Journal of Environmental Science and Health Part B (2007) 42, 559–567Copyright C© Taylor & Francis Group, LLCISSN: 0360-1234 (Print); 1532-4109 (Online)DOI: 10.1080/03601230701389512

Growing hot pepper for cabbage looper, Trichopulsia ni(Hubner) and spider mite, Tetranychus urticae (Koch) control

GEORGE F. ANTONIOUS, JANET E. MEYER, JAMI A. ROGERS and YOON-HYEON HU

Kentucky State University, Land Grant Program, Department of Plant and Soil Science, Frankfort, KY

With the public perception that synthetic pesticides leave harmful residues in crop produce for human consumption, there has beenincreased interest in using natural products for pest control. The potential of using fruit extracts of hot pepper for controlling thecabbage looper, Trichopulsia ni (Hubner) and spider mite, Tetranychus urticae Koch is explored in this investigation. Crude extractsfrom fruits of Capsicum chinense, C. frutescens, C. baccatum, and C. annuum, were prepared and tested under laboratory conditions fortheir insecticidal and acaricidal performance. Mortality was greatest (94%) when fruit extract of accession PI-593566 (C. annuum) wassprayed on larvae of the cabbage looper, while crude extracts of accessions PI-241675 (C. frutescens) and PI-310488 (C. annuum) wererepellent to the spider mite. We investigated differences in chemical composition of the crude fruit extracts that may explain the observeddifferences in mortality and repellency between accessions. Gas Chromatography-Mass Spectrometry spectrometric analysis revealedthat capsaicin and dihydrocapsaicin, the pungent components of pepper fruit, were not correlated with toxicity or repellency, indicatingthat the two capsaicinoids are not likely related to the efficacy of pepper fruit extracts. Major compounds in hot pepper fruit extractswere detected and identified as pentadecanoic acid methyl ester, hexadecanoic acid methyl ester, and octadecanoic acid methyl ester.Spectrometric analysis and toxicity to cabbage looper larvae revealed that pentadecanoic acid methyl ester is likely related to cabbagelooper mortality. However, the concentration of pentadecanoic acid methyl ester in some accessions was insufficient to explain theobserved mortality of cabbage looper and repellency of spider mite. Fruit extracts of accessions PI-593566 (C. annuum) and PI-241675(C. frutescens) could be useful for managing populations of cabbage loopers and spider mites, which could reduce reliance on syntheticpesticides. Further study is needed to investigate performance of hot pepper extracts under ultra-violet light and field conditions.

Keywords: Capsicum; capsaicinoids; phytochemicals; pentadecanoic acid methyl ester; methylketones; mass spectra.

Introduction

Farmers are expected to meet the food, feed and fiber needsof growing human populations as well as the demandsof diverse consumer groups, while preserving ecosystems,health, and biodiversity. This requires modern, highly effec-tive plant protection products. These products must be safefor the environment and wildlife, and safe for all who con-sume the food. Organic products have become increasinglypopular in recent years, as consumers have grown morehealth conscious and environmentally aware. Farmers arein need of insect pest management strategies that are ef-fective, affordable and environmentally sound. We aim todevelop environmentally safe plant-based protection prod-ucts having no human toxicity that would be available forlow-resource farmers.

Address correspondence to George Antonious, Kentucky StateUniversity, Land Grant Program, Department of Plant and SoilScience, 218 Atwood Research Center, Frankfort, KY 40601-2355; E-mail: george.antonious@kysu.eduReceived January 5, 2007.

The cabbage looper, Trichopulsia ni (Hubner), can bea very damaging insect primarily to cole crops. Lar-vae consume three times their weight in plant materialdaily.[1] High populations may move to the fruit and feedon the fruit surface, increasing crop damage. The two-spotted spider mite, Tetranychus urticae Koch, is a well-known herbivorus pest of cultivated crops. Many cropsmust be protected with synthetic acaricides during thehot and dry seasons that favor severe outbreaks of spidermites.

Pests are estimated to cost U.S. farmers and consumersover $130 billion every year.[2] Many studies have indicatedthe potential ecological damage due to the widespread useof synthetic pesticides.[3,4] Basic and applied research toprovide alternative pesticides with low impact on humanhealth and environmental quality is needed. Dried plantsor their extracts have been used by farmers in many devel-oping countries to protect food and fiber from insects. Chilipepper powder deterred oviposition of the onion fly, Deliaantiqua.[5] Capsaicin in hot pepper has been reported to re-duce larval growth of the spiny bollworm, Earias insulana[6]

and the use of oleoresin from Capsicum as a repellentagainst cotton pests has been reported.[7]

560 Antonious et al.

Fig. 1. Mortality of 3rd instar larvae of cabbage looper, Trichopulsia ni Hubner sprayed with hot pepper fruit extracts prepared inwater from 23 pepper accessions. Bars accompanied by different letter(s) for each exposure period indicated significant differences(P < 0.05) using analysis of variance (ANOVA) procedure (SAS Institute).[13]

This investigation is a continuation of our previous workon natural products for pest control[8−10] and was de-signed to: 1) select hot pepper accessions producing highfruit quality and yield; 2) test the toxicity of 24 acces-sions of hot pepper fruit extracts to cabbage looper lar-vae; 3) test the repellency of hot pepper fruit extracts tospider mites; and 4) characterize the composition of hotpepper fruit extracts having insecticidal/acaricidal perfor-mance for potential identification of compounds responsi-ble for toxicity and/or repellency for use as a pest controlagent.

Materials and methods

Seeds of 24 Capsicum accessions were obtained from theUS Department of Agriculture/Agricultural Research Ser-vice (USDA/ARS) Plant Introduction Station, Tifton, GAand planted at Kentucky State University (KSU) ResearchFarm in the greenhouse in the spring and transplantedto the field in June of 2005. Five C. chinense Jacq. (PI-594139, PI-438643, PI-438614, PI-435916, and PI-224448);six C. frutescens L (PI-241675, PI-239703, PI-586675, PI-439506, PI-257069, and PI-257051); seven C. baccatum L(PI-260434, PI-281340, PI-238061, PI-439381, PI-370004,PI-267729, and Grif-9354); six C. annuum L (PI-438649, PI-310488, PI-593566, PI-547069, PI-246331, and PI-632921)were selected to represent four pepper cultivated species,

and a cross-section of the geographic range of origin of thesespecies. Plants were fertilized with Peters (NPK fertilizer) at200 ppm in the greenhouse. Two weeks after transplantingto the field, Nature Safe Fertilizer (Advance Turf Solutions,Louisville, KY) containing the elements NPK (10:2:8) wasside-dressed at the rate of 5 lbs 1000 ft−2. Plants were wa-tered twice a week using drip irrigation, and no pesticideswere used.

At harvest, mature fruits of 120 d old were characterizedfor length, width, and weight. Fruits were dried in an ovenat 65◦for 48 h to a constant weight, ground using a mortarand pestle, and sieved to pass through a No. 18 (1 mm) meshscreen. Hot pepper fruit extracts were prepared by shaking20 g dried fruit powder of each accession with 100 mL ofdistilled water with 10 drops of 2% sodium dioctyl sulfo-succinate (Sur-Ten; Aldrich Chemical Company, Milwau-kee, WI, USA) for 1h using Lab-Line Multi-Wrist Shaker(Lab-Line instrument Inc., Melrose Park, IL, USA). Themixture was passed through a double-layer of cheeseclothand squeezed manually. The extracts were then vacuum fil-tered using Buchner funnels. Hot pepper fruit extracts werealso prepared by blending 50 g fresh fruits of each acces-sion with 100 mL of methanol for 2 min. The extracts werefiltered using Buchner funnels.

Cabbage looper eggs were obtained from the Universityof Kentucky, Department of Entomology, Lexington, KY40546 and reared on an artificial diet.[11] Ten replicates of

Growing hot pepper for pest control 561

Table 1. Characteristics† of hot pepper fruits grown at Kentucky State University Research Farm, Franklin County, Kentucky, 2005

Accession Taxon Weight of Fruits, g Plant−1 No of Fruits Plant−1 Fruit Weight, g Fruit Length, cm Fruit Width, cm

PI-224448 C. chinense 509 cd 43 efghi 10.4 c 4.4 d 3.7 aPI-435916 C. chinense 979 b 114 def 9.3 c 3.4 def 2.9 cdePI-438614 C. chinense 964 b 105 defgh 9.9 c 3.7 de 3.2 bcPI-438643 C. chinense 984 b 107 defgh 8.8 c 3.5 de 3.0 bcdPI-594139 C. chinense 495 cde 51 efghi 8.3 cd 3.8 de 3.3 bPI-239703 C. frutescens 37 hi 108 defgh 0.3 h 2.8 efg 0.7 jklmPI-241675 C. frutescens 32 hi 71 efghi 1.0 gh 1.4 h 1.0 hijPI-257051 C. frutescens 46 ghi 85 edfghi 0.6 h 3.2 def 0.6 lmPI-257069 C. frutescens 28 hi 26 i 1.6 fgh 2.9 efg 0.9 jklPI-439506 C. frutescens 25 i 57 efghi 0.4 h 1.6 gh 0.6 klmPI-586675 C. frutescens 217 fgh 195 bc 0.3 h 3.1 def 0.9 ijkPI-238061 C. baccatum 229 fg 398 a 0.6 h 1.4 h 0.9 jklPI-260434 C. baccatum 406 def 391 a 1.3 fgh 3.0 def 0.9 jklmPI-267729 C. baccatum 340 def 24 i 17.0 b 8.0 b 3.0 bcdPI-281340 C. baccatum 402 def 34 ghi 14.5 b 15.3 a 1.9 fPI-370004 C. baccatum 614 c 148 bcd 5.5 ed 7.9 b 1.3 ghPI-439381 C. baccatum 508 cd 158 bcd 4.1 ef 3.9 de 1.2 ghiGrif-9354 C. baccatum 598 c 322 a 2.3 fgh 4.0 de 1.4 gPI-246331 C. annuum 373 def 109 defg 3.8 efg 7.5 b 1.0 hijPI-310488 C. annuum 71 ghi 118 cde 0.7 h 2.1 fgh 0.9 jklPI-438649 C. annuum 1529 a 39 fghi 48.4 a 15.2 a 2.7 dePI-547069 C. annuum 317 ef 203 b 1.6 fgh 4.3 d 0.7 jklmPI-593566 C. annuum 284 f 18 i 14.6 b 6.1 c 2.6 ePI-632921 C. annuum 3 i 31 hi 0.1 h 0.8 h 0.5 m

†Each value in the table is an average of 10 replicates. Values in each column accompanied by the same letter(s) are not significantly different fromeach other (P > 0.05) using Duncan-Waller Least Significant Difference (LSD).

10 third instar larvae were sprayed with hot pepper waterextract at 200 mg fruit powder mL−1 with a fine mist sprayer(Rite Aid, Frankfort, KY) held approximately 6 inches froma 9 cm glass Petri dish. This treatment essentially saturatedthe larvae. Larvae were transferred to plastic Petri dishes(60 × 20 mm) supplied with 3 g of artificial diet and thedishes were covered with lids. Mortality was recorded at 6and 24 hrs. Larvae showing no movement when probed wererecorded as dead. A control set of 10 replicates of 10 lar-vae each were sprayed with distilled water (100 ml distilledwater with 10 drops of 2% Sur-Ten). To validate the bioas-say used in this study, 4 methylketones (2-undecanone, 2-dodecanone, 2-tridecanone, and 2-pentadecanone), knownorganic insecticides [9,10] (Fig. 1) were tested against thethird instar cabbage looper larvae and used as positive con-trol for comparison purposes. Mortality of cabbage looperlarvae were calculated using Abbott’s formula. [12] Meanswere compared using the analysis of variance (ANOVA)procedure. [13]

The methanol extracts were tested against gravid femalespider mites using a diving board bioassay that was devel-oped by Guo et al.[14] The diving board bioassay assemblywas prepared using paper clamps and filter paper strips of0.5 cm × 1.5 cm and 0.2 cm × 1.5 cm. One end of each stripwas clamped by a small binder clip with two strips per clip.Two binder clips were then clamped side by side by a larger

binder clip. This allowed simultaneous tests of two mites.Ten µL of a crude extract was applied onto one of the 0.5 ×1.5 cm paper strips using micropipette. The adjacent stripwas treated with solvent only (methanol). Methanol wasallowed to evaporate completely from the treated and un-treated paper strips. Then, the 0.2 × 1 cm filter paper stripwas placed as a bridge connecting a control and treatedstrips.[14] One gravid female mite (n = 30) was placed inthe center of each bridge and given the freedom to exitover the treatment or control strip. A small mirror placedunder the assembly allowed simultaneous observation ofthe upper and lower surfaces. Exits over treatment or con-trol strips were recorded and exit ratios were determined(treated: control) for each of 30 mites per accession. Exitratios were tested for a significant departure from the ex-pected 1:1 exit ratio by χ2. Repellency data were calculatedusing Probit Analysis.[13]

Attempts were also made to correlate mortality of cab-bage looper and repellency to spider mite with constituentsof fruit extracts, in an attempt to identify the cause of toxi-city and/or repellency. Ten mL of each fruit filtrate (n = 3)were passed through 13 mm GD/X disposable syringe filterof 0.45 µm pore size (Whatman Inc., Clifton, NJ, USA) forfurther purification. One µL of crude extract from each ac-cession (n = 3) was injected into a HP gas chromatograph(GC) model 5890A equipped with a mass spectrometer (HP

562 Antonious et al.

Table 2. Concentrations† of three decanoic acid methyl esters detected in methanol extracts of hot pepper accessions of four Capsicumspecies grown at Kentucky State University Research Farm, Franklin County, Kentucky, 2005

Concentration, µg g−1 fruit

Pentadecanoic Acid Hexadecanoic Acid Octadecanoic AcidAccession Taxon Methyl Ester Methyl Ester Methyl Ester

PI-224448 C. chinense 12 c 41 de 4 bPI-435916 C. chinense 19 c 40 de 149 bPI-438614 C. chinense 29 c 29 de 0 cPI-438643 C. chinense 30 c 30 de 29 bPI-594139 C. chinense 10 c 53 de 76 bPI-239703 C. frutescens 47 c 383 bcde 1547 aPI-241675 C. frutescens 509 ab 504 abcd 968 abPI-257051 C. frutescens 363 bc 970 a 96 bPI-257069 C. frutescens 86 c 255 cde 12 bPI-439506 C. frutescens 187 bc 320 cde 721 abPI-586675 C. frutescens 751 a 503 abcd 0 cPI-238061 C. baccatum 63 c 104 de 367 bPI-260434 C. baccatum 80 c 714 ac 84 bPI-267729 C. baccatum 56 c 64 de 3 bPI-281340 C. baccatum 46 c 24 e 54 bPI-370004 C. baccatum 0 d 25 e 57 bPI-439381 C. baccatum 34 c 859 ab 148 bGrif-9354 C. baccatum 120 c 119 de 128 bPI-246331 C. annuum 88 c 88 de 25 bPI-310488 C. annuum 97 c 173 de 93 bPI-438649 C. annuum 0 d 0 f 0 cPI-547069 C. annuum 31 c 51 de 164 bPI-593566 C. annuum 71 c 0 f 0 cPI-632921 C. annuum 828 a 802 ab 300 b

Statistical comparisons were made between accessions for each compound.†Each value in the table is an average of three replicates. Values in each column accompanied by the same letter(s) are not significantly different fromeach other (P > 0.05) using the analysis of variance [ANOVA] procedure.

5971) operated in total ion monitoring and an automatic in-jector (HP 7673) with electron impact ionization (EI) modeand 70 eV electron energy. The instrument was auto-tunedwith perfluorotributylamine (PFTBA) at m/z 69, 219, and502. GC/MS separations were accomplished using a 25 m×0.20 mm ID capillary column with 0.33 µm film thickness(HP-1). Operating conditions were 230 C, 250 C, and 280 Cfor injector, oven, and detector, respectively with a carriergas (He) flow rate of 5.2 mL min−1. Under these conditions,retention times (Rt ) for capsaicin, and dihydrocapsaicinin pepper extracts were 11.50 and 11.75 min, respectively.Rt for pentadecanoic acid methyl ester, hexadecanoic acidmethyl ester, and octadecanoic acid methyl ester in pepperextracts averaged 18.07, 19.26, and 22.47, respectively. Toconfirm the identity of each compound detected in the fruitextracts, retention times on the column were compared withexternal standard solutions of each compound. Purifiedstandards of capsaicin (N-vanillyl-8-methyl-6-noneamide)and dihydrocapsaicin were obtained from Sigma-AldrichInc. (Saint Louis, MO 63103, USA) and used to preparecalibration curves. Pentadecanoic acid methyl ester, hex-adecanoic acid methyl ester, and octadecanoic acid methylester were obtained from Fisher Scientific Company (Turn-

berry Drive, Hanover Park, IL 60133). Minimum detectablelevels of the two capsaicinoids, capsaicin and dihydrocap-saicin, found in the fruit extracts averaged 0.02 to 0.005 µgg−1 fruit. Minimum detectable levels of the three decanoicacid methyl esters found in the fruit extracts averaged 0.1to 2.0 µg g−1 fruit.

Results and discussion

Hot pepper producers look for varieties that yield largequantities of high quality peppers. Characteristics of in-terest included yield, fruit size and shape, wall thickness,and plant size.[15] Among the 24 field-grown accessions,PI-438649 produced the greatest fruit weight (48.4 g),while PI-632921 produced the lowest fruit weight (0.1 g)(Table 1).

Water extracts of accessions PI-593566 of C. annuum,PI-281340 of C. baccatum, and PI-586675 of C. frutescenswere highly toxic to the cabbage lopper larvae (Fig. 1), themost difficult pest of crucifer crops to control during thepast decade.[16] Using GC/MS, we investigated the con-tents of fruit extracts that may explain the observed dif-ferences in toxicity to 3rd instar larvae of cabbage looper

Growing hot pepper for pest control 563

Fig. 2. Electron impact mass spectrum of (a) pentadecanoic acid methyl ester (C16H32O2), (b) hexadecanoic acid methyl ester(C17H34O2), and (c) octadecanoic acid methyl ester (C19H38O2) detected in the fruits of hot pepper indicating molecular ions ofm/z 256, 270 and 298, respectively along with other characteristic fragment ions. (Continued)

564 Antonious et al.

Fig. 2. (Continued).

and repellency to spider mite among accessions. Three de-canoic acid methyl esters (pentadecanoic acid methyl es-ter, hexadecanoic acid methyl esters, and octadecanoic acidmethyl ester) predominated pepper fruit extracts (Table 2).As shown in Table 3, the three decanoic acid methyl es-ters exhibited the greatest spider mite repellency. AccessionPI-241675 of C. frutescens was considerably repellent tospider mite compared to all other accessions tested. Thisaccession contained significant concentrations of decanoicacid methyl esters (Table 2).

In the crude extracts of the 24 accessions, neither cap-saicin concentration (r = −0.01, P = 0.94) nor dihydrocap-saicin concentration (r = −0.08, P = 0.71) in hot pepperextracts was correlated with χ2 value from the diving boardbioassays. Concentration of capsaicinoids (capsaicin plusdihydrocapsaicin) was also not correlated with the χ2(r =−0.03, P = 0.88) value (data not shown) from cabbagelooper mortality.

Mass spectrometry in total ion mode of hot pepper fruitextracts indicated that the molecular ions at m/z 256, 270,

and 298, which correspond to pentadecanoic acid methylester, hexadecanoic acid methyl ester, and octadecanoic acidmethyl ester, respectively, have two common ion fragmentsat m/z 74 and 87 that can be used for monitoring decanoicacids in hot pepper fruit extracts (Fig. 2 a-c). To test if thethree decanoic acid methyl esters in pepper fruit extractsand/or capsaicinoids (capsaicin and dihydrocapsaicin) arelethal to cabbage looper larvae, pure standards of thesecompounds and four methylketones (Fig. 3) were used incabbage looper bioassay. Bioassays of pure standards ofthe three decanoic acid methyl esters using cabbage looper,Trichopulsia ni larvae have shown that pentadecanoic acidmethyl ester was the most effective (74% mortality) com-pared to hexadecanoic and octadecanoic acid methyl es-ters (Fig. 4). Figure 4 also indicated that capsaicin anddihydrocapsaicin, the major capsaicinoids in hot pepperwere not toxic to cabbage looper. Concentrations of thethree decanoic acid methyl esters varied among hot pepperaccessions (Table 2). Accession PI-586675 (C. frutescens)contained the highest concentration of pentadecanoic acid

Growing hot pepper for pest control 565

Fig. 3. Chemical structures of capsaicin, dihydrocapsaicin, pentadecanoic acid methyl ester, hexadecanoic acid methyl ester andoctadecanoic acid methyl ester detected in the fruits of Capsicum species, and four methyl ketones (2-undecanone, 2-dodecanone,2-tridecanone, and 2-pentadecanone) used for comparison purposes.

methyl ester (571 µg g−1), while accession PI-281340 (C.baccatum) contained low concentration of pentadecanoicacid methyl ester (Table 2). However, cabbage looper mor-tality caused by the two accessions were not significantlydifferent (Fig. 1).

Methyl esters are aliphatic long-chain saturated fattyacids that are common components of plant lipids. Thefatty acids from which they are derived, such as oleic acidand stearic acid and their esters are not substances that onewould expect to be carcinogenic. These same fatty acids, inthe form of their esters with aliphatic alcohols, are com-

Fig. 4. Mortality of 3rd instar larvae of cabbage looper, Trichopulsia ni (Hubner) sprayed with 1 mg mL−1 solutions of two capsaicinoids,three dodecanoic acid methyl esters, and four methyl ketones prepared in methanol. Bars accompanied by different letter(s) for eachexposure period indicated significant differences (P < 0.05) using analysis of variance (ANOVA) procedure (SAS Institute, 2001).[13]

ponents of natural waxes. Extracts from pepper fruits mayprovide an opportunity for use in crop protection as alter-native to synthetic pesticides.

Plants produce a vast array of volatiles and tannins thatplay an important role in plant defense.[17] Hot pepper alsocontain significant amount of tannins[18,19] that break downand behave as toxins and deterrents, particularly for insectsthat do not typically feed on diets rich in tannins.[20]

It could be concluded from this study that in most casesthe amount of the three decanoic acid methyl esters in fruitextracts was insufficient to explain the observed mortality of

566 Antonious et al.

Table 3. Repellency of three decanoic acid methyl esters and hotpepper fruit extracts prepared from 24 accessions of four culti-vated Capsicum species as measured by the spider mite divingboard bioassay

Total exits*

Sample Treated Control χ2

Pentadecanoic Acid ME† 2 28 22.53**Hexadecanoic Acid ME† 0 30 30.00**Octadecanoic Acid ME† 9 21 4.80*Pentadecanoic Acid ME‡ 14 16 0.13ns

Hexadecanoic Acid ME‡ 13 17 0.53ns

Octadecanoic Acid ME‡ 16 14 0.13ns

PI-224448 (C. chinense) 10 20 3.33ns

PI-435916 (C. chinense) 17 13 0.53ns

PI-438614 (C. chinense) 16 14 0.13ns

PI-438643 (C. chinense) 10 20 3.33ns

PI-594139 (C. chinense) 15 15 0.00ns

PI-239703 (C. frutescens) 18 12 1.20ns

PI-241675 (C. frutescens) 4 26 16.13**PI-257051 (C. frutescens) 13 17 0.53ns

PI-257069 (C. frutescens) 14 16 0.13ns

PI-439506 (C. frutescens) 13 17 0.53ns

PI-586675 (C. frutescens) 13 17 0.53ns

PI-238061 (C. baccatum) 10 20 3.33ns

PI-260434 (C. baccatum) 14 16 0.13ns

PI-267729 (C. baccatum) 13 17 0.53ns

PI-281340 (C. baccatum) 16 14 0.13ns

PI-370004 (C. baccatum) 11 19 2.13ns

PI-439381 (C. baccatum) 16 14 0.13ns

Grif-9354 (C. baccatum) 14 16 0.13ns

PI-246331 (C. annuum) 15 15 0.00ns

PI-310488 (C. annuum) 9 21 4.80*PI-547069 (C. annuum) 14 16 0.13ns

PI-593566 (C. annuum) 15 15 0.00ns

PI-632921 (C. annuum) 16 14 0.13ns

PI-438649 (C. annuum) 12 18 1.20ns

†The exit ratio is the ratio of the number of mites exiting over the hotpepper extract and number exiting over the control (methanol extract).The expected ratio used to calculate χ2 was 1:1.∗Significant departure at P < 0.05 and highly ∗∗significant departure atP < 0.01 from an expected ratio as determined by χ2.†Represents 1000ppm.‡represents 100ppm.

cabbage looper and repellency of spider mites. Some otherunidentified compounds in the crude extracts are playinga role in mortality and repellency, either directly as toxicmaterials or in some synergistic effects involving more thanone chemical compound. The results suggested that crudeextracts from pepper fruits can be explored for developingnatural products for use as biodegradable alternatives tosynthetic insecticides/acaricides. Using repellent chemicalsfor crop protection is a unique way to prevent insects andspider mites from laying eggs on target plants and prevent-ing leaf and fruit damage. Accessions PI-593566 of C. an-nuum (Fig.1) and PI-241675 of C. frutescens (Table 3) might

be incorporated into plant breeding programs to producefruit with high concentration of pest control agents.

Acknowledgments

We thank John Snyder for his assistance in statistical analy-ses, and Kenneth Haynes for providing cabbage looper eggs.This investigation was supported by a grant from USDA/Corporative State Research, Education, and Extension Ser-vice to Kentucky State University under agreement No.KYX-2004-15102.

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[2] Carruthers, R.I. Invasive species research in the United Sates ofAgriculture. Pest Management Sci. 2003, 59, 827–834.

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[14] Guo, Z.; Weston, P.A.; Snyder, J.C. Repellency to two-spotted spidermite, Tetranychus urticae Koch, as related to leaf surface chemistryof Lycopersicon hirsutum accessions. J. Chem. Ecol. 1993, 19, 2965–299.

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