Omar, Dzolkhifli

Universiti Putra Malaysia Institutional Repository

Agricultural SciencesEffect of Adding Pectin to the Controlled-release Formulation of Alachlor andDiuronDzolkhlfllOmarFaculty of AgricultureUniversiti Putra Malaysia43400 UPM, Serdang, SelangorMalaysiaTelephone Number of Corresponding Author: 03-89466939E-mail ofCorrespondingAuthorzolkijli@agri.upm.edu.myKey words: alachlor, diuron, formulation, control-release, pectinIntroductionImproved technology through the use of controlled-release formulation (CRF) enables efficient and economicalapplication of the active agent. A controlled-release system by encapsulation of pesticide in polymer sodium alginatewas commonly used. However, the initial release was relatively slow compared with the conventional formulation.The following studies prepared the CRF using pectin as a substitution to alginate. The release rates of the activeingredient (a.i.) from the formulations were determined and evaluated for their efficacy against D. ocimifolia and P.conjugatum.Materials and MethodsPreparation of CRFfhe CRF of diuron and alachlor were prepared by monolithic system. The solution was drippedinto calcium dichloride solutions with the aid of peristaltic pump for gelification. After 5 minutes, the granules wereremoved, rinsed and air dry at room temperature.Release rate of diuron and alachlorThe release of a.i. from CRF was determined by chemical assay using a highperformance liquid chromatography with UV detector. The determination of release rate by bioassay technique wasconducted in the glasshouse using Cucumis sativus and Brassica juncea seedlings as bioindicators for alachlor anddiuron, respectively.Effect on germination ofw:!ed~The seeds of D. ocimifolia and P. conjugatum used to evaluate the efficacy ofCRF weresown at i and 2 months after application. Percent mortality was determined at 14 days after sowing.Results and DiscussionThe texture of pectin CRF granules was scfter than the alginate CRF. Addition of alginate increased the mechanicalresistance or the pectin CRF granules. Chemical assay using a high performance liquid chromatography with ultra-violet detector showed the pectin-kaolin CRFs (PIKI, P2KI, PIK and P2K) release a.i. faster compared withalginate:pectir.-kaolin CRFs (APIKI, AP2KI, APIK and AP2K) and alginate-kaolin CRFs (AKI and AK2) six hoursafter placement in water. The release reached a constant level at three, five and seven days after placement in water forpectin-kaolin, alginate:pectin-kaolin and alginate-kaolin CRFs, respectively.The determination of release rate by bioassay technique showed the CRF of alachlor (APIKI, AP2KI, PIKI andP2KI) showed a better performance in inhibiting a shoot and root length of C. sativus compared to AKI at 3 days aftertreatment (DAT),. Similar result was "bserved for the fresh weight of C. sativus at 15 DAT. The APIKI, AP2KI,PIKI and P2KI also showed a similar performance with the conventional spray formulation of alachlor (CFI) at theinitial treatments. These indicated that the present of pectin in the CRF improved the initial release of alachlor, At 160DAT, all the CRFs showed a better effect compared to CFI indicating the prolonged activity of alachlor through theCRF. Similar result was observed for the CRFs of diuron in inhibiting the germination of B. juncea. At 7 DAT, thepectin-koalin CRF (PI K and P2K) showed similar performance with the conventional spray formulation of diuron (CF)and significantly higher mortality was recorded from the CRFs of diuron compared to CF at 120 and 160 DAT.At 7 week after treatments (WAT), all the CRFs of alachi or except PIKI and P2Kl showed a significantly lower ongennination of P. conjugatum compared to CFl. In contrast, only AKl, AP2KI, PIKI, P2Kl and ALSAWI showed asignificantly lower germination of D. ocimifoli compared to CF I.. The effectiveness of diuron CRFs on P. conjugatumshowed a significantly lower germination for all CRFs compared to CF except AK2, PIK, and APISAW_ On D.ocimifolia, only APISAW, APIPH and AP2PH showed a significantly lower germination compared to CF. In general,the alchlor alginate:pectin-koalin CRF of AP2KI showed a better control on germination of both weeds.Conclusions63UPM Research Report 1997-2000. Vol II.Section 2-Extended AbstractsPectin increased initial release of CRF but further works are needed to improve the texture and residual preemergenceactivity.Benefits from the studyThe CRF prolongs the activity of alachlor and diuron compared with the conventional spray formulation and increasesthe safety due to no hazard of spray drift.Patent(s), if applicable:NilStage of Commercialization, if applicable:NilProject Publications in Refereed Journals:NilProject Publications in Conference Proceedings:NilGraduate ResearchName of Research Topic Field of Expertise Degree Awarded Graduation YearGraduateSofiah Baseri Modification with Pesticide MSc 2003pectin of alginate Toxicologycontrolled-releaseformulation ofalachlor and diuron:their release kineticsand efficacies.IRPA Project numbtrOl-02-04-0380UPM Research ClusterAFF64

Effect of adding pectin to the controlled-release formulation of alachlor and diuron

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Effect of adding pectin to the controlled-release formulation of alachlor and diuron

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