Effect of Dimethoate Residues on Soil Micro-arthropods Population in the Valley of Zendan,Yemen

Abstract

ABSTRACT:The present study aimed to screen the effect of overuse of the insecticide Dimethoate and its residues within 0 -15 cm soil layer on the soil micro-arthropods population, which play a very important role in maintenance of the fertility of the soil. The valley of Zendan is located in Arhab Destrict, Sana'a Governorate, Yemen. The valley is about 50 km north-east of Sana'a city and this geographical area is a large producer of Qat (Catha edulis Forsk); the plant which most of the people in the country chew. In this study the valley divided into three stations, each station contained three treated substations and three control substations. The control substations selected from the farms, which are historically free from pesticides. Due care has been taken to insure that the treated sub-stations were from the closest area to the control substations. The average use of Dimethoate 40% E.C is 1-2 ml/L water. The treatment replication was 1-3 times within the period of 2-3 weeks. In this study also, we analyzed the total concentration of Dimethoate, and its metabolite; Omethoate in the soil layer of 0-15 cm. The analysis of Dimethoate and Omethoate residues from representative soil samples covered the major part of the Zendan valley was done by the technique of LC-MS, and the results revealed that the detected levels ranged from 0.914 to 5.180 mg/kg air-dried soil for Dimethoate residues and 0.001 to 0.067 mg/kg air-dried soil for Omethoate residues. For studying the effect of Dimethoate residues on the soil micro-arthropods population, soil samples from each substation were collected with core sampler. The soil micro-arthropods were extracted for 48 hours and collected in vials containing 70% alcohol by using the extraction funnels technique. The number and type of soil microarthropods extracted from each substation were separated and recorded and the data obtained was analyzed. The outcomes of the study revealed that Dimethoate and Omethoate residues are beyond the Total Threshold Limit Concentration (TTLC) and significantly reduced the population of the non-target soil micro-arthropods that included mainly mites, collembolans, beetle larvae, trips, cutworms, symphyla and seed corn maggot. Mites and collembolans were the most affected micro-arthropods by Dimethoate and Omethoate residues. The reduction in the soil microarthropods population varied from 59% to 69% as compared to its population in control substations. The maximum decline of soil microarthropods was found to be in substations where the highest residues of Dimethoate and Omethoate were recorded. Thus indiscriminate use of pesticides such as Dimethoate will definitely affect the soil fertility in the area and that will reduce the crop yield in future. @JASEM

Impact of Systemic Insecticides on Organisms and Ecosystems

“…Bendiocarb impacts on predaceous arthropods and oribatid mites were less severe and temporary compared to the impacts of non-systemic OPs, but increased trap catches of ants two weeks after application [55], possibly as a result of a longer-term effect. Many soil arthropods, in particular mites and springtails, were the most affected by dimethoate -and its metabolite omethoate-residues in soil after sprays of 1-2 ml/L in the farms of the Zendan valley, Yemen [4]. Similar observations were made when dimethoate was sprayed on vegetation of arable fields [85] or in soil microcosms [180]; the springtail populations recovered but attained lower densities a year later, while their dominance structure had changed.…”

Pesticides and Soil Invertebrates: A Hazard Assessment

“…Chlorpyrifos significantly reduced springtail species richness in one study (Fountain et al, 2007), which was not significantly affected by chlorpyrifos or dimethoate in another (Endlweber et al, 2006). Ethoprophos reduced biomass of F. candida by 60% (Leitão et al, 2014), growth was impaired by dimethoate in another (Al-Haifi et al, 2006), and chlorothalonil altered F. candida gene expression in a third tested parameter (Simões et al, 2019). In the only study of another Order of Entognatha -Protura -abundance was unaffected by imidacloprid (Peck, 2009).…”

“…In our analysis, Protura, Pauropoda, and Tardigrada were each analyzed in only one study (Peck, 2009;Carrascosa et al, 2014;Vaj et al, 2014), and Symphyla and Diplura were only analyzed in the context of mixed organism groups (Al-Haifi et al, 2006;Atwood et al, 2018). In addition, there were fewer than 20 tested parameters for parasitic wasps, termites, and Myriapods, including millipedes and centipedes.…”

The potentiality of Lysinibacillus sphaericus DM-3 and Bacillus cereus DM-5 in degrading dimethoate

“…The relative high solubility of dimethoate in water indicates its low affinity for most types of soil and thus it has a relatively high potential for movement through farming soils (Van Scoy et al, 2016). Therefore, residues of dimethoate and its toxic analog omethoate were detected in soil and many crops (Al-Haifi et al, 2006).…”