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1.
Summary. Delia antiqua (Diptera: Anthomyiidae) females lay eggs between the leaves of onion plants or in the soil around the base of the plants,
then the maggots feed on the onion bulb and roots causing rapid secondary infection by fungi and bacteria. It is well known
that the first sensory modality used by the onion fly is vision, therefore the shape (vertical narrow cylinders) and colour
(yellow) of the plant play a crucial role in the recognition of a potential host plant. In the past it has been shown that
n-dipropyl disulfide (Pr2S2), a typical component of onion volatiles, is an important chemical host plant cue. We extracted host leaf surface to verify
if Pr2S2 is the major chemical oviposition stimulant and to determine if other as yet unknown substances may play a role in host-plant
selection. We confirmed that the females laid more eggs around onion plants with leaves than when only the onion bulb was
present and that the odour of chopped onion stimulates oviposition. Extraction of the surface of onion leaves revealed that
only the apolar fraction contained substances that stimulate egg-laying in D. antiqua. GC-EAD analysis indicated that a minor constituent, Pr2S2, is perceived by the olfactory receptor on the antennae of the onion fly females. This confirmed the importance of Pr2S2 as oviposition stimulant. Contact with the polar fraction did not stimulate egg-laying behaviour in this Delia species. We discuss the oviposition strategy of D. antiqua in comparison with its closely related species, D. radicum, in which the oviposition behaviour is stimulated mainly through contact with the cabbage leaf surface and only partially
by the host volatiles. 相似文献
2.
Peter Roessingh Katja H. Hora S. Ying Fung Anja Peltenburg Steph B. J. Menken 《Chemoecology》2000,10(1):41-47
Summary. The sugar alcohol dulcitol is a strong feeding stimulant for larvae of the small ermine moth Yponomeuta cagnagellus. In this paper we tested the hypothesis that dulcitol also acts as an oviposition stimulant for this species. We found that
the sugar-alcohol dulcitol was present on the surface of the host Euonymus europaeus. We also showed that (as yet unidentified compounds) can be systemically transferred (i.e. by uptake and transport via the
vascular system) from E. europaeus, to the non-host Crataegus monogyna and stimulate oviposition. However, no evidence was found that this stimulatory activity was due to dulcitol. Systemic enrichment
of C. monogyna with dulcitol did not induce oviposition on this plant. Neither was the application of pure dulcitol on artificial twigs
effective. In addition it was shown that when dulcitol was removed from host plant extracts, oviposition stimulatory activity
was retained in the fraction without dulcitol. Synergism between dulcitol and other stimulants could not be demonstrated,
however, high concentrations of dulcitol in combination with the main stimulant(s) showed a trend towards enhanced oviposition.
It is concluded that the sugar alcohol dulcitol can only play a limited role in adult host acceptance behaviour. The hypothesis
that a host shift in the genus Yponomeuta from Celastraceae to Rosaceae might have been facilitated by the presence of small amounts of dulcitol in Rosaceae therefore
needs to be restricted to larval feeding behaviour.
Received 20 August 1999; accepted 6 December 1999 相似文献
3.
Summary Differential acceptance of garlic mustard,Alliaria petiolata byPieris rapae L. andP. napi oleracea is explained by their differential sensitivities to oviposition stimulants and deterrents in the plant. Fractions containing the stimulants and deterrents were isolated by solvent partitioning between water and n-butanol and by open-column chromatography followed by HPLC.P. napi oleracea showed no preference when offered a choice ofA. petiolata or cabbage, but was strongly stimulated to oviposit by post-butanol water extracts ofA. petiolata. The most abundant glucosinolate in this extract was identified as sinigrin, which could explain the high degree of stimulatory activity.P. rapae preferred cabbage plants overA. petiolata, and the relatively low stimulatory activity was also associated with the glucosinolate-containing aqueous extract. However, this species was strongly stimulated by a fraction that contained small amounts of glucotropaeolin along with unknown compounds. Deterrents to both species were found in the butanol extract fromA. petiolata, andP. napi oleracea was more sensitive thanP. rapae to these deterrents. Some HPLC fractions from the BuOH extract were strongly deterrent toP. napi oleracea, but were inactive toP. rapae. The ecological significance of these behavioral differences between the twoPieris species is discussed. 相似文献
4.
Summary. We tested the hypothesis that Daphne gnidium is an ancestral host plant of Lobesia botrana. To this end, we studied the oviposition response of this moth to various aerial organs of this plant. Our results show that
females prefer to lay eggs on daphne berries rather than on grapes (cv. chasselas) and that polar surface extracts of daphne
berries and leaves strongly stimulate oviposition in a dosedependant way, whereas flower extracts are weakly stimulant and
branch extracts are inactive or deterrent for oviposition. Furthermore, a total extract of daphne berries stimulates oviposition
in semi-natural conditions when applied onto fresh grapes. Oviposition stimulants from berries were isolated by HPLC coupled
with a dual-choice oviposition bioassay. The ecological value of D. gnidium for L. botrana is discussed and the possible use of oviposition stimulants from daphne, contrasting with the oviposition signal of the cultivated
host plant, is proposed in the perspective of developing behavioural manipulation methods such as stimulo-deterrent diversionary
strategies compatible with IPM programs. 相似文献
5.
Leaf surface chemicals stimulating oviposition byPieris rapae (Lepidoptera: Pieridae) on cabbage 总被引:3,自引:0,他引:3
Summary The chemical stimulation of oviposition byPieris rapae on cabbage was investigated by leaf washing and extraction. Isolation of the stimulant by various chromatographic techniques was monitored by a bioassay using Sieva bean as a surrogate host plant. Cold water, chloroform, or chloroform followed by cold water washes failed to release the stimulant from leaf surfaces. Boiling water or chloroform followed by methanol was required. The most active stimulatory compound was identified as 3-indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates were identified as sinigrin, which was only slightly active, and glucoiberin, which was completely inactive as a stimulant. The significance of the selective response ofP. rapae andP. brassicae to different glucosinolates and the implications of the binding of polar allelochemicals to leaf surfaces is discussed with respect to host utilization and perception mechanisms of pierids. 相似文献
6.
Olivier Roux Charles Gers Josèphe Nathan Tene-Ghomsi Laurence Arvanitakis Dominique Bordat Luc Legal 《Chemoecology》2007,17(1):13-18
Summary. Cotesia plutellae is a specialist parasitoid of Plutella xylostella. This specificity is potentially under the control of several factors before and after oviposition. Thereby, the stimuli
that lead female parasitoids to host locations and to oviposition, might be at the basis of the specificity. We explore here
the response of C. plutellae females exposed to host cuticular lipids. A total cuticular lipid extract of host caterpillars was fractionated into a hydrocarbon
fraction and a non-hydrocarbon fraction. Neither fraction alone had any effect on oviposition behaviour in C. plutellae but the hydrocarbon fraction alone did seem to have a positive effect on the rate of antennal contact by the females. To
induce oviposition behaviour, both fractions were necessary and reflect cooperation between at least one compound in each
fraction. Identification of cuticular lipids shows that hydrocarbons were dominant (77%). Non-hydrocarbon compounds were mainly
represented by 15-nonacosanone (18% of the total lipid extract). This ketone is rare in insect cuticle lipids and is thought
to originate from the cabbage epicuticle where it is dominant with n-C29 and 14- and 15-nonacosanol also found among the cuticular lipids of the host caterpillar. 相似文献
7.
Ruurd de Jong Nevile Maher Bruno Patrian Erich St?dler Tammo Winkler 《Chemoecology》2000,10(4):205-209
Summary. Two recently identified compounds ("CIFs"), present on the leaf surface of Brassica oleracea (cabbage), are the strongest oviposition stimulants known for the cabbage root fly, Delia radicum. Cabbage leaves contain these compounds in extremely low concentrations, and the amount of CIFs obtained from purifying leaf
extracts was so small that it limited further research. We were able to purify far more of these two compounds from the roots
of Brassica napus var. napobrassica (rutabaga). Apart from being a richer source of CIFs, rutabaga roots are considerably easier to collect and process than
leaves. In addition, we isolated and identified a new CIF compound from the roots that is also very active in stimulating
oviposition in the cabbage root fly.
Received 26 May 2000; accepted 26 July 2000 相似文献
8.
Summary. The cabbage root fly possesses highly specialised and extremely sensitive receptors for “CIF”, a group of compounds present
on cabbage leaves in very small amounts, and the strongest oviposition stimulants known. Here we present evidence that the
same receptors are sensitive to a methanol extract of cabbage root fly eggs, which may contain the fly's host marking pheromone.
Based on these results, the possible role of CIF in cabbage root fly behaviour and in cabbage plants is discussed.
Received 4 April 2001; accepted 24 September 2001. 相似文献
9.
Summary. The ability to perceive and respond to phytochemicals that reliably indicate poor suitability of a potential host plant confers
a selective advantage to ovipositing female swallowtail butterflies. Papilio glaucus females are generalists that nonetheless do not oviposit on red bay (Persea borbonia: Lauraceae). Red bay is toxic to P. glaucus neonates but is commonly found in habitats alongside their principal host plant, Magnolia virginiana, in central Florida. The hypothesis that deterrent compounds present in the leaves of red bay mediate its rejection by P. glaucus was evaluated in our study. Florida populations of P. glaucus did not oviposit on host leaves sprayed with the methanol extract of red bay foliage, although they accepted solvent-treated
and untreated tulip tree leaves in 3 choice bioassays. Additionally, tulip tree leaves sprayed with methanolic extracts of
red bay also deterred oviposition by P. glaucus females from Ohio, Kentucky and Pennsylvania, although these populations do
not naturally encounter red bay. Clearly, deterrent compounds found within this non-host are the basis of its rejection by
populations of P. glaucus and such recognition is fundamental to the species, not just a reflection of local adaptations.
Received 2 April 1999; accepted 11 June 1999. 相似文献
10.
Summary. In earlier investigations on host plant discrimination of leaf beetles glucosinolates were described as feeding stimulants
for the Brassicaceae specialist Phaedon cochleariae F. (Coleoptera: Chrysomelidae). However, since these findings could not be confirmed in later studies offering 2-propenylglucosinolate
in concentrations corresponding to those detected in host plant leaf material, the identification of feeding stimulants of
this leaf beetle species remained unclear. In order to investigate which compounds of the host plant Sinapis alba (Brassicaceae) are involved in feeding stimulation, leaf extracts of different polarities were tested in bioassays with adults
of P. cochleariae. Number of feeding beetles and net consumption rates were highest on pea leaves painted with methanol extracts of S. alba, whereas weak feeding responses were also detectable for hexane extracts. In subsequent bioassay-guided fractionations of
methanol extracts with semi-preparative high performance liquid chromatography, two distinct fractions, one containing glucosinolates
and another containing flavonoids, were found to stimulate beetles to feed to variable degrees. Other collected fractions
had zero activity. The combination of both active fractions evoked significantly higher consumption rates and stimulated more
beetles to feed than fractions tested individually. At least one compound of each fraction, among these the main glucosinolate
of S. alba, 4-hydroxybenzylglucosinolate, act additively. Effects of two different naturally-occurring ratios of glucosinolates and
flavonoids on the strength of feeding responses were investigated by use of extracts of two sets of host plants differently
exposed to radiation. One set was outdoors-exposed, whereas the second set was kept in the greenhouse. However, the feeding
behaviour of P. cochleariae was not affected by the significantly different relative compositions of both compound classes in the host material. In conclusion,
mustard leaf beetles need a combination of distinct plant metabolites acting in concert for feeding stimulation, whereby the
mere presence of these stimulants, but probably not the ratio of involved compounds, determines their feeding response. 相似文献
11.
Keiichi Honda Hiroshi Minematsu Ken’ichiro Muta Hisashi ?mura Wataru Nishii 《Chemoecology》2012,22(1):55-63
The sulfur butterfly, Colias erate, utilizes various legumes as host plants. We examined the chemical constituents of its primary host plant, Trifolium repens (white clover), to identify phytochemicals inducing oviposition by C. erate females. Since one of the four aqueous subfractions prepared from a methanolic extract of the plant has previously been shown
to be the most responsible for the oviposition-stimulatory activity exerted by the plant, chemical analyses were conducted
of the fraction concerned. Activity-directed fractionation of the subfraction by ion-exchange chromatography revealed that
the key substance(s) resided in the neutral fraction. Preparative TLC of the neutral fraction and subsequent spectral analyses
identified d-(+)-pinitol, glycerin, methyl β-d-glucoside, and myo-inositol as characteristic components together with ubiquitous sugars (e.g., sucrose and glucose). Of these, only pinitol
singly evoked significant oviposition responses at concentrations over 0.05%. In dual-choice bioassays, however, females laid
significantly more eggs on pinitol solutions admixed with glycerin or methyl β-d-glucoside than on pinitol alone. Two cyanoglucosides, linamarin, and lotaustralin, occurring in the other aqueous subfractions,
also synergistically increased the oviposition response in combination with pinitol. The results clearly indicated that pinitol
is a crucial oviposition stimulant involved in host recognition, while glycerin, methyl β-d-glucoside, linamarin, and lotaustralin function as synergists. We further examined the oviposition responses of C. erate females to aqueous fractions, along with their chemical compositions, that had been prepared from five other host plants
and a non-host plant, Aristolochia debilis (Aristolochiaceae), on which oviposition occasionally took place in an outdoor cage during the experiments.
The plant species accepted by ovipositing females were all found to contain pinitol in amounts enough to induce egg laying
by the butterfly, thus leading to the conclusion that pinitol serves as the essential mediator in recognizing and accepting
potential host plants. 相似文献
12.
Summary. Summary. Oilseed rape, Brassica napus L. (cv Express),
plants were grown under three different sulphur regimes:
sulphur-free (S0), normal sulphur (Sn, normal field concentration)
and a sulphur-rich (S+, 2 × concentration of Sn). We
performed dual choice oviposition assays with the diamondback
moth, Plutella xylostella, using real plants and,
for the first time with this insect, artificial leaves sprayed
with methanolic leaf-surface extracts. The results mirrored
those of a separate study of preferences for whole plants.
Females laid more eggs on surrogate leaves that were
treated with Sn extracts than on S0 plants, while only a
slight, not significant, difference was observed between
extracts of normal and sulphur-rich plants. This shows
that chemical compounds on the leaf surface mediate the
oviposition preference and that the female insect can
perceive the quality of the host-plants in terms of their
fertilisation status.Since leaf volatiles are known to be oviposition stimulants,
we investigated the effects of leaf-surface extracts on
insect olfactory responses using electroantennograms
(EAGs). In agreement with the behavioural data, we found
that extracts of sulphur-treated plants yielded higher EAG
amplitudes than the S0 extracts. Since the leaf content of the
volatiles isothiocyanates is influenced by sulphur nutrition,
we analysed the extracts for these compounds. Above the
detection threshold of our GC-MS system, no isothiocyanates
were found. Thus, other compounds present in the
surface extracts must be perceived by the antenna.However, the HPLC analysis revealed 11 different
glucosinolates. Progoitrin (2-Hydroxy-3-butenyl) and
gluconapoleiferin (2-Hydroxy-4-pentenyl), which belong to
the hydroxy-alkene class of glucosinolates, were the most
abundant compounds. The total glucosinolate content
sharply increased from S0 to Sn plants, whereas it was slightly
lower in n versus S+ plants. Since it is known that glucosinolates
can stimulate oviposition, it seems likely that the
increased content we observed was influencing the insect
preference in this study too. 相似文献
13.
Summary. In the natural habitat of Papilio polytes, a
Rutaceae feeder utilizing Toddalia asiatica as a major host plant, some other rutaceous plants such as
Murraya paniculata
(abundant) and Glycosmis citrifolia (relatively rare)
occur sympatrically as potential hosts. Whereas
G. citrifolia
is occasionally infested in the field, M. paniculata
remains entirely unexploited by the butterfly. We thus examined the
phytochemical mechanisms that can explain the differential
acceptance of the two plants by ovipositing females of
P. polytes. The foliage of
G. citrifolia was found to readily
induce oviposition and females deposited eggs in response
to a methanolic extract of the plant. Stimulatory activity-directed
fractionation of the extract revealed the presence of
two characteristic compounds, trans-4-hydroxy-N-methylproline
and 2-C-methylerythronic acid, known to serve as
oviposition stimulants for the butterfly. In addition, larvae
performed as well or better onG. citrifolia
as on T. asiatica.
Similar examination of the inhibitory chemical constituents
of M. paniculata led to the isolation of an oviposition deterrent. The compound, identified as trigonelline
(N-methylpyridine-
3-carboxylic acid), exhibited moderate
oviposition deterrency to females. These results combined
with our previous data are in agreement with the observed
differential utilization of the two plants by
P. polytes in the field. 相似文献
14.
We examined the behavior of individual mature female Mediterranean fruit flies (medflies), Ceratitis capitata (Wiedemann), transferred from a holding cage without fruit to a clean host kumquat fruit already occupied by another medfly
female engaged in ovipositional behavior. A significantly greater proportion of transferred (=test) ovipositionally naive
females initiated ovipositor boring into a fruit in the presence than in the absence of an occupying medfly. Moreover, test
females commenced boring significantly sooner in the presence than in the absence of another medfly. Interestingly, similar
results occurred when a test medfly was transferred to a kumquat occupied by an ovipositing female oriental fruit fly, Bactrocera dorsalis Hendel. In contrast, there was no enhancement of propensity to bore when a test medfly was transferred to a kumquat occupied
by a female Biosteres arisanus (Sonan), a parasitoid attacking medfly eggs. The principal proximate stimulus giving rise to the higher tendency to oviposit
of a test medfly in the presence of an occupying medfly or oriental fruit fly appeared to be wing-waving by the occupant during
an encounter. We consider our findings to be good evidence of socially facilitated ovipositional behavior in ovipositionally
naive medflies, and suggest that such females may benefit from acquisition of a cue demonstrating the acceptability of a host
for oviposition.
Received: 7 July 1997 / Accepted after revision: 30 August 1997 相似文献
15.
Alzanzalakhet, Melia azedarach L. (Sapindales: Meliaceae) is a common medicinal plant which is found in Hail desert in Saudi Arabia and traditionally used for various purposes. In this study, toxin effectiveness of the ethanolic, acetonic, and aqueous extracts of M. azedarach leaves was tested to determine a larvicidal activity against the cucurbit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae). Different treatments with M. azedarach extracts varied significantly in their impact on mortality of D. ciliatus larvae. Results showed that all tested extracts in the three solvents exerted a positive pattern for reducing larvae of D. ciliatus. However, the ethanolic M. azedarach extract was the most potent compared with other tested solvents. The highest mortality of the D. ciliatus larvae was shown to be 94%, 74%, and 68% when the concentration was 1?×?105?ppm for ethanolic, acetonic, and aqueous extracts, respectively. In contrast, the concentration 1?×?101?ppm resulted in the lowest mortality of D. ciliatus larvae at 40%, 34%, and 12% for ethanolic, acetonic, and aqueous extracts, respectively. Overall, the results of this study suggest that the ethanolic extract of M. azedarach leaves may be used as a sustainable method for controlling D. ciliatus larvae. 相似文献
16.
Leaf surface compound fromBrassica oleracea (Cruciferae) induces oviposition byPieris brassicae (Lepidoptera: Pieridae) 总被引:4,自引:0,他引:4
Joop J. A. van Loon Anton Blaakmeer Frans C. Griepink Teris A. van Beek Louis M. Schoonhoven Aede de Groot 《Chemoecology》1992,3(1):39-44
Summary Chemicals present on the surface of cabbage (Brassica oleracea L.) leaves were extracted by dipping these leaves for 3 s in dichloromethane followed by a 3 s dip in methanol. When offered in dual choice bioassays using green paper cards as a substrate, the methanol extract stimulated oviposition activity byPieris brassicae L. (Lepidoptera: Pieridae) females. The oviposition stimulant was isolated using medium pressure liquid chromatography, reversed-phase HPLC, ion-pair HPLC and ion exchange chromatography. Using1H-NMR spectroscopy, the stimulant could be identified as glucobrassicin (3-indolyl-methyl-glucosinolate). When pure glucobrassicin was offered at a dose identical to that in the crude methanol extract, butterflies did not discriminate between these two substrates in a dual choice test. It is argued that a high sensitivity for indole glucosinolates as host recognition factors may confer an adaptive value for these specialist crucifer feeders. The nutritional significance of their precursor tryptophan and the non-volatile nature of the aglycones formed upon enzymic hydrolysis in damaged tissues are proposed as properties of indole glucosinolates that contribute to this possible adaptive advantage. 相似文献
17.
Summary. Previous studies indicated the presence of antennally-active compounds in extracts of eggs laid by female cabbage root flies,
Delia radicum, that stimulated oviposition by conspecific females. We confirmed that previously laid D. radicum eggs stimulated oviposition by other D. radicum females, in a dose-dependent manner. Methanol extracts of conspecific eggs stimulated oviposition by females D. radicum, whereas egg extracts of D. antiqua and Psila rosae had no effect. Electrophysiological recordings from the tarsal sensilla of D. radicum females indicated that neurones of the C5 sensillum responded to the egg extracts from both D. radicum and D. antiqua, but not P. rosae. Chemical analysis revealed that the extract of eggs from D. radicum contained the thia-triaza-fluorene compound, 1,2-dihydro-3-thia-4,10,10b-triaza-cyclopenta[.a.]fluorene-1-carboxylic acid
(CIF-1), an oviposition stimulant found previously only in cruciferous plants. Another potentially active component has yet
to be identified. 相似文献
18.
Hiroe Yasui Sadao Wakamura Norio Arakaki Mitsunobu Kishita Yasutsune Sadoyama 《Chemoecology》2003,13(2):75-80
Summary. Ether extract of the abdominal gland of female black
chafers Holotrichia loochooana loochooana (Sawada) (Coleoptera:
Scarabaeidae) induced a series of pre-mating behaviors that included
short-distance orientation, mounting and abdominal bending toward
females in the laboratory. When the extract was chromatographed on a
silica gel column, the activity was eluted with 50% ether in hexane and
ether fractions. GC-MS analyses revealed that both the active fractions
contained anthranilic acid (2-aminobenzoic acid) as a major compound.
When partitioned to basic, acidic and amphoteric fractions, pheromonal
activity was observed with the latter two fractions and anthranilic acid
was detected in these fractions by HPLC analyses. The amount of
anthranilic acid in the female extract was estimated to be ca. 1.3
μg/female. Authentic anthranilic acid induced pre-mating behavior in
males of at levels equal to that elicited by the compound in the
extract. It also attracted male beetles to the traps in the field.
Received 29 October 2002; accepted 9 January 2003.
R1D="
Correspondence to:Hiroe Yasui, e-mail:yasui@affrc.go.jp 相似文献
19.
Summary. Surrogate leaves treated with methanolic leaf
surface extracts of Brassica napus L. (cv Express) plants
that received three different sulphur fertilisation treatments
showed even more marked differences by the oviposition
choice of Delia radicum L. than the potted plants. This
confirms that the oviposition preference of D. radicum is
mediated by chemical compounds on the leaf surface and
that the quality of host-plants in terms of their nutrition
status can be perceived by the female insect.The oviposition data were positively correlated with the
content of fractionated surface extracts containing either
CIF (cabbage identification factor; 1,2-dehydro-3-thia-
4,10,10b-triaza-cyclopenta[.a.]fluorine-1-carboxylic acid)
or glucosinolates. Electrophysiological recordings from the
tarsal chemoreceptor sensilla C5 and D3,4 showed that receptor
neurons react to glucosinolate- and CIF-fractions. We
found that the chemosensory activity of specific glucosinolate-
and CIF-receptor neurons corresponded with the
respective behavioural activity in the oviposition choice
assays. The responses of D. radicum to glucosinolates in
the electrophysiological recordings studies corresponded
to the observed oviposition preference on plants or artificial
leaves characterised with an higher amount of glucosinolates
on leave surfaces. The presented data suggested
that CIF and glucosinolates are involved in host-plant
preference of D. radicum and are perceived by tarsal
chemoreceptors. 相似文献
20.
Ethyl alcohol, acetone, and petroleum ether extracts of three plant species belonging to three different botanical families [Strychnos nux-vomica (Loganiaceae), Euphorbia lathyrus (Euphorbiaceae), and Datura stramonlum (Solanaceae)], a chemical insecticide; profenofos and their combinations were tested against second and fourth instars of Spodoptera littoralis under lab conditions. Results revealed that the ethanol extract of S. nux-vomica was the most effective among all plant extracts, where the corrected mortality% were 92, 81, 58, and 27% to 2nd instar and 89, 74, 34, and 11% to 4th instar at concentrations 0.5, 0.25, 0.125, and 0.0625%, respectively. Calculated LC50's were 0.11, 0.22, and 0.34% to 2nd instar and 0.17, 0.37, and 0.52% to 4th instar for ethanol, petroleum ether, and acetone extracts, respectively. Acetone extracts of all plants were of lower effect. The chemical insecticide profenofos displayed higher efficacy than plant extracts (LC50 = 0.002 and 0.003% for S. littoralis 2nd and 4th larval instars, respectively). The co-toxicity factor reached 76 and 60 when mixing S. nux-vomica + profenofos and D. stramonlum + profenofos at ratio 1:1 against S. littoralis 2nd instar larvae, thus indicating a potentiating effect. While treatment of the 4th instar larvae by the same mixtures resulted in a co-toxicity factor below 20 at all mixing ratios indicating, only, an additive effect against this instar. 相似文献