Toxic Effect of Some Plant Extracts on the Mortality of Flour Beetle Tribolium confusum (Duval) (Coleoptera: Tenebrionidae)

Wand Khalis Ali

doi:10.4172/2161-0983.1000115

Abstract

The study was carried out in the Entomology Laboratory of the Department of Biology, College of Science, Salahaddin University, Erbil, Kurdistan Region, and Iraq. Methanol extracts of six local plants (Anethum graveolens, Apium graveolens, Eucalyptus glauca, Malva parviflora, Mentha longifolia and Zingiber officinale) were studied for their toxicity effect on mortality of the last larval stage of Tribolium confusum by assessing the mortality value of the larvae for different plant extracts and different exposure times (1-5 hrs) and estimating the value of LT50 for each plant extract. The mortality were varying from plant to plant as follows: Anethum graveolens reached its maximum value of 56.67% at 4.5 hrs, for Eucalyptus glauca it was 90% at 2 hrs., for Apium graveolens it was 93.33% at 5 hrs exposure and Mentha longifolia it was 93.33% at 4 hrs, while for Malva parviflora reached 96.67% at 3 hrs, and for Zingiber officinale reached its maximum value of 100% at 2 hrs. The LT50 values for T. confusum ranged from 1.111 for Zingiber officinale to 3.146 for Anethum graveolens whiles the obtained LT50 values were 2.451, 1.392, 1.364 and 1.143 for Apium graveolens, Mentha longifolia, Malva parviflora and Eucalyptus glauca respectively. The results indicate that Zingiber officinale was the most toxic plant and Anethum graveolens the least toxic.

Highlights

Wheat suffers heavy losses during storage due to insect pests
As observed in this study, the result reached its maximum value in the case of Anethum graveolens, it was 56.67% at 4.5 hrs exposure, Apium graveolens: 93.33% at 5 hrs, Eucalyptus glauca: 90% at 2 hrs, Malva parviflora: 96.67% at 3 hrs, Mentha longifolia: 93.33% at 4 hrs, and Zingiber officinalis 100% at 2 hrs
Anethum graveolens was able to induce 50% mortality at 3.5 hrs, whiles Apium graveolens was able to induce more than 50% mortality after 0.5 hrs, and achieved 93.33% at 5 hrs after treatment and Eucalyptus glauca induced more than 50% mortality after 1 hr, and 90% at 2 hrs after treatment

Summary

Introduction

Wheat suffers heavy losses during storage due to insect pests. According to the FAO estimate 10 to 25% of the world’s harvested food is destroyed annually by insects and rodent pests [1]. Insect pests cause damage to stored grains and processed products by reducing their dry weight and nutritional value [2]. The confused flour beetle, Tribolium confusum is one of the most serious pests of stored cereals and processed cereal products worldwide [3,4,5]. Residual chemical insecticides and fumigation are currently the methods of choice for the control of insects of storedproducts [6]. Their widespread use has led to some serious problems, including the development of insect strains resistant to insecticides [7], toxic residues on stored grains, and health hazards to grain handlers. Increased public concern over the residual toxicity of insecticides applied to stored products, the occurrence of insecticide-resistant insect strains, and the precautions necessary to work with traditional chemical insecticides stress the usage of botanicals to control insects of stored product [8]

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