Melia azedarach Extracts: A Potential Tool for Insect Pest Management

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1 2 Melia azedarach Extracts: A Potential Tool for Insect Pest Management M.T. DEFAGÓ 1, A. MANGEAUD 1, V. BENSOVSKY 1, C. TRILLO 1, C. CARPINELLA 2, S. PALACIOS 2 AND G. VALLADARES 1* Abstract Plant derivatives possessing insect repellent and antifeedant properties could offer an alternative approach for managing crop pests and dealing with insect-transmitted diseases. This chapter summarizes results from studies on insecticidal effects of Melia azedarach extracts from Central Argentina. Extracts from different plant structures (green/ripe fruits, green/senescent leaves) and a variety of insect feeding strategies have been considered. Antifeedant effects were tested on more than 23 species in laboratory choice tests. Further effects on insect feeding and survival were studied in no-choice tests on 12 species. In the choice tests, M. azedarach extracts strongly deterred feeding in most of the species, with those in Coleoptera being particularly sensitive. Increased mortality rates, reduced food consumption, lower body weight and delayed development were recorded in no-choice tests. Increases in mortality might be related to the strong antifeedant activity of the extracts. Results from other authors are also reviewed, in order to provide an updated assessment of M. azedarach extract activity. Key words : Allelochemicals, Antifeedant, Melia azedarach, Insect, Toxin, Pesticides Introduction Increasing concern about the risks from synthetic insecticides to the environment and human health has lead to a major trend in current pest 1. Centro de Investigaciones Entomológicas de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 1611, (X5016GCA) Córdoba, Argentina. 2. Laboratorio de Química Fina y Productos Naturales, Facultad de Ciencias Químicas, Universidad Católica de Córdoba, Camino a Alta Gracia Km.10- (5000), Córdoba, Argentina. * Corresponding author : gvalladares@efn.uncor.edu

2 18 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V management, which involves searching for less hazardous chemicals or biologically based products (Isman, 2006). Botanical products fit within this strategy, being biodegradable and effective against pests without harming beneficial insects (Hasseeb et al., 2004). Particularly interesting are plant allelochemicals that render plants unattractive or unpalatable (Saxena, 1987; Silva et al., 2002). Many plant allelochemicals have shown feeding or oviposition deterrent (Bernays & Chapman, 1994), repellent and growth regulating activity (Sadek, 2003; Schmutterer, 1990; Senthil Nathan et al., 2006). In this context, interesting insecticidal potency has been found in the "Chinaberry tree" Melia azedarach L., which occurs abundantly in Argentina (Lee et al., 1991; Schmutterer, 1989, 1995; Valladares et al., 1997). Insects may respond differently to allelochemicals depending on their life-stage and trophic specialization (Bernays, 1999; Glendinning, 2002; Jolivet, 1998; Karban & Agrawal, 2002). Generalists seem to be less sensitive to deterrents than their more specific relatives (Bernays, 2001; Bernays & Chapman, 1994), whereas specialists would tolerate or detoxify fewer secondary substances (Guillet et al., 2000; Jolivet, 1998). Here we analyze effects of M. azedarach extracts considering insects with various feeding strategies, including agricultural and sanitary pests, with emphasis on our tests using extracts and insects from Central Argentina. Antifeedant, Repellent and Oviposition Deterrent Effects Herbivore insects Chewers A variety of preparations from crude extracts of different parts of M. azedarach plants have been applied to assess antifeedant activity. Leaf and fruit extracts of M. azedarach showed antifeedant activity on insects of various Orders, including Saltatoria, Heteroptera, Homoptera, Coleoptera, Lepidoptera and Diptera (Ascher et al., 1995). Results from our experiments showed (Table 1) that extracts from senescent and green leaves as well as ripe and unripe fruits from Argentinian M. azedarach extracts inhibited feeding activity in several chewing insects in the Orders Coleoptera, Lepidoptera and Orthoptera. Ripe fruit extracts deterred feeding in all Coleoptera species (Table 1), including specialists and generalists, and usually with values of antifeedant index (AI) higher than 75%, which is considered a strong deterrent effect (Hassanali & Bentley, 1986). The lowest response to fruit extract within this order was found on Sitophylus oryzae, which instead was strongly affected by senescent leaf extract. Strong antifeedant effects of M. azedarach extracts have also been reported for other grain feeding curculionids (Fernandes et al., 1996; Palma & Serrano, 1997), although lack of effects have also been found on insects belonging to this family (Imti & Zudir, 1997).

3 Melia azedarach Extracts: A Potential Tool for Insect Pest Management 19 Table 1. Results from feedig choice tests with M. azedarach extracts and insect chewing species (Results at 24h) ORDER : LEPIDOPTERA Host Extract Insect AI d Dosage range a type stage c (%) (%) Fam: Arctiidae Spilosoma virginica P SL b L 74,4* 10 RF L 96,0* 2 Fam: Noctuidae Anticarsia gemmatalis O SL L 88,3* 10 RF L 86,0* 10 Rachiplusia nu P SL L 53,8* 10 RF L 22,0 10 Spodoptera frugiperda P RF L 60,0* 10 Spodoptera ornithogalli P SL L 40,2 5 Spodoptera eridania P SL L 83,1* 2 RF L 100* 2 Fam: Pieridae Colias lesbia O SL L 100* 10 RF L 76,1* 2 ORDER: COLEOPTERA Fam: Curculionidae Sitophylus oryzae P SL A 100* 10 RF A 51,8* 10 Pantomorus leucoloma P RF A 81,0* 2 Priocyphus bosqui U RF A 95,0* 10 Fam: Tenebrionidae Tribolium confusum P RF A 88,4* 10 Fam: Coccinellidae Epilachna paenulata O SL A 100* 10 RF A 90,0* 2 SL L 100* 10 RF L 88,0* 10 Fam: Chrysomelidae Diabrotica speciosa P SL A 100* 10 SL A 100* 10 M RF L 65,7* 10 Chrysodina sp. P RF A 100* 10 Epitrix argentinensis O RF A 97,0* 10 Eumolpinae sp. U RF A 100* 5 Plagiodera erypthroptera O RF A 91,0* 2 Xanthogaleruca luteola M SL A 100* 10 RF A 100* 10 RF L 86,4* 2 GL A 100* 10 UF A 93,8* 10 Fam: Lagridae U SL A 75,8* 5 ORDER: ORTHOPTERA Fam: Romaleidae Cromachris miles P RF N 72,0* 10 a P: Polyphagous, O: Oligophagous, M: Monophagous, U: unknown b RF, Ripe fruit; SL, Senescent leaf; UF, Unripe fruit; GL, Green leaf. c A= Adult, L= Larva, N= Nymph. d AI: Antifeedant index = [(1- treatment consumption/ control consumption) x 100] * Consumption significantly lower on extract treated food, p< 0.05, Wilcoxon signed paire rank test

4 20 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V A strong antifeedant activity was also found on various Chrysomelidae species displaying a range of feeding specificity (Carpinella et al., 2003). Ventura and Ito (2000) observed antifeedant effects on Diabrotica speciosa for M. azedarach flower, fruit and stem, but not for leaf extracts. In our tests, extracts from senescent leaves deterred feeding by this species with the same impact of fruit extracts. The highly specialized Xanthogaleruca luteola was extremely sensitive to all extract types (Defagó et al., 2006). Larvae of the two species mentioned above were less sensitive than their adults (Table 1). Larvae and adults of Epilachna paenulata (Coccinellidae) were strongly inhibited by fruit and leaf extracts (Table 1), coinciding with effects of the limonoid Melianone on the closely related E. varivestis (Kraus et al.,1986). In the choice tests, Lepidoptera species ate less food when this was treated with different M. azedarach extracts. For most species AI values indicated a moderate to high inhibitory activity (Table 1), with the exception of Rachiplusia nu and Spodoptera ornithogalli. Antifeedant effects of M. azedarach extracts have been reported for other Spodoptera species (Carpinella et al., 2002; Huang et al., 1995; MacLeod et al., 1990; Nakatani et al., 1994; Rossetti et al., 2005; Schmutterer, 1995). Strong antifeedant effect of crude extracts of Melia azedarach on Lepidoptera species were also observed by other authors (Breuer & Devoka, 1990; Chiu, 1986; Palacios et al., 1993; Dilawari et al., 1994), on Mythimna separata, Thaumetopoea pityocampa, Colias lesbia and Plutella xylostella respectively. Suckers and leafminers Extracts also affected whiteflies Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae). In a greenhouse cucumber crop, extract application resulted in significantly lower whitefly populations on treated than on untreated plants (Fig 1) (F= 7.87, df=2;27, p=0.02). Similarly, in a greenhouse tomato plantation, whitefly mortality increased up to 95% (Fig 2) in the 24 h following M. azedarach fruit extract application (Mangeaud et al., unpublished data). Whitefly abundance significantly decreased after the first extract application (F=86.14, df=1;8, p< 0.001). The number of insects started increasing after 4 days and 8 days after the application. There were no significant differences between treated and untreated plants (F=1.02, df=1;8, p=0.34). A second application (on day 8) resulted in a significant reduction in insect population, which lasted for the next eight days. These results suggest that crude extracts of M. azedarach have residual effects lasting about 5-8 days. Similar conclusions were reached by Banchio et al. (2003); Meisner et al. (1980); Schmutterer (1988) with other insects. Repellent or antifeedant effects of M. azedarach leaf, fruit and callus extracts have also been reported on another whitefly, Bemisia tabaci (Abou- Fakhr Hammad et al., 2001; Nardo et al., 1997).

5 Melia azedarach Extracts: A Potential Tool for Insect Pest Management Number/lead Time (days) Control Extract Fig 1. Number of whiteflies Trialeurodes vaporariorum on cucumber plants after application of Melia azedarach extracts (choice test) Number/apex Time (days) Fig 2. Extract Control Number of whiteflies Trialeurodes vaporariorum on tomato plants after successive applications of Melia azedarach extracts (choice test). The arrows indicate extract applications External application of M. azedarach extracts on host plant leaves before exposure to females of the leafminer pest Liriomyza huidobrensis Blanchard (Diptera: Agromyzidae) resulted in up to 90% fewer punctures in comparison with untreated plants. Since leafminer adult females puncture leaves with their ovipositor in order to feed an insert their eggs, this result indicates

6 22 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V strong oviposition as well as feeding deterrent effects (Banchio et al., 2003). Similar effects were observed on L. trifolii with neem extract application (Stein & Parrella, 1985). Hematophagous insects Fruit extracts of M. azedarach applied to refuges of "assassin bugs" involved in the transmission of Chagas disease, Triatoma infestans (Hemiptera: Reduviidae), showed strong repellent effects on nymphs, with unripe fruit extracts being completely avoided by the insects (Table 2) (Valladares et al., 1999). Arias and Hirschmann (1988) also reported repellent effects on this species. The extracts also deterred oviposition by Aedes aegypti (Diptera: Culicidae), the mosquito species responsible for transmission of dengue disease. Effects in this case were restricted to leaf extract. When simultaneously offered oviposition substrates treated with different extract types, mosquito females laid 93% fewer eggs on traps treated with leaf extract than on untreated ones (Table 2); fruit extract did not affect mosquito oviposition behaviour so that similar number of eggs were laid on treated and untreated traps (Coria et al., in press). Strong oviposition deterrency of M. azedarach extracts was also observed by Senthil Nathan et al. (2006) on Anopheles stephensi females, although in this case the effects were noticeably stronger for fruit than for leaf extracts. Table 2. Extracts a Repellent effects of M. azedarach extracts on Triatoma infestans and Aedes aegypti Triatoma infestans nymphs in refuges (%) b Extract Ethanol Water Ripe fruit 9* Leaf 26* Unripe fruit 0* Aedes aegypti eggs in ovitraps treated (%) c Extract Control Ripe fruit Leaf 7* 93 a Ethanol solutions b Values from five replicates of nine nymphs each c Average percentage of eggs obtained in ovitraps treated with M. azedarach leaf extract and control with water and ethanol (5 and 4 replications respectively) *Significantly different from random distribution expected value (p< 0.05, X 2 -test) Toxic and growth regulating effects Phytophagous insects Chewers Fruit extracts of M. azedarach negatively affected survival on various Coleoptera species. All larvae and adults of X. luteola had died after 14 days

7 Melia azedarach Extracts: A Potential Tool for Insect Pest Management 23 of receiving extract-treated food; mortality appeared to be caused mainly by starvation due to the strong antifeedant effect of the extracts (Valladares et al., 1997). Mortality was higher when the extracts were orally administered than sprayed with them, and larvae were slightly more susceptible than adults. In the grain-feeding weevil Tribolium confusum larvae receiving extract-treated food needed a month longer than controls to reach pupal stage (Del Tio et al., 1996). Defagó et al. (2004) observed toxic effects on larvae and adults of E. paenulata fed with pumpkin leaves treated with M. azedarach fruit extract (Fig 3). Mortality rates were significantly raised on the third (F: 6.79; gl 7,45; p<0.001) and sixth day (F: 5.44; gl 7,41; p<0.001) from the start of the experiment for the higher concentrations tested (15 &10 %, respectively). The insects died before those deprived of food, suggesting toxic effects. Mortality rates at lower extract concentration (5%) were similar to those observed on starved insects, indicating that they died from starvation resulting from the strong antifeedant effects of the extracts, as suggested by Breuer and Devkota (1990); Valladares et al. (1997, 2003). At even lower concentrations (1, 0.5 and 0.25%), mortality rates were initially similar to those of insects receiving untreated food. Significant increases in mortality were observed only after 11 days at 1% extract concentration (F: 4.27; gl 3,20; p<0.02) and 15 days for lower dosages (F: 8.34; gl 3,16; p<0.02) (Fig 3). In the latter cases, the extract would be acting as a stomach poison or secondary antifeedant, instead of being detected by chemo receptors located in the mouthparts (primary antifeedants) (Chen et al., 1996). Similar observations were recorded by Wen and Schmutterer (1991) on the locust Locusta migratoria migratorioides. Cumulative Mortality (%) Time (days) S Fig 3. Cumulative mortality (%) in E. paenulata larvae fed with leaves treated with M. azedarach fruit extract at various concentrations. Each point represents the mean of 6 replications (4 individuals each). S: starved larvae In the above discussed tests with E. paenulata, the lethal time (TL 50 ) required to eliminate half of the adult population increased with decreasing

8 24 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V extract concentration (Tabla 3). Dose-related lethal times have also been observed with neem extracts (Hellpap, 1983). Lethal effects were faster on E. paenulata larvae, their lethal time being half of the values recorded for adults for comparable extract concentrations (Table 3). Table 3. Lethal time 50 (TL 50 ): number of days required to reach 50% mortality in Epilachna paenulata larvae and adults fed on leaves treated with different concentrations of M. azedarach extracts TL50 (days) Extract 0.25% 0.5% 1% 5% 10% concentration Larvae Adults Lethal concentration (CL 50 ) for E. paenulata larvae fed with M. azedarach fruit extract was 1.79% ( ), at 8 days from the start of the experiment, when maximum mortality rates were observed. A lower CL 50 was required for adults: 1.14% ( ) after 13 days of feeding on extracttreated leaves. When leaf extract was tested, higher CL 50 values were required in comparison with fruit extract: four times higher for E. paenulata larvae (6.86%) and twice the fruit value for adults (3.78%) (Valladares et al., 2003). In a separate test, E. paenulata larvae were fed for only 48hs with pumpkin leaves treated with M. azedarach fruit extract, and subsequently fed with untreated leaves. Mortality rates of treated larvae were higher (F: 3.71; gl 4,19; p< 0.02) when compared not only to control but also to starved larvae, between days 4 and 8 of the experiment (Fig 4), thus suggesting toxic effects lasting up to 6 days after extracts were withdrawn from the diet. From day 8 onwards, mortality of treated larvae was stationary, and the surviving larvae fed (Fig 5) and reached similar weight (Fig 6) in comparison with larvae that were never exposed to the extracts. All surviving larvae pupated, suggesting lack of growth disrupting effects and certain compensation capacity of the insects after a short exposure to the extract. These results differ from a comparable experiment with larvae of E. varivestis and dried methanolic leaf extracts of M. azedarach (5 and 2.5%), in which strong growth-disrupting effects were demonstrated, with no larvae pupating and all dying within 11 days after the start of the experiment (Steets, 1975). M. azedarach fruit extract was also administered to adult couples of E. paenulata for 7 days, in sublethal concentrations (0.25-1%), resulting in egglaying being significantly delayed (Table 4). Fecundity and fertility were not affected. Instead, neem extracts administered in food for 3 to 5 days reduced fecundity in E. varivestis by 70-90% (Ascher, 1980). The mechanisms involved in M. azedarach effects on insect reproduction seem to differ from those invoked for neem extracts. Whereas the latter appears to interfere with production of insect hormones (Ascher, 1993; Rembold & Sieber, 1981),

9 Melia azedarach Extracts: A Potential Tool for Insect Pest Management 25 M. azedarach effects would be mediated mainly by its strong antialimentary effect (Frazier & Chyb, 1995). Indeed, a comparison of the major active component of both extracts showed stronger antifeedant effects for M. azedarach in comparison with neem, at least in the first hours of exposure (Carpinella et al., 2003). Cumulative Mortality (%) Time (days) S 0% 2% 5% 10% Fig 4. Cumulative mortality (%) in E. paenulata larvae fed for the first 2 days with leaves treated with M. azedarach fruit extract at various concentrations. Each point represents the mean of 4 replications (4 individuals each). S: starved larvae. The arrow indicates the moment of extract withdrawal 40 Foliar consumption(%) Time (days) Fig 5. Leaf area (%) consumed daily by E. paenulata larvae after receiving for 2 days food treated with M. azedarach ripe fruit extract (each point is the mean of 4 replicates with 4 individuals each)

10 26 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V Weight (mg) Time (days) 0% 2% 5% 10% Fig 6. Mean weight (mg) of E. paenulata larvae after receiving for 2 days food treated with M. azedarach ripe fruit extract (subsequently fed untreated food) Extracts of senescent leaves of M. azedarach also affected survival of E. paenulata larvae and adults, after 4 and 7 days respectively, of being provided with their food. Larvae also ate less food and suffered a remarkable weight loss along the experiment, these effects being directly related to extract concentration (Valladares et al., 2003). Leaf extracts of M. azedarach showed stronger antifeedant effects on E. varivestis larvae than analogous extracts from Azadiractha indica (Schmutterer, 1995). Leaf extracts of M. azedarach also inhibited growth and disrupted metamorphosis in E. varivestis (Zhu & Ermel, 1991). In dose-response assays, feeding of Diabrotica speciosa decreased significantly with increasing concentrations of M. azedarach flower extracts (Ventura & Ito, 2000). Survival, growth and development of various Lepidoptera species were also impaired by M. azedarach extracts. In this regard, fruit extracts have proved effective on Spodoptera eridania, S. frugiperda, S. littorali, Anticarsia ipsilon, Sesamia nonagrioides and Hyblaea puera (Juan et al., 2000; Rodriguez Hernandez & Vendramim, 1998; Rossetti et al., 2005; Schmidt et al., 1997; Senthil Nathan & Schoon, 2006). Efficiency of food conversion into biomass decreased when extract was incorporated in the diet of Lepidoptera larvae (Rossetti et al., 2005; Senthil Nathan & Schoon, 2006), demonstrating that Melia extracts affect the absorption of ingested food and the subsequent conversion into insect tissues (Schmidt et al., 1997). Leaf extracts provided in the diet also resulted in significantly increased larval mortality and/or slower development rates for Spodoptera frugiperda

11 Melia azedarach Extracts: A Potential Tool for Insect Pest Management 27 Table 4. Effects of M. azedarach ripe fruit extract on oviposition, fecundity and fertility of E. paenulata females, after feeding with extract for seven days Dosage n First day of Number of Number Total Fecundity Fertility (%) oviposition egg batches eggs /batch number (%) of eggs (0.80) a 6 (1.10) 52 (1.35) 307 (56.12) 16 (2.31) 52 (10.36) (0.99) b 5 (0.62) 46 (2.69) 233 (39.99) 16 (2.10) 55 (10.37) (1.16) b 4 (3.03) 45 (3.03) 188 (22.52) 14 (1.46) 49 (12.41) (1.21) b 4 (0.55) 49 (2.24) 199 (27.96) 15 (1.73) 50 (8.03) Means (± SEM) of 10 repetitions. Values within columns followed by the same letter are not significantly different (Tukey, p < 0.05). Table 5. Mean cumulative percentage mortality of Homoptera species sprayed with various M. azedarach fruit extracts. Insect Extract base Mortality (%) Dosage Control Treated (%) Aphis gossipii water * 10 oil water + oil * 20 Aphis spiraecola water oil water + oil Brevicoryne brassicae water * 10 Uroleucon sp. water Cavaliera aegopodii oil * 20 * Significant differences between treated and control insects (Duncan test, p<0.05)

12 28 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V (De Brito et al., 2004; McMillian et al., 1969), S. littoralis (Khadr & El-Monem, 1986), S. eridania (Rossetti et al., 2005), and Tuta absoluta (Brunherotto & Vendramim, 2001). The leaf extract was the most effective for T. absoluta, followed by unripe fruits, branches and ripe fruits, in a comparative study considering length and viability of various life stages as well as male and female weight (Brunherotto & Vendramim, 2001), although in a study by Senthil Nathan and Schoon (2006) leaf extracts were only effective at high concentrations. Sucking insects A limited number of studies have revealed different responses to M. azedarach by polyphagous whiteflies. Applications of M. azedarach extracts obtained from leaves and unripe fruits on bean plants resulted in 100% mortality of Bemisia tabaci adults after only four days (Nardo et al., 1997). Mortality rates of adult B. tabaci on plants sprayed with M. azedarach leaf and fruit extracts were similar to values for unfed insects, but significantly higher than those on untreated plants (Abou-Fakhr Hammad et al., 2000). Thus, observed mortality could be due to the extreme antifeedant / repellent effect of the extracts as discussed above for E. paenulata. Extracts from various plant structures (ripe / unripe fruit, leaves, branches) affected mortality rates in B. tabaci, increasing up to 50% for eggs and up to 5 times for nymphs, in relation to controls (De Souza & Vendramin, 2001). We tested aqueous and oil-based M. azedarach ripe fruit extracts by spraying them on various aphid (Homoptera: Aphididade) species, with assorted results (Table 4). Two (Aphis gossypii and Brevicorine brassicae) out of four species treated with aqueous solutions showed significant increases in mortality rates. Oil-based formulations were effective against A. gossypii and Cavariella aegopodii. Other aphid species negatively affected by M. azedarach extracts include Brevicoryne brassicae (ethanolic extract), Aphis citricola (seed oil) and A. fabae (methanolic extract) (Ascher et al., 1995). Fruit extracts of argentinian M. azedarach trees (10%) showed translaminar activity, penetrating leaf tissues, and induced increased pupal mortality rates (i.e. lower adult emergence) in the agromyzid leafminer Liriomyza huidobrensis. Larval survival and adult fecundity were not affected (Banchio et al., 2003). Extracts were only effective when leaves already infected with leafmining larvae were treated, suggesting a short residual activity. In the field, extract application resulted in lower adult emergence for the leafminer, without noticeable effects on its parasitoids, suggesting a selective activity consistent with Integrated Pest Management requirements (Banchio et al., 2003). Hematophagous insects Nymphs of Triatoma infestans reared in refuges treated with M. azedarach green fruit extract (5%) were noticeably smaller (F: 5.3; gl 1,2; p = 0.007) and had lower body weight (F: 15.2; gl 1,2; p = 0.001) than controls after exposure

13 Melia azedarach Extracts: A Potential Tool for Insect Pest Management 29 to the extract for one intermoulting period, suggesting that the effects could be dramatic if accumulated along the insect life cycle (Arias & Hirschmann, 1988; Valladares et al., 1999). Table 6. Mean cumulative mortality (%) at each life-cycle stage of Culex pipiens larvae reared in a Melia azedarach fruit extract solution Insect stage 0 g/l 0.05g/l 0.1g/l 0.25g/l Larva I 2 a 13 a 74 b 86 b II 1 a 9 a 78 b 100 b III 1 a 8 a b 64 IV 9 a 16 a 70 b Pupa 14 a 26 a 72 b Means within rows followed by the same letter are not significantly different (Duncan, p< 0.05) Larvae of Culex pipiens (Diptera: Culicidae) mosquitoes suffered increased mortality (up to 100% with 0.25 g/l extract) when reared in water treated with M. azedarach fruit extract (Table 6). Instead, the same fruit extract at concentration of up to 1g/l did not affect survival of Aedes aegypti. However, larvae of the latter mosquito were strongly affected by senescent leaf extract, which induced 100% mortality with a concentration of 0.5g/l, and significantly delayed development time (Coria et al., in press). Stronger larvicide effects for M. azedarach fruit than for leaf extracts were recorded on another mosquito species, Anopheles stephensi, in this case never reaching 100% mortality but also showing prolonged development time (Senthil Nathan et al., 2006). Conclusions Extracts obtained from different structures of Melia azedarach trees were expected to vary in their insecticidal effects, and such variations could also depend on insect feeding habits, with their distinct morphological, physiological and behavioural characteristics. The results here presented reveal that M. azedarach extracts possess a wide activity array and affect insects in all the taxonomical and ecological categories so far studied, without clear relationships between relative efficiency of plant structure and insect type. Insects feeding on plants, either chewing or mining their tissues or sucking their sap, as well as blood feeding species, can be negatively affected by these extracts. Effects include inhibition of feeding and oviposition, increased mortality, delayed development and impaired reproduction. Effects on beneficial insects such as parasitoids and predators need further research, but the available evidences and suggest that they might not be affected. The results here summarized, added to low environmental impact, relatively low production costs and availability in extensive regions of the world, suggest that extracts of Melia azedarach could offer an interesting tool for the safe management of agricultural and sanitary insect pests.

14 30 RPMP Vol. 23 Phytopharmacology & Therapeutic Values V References Abou-Fakhr Hammad, E.M., N.M. Nemer, Z.K. Hawi and L.T. Hanna Responses of the sweetpotato whitefly, Bemisia tabaci, to the chinaberry tree (Melia azedarach L.) and its extracts, Ann. Appl. Biol. 137: Abou-Fakhr Hammad, E.M., H. Zournajian and S. Talhouk Efficacy of extracts of Melia azedarach L. callus, leaves and fruits against adults of sweetpotato whitefly Bemisia tabaci (Hom., Aleyrodidae), J. Appl. Ent. 125: Arias, A.R. and G.S. Hirschmann The effects of Melia azedarach on Triatoma infestans bugs, Fitoterapia 59: Ascher, K.R Some physical (solubility) properties and biological (sterilant for Epilachna varivestis females) effects of a dried methanolic neem (Azadirachta indica) seed kernel extract. In: Schmutterer H., K.R.S. Ascher and H. Rembold, eds., Natural pesticides of the neem tree and other tropical plants, Proc. 1 st Int. Neem Conf., Rottach- Egern, Germany, pp Ascher, K.R Nonconventional insecticidal effect of pesticides available from the neem tree Azadirachta indica, Arch. Insect Biochem. Physiol. 22: Ascher, K.R.S., H. Schmutterer, C.P.W. Zebitz, and S.N.H. Naqvi The persian lilac or chinaberry tree: Melia azedarach L. In: Schmutterer H. ed., The Neem Tree. VCH. Weinheim, Federal Republic of Germany, pp Banchio, E., G. Valladares, M. Defagó, S. Palacios and C. Carpinella Effects of Melia azedarach (Meliaceae) fruit extracts on the leafminer Liriomyza huidobrensis (Diptera, Agromyzidae): Assessment in laboratory and field experiments, Ann. Appl. Biol. 143: Bernays, E.A When host choice is a problem for a generalist herbivore: experiments with the whitefly, Bemisia tabaci, Ecol. Entomol. 24: Bernays, E.A. and R.F. Chapman Host-Plant Selection by Phytophagous Insects. Chapman & Hall, New York, NY, U.S.A. p Bernays, E.A Neural limitations in phytophagous insects: Implications for diet breadth and evolution of host affiliation, Ann. Rev. Entomol. 46: Breuer, M. and B. Devoka Control of Thaumetopoea pityocampa (Den. and Schiff.) by extracts of Melia azedarach L. (Meliaceae), J. Appl. Ent. 110: Brunherotto, R. and J.D. Vendramim Bioactividade de extractos aquosos de Melia azedarach L. sobre o desenvolviento de Tuta absoluta (Meyrik) (Lepidoptera: Gelechiidae) em tomateiro, Neotrop. Entomol. 30(3): Carpinella, C., C. Ferrayoli, G. Valladares, M. Defagó and S. Palacios Potent insect antifeedant limonoid from Melia azedarach, Biosci. Biotech. Biochem. 66: Carpinella, C., M.T. Defagó, G. Valladares and S. Palacios Antifeedant and insecticides properties of a limonoid from Melia azedarach (Meliaceae) with potential use for pest management, J. Agric. Food Chem. 51: Chen, C.C., S.J. Chang, L.L. Chen and R.F. Hou Effects of chinaberry fruit extract on feeding, growth and fecundity of the diamondback moth, Plutella xylostella (Lep., Yponomeutidae), J. Appl. Entomol. 120: Chiu, S.F Experiments on the practical application of chinaberry, Melia azedarach, and other naturally occurring insecticides in China. In: Schmutterer, H. and K.R.S. Ascher, eds., Natural pesticides from the neem (Azadirachta indica A. Juss) and other tropical plants, Proc. 3 rd. Int. Neem Conf., Nairobi, pp

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