I= GROWTH INHIBITING AND DETERRENT EFFECTS OF PLANT EXTRACTS ON MAJOR INSECT PESTS OF STORED GRAINS
Pakistan Research Repository Home
 

Title of Thesis
GROWTH INHIBITING AND DETERRENT EFFECTS OF PLANT EXTRACTS ON MAJOR INSECT PESTS OF STORED GRAINS

Author(s)
Javed Iqbal
Institute/University/Department Details
University Of Arid Agriculture/ Facult Of Crop And Food Sciences
Session
2005
Subject
Entomology
Number of Pages
187
Keywords (Extracted from title, table of contents and abstract of thesis)
plant extracts, insect, pests, grains, plant materials, neem, azadirachta indica a. juss, rhizomes of sweet flg acorus calamus l., turmeric curcuma longa (l.), deterrent,

Abstract
Extracts of seeds of neem Azadirachta indica A. Juss, rhizomes of sweet flg Acorus calamus L. and turmeric Curcuma longa (L.) each in petroleum ether, acetone and ethanol at different application rates were evaluated for their repellent, growth inhibiting, feeding deterrent and synergistic effects against the red flour beetle Tribolium castaneum (Herbst), angumois grain moth Sitotroga cerealella (Olivier) and lesser grain borer Rhizoperha dominica (Fabricius). Petroleum ether extracts of neem and sweet flag applied to wheat grain, bag or both compared with Coopex dust (0.5%) and polythene enclosure (0.2 mm), provided efficient protection to wheat upto six months. Among the test plants, sweet flag was significantly better repellent upto two weeks but neem showing comparatively lower repellency upto two weeks persisted better upto eight weeks in Treated Paper Strip Repellency Method (contact) repellency). For olfactory repellency, evaluated in an Olfactometer for five minutes, sweet flag proved better repellent. In growth inhibition studies (T. castaneum fed for five days on wheat flour treated @ 1000, 500, 250, and 125 ug/gm of the plant extracts) significantly lower progeny (larvae, pupae and adults) was produced in sweet flag. Other plant extracts were also promising growth inhibitors. In feeding deterrent studies conducted by confining R. domninica adults on extracts treated filter paper discs treated at 1000, 500 or 100 ug/cm2 in a micro-cage paper treated with neem extracts had significantly lower number of feeding punctures as compared with those having turmeric and sweet flag extracts. Among solvents, extracts in petroleum ether were significantly better repellents and growth inhibitors but those in ethanol were significantly better feeding deterrents. Repellent, growth inhibition and feeding deterrent properties were dose-dependent. At higher application rates comparatively higher repellency, growth inhibition and feeding deterrence were achieved. Petroleum ether extracts of sweet flag being the most effective repellent and growth inhibitor was chemically fractionated by Thin Layer Chromatography (TLC), using petroleum ether: acetone (3:1) and five major fractions obtained from column chromatography using Silica get 60 G and elution with petroleum ether:acetone (3:1). Fractions 2 and 3 having Rf values of 0.75 and 0.63 respectively, were significantly better repellent and growth inhibitor. In synergistic studies or combined application of the petroleum ether extracts, sweet flag synergized with neem in different ratios but not with turmeric for inhibition of S. cerealella progeny. T.castaneum was less affected by combined applications. In warehouse trials, neem and sweet flag extracts applied to both bag @1000 ug/cm2 and wheat grain @ 1000 mg/kg provided efficient protection against major stored grain insects. It was concluded that better repellent and growth inhibiting effects of sweet flag were probably due to the presence of “asarone” (C12H16O3; MW 208) in its petroleum ether extract which has comparatively lower molecular weight and higher volatilization rate than azadirachtin (C35H44O16; MW 720) in ethanol extract of neem which showed better feeding deterrency due to its higher molecular weight. Petroleum ether extract of turmeric had “turmerone” (C15H22O; MW 218) and “ar-turmerone” (C15H2O; MW 216) which had medium level of behavioural and biological effects due to their molecular weight remained in between “asarone” and azadirachtin”.

Download Full Thesis
2356.52 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
130.65 KB
2 1 Introduction
40.22 KB
3 2 Review Of Literature 6
204.1 KB
4 3 Materials And Methods 29
330.4 KB
  3.1 Collection And Preparation Of Plant Materials 29
  3.2 Insect Culture 29
  3.3 Chemical Studies 29
  3.4 Biological Studies 31
  3.5 Synergistic/Combination Studies 34
  3.6 Warehouse Studies 35
  3.7 Statistical Analyses 36
5 4 Results And Discussion 43
1649.27 KB
  4.1 Repellency Studies 43
  4.2 Feeding Deterrency Studies 69
  4.3 Growth Inhibition Studies 87
  4.4 Warehouse Studies 140
6 5 Summary 160
66.4 KB
7 6 Literature Cited 168
170.12 KB