Insecticidal Activity Of Sarisan

Sarisan (1-Allyl-2-Methoxy-4,5-Methlene-Dioxybenzene) which is a kind of phenylpropanoid substance was isolated from Ligusticum sinense Oliv. , and its insecticidal activity was first reported by Research and Development Center of Biorational Pesticide, Northwest A&F University. To further vertify the bioactivities and mechanism of sarisan, the toxicity and action of sarisan against several normal pests were investigated under the laboratory conditions. Poisoning symptom was observed. Effects on some important physiological and biochemical criteria in Mythimna separatea　Walker　were tested. The main results are given as follows: (1) Sarisan showed strong contact activity against the 4th-instar larvae of Mythimna separata Walker, Myzus persicae(Sulzer), the 5th-instar larvae of Pieris rapae L.and Musca domestica Linnaeus, whose values of LD₅₀ were 35.06(12 h),1.11(24 h),66.28(24 h) and 3.45(4h)μg /larva. Sarisan also displayed strong fumigation activity against 4th-instar larvae of Mythimna separata Walker,Musca domestica Linnaeus,Sitophilus zeamais Motschulsky and Culex pipiens pallens with LD₅₀ values 16.92 (12h),5.77 (4h),7.53 (72h) and 4.24μL/L(4h), respectively. The KT₅₀ values were 4.80min and 11.64min against Culex pipiens pallens and Musca domestica Linnaeus with the fumigation of sarisan under the dosage of LC80. Strong inhibition of the formation of Sitophilus zeamais Motschulsky populations was exhibited, too. Moreover, repellent activity of sarisan was proved against　Musca domestica Linnaeus. and Sitophilus zeamais Motschulsky. (2)The bioactivity actions of sarisan against insects included fumigation, repellent,contact, population inhibiting, of which fumigation and contact were dominant. (3)In vivo symptom was characterized by a definite sequence of events, starting with excitation, convulsion, paralysis, and death. But some in paralysis could recover at a lower dose, Mythimna separata Walker, Pieris rapae L.and Musca domestica Linnaeus. hyperemesised when treated with sarisan, hollow duodenum phenomenon was found in Mythimna separata Walker. (4)It was found that AChE and Na+,K+-ATPase of Mythimna separata Walker were strongly inhibited by sarisan, and sarisan also increased Glu content but decreased GABA content. During excitation, convulsion and paralysis of pests treated, the inhibition rate of AChE was 21.64%,29.75% and 35.22%, respectively., 33.29%, 44.45% and 23.98% for Na⁺,K⁺-ATPase. (5) Sarisan didn't showed very strong effect on esterase and carboxylesterase of Mythimna separata Walker, while it could activate or inhibit esteraseisozyme. Insignificant inhibition of MFO O-demethylase and GSTs activities was found. The result of this research showed that sarisan had a good development outlook for it had good bioactivity, wide spectrum, various actions and special mechanism; its characteristics also involve the simple structure. Furthermore, it can be found in many kinds of plant essential oil and it is abundant in nature.