Table 1.

Plant defense secondary metabolites identified for their potential contribution to resistance against various target insect pests

Class	Secondary metabolite	Subclass	Target insect	Main observed effect	Reference
Phenylpronanoids	Caffeic acid	Hydroxycinnamic acid	Acanthoscelides obtectus Coleoptera: Bruchidae	Knockdown effect: reduced mobility and increased mortality in adults (in vitro bioassay)	Regnault-Roger et al. (2004)
			Helicoverpa zea Lepidoptera: Noctuidae	Prooxidant: oxidative stress in midgut proteins Development rate, survivorship and pupal weight negatively influenced at 4 mM	Summers and Felton (1994)
			Sitobion avanae Homoptera: Aphididae	Reduction of phloem sap ingestion at 2.5 mM	Leszczynski et al. (1995)
			Helicoverpa armigera Lepidoptera: Noctuidae	Protease inhibitor. Body weight and survival significantly reduced in the range of 50–200 ppm	Joshi et al. (2014)
	Chlorogenic acid	Monolignols	Dalbulus maidis Hemiptera: Cicadellidae	Antifeedant activity in adults at 400 ppm (in vitro bioassay)	Dowd and Vega (1996)
			Plagiodera versicolora Coleoptera: Chrysomelidae	Antifeedant activity above 50 µg/disk	Jassbi (2003)
			Agelastica alni Coleoptera: Chrysomelidae	Feeding deterrent at concentration of 2.48% by weight (dual choice bioassay)	Ikonen et al. (2002)
			Trichoplusia ni Lepidoptera: Noctuidae	Reduced larval growth and development at 100 ppm (2.8 mM) and 1000 ppm (28 mM)	Beninger et al. (2004)
			Lymantria dispar Lepidoptera: Lymantriidae	Reduced larval growth and development at 100 ppm (2.8 mM) and 1000 ppm (28 mM)	Beninger et al. (2004)
			Spodoptera litura Lepidoptera: Noctuidae	Developmental retardation and increased larval mortality (>60%) at 0.7–0.8 µg/ml	Mallikarjuna et al. (2004)
			Frankliniella occidentalis Thysanoptera: Thripidae	Reduced relative growth rate and survival of first instar larva at 5% (5 mg/ml)	Leiss et al. (2009a)
			Helicoverpa zea Lepidoptera: Noctuidae	Prooxidant: chronic exposure at 4 mM inducedoxidative stress in midgut proteins. Development rate and pupal weight are negatively influenced	Summers and Felton (1994)
	Ferulic acid	Monolignols	Acanthoscelides obtectus Coleoptera: Bruchidae	Knockdown effect: reduced mobility and increased mortality of adults at day 8 (in vitro bioassay)	Regnault-Roger et al. (2004)
			Choristoneura fumiferana Lepidoptera: Tortricidae	Oviposition deterrent 7.8 nmol/cm2 (dual choice bioassay)	Grant and Langevin (2002)
			Sitodiplosis mosellana Diptera: Cecidomyiidae	Correlation study: positive correlation to resistance. Floret infestation lower in resistant cultivar (Arin cv contains 70.5 mg/100 g DW ferulic acid)	Abdel-Aal et al. (2001)
			Sesamia nonagrioides Lepidoptera: Noctuidae	Correlation study: ferulic acid concentration was correlated with the resistance level in the genotypes Structural resistance: cell wall fortification and lignification	Santiago et al. (2006)
			Rhopalosiphum padi Homoptera: Aphididae	Constitutive defense of resistant cultivar Regina and induced	Havlickova et al. (1996, 1998)
			Sitobion avanae Homoptera: Aphididae	Reduced sieve element salvation at 2.5 mM	Leszczynski et al. (1995)
				Prolonged reproductive period and reduced daily fecundity	Chrzanowski et al. (2012)
			Sitodiplosis mosellana Diptera: Cecidomyiidae	Constitutive levels exceeding 0.35 µg/g fresh weight (1.57 µg/g dry weight) increased mortality of newly hatched larvae	Ding et al. (2000)
			Dalbulus maidis Hemiptera: Cicadellidae	Antifeedant activity in adults at 400 ppm (in vitro bioassay)	Dowd and Vega (1996)
	p-Coumaric acid	Monolignols	Etiella zinckenella Lepidoptera: Pyralidae	Oviposition deterrent at 0.5 mg	Hattori et al. (1992)
			Rhopalosiphum padi Homoptera: Aphididae	Constitutive defense; higher concentration in resistant cultivar Regina	Havlickova et al. (1996, 1998)
			Sesamia nonagrioides Lepidoptera: Noctuidae	Structural resistance: cell wall fortification and lignification	Santiago et al. (2006)
			Sitobion avanae Homoptera: Aphididae	Reduction ingestion of phloem sap	Leszczynski et al. (1995)
			Dalbulus maidis Hemiptera: Cicadellidae	Antifeedant activity in adults at 400 ppm (in vitro bioassay)	Dowd and Vega (1996)
	Scopoletin	Coumarin	Zygogramma exclamationis Coleoptera: Chrysomelidae	Phytoalexin: feeding deterrent. Topical application of 100 µg/ml reduces preference	Olson and Roseland (1991)
			Sitobion avanae Homoptera: Aphididae	Reduced ingestion of phloem sap at 2.5 mM	Leszczynski et al. (1995)
			Plutella xylostella Lepidoptera: Plutellidae	Antibiosis >2500 µg/g diet growth inhibitor LD50 ≈ 8300 µg/ml	Peterson et al. (2003)
			Spilarctia obliqua Lepidoptera: Noctuidae	Antifeedant and growth inhibitor. At 250 µg/g deterrence and growth inhibition was similar to that of azadirachtin	Tripathi et al. (2011)
			Coptotermes formosanus Isoptera: Rhinotermitidae	Termicidal and antifeedant effects at 5 µmol	Adfa et al. (2010)
			Anopheles arabiensis Diptera: Culicidae	Repellent activity at 100 µg/ml	Narayanaswamy et al. (2014)
	Sinapic acid	Monolignols	Choristoneura fumiferana Lepidoptera: Tortricidae	Oviposition deterrent at 78.6 nmol/cm2	Grant and Langevin (2002)
			Delia radicum Diptera: Anthomyiidae	Oviposition deterrent; 10 mM in buffered solution reduced number of eggs by 60–70%	Jones et al. (1988)
			Rhopalosiphum padi Homoptera: Aphididae	Constitutive defense; higher expression correlated with resistance in cultivar Regina (lower reproduction rate). Induction upon feeding on resistant cultivar	Havlickova et al. (1996, 1998)
			Sitobion avanae Homoptera: Aphididae	Reduced ingestion of phloem sap at 2.5 mM	Leszczynski et al. (1995)
			Frankliniella occidentalis Thysanoptera, Thripidae	Significant increase in mortality of first instar larvae at 25% of natural plant concentrations (0.53 mg/g)	Leiss et al. (2013)
	t-Cinnamic acid	Monolignols	Mechoris ursulus Coleoptera: Attelabidae	Contact toxicity: mortality of 86.7% at a rate of 5 mg/paper	Park et al. (2000)
Flavonoid	Luteolin	Flavones	Acyrthosiphon pisum Hemiptera: Aphididae	Probing and feeding deterrent at 100 µg cm−3	Goławska and Łukasik (2012)
			Frankliniella occidentalis Thysanoptera: Thripidae	Significant increase in mortality of first instar larvae at 25% of natural plant concentrations (0.53 mg/g)	Leiss et al. (2013)
	Luteolin-7-glucoside		Acanthoscelides obtectus Coleoptera: Bruchidae	Toxin: knockdown effect: reduced mobility and increased mortality	Regnault-Roger et al. (2004)
	Luteolin 7-O- β -D-apiofranosyl-(1→2)-β-D-glucopyranoside		Liriomyza trifolii Diptera: Agromyzidae	Ovipositional deterrent at 4.90 µg/cm2	Kashiwagi et al. (2005)
	Methyl-luteolin glycoside 2		Phratora vulgatissima Coleoptera: Chrysomelidae	Constitutive defense: negative correlation with oviposition in Salix F2 hybrids	Torp et al. (2013)
	Rutin	Flavones	Acanthoscelides obtectus Coleoptera: Bruchidae	Knockdown effect in bioassay: reduced mobility and increased mortality of adults	Regnault-Roger et al. (2004)
			Anticarsia gemmatalis Lepidoptera: Noctuidae	Larval development, amount of food consumed, and pupal weight were negatively influenced at 0.65% (mg/ml)	Salvador et al. (2010)
			Phyllotreta cruciferae Coleoptera: Chrysomelidae	Feeding deterrent of 1 month old flea beetle (binary feeding bioassay)	Onyilagha et al. (2012)
			Spodoptera litura Lepidoptera: Noctuidae	Developmental retardation and increased larval mortality (>60%) at 0.7–0.8 µg/ml	Mallikarjuna et al. (2004)
			Lymantria dispar Lepidoptera: Lymantriidae	Larval growth inhibitor. Larval weight reduced by 45% at 0.05% at day 15	Beninger and Abou-Zaid (1997)
			Helicoverpa armigera and Helicoverpa zea Lepidoptera: Noctuidae	Feeding deterrent at 10−3 M	Simmonds (2003)
			Helicoverpa armigera Lepidoptera: Noctuidae	Cessation of feeding inhibits larval growth (1 µg/ml)	Jadhav et al. (2012)
			Spodoptera litura Lepidoptera: Noctuidae	Larval development arrested, increased pupal mortality and malformation of adults at 1 µg/ml	Jadhav et al. (2012)
	Kaempferol glycosides	Flavonols	Frankliniella occidentalis Thysanoptera: Thripidae	Constitutive defense. Resistance in Senecio F2 hybrids correlates with kaempferol-glucoside	Leiss et al. (2009b)
			Mamestra configurata Lepidoptera: Noctuidae	Kaempferol-3,7-diglucoside acts as feeding deterrent when applied at concentration > endogenous levels; 0.05–0.45 µmol per leaf disk (choice feeding assay)	Onyilagha et al. (2004)
			Pieris rassicae Lepidoptera: Pieridae	Reduced levels of kaempferol 3-O-rhamnoside 7-O-rhamnoside, mediated by overexpression of MYB75, increased susceptibility to feeding. Growth negatively affected when applied exogenously at 100 µM	Onkokesung et al. (2014)
	Quercetin	Flavonols	Spodoptera litura Lepidoptera: Noctuidae	Developmental retardation and increased larval mortality (>60%) at 0.7–0.8 µg/ml	Mallikarjuna et al. (2004)
			Lymantria dispar Lepidoptera: Lymantriidae	Larval growth inhibitor. Larval weight reduced by 33% at 0.05% at day 15	Beninger and Abou-Zaid (1997)
			Acyrthosiphon pisum Hemiptera: Aphididae	Probing and feeding deterrent at 100 µg cm−3. At higher concentration mortality and development time are increased whereas fecundity is decreased	Goławska et al. (2014)
			Spodoptera frugiperda Lepidoptera: Noctuidae	Feeding deterrent (57%) at 100 µg/cm2	Diaz Napal and Palacios (2015)
				78% Larval mortality at 0.1 mg/g	Gallo et al. (2006)
			Helicoverpa armigera Lepidoptera: Noctuidae	Negative effect on growth reducing larval weight by ~50% at 16 mg/g development reducing pupation by 50% at 8 mg/g) and survival (>80% mortality at 32 mg/g)	Li et al. (2016)
				Deleterious effects growth, pupation and adult emergence, and survivalat 3 and 10 mg/g	Liu et al. (2015)
			Bactrocera Cucurbitae Diptera: Tephritidae	Growth regulator and or deterrent: reduction in food assimilation as well as larval and pupal weight at 125 ppm	Sharma and Sohal (2013)
			Aphis fabae Hemiptera: Aphididae	Inhibitory activity on progeny deposition 0.1 M	Lattanzio et al. (2000)