Metabolic fate of mancozeb in tomato (Lycopersicon esculentum)

The metabolic fate of mancozeb in tomato (Lycopersicon esculentum Mill.) fruits was evaluated. Results indicate rapid dissipation of mancozeb and its metabolic conversion to ethylenethiourea (ETU), the carcinogenic metabolite. Treatment with mancozeb at flowering stage resulted translocation of ETU in newly emerged fruits indicating the systemic nature of ETU. ETU was detected within one hour of final spraying of mancozeb at the doses of 1.5 and 3?kg a.i./ha. The residue level of ETU increased up to 3-day for both the treatments, which then rapidly dissipated to safer metabolite ethyleneurea (EU) and reached the below detectable limit within 25 days. Cooking of fresh tomatoes caused decontamination of mancozeb residues, which was associated with simultaneous increase in ETU residues. The degradation pattern of ETU after application of mancozeb was slower as compared to the spraying of ETU as such on the crop. A pre-harvest interval of 25 days is recommended.     

Persistence of chlorpyriphos in okra (Abelmoschus Esculentus) fruits and soil

Persistence of cypermethrin and chlorpyriphos in okra and soil were studied following the application of pre-mix formulation of insecticides Action 505EC (chlorpyriphos 50%?+?cypermethrin 5%) at single (275?g a.i.?ha^?1) and double dose (550?g a.i.?ha^?1). The average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg^?1 in single and double dose, respectively, which dissipated to 92% after 10 days for both the dosages. Residues of soil under okra crop were found to be 0.15?mg?kg^?1 at the single and 0.36?mg?kg^?1 at the double doses. These residues persisted up to 3 days at single and 5 days at double dose. The half-life (t _1/2) periods of chlorpyriphos on okra and soil were observed to be 0.6 days and 1.9 days for single and double dose, respectively. Residues of chlorpyriphos reached below detectable level (BDL) of 0.01?mg?kg^?1 in okra fruits after 7 days at single dose and in 15 days in double dose. In soil, residues of chlopyriphos persisted up to 5 and 7 days in single and double dose, respectively. Following foliar applications of a insecticide formulation (Action 505EC, (chlorpyriphos 50%?+?cypermethrin 5%) on okra at @ 275 and 550?g active ingredient (a.i.)?ha^?1 resulting in active applications of chlorpyriphos at the rate of 250 and 500?g a.i.?ha^?1 the average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg^?1, respectively. These residue levels dissipated to 92% after 10 days at both the dosages. Residues of soil under the okra crop were found to be 15?mg?kg^?1 at the single and 36?mg?kg^?1 at the double dose. The residues persisted up to 3 days at the single and 5 days at the double dose. The half-life (t _1/2) periods of chlorpyriphos on okra were observed to be 0.6 days for application rates, and 1.9 days for soil. Okra fruits and soil samples collected on the 7th and 15th day after application did not show any chlorpyriphos residues above their determination limits of 0.01 and 0.005?mg?kg^?1, respectively.     

Effect of commercial pesticides on plant growth-promoting activities of Burkholderia sp. strain L2 isolated from rhizosphere of Lycopersicon esculentum cultivated in agricultural soil

The in vitro study was carried out to examine the toxicity of four commercially used pesticides (phorate, mancozeb, chlorpyrifos, and endosulfan) at the recommended dose (1X) and higher field doses (1.5X, 2X, 2.5X, and 3X) on plant growth-promoting activities of Burkholderia sp. strain L2, isolated from pesticide-treated rhizosphere of Lycopersicon esculentum. At the recommended dose, level of toxicity of all the pesticides to phosphate solubilization activity and indole-3-acetic acid (IAA) production was less detrimental as compared to exceeding doses. At maximum dose rate of each pesticide, the percentage decrease in phosphate solubilization and IAA production over control was found in order of chlorpyrifos < mancozeb < endosulfan < phorate. Present study proves that Burkholderia sp. strain L2 could be used as a potential microbial inoculant in the agricultural soil having persistent pesticide residues.     

Validation of QuEChERS-based method for determination of flusilazole residues in grape by high-performance liquid chromatography with photodiode array detector

A high-performance liquid chromatography with photodiode array detector analytical method was developed to determine the residue levels of flusilazole in grape and investigate the dissipation pattern and safety. The results showed that the mean recoveries were in the range of 86%–90%. Limits of detection and quantification were 0.008 and 0.02 mg/kg, respectively. The residue levels of flusilazole were best described by first-order rate kinetics and with half-lives ranging from 4.2 days (recommended dose) to 4.6 days (double the recommended dose). In conclusion, flusilazole at the recommended or even at double the recommended doses does not pose any apparent hazards to consumers.     

Dislodgeable residues of profenofos on jasmine and risk assessment of post application exposure to flower bud pickers

A field study was conducted to measure the dislodgeable residues of profenofos applied to jasmine (Jasminum sambac) and risk assessment was done for laborers engaged in picking of flower buds. Profenofos was applied at 0.10, 0.15, and 0.20% concentration and the jasmine bud samples were analysed for residues using GC. The initial deposit of 1.6–3.8, 3.8–7.1, and 5.2–7.6 µg cm^?2 was detected on jasmine buds at 0.10, 0.15, and 0.20% concentration, respectively. At the recommended dose of 0.10%, the half-life was 1–2 days and the dislodgeable residues disappeared within 7 days. The results indicate faster disappearance of dislodgeable residues on jasmine buds. Risk assessment was done based on dislodgeable foliar residues and exposure estimates based on surrogate data and expressed as Margin of Exposure (MOE). The entry restrictions for exposure of jasmine flower pickers to profenofos, would be at least, 1 day following application, for the recommended concentration of 0.10% (MOE = 106) and 3 days, at higher concentrations of 0.15% (MOE = 156) and 0.20% (MOE = 115).     

Effect of insecticides alone and in combination with fungicides on nitrification and phosphatase activity in two groundnut (Arachis hypogeae L.) soils

The effect of selected pesticides, monocrotophos, chlorpyrifos alone and in combination with mancozeb and carbendazim, respectively, was tested on nitrification and phosphatase activity in two groundnut (Arachis hypogeae L.) soils. The oxidation of ammonical nitrogen was significantly enhanced under the impact of selected pesticides alone and in combinations at 2.5 kg ha⁻¹ in black soil, and furthermore, increase in concentration of pesticides decreased the rate of nitrification, whereas in the case of red soil, the nitrification was increased up to 5.0 kg ha⁻¹ after 4 weeks, and then decline phase was started gradually from 6 to 8 weeks of incubation. The activity of phosphatase was increased in soils, which received the monocrotophos alone and in combination with mancozeb up to 2.5 and 5.0 kg ha⁻¹, whereas the application of chlorpyrifos singly and in combination with carbendazim at 2.5 kg ha⁻¹ profoundly increased the phosphatase activity after 20 days of incubation, in both soils. But higher concentrations of pesticides were either innocuous or inhibitory to the phosphatase activity.     

Phytotoxicity of copper fungicides to guava fruits

The copper fungicides viz., Bordeaux mixture, stabilized Bordeaux mixture and copper oxychloride were found phytotoxic to guava fruits, while carbendazim, benomyl and mancozeb were non-phytotoxic. Bordeaux mixture was highly phytotoxic and caused heavy russetting, followed by stabilized Bordeaux mixture and then copper oxychloride. The higher concentrations of these fungicides were more toxic than their lower doses. Russetted fruits failed to attain normal size and thus reduced the quality of fruits to a greater extent.     

Testicular damage after chronic exposure to carbendazim in male goats

The present investigation was aimed to determine the effect of chronic exposure of carbendazim on cellular changes in testes of male goats. The goats were randomly divided into two groups, control and treatment (N?=?7 each). The treatment group was exposed to carbendazim at the dose rate of 50?mg?kg^?1 body weight per day orally, once daily for 180 consecutive days. Testes were removed from control and experimental animals surgically on the 90th, 120th, and 180th day. On the 180th day of the treatment, a maximum number of seminiferous tubules became atrophic, and vacuolization of germinal epithelium, and sloughing of the germinal epithelium and sertoli cells was more marked as compared to days 90 and 120. Some of the seminiferous tubules were devoid of germinal cells. These pathological findings were supported by ultrathin and electron microscopic examination. On the basis of the present investigation it could be concluded that chronic exposure of carbendazim in male goats did not allow proper maturation of testis.     

氰戊菊酯对小白菜抗氧化酶活性及丙二醛（MDA）含量的影响

为探讨菊酯类农药胁迫对蔬菜生理生化过程的影响,以小白菜为研究对象,采用大田试验研究了不同浓度氰戊菊酯(20%乳油,推荐用量:稀释1500倍;加倍用量:稀释750倍)对小白菜抗氧化酶活性及丙二醛(MDA)含量的影响.结果表明:喷施推荐用量及喷施加倍用量氰戊菊酯对小白菜抗氧化酶活性均有不同程度的影响.超氧化物歧化酶(SOD)活性在喷施氰戊菊酯后3d内明显受到抑制,之后明显增加,第21d又受到抑制;过氧化氢酶(CAT)活性在喷药后小幅增加,第21d与对照基本一致;过氧化物酶(POD)活性在喷药后明显受到抑制.喷施推荐用量及喷施加倍用量氰戊菊酯均可引起小白菜MDA含量显著增加,且喷药浓度越高MDA含量越大,存在一定的剂量效应关系,表明氰戊菊酯胁迫促进了小白菜的膜脂过氧化作用.氰戊菊酯可对小白菜产生一定的氧化损伤,导致SOD、CAT、POD活性发生不同程度的变化.氰戊菊酯胁迫对SOD和POD活性以及MDA含量的影响相对较大,其中对MDA的影响最大,MDA含量可作为植物受到氰戊菊酯胁迫时的标记物.     

Measurement of residues of benomyl and mancozeb pesticides in shrub and nonshrub cucumbers sampled from different regions of Mazandaran province (Iran)

Farmers use mancozeb against cucumber pests, such as Perono spoxa, in large amounts without consideration of potential chronic human health hazards resulting from pesticide accumulation in food and fruits. Considering the necessity of food for humans and importance of fruit in daily diet, as well as the determination of pesticide residues in food and fruits as mandated by WHO and FAO, the residues benomyl and mancozeb, the most prominently used pesticides in Iran, were measured. In this study cucumbers from 76 sample regions were used. Data showed that the amounts of benomyl was related to the type of cucumber in the regions, but there was no significant relationship between the amount of mancozeb and type of cucumber.     

Sub-chronic exposure to carbendazim induces biochemical and hematological alterations in male goats

The present investigation reports the effect of repeated (90 days) administration of carbendazim on the biochemical and hematological parameters in male goats. Carbendazim administered orally at a daily dose of 50 mg kg^?1 body weight for 90 consecutive days resulted in increased plasma concentration of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), creatinine and albumin, while alkaline phosphatase (ALP) and glucose levels were decreased. Decrease in total leukocyte (TLC) and neutrophil count and increase in lymphocyte count was observed in the treatment group. The findings of the present investigation indicate that sub-chronic exposure to carbendazim in male goats causes hepatic and slight kidney dysfunctions.     

Dissipation kinetics of novaluron in tomato,an arid ecosystem pilot study

Novaluron, a newly introduced insecticide, is used for control of a number of field pests. However, information regarding novaluron residues and dissipation profile is limited. In this study, dissipation and residual levels of novaluron in tomato under open field conditions were investigated using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) with quick, easy, cheape, effective, rugged (QuEChERS) method. The method was validated using blank samples spiked at three levels and results showed that recoveries ranged from 93% to 99%. Novaluron residues tend to dissipate following first-order rate kinetics with half-life of 2.08 days. Data demonstrated that the use of novaluron at recommended doses would not pose any hazards to consumers. The present results aid to establish the safe use of this pesticide on tomatoes, and possibly on other crops in Egypt.     

Influence of manufacturing process on the residues of certain fungicides used on tea

Green tea shoots which were sprayed with fungicides such as hexaconazole, propiconazole, carbendazim, and tridemorph were collected from tea bushes after 24 h of fungicide application to study the effect of manufacturing process on the residues. Significant loss of residues was noted at each stage of the manufacturing process. The total loss in residues upon manufacturing of these fungicides ranged from 12.20% to 57.14%. Among the various influential factors that determine the loss of residues, vapor pressure of the fungicides was most prominent in the contribution to residue loss. A high vapor pressure of the fungicide tridemorph amounted to a residue loss of 57.14%, while the low vapor pressure of the other three fungicides caused a loss of less than 22.22%.     

Persistence of carbaryl and its risk assessment through consumption of treated grapes

The average initial deposits of carbaryl were observed to be 1.4 and 3.1?mg?kg^?1, respectively, following four applications of the insecticide at 4.95 and 9.9?kg active ingredient per hectare. Residues of carbaryl dissipated below its limit of quantification of 50?µg?kg^?1 after 7 and 10 days at single and double the application dosage, respectively. The half-life values (t _1/2) of carbaryl were worked out to be 1.3 and 0.7 days, respectively, at single and double dosages. The acceptable daily intake (ADI) for carbaryl has been fixed at 8?µg?kg^?1 body weight per day. Keeping in view the residues of carbaryl observed one day after the last application, a child of 10?kg and an adult of 60?kg will have an intake of 77 and 154?µg carbaryl after consumption of 100 and 200?g grapes, in comparison to its ADI of 80 and 480?µg; thus, no health risk is to be expected. Therefore, a waiting period of 1 day has been suggested for the safe consumption of carbaryl-treated grapes to avoid any health hazards.     

Distribution of organo-chlorine pesticides (DDT and HCH) between plant and soil system

This paper reports a study of the distribution of organo-chlorine pesticides (DDT and HCH) between rice plants and the soil system by spraying before the heading stage at four different dosage levels--control, normal dosage (15 kg ha(-1) of 6% HCH and 7.5 kg ha(-1) of 25% DDT), double dosage and four times dosage. Soil and plant samples were taken respectively at the 1st h, 3rd, 10th, 20th, and 40th day after spraying and at the harvest time. The results indicate that less than 5% of HCH and 15% of DDT were absorbed by the surface of rice leaves for normal dosage. Most of both pesticides moved into the soil in solution after spraying. Compared with DDT, HCH was degraded and run off more easily. HCH residues in the surface soil layer (1-3 cm) were already below 6.4 microg kg(-1) at the mature stage, lower than Chinese Environmental Quality Standard for Agricultural Soils: HCH < 0.05 mg kg(-1). However DDT residues in the surface soil layer remained 172 microg kg(-1), higher than the national standard: DDT < 0.05 mg kg(-1). According to the test f OCP residues in rice seeds, it can be concluded that the OCP sprayed onto the surface of rice leaves can move into rice plants and accumulate in the seeds at the mature stage. HCH residues in rice seeds of the double and four times dosage treatments, and DDT residues in all treatments, exceeded the Chinese National Food Standard (HCH < 0.10 mg kg(-1), DDT < 0.20 mg kg(-1)).     

Dissipation of the triketone mesotrione herbicide in the soil of corn crops grown on different soil types

The new triketone herbicide mesotrione corresponds to the older sulcotrione in which the 2‐chloro benzoyl substituent is replaced by a nitro group, generating an herbicide of greater efficiency and a broader spectrum of activity. Mesotrione has been applied within the same 15 days period pre‐emergence at the rate of 150gha^‐1 to four corn crops made at different sites located 40 km apart in Belgium and of soils of different textures, but similar pH and organic matter (old humus) contents. The mesotrione soil half‐life in the 0–10 cm surface soil layer (which contained more than 90% of the residue) was 50 days in loam soil (at Zarlardinge), 41 days in sandy loam soil (at Melle) and in clay soil (at Koksijde), and 34 days in sandy soil (at Zingem). The cumulative effects of the recent organic fertilizer treatments and of the soil texture could explain the differences between the soil half‐lives. The time for the 90% dissipation of mesotrione was between 3.6 (in the sandy soil) to 4.7 months (in the sandy loam, loam and clay soils). The low mesotrione soil residues remaining after the corn harvest should disappear with the usual heavy rains in autumn, and the tilling which precedes the following crop and dilutes the mesotrione soil residue. These low mesotrione soil residues thus should have no phytotoxicity toward the following crop, especially at the lower application dose of 100 g mesotrione ha^‐1 used in practice.     

噻苯隆在甜瓜和土壤中的残留及消解动态

建立了超高效液相色谱-串联质谱分析噻苯隆在甜瓜和土壤中残留的方法.本方法甜瓜中噻苯隆的平均回收率为90.2%—107.3%,变异系数为3.5%—12.9%;土壤中噻苯隆的平均回收率为81.4%—94.0%,变异系数为3.1%—8.8%.采用田间试验研究了噻苯隆在甜瓜和土壤中的残留动态.结果表明,河南和山东,噻苯隆在甜瓜中的消解半衰期为0.7—1.2d,土壤中的消解半衰期为4.1—7.6d.在甜瓜上使用0.1%的噻苯隆可湿性粉剂,按照最高推荐剂量和最高推荐剂量的1.5倍,施药一次,收获期距最后一次施药35d,噻苯隆在甜瓜和土壤中最终残留量均小于0.001mg.kg-1.说明噻苯隆为低残留,易降解农药.     

Comparative study on the effect of chemicals on Alternaria blight in Indian mustard--a multi-location study in India

High severity of Altemaria blight disease is a major constraint in production of rapeseed-mustard in India. The aim of this study was to investigate the suppressive potential of chemicals viz., zinc sulphate, borax, sulphur, potash and calcium sulphate, aqueous extracts viz., Eucalyptus globosus (50 g l-1) leaf extract and garlic (Allium sativum) bulb (20 g l-1) extract, cow urine and bio-agents Trichoderma harzianum, Pseudomonas fluorescence in comparison with the recommended chemical fungicide (mancozeb), against foliar disease Alternaria blight of Indian mustard [Brassica juncea (L.) Czern. and Coss] under five different geographical locations of India. Mancozeb recorded the lowest mean severity (leaf: 33.1%; pod: 26.3%) of Alternaria blight with efficacy of garlic bulb extract alone (leaf = 34.4%; pod = 27.3%) or in combination with cow urine (leaf = 34.2%; pod = 28.6%) being statistically at par with the recommended chemical fungicide. Chemicals also proved effective in reducing Alternaria blight severity on leaves and pods of Indian mustard (leaf = 36.3-37.9%; pod = 27.5-30.1%). The effective treatments besides providing significant reduction in disease severity also enabled increase in dry seed yield of the crop (mancozeb = 2052 kg ha-1; garlic = 2006 kg ha-1; control = 1561 kg ha-1).     

Residues and dissipation of the pesticide emamectin benzoate under Egyptian field condition: a case study

A simple, rapid analytical procedure for the quantification of emamectin benzoate in tomato was developed using high performance liquid chromatography with fluorescence detector (HPLC-FLD). Emamectin benzoate residues were extracted from tomato samples with n-hexane:ethyl acetate (1:1, v/v). The method involved derivatization using trifluoroacetic anhydride and 1-methylimidazole, prior to analysis by HPLC-FLD. Limit of quantification of this method was found to be 0.01 mg/kg, while limit of detection was 0.005 mg/kg. The dissipation of emamectin benzoate on tomato was studied, and half-life (t_1/2) was estimated in a field study carried out at three different locations. Emamectin benzoate was sprayed on tomato at recommended dosage. Samples of tomato were collected at 0, 1, 3, 7, 10, and 15 days after treatment. The t_1/2 of emamectin benzoate when applied at the recommended doses in tomato was approximately 2.5 days. The residue of emamectin benzoate reached below the maximal residue limit (MRL) 10 days after spraying at the tested dosage. Hence, a safe pre-harvest interval of 10 days is suggested before harvesting of tomato. This study would also be helpful for the Egypt government to establish the MRL of emamectin benzoate in tomatoes and provide guidance on the proper and safe use of this insecticide.     

虱螨脲在棉花和土壤中的残留动态

在长沙和郑州2地进行田间试验,采用液相色谱技术研究虱螨脲在棉籽、棉叶及土壤中的残留动态.结果表明:虱螨脲在棉叶、棉籽和土壤中的添加回收率分别为86.0%～94.7%、88.5%～92.1%和83.9%～97.7%;最低检出浓度分别为0.025、0.025和0.006 mg·kg-1.虱螨脲在棉叶和土壤中的半衰期分别是3.06～3.45和2.51～2.88 d.在推荐使用剂量和高剂量条件下,收获的棉籽中虱螨脲最终残留量均未检出,拟推荐我国棉籽中虱螨脲的MRL(最高残留限量)值为0.05 mg·kg-1.