4 1 tomatoes 95.7 0.040 not established not detected
4 3 tomatoes 95.0 0.040 not established not detected
4 5 tomatoes 95.0 0.040 not established not detected

All tested diamides demonstrated high environmental safety: by the time of harvesting the crop">harvesting field crops, their residues disappear completely from the produce.

Behavior of cyantraniliprole in protected soil

Under greenhouse conditions, the behavior of insecticides has its own specifics. With four-fold root application of cyantraniliprole through a drip irrigation system at an application rate of 100 g a.i./ha, the dynamics of its content in cucumbers and tomatoes differs significantly. In tomatoes grown in protected soil, the active ingredient was completely absent throughout the observation period — from the first to the fifth day after treatments.

In cucumbers grown in protected soil, the preparation was also not detected on the first day after irrigation. However, on the third day, its concentration was 0.023 mg/kg, and on the fifth day, it decreased to 0.014 mg/kg. Such temporary accumulation is explained by the fact that the active ingredient gradually moves from the root zone to the above-ground organs of the plant.

The extraction efficiency of cyantraniliprole from cucumber and tomato fruits during laboratory analysis was 75.7–95.7%. The developed control methodology reliably detects even micro-amounts of the substance, since its lower limit of quantification (LOQ) lies significantly below the maximum permissible thresholds of its content.

In the Republic of Belarus, the hygienic standard (MRL) for cyantraniliprole in cucumbers and tomatoes is not officially established. When growing greenhouse vegetables, follow the requirements of SanPiN 1.2.3685-21: the maximum permissible level for cucumbers is 0.3 mg/kg, for tomatoes — 0.1 mg/kg. The residual amounts recorded in the experiments in cucumbers (maximum 0.023 mg/kg) are well within these standards.

On amendments and additions to the Resolution of the Ministry of Agriculture and Food of the Republic of Belarus of August 22, 2006, No. 49 [Electronic resource]: Resolution of the Ministry of Agriculture and Food of the Republic of Belarus, November 16, 2016, No. 32 // Pravo.by. – Access mode: https://pravo.by/document/?guid=12551&p0=W21731795 – Access date: 11.03.2024.

Handbook of Pesticides and Agrochemicals [Electronic resource] // Agro XXI. – Access mode: https://www.agroxxi.ru/goshandbook/wiki/active_substance_pesticides/pesticides. – Access date: 11.03.2024.

E. A. Myshkevich, S. A. Arashkovich, M. P. Loseva RUE «Institute of Plant Protection», Priluki, Minsk region

RESULTS OF TESTS OF THE CONTENT OF

RESIDUAL AMOUNTS OF ACTIVE SUBSTANCES

OF MODERN INSECTICIDES OF THE DIAMIDE

GROUP IN AGRICULTURAL PRODUCTS IN THE

CONDITIONS OF THE REPUBLIC OF BELARUS

Annotation. The behavior of the active substances of insecticides of the diamide group: chloranthraniliprole, tetraniliprole and cyantraniliprole used in protection against harmful objects of various crops has been studied. The active substances chloranthraniliprole and tetraniliprole were not detected in any of the samples studied for 2020–2022. Cyantraniliprole was detected in cucumber fruits on days 3 and 5 after four times treatment in the amount of 0.023 mg/kg and 0.014 mg/kg respectively, which is below the maximum permissible level – 0.03 mg/kg. If the application standards and waiting times are observed, agricultural products are not contaminated with residual amounts of the active substances studied.

Key words: residual amounts, chloranthraniliprol, tetaniprol, cyanthraniliprol.

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