Essential oil of Adhatoda vasica leaves contain vasicine, vasicinone and maiontone. The plant has lot of medicinal value against many diseases. Insecticidal activity of Adhatoda vasica was highlighted previously. Hence a thorough seasonal survey is taken up in A vasica to estimate the variation in the quantity and quality of the essential oils and alkaloids of A. vasica found in Virudhunagar District. The investigation proposes to study the various insect pests of the plants in exsitu cultivated plants of the Virudhunagar district. The data are compared with 50 plants collected from different areas and cultivated at the experimental gardens. Harvest was made at the interval of three months and a comparative analysis is presented after pest infestation. The above study is more valuable since the cost effectiveness of the tuberculosis treatment with A. vasica is commendable.

Impact of time of sowing and sun drying of cotton stalks and on the management of cotton stem weevil , Pempherulus affinis Faust was studied at Cotton Research Station, Srivilliputtur, Tamil Nadu. In early sown cotton crop infestation and plant mortality was more compared to the late sown cotton crop. It was also observed that off season crop (i.e., Winter season crop in the Summer Cotton Tract) was much affected compared to the regular season crop (i.e.,Summer season crop in the Summer Cotton Tract). Weevil emergence was nil from sun dried cotton stalks kept under sun in situ after pulling out. But weevil emergence was observed in stored / heaped cotton stalks. Importance of in situ drying of cotton stalks after pulling out the cotton stalks to arrest the carry over of the pest to next season is brought out in the present study

Experiments were carried out in field conditions to analyse the effect of induced resistance on certain major pests of rice viz., leaf folder, stem borer and gall midge. The population of these insects were assessed at regular intervals on plants imposed with treatments including neem cake (NC),farm yard manure (FYM), Azospirillum (Azos), phosphobacterium (Phos), Silicate Solublising Bacteria (SSB) and lignite fly ash(LFA).The results revealed that the combination of FYM, three biofertilizers, lignite fly ash and neem cake applied in splits significantly reduced the incidence leaf folder (76.69%), stem borer (58.66 ) and gall midge (66.81%) as compared to NPK applied as inorganic form. The insect population was correlated with silica content and it was analysed in the leaf sheath and laminae of plants treated with organic sources of nutrients. As the age of the plant increased, silica content proportionately increased in the plants. There was significant difference in silica content on 45 and 60 DAT among treatments. The treatment viz., application of three biofertilizers, lignite fly ash along with FYM and neem cake either as basal (7.8%) or in splits recorded high silica content (8.10 %) as compared to other treatments.It was found that the occurrence of these major insects was negatively correlated with silica content. Correlation values between silica and insects were -0.789 for leaf folder, -0.930 for stem borer and -0.958 for gall midge. The main cause for the death of insects due to fly ash application was wearing of mandibles and main feeding organs of insects which resulted in functionless mandibles so that the insects of paddy die without food. Further, the incidence of major insects was negatively correlated with yield. Application of organic sources of nutritions significantly increased the rice grain yield. The treatment with biofertilizers, lignite fly ash, FYM and neem cake in splits recorded significantly higher grain yield (5.49 t/ha) which was on a par with NPK applied plots (5.38 t/ha).and the per cent increase in yield over NPK was 2%.It is concluded that application of organic sources of nutrition reduced the incidence of leaf folder, stem borer and gall midge and increased the yield in rice.

The neonate larvae of Othreis materna (L.) fed only on the leaves of Tinospora cordifolia (Willd.), whereas the larvae of O. fullonia (Clerck) completed their life cycle on the hosts viz., T. cordifolia, Tiliacora acuminata Miers. and Diploclisia glaucescens (Blume) from neonate stage itself and it could not feed on Cocculus hirsutus (L.) Diels. and Erythrina indica (Lam.). Except T. cordifolia and E. indica the larvae of O. homaena reared on C. hirsutus, T. acuminata and D. glaucescens completed the life cycle. The larval duration was lesser when reared on C. hirsutus than the T. acuminata and D. glaucescens. The neonate larvae of Rhytia hypermnestra (Stoll) fed only on T. cordifolia with successful survivability. The proboscis of male and female of O. materna, O. fullonia, O. homaena and R. hypermnestra had three sclerotised oblique blades with sharp edges, six erectile barbs arranged in two rows near the tip which was sharply pointed. The total length of the proboscis of O. materna measured 13.90 mm and the sclerotised tip was very short measuring 1.21mm in male whereas it was 14.30 and 1.27 mm in female, respectively. The proboscis length of male O. fullonia, O. homaena and R.hyperm nestra was measured to be 15.25, 13.40 and 15.15 mm, respectively whereas in female it was 17.50, 14.70, 15.60 mm. The sclerotised tip of male moth measured 1.34, 1.30 and 1.27 mm, respectively and in female 1.49 mm in O. fullonia and 1.34 mm in both O. homaena and R. hypermnestra.

The lab performance of certain released Bt cotton hybrids for their effect on Spodoptera litura were evaluated in comparison with non Bt cotton plant parts. Bt cotton hybrids viz., Bt bunny, six Bollgard II (cry 1 Ac + cry 2 Ab genes) hybrids e.g. RCH 2 Bt , RCH 515 Bt , RCH 596 Bt, RCH 530 Bt, RCH 134 Bt and RCH 533 Bt and two non Bt cotton viz., Non Bt bunny and RCH 2 non Bt cotton against cotton leaf worm, S. litura third instar larva. Four plant parts viz., young green bolls, top fully opened young leaves, middle leaves and squares were tested. Among the Bt cotton hybrids and non Bt cotton evaluated, RCH 2 Bt top fully opened young leaves showed highest per cent mortality followed by squares, middle leaves and young green bolls observed at 168 hours after the treatments (HAT) followed by top fully opened young leaves, squares, middle leaves and young green bolls of RCH 515 Bt which recorded 46.67, 38.34, 37.67 and 30.00 per cent mortality, respectively after 168 HAT when compared to squares, green bolls, top fully opened leaves and middle leaves of RCH 2 non Bt cotton which recorded 4.83, 4.17, 3.33 and 0.00 per cent mortality respectively after 168 HAT.

The reduviid predator, Coranus spiniscutis was reared in the laboratory on rice moth Corcyra cephalonica larvae for studying its biology and mating behaviour. Female laid eggs in single and the incubation period was 4.66 ± 0.77 days. The stadial period was maximum for fifth and minimum for third instars. The sex ratio was 1:0.8 for male and female. The preoviposition and, oviposition periods were 6.20 ± 0.93, 60.32 ± 2.52 days, respectively. The sequential acts of mating behaviour were: arousal, approach, riding over, genitalia extension, connection achievement and post copulatory acts. This study helps to integrate this reduviid in IPM programme either directly or indirectly

Bhendi or Okra, Abelmoschus esculentus (L.) Moench (Malvaceae) is one of the important vegetable crops grown throughout the tropical and warm temperate regions of the world. It is ravaged by many insect pests right from germination to harvest. Among the insect pests, fruit borers viz., Earias spp. and Helicoverpa armigera (Hübner) causes extensive damage to fruits and results in 50 per cent yield loss. Management with biocontrol agents is the most appreciated method for environmental safety. Among the various groups of biocontrol agents, braconid parasitoids are well known for the management of different lepidopteran larvae, including bhendi fruit borer complex. The braconid parasitoid, Bracon brevicornis Wesmael was found to be very effective against bhendi fruit borers. However, temperature and host insects play a major role in the developmental biology of the parasitoids which ultimately decides its efficacy. Experiments conducted on the effect of different temperature viz., 20, 25, 30 35o C and room temperature, on the developmental biology of B. brevicornis on different host larvae viz., E. vittella and H. armigera in comparison with the laboratory host, C. cephalonica revealed that the temperature regime of 25o C is highly suitable with a short life cycle of 8.22, 8.27 and 8.07 days respectively followed by room temperature (ranged between 22 to 32°C). Among the host larvae studied, C. cephalonica and E. vittella were found to be more suitable with maximum number of eggs, grubs, cocoons, adult males and females respectively. H. armigera was next in the order of preference recording less number of eggs, grubs, cocoons, and adults. The developmental period was also found to be less in C. cephalonica and E. vittella followed by H. armigera. Though the life cycle is very short at 35o C, the progeny production is comparatively less with more males than females. At 20o C the life cycle is prolonged with minimum progenies yielding more males than females.

Two field trials were conducted to evaluate the bioefficacy of Bacillus thuringiensis Berliner, water soluble granular formulation against the rice leaffolder, Cnaphalocrocis medinalis Guenee. The study revealed that the treatment containing B.t. formulation @ 2.5 kg/ha registered the lowest leaffolder damage of 8.21 per cent that was on par with monocrotophos 36 WSC @ 500 g ai/ha in 7 DAS during the first spraying. On 10 DAS of the first spraying all the treatments recorded more than 13.00 per cent damage, but the low leaffolder damage of 13.65 per cent was recorded in B.t. formulation @ 2.5 kg /ha. The highest leaf folder damage of 18.40 and 17.38 per cent was registered in B.t. formulation @1.0 kg/ha and untreated control, respectively. The B.t. formulation failed to check the leaffolder damage due to the outbreak of the pest induced by high temperature coupled with low relative humidity. The highest grain yield of 28. 58 kg/ plot was registered in B.t. formulation @ 2.5 kg/ha, followed by B.t. formulation @ 2.0 kg/ha.

A random survey was conducted to obtain endophytic bacterial isolates in different agroecosystems comprising of ten districts in Tamil Nadu. Nineteen endophytic bacterial isolates were obtained from surface-sterilized roots of different crops. Study on the morphological, phenotypic and biochemical characterization of endophytic bacteria revealed that eight isolates viz., EB1 to EB8 belong to the group of Pseudomonas sp., ten isolates viz., EB9 to EB18 belong to the group of Bacillus sp. and isolate EB19 belongs to Methylobacterium sp. On seed bacterization with nineteen endophytic bacterial isolates, four isolates viz., EB3, EB16, EB18 and EB19 significantly enhanced the germination percentage, shoot and root length and vigour index of bhendi seedlings by roll towel technique and pot culture studies. Eight endophytic bacterial isolates were screened for their nematicidal action against Meloidogye incognita under pot culture conditions. The study revealed that the culture filtrates of endophytic bacterial isolates viz., EB3, EB16, EB18 and EB19 significantly reduced the number of adult females, egg masses, eggs/ eggmass, root and soil infestation of M. incognita. The lowest root gall index (1.00) was registered both in EB16 and EB18 isolates and it was followed by EB19 and EB3 (1.33) compared to untreated control (4.67).

The primary and secondary forms of Photorhabdus luminescens a symbitotic bacterium of an entomopathogenic nematode Heterorhabditis indica (RCR) was evaluated against Thrips palmi Karny a serious pest on cotton. The treatment included different concentration (101 to 1010 cells/ CFS/ml) of cells and cells free supernatant which was obtained by centrifugation (4000 rpm for 20 min) of broth culture. The treatment was imposed through potter’s tower on aphid colony containing (20 per leaf/replication plants). Observation of aphid mortality was recorded at 24 and 48 hr. The results revealed that both the forms were pathogenic to T. palmi but the cells free supernatant (CFS) of both the forms was more virulent than cells causing high mortality within 24 to 48 hr. The cells of primary and secondary form recorded 67.50 and 72.50 per cent mortality whereas corresponding CFS recorded 85.00 and 80.00 per cent mortality, respectively at the concentration of 1010 cells/ ml. The LC50 of both primary 2.38× 107 cells/ml and secondary form cells 2.35 × 107 cells / ml and CFS of P. luminescens decreased with increase in exposure time from 24 to 48 hr. These results indicate the possibility of developing CFS as a potential biocontrol component against T. palmi.

Evaluation of the growth and sporulation Nomuraea rileyi isolates on different health drinks sources media showed potato maltova agar was significantly superior to other media and supported the maximum biomass, mycelial growth and conidial count. In case of PDBC isolate, among the six different health drinks sources tested, the maximum radial growth, biomass and spore production were observed in potato maltova agar medium both in solid as well as in the liquid medium. Similar trend of growth and development was observed with DOR and local isolates of N. rileyi.

The two culture media tested both Potato Dextrose Agar (PDA) and Sabouraud Dextrose Agar ( SDA) recorded maximum mycelial growth in Beauveria bassiana isolates. Maximum growth was observed in the isolates of VpNlKKL 2121 (65.22mm), BbMtKKL 2107 (65.16mm), BbMdKKL 2106 (63.44mm) and FmNvKKL 2121 (62.78mm) and minimum growth was noticed in VpPmKKL 2120 (37.33mm) in PDA media. With SDA media maximum growth was observed in BbMtKKL 2107 (68.02mm) and BbMdKKL 2106 (66.91). Slowest growth was noticed in VpPmKKL 2120 (32.18 mm) .Highest spore count was noticed in B. bassiana isolates BbMtKKL 2107 (8.90 X 108 spores /ml) and BbMdKKL 2106 (8.77 X 108 spores / ml) isolates and are on par with FmNvKKL 2124 and VpPmKKL 2120 with PDA media. All other isolates had similar effect. Similarly, BbMdKKL 2106 isolate of B. bassiana in SDA media showed maximum spore count of 8.95 X 108 spores / ml and other isolates were on par with each other, except FpEvKKL 2119 which recorded least spore count of 0.52 X 108 spores / ml. Of the various fungi tested in (Potato Dextrose Broth)PDB and(Sabouraud Dextrose Broth) SDB (liquid broths) revealed that isolate BbMtKKL 2107 produced highest yield of (1.87g) followed by FpCmKKL 1526 (1.66g) and BbMdKKL 2106 (1.40g) and they were on a per with each other and remaining cultures four cultures were on par with each other. With reference to SDB media tested, highest yield was noticed in FpCmKKL 1526 (2.10g).

Explorative surveys were conducted to collect native isolates of the entomopathogenic fungus, Metarhizium anisopliae from forest pests and soil to study their potential for developing mycoinsecticides for management of selected forest pests. Nine promising isolates identified from among a collection of 25 isolates were examined for their pathogenicity against the forest pests, Hyblaea puera, Paliga machoeralis, Spilarctia obliqua, Hypsipyla robusta and Odontotermes spp. Besides this, the comparative conidia germination of the isolates under selected cultural conditions was also examined to identify the candidate isolates for pesticide development. The LC50 of the isolates ranged from 0.01 x105 to 759.21 x105 for the different pests. Isolate Ma2 was the most virulent against H. puera, P. machoeralis and Odontotermes sp. with significantly low LC50 values, viz., 0.65, 0.11 and 0.01x105 conidia, respectively for the three pests. Ma7 showed lowest LC50 of 1.20 and 1.77x105 spores against S. obliqua and H. robusta. Ma13 also showed high virulence against Odontotermes sp. The isolate Ma2 showed significantly higher germination under all the conditions evaluated. Radial growth and biomass, which are critical factors for selecting a strain for mass production, was also highest in Ma2 (64.5mm and 5.1gram/lit) followed by Ma7 (42.5mm and 4.6gram/lit). These observations indicate at least two of these isolates hold good potential for formulating a biopesticide for forest pest management.

Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis are excellent candidates for biological control of insect pests. Attributes making the nematodes as ideal biological include their broad host range, high virulence, safety for nontarget organisms and high efficacy in favourable habitat. Identification and characterization of EPNs in Iran was started since 2000. Several species of Steinernema and Heterorhabditis were isolated. Species from Steinernema are Steinernema carpocapsae, Steinernema feltiae, Steinernema glaseri, Steinernema monticolum and Steinernema bicornutum. From Heterorhabditis genus, only Heterorhabditis bacteriophora has been identified so far. Based on few studies, phylogenetic position of native EPNs species/isolates was investigated. In addition to EPNs, their symbiotic bacteria are identified and characterizied. In laboratory, infectivity of several isolates of EPNs assayed against different soil inhabiting pests. This accompanied by field evaluation of few numbers. Many indigenous EPNs were used in laboratory and field trials to evaluate their potential in control some economically important insect pests of crop, fruit and forest trees. Those insect hosts were Polyphylla olivieri (Coleoptera: Scarabaeidae), Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae), Leptinotarsa decemlineata (Coleoptera : Chrysomelidae) and Spodoptera exigua (Lepidoptera :Pyralidae). Increasing information about EPNs potential will provide suitable biopesticides for using pest management programs.

Field experiments conducted for the evaluation of efficacy of biocontrol agents viz., Pseudomonas fluorescens and Trichoderma viride, against root knot nematode, Meloidogyne incognita in mulberry (V1 variety) revealed that soil application of both P. fluorescens and T. viride alone or in combination was able to control the nematode population and improve the mulberry leaf yield and nutritional standards. Combined soil application of P. fluorescens (@ 10 g/plant) + T. viride (@ 10 g/plant) as soil application was effective to check the root knot nematode disease and to improve growth of mulberry with increased leaf yield and reduced nematode population.

Powdery mildew caused by Phyllactinia corylea (Pers.) Karst is a serious disease of mulberry inflicting considerable qualitative as well as quantitative losses. Owing to non eco-friendly nature, toxicity to silkworm, high cost and other side effects of chemical control measures, search for other management strategies devoid of such drawbacks becomes inevitable. In the present study, five biocontrol agents viz., Trichoderma viride, Trichoderma harzianum, Gliocladium roseum, Trichothecium roseum and Chaetomium indicum were evaluated for their efficacy against powdery mildew of mulberry. Culture filtrate of these biocontrol agents were tested in vitro for their fungitoxicant activity against conidial germination of P. corylea. Among the culture filtrate of biocontrol agents tested, both T. viride and T. harzianum @ 50.0% were highly effective and inhibited the conidial germination by 75.08% and 72.23%, respectively. Gliocladium roseum, T. roseum and C. indicum each at 6.25% concentration were the least effective treatments and did not provide more than 11.0% conidial germination inhibition. The in vitro treatments exhibiting conidial germination inhibition of more than 50.0% were also tested in vivo for the management of the disease. Culture filtrates of T. viride and T. harzianum both at 50.0% concentration were equally most effective and were at par with carbendazim 50 wp @ 0.05% by providing 65.14% — 68.68% disease control.

Effect of different methods of application of Pseudomonas fluorescens commercial formulation under direct seeded wet sowing rice against bacterial leaf blight (Xanthomonas oryzae pv. oryzae) incidence, growth promotion and yield improvement was assessed under field condition. Among the different methods tried, the combination of seed treatment, soil application and foliar spray with P. fluorescens recorded the minimum disease incidence of bacterial leaf blight with maximum yield in comparison with the chemical treatment and control.

Aqueous extract of neem seed kernel (NKAE) was tested in laboratory conditions to evaluate its effects on larval weight, larval duration, mortality percent, adult emergence percent and antifeedant activity against red slug caterpillar, Eterusia magnifica (Lepidoptera: Zygaenidae).Different concentrations of NKAE as 2,4,6,8 and 10% were used separately to evaluate the effects of NKAE. NKAE was found to be effective and concentration dependant against Eterusia magnifica. Larval weight was concentration dependant and decreased with the increase of NKAE concentrations. Antifeedant activity was in ascending order with increase in concentrations. The highest leaf area consumed were recorded at 2% concentration in fifth instar as 1158.6+254.79 sq cm and it was lowest at 8% concentration in first instar larva as 92.2+26.04 sq cm. The leaf area protection of NKAE was recorded as 48.09+12.61-61.59+11.28% in first, 22.74+13.59-54.31+14.16% in second, 60.05+11.94-87.5+2.98% in third, 33.9+10.79-65.82+15.71% in 4th and 30.32+10.2-64.48+19.35% in 5th instar larva at 2-10% concentrations respectively. Preference index obtained for NKAE in all tested concentrations indicated its deterrence against feeding of red slug caterpillar. The larval duration recorded maximum as 5.8+0.45, 6.6+0.55, 7.6+0.55, 7.6+0.55 and 13.6+2.1 days at 8 percent concentrations over control as 4.4+0.55, 5.4+0.54, 5.6+0.55, 6.6+0.55 and 10.6+1.7 days in 1st, 2nd, 3rd, 4th and 5th instar larva respectively. The larval mortality was maximum after 72 hrs of treatment at all the concentrations and recorded 12.92+0.02-98.23+2.1% in 1st, 9.07+0.4 - 39.4+2.2% in 2nd, 7.53+0.7 – 32.63 +0.8% in 3rd and 2.59+1.0 – 11.9+0.6% in 4th instar at 2, 4, 6, 8 and 10 percent concentrations of NKAE respectively. Adult emergence percent was reduced to 0-35.63+1.7 in male and 0-29.4+1.1 percent in female at 8-2 percent concentrations as against 99.1±0.6 and 97.6+0.5 respectively in the untreated control.

Marine sponges (Porifera) are one of the most productive marine organisms. Eighty per cent of sponges (ethanolic extracts) were found to have insecticidal activity against fifth instar larvae of Culex quinquefasciatus (Say.) (Diptera: Culicidae) and Achaea janata (Linn.) (Noctuidae: Lepidoptera) and Pericallia ricini (Fab.) (Lepidoptera: Arctidae). Of the twelve sponges, five of them like Clathria longitoxa (Hentschel) (Poecilosclerida: Microcionidae), Callyspongia diffusa (Ridley) (Haplosclerida: Callyspongiidae), Haliclona pigmentifera (Dendy), Sigmadocia carnosa (Dendy), (Haplosclerida: Chaliniidae), and Denrilla nigra (Dendy) (Dendroceratidae: Darwinellidae) showed significant insecticidal activity. This paper clearly elucidated that C. longitoxa and Callyspongia diffusa (Rid.) were found to be more active than the remaining tested sponges. Screened twelve sponges showed the inhibition of larval growth ranged between 9-70% on A. janata and 10- 96% on P. ricini respectively. From the results, we conclude that secondary metabolites of sponges were found to be an effective biopesticides against lepidopteran pests and larvae of C. quinquefasciatus.

The effect of acetone and water extracts of Acacia auriculiformis A. Cunn. bark was investigated on biology of Bactrocera cucurbitae (Coquillett). The eggs, larvae and adults were treated with different concentrations (1, 5, 25, 125 and 625 ppm) of the bark extracts. Both the extracts significantly prolonged the larval period and total developmental period. Percentage pupation, percentage emergence, oviposition and egg hatching decreased in a dose dependent manner. The LC50 values were lower for the acetone extract as compared to water extract indicating that acetone extract was more toxic than water extract. The present findings demonstrated the potential of the plant extracts in controlling melon fruit fly.

Laboratory experiment was conducted to ascertain the repellence potentials of some aqueous Plant extracts against okra flea beetles (Podagrica uniforma). Six treatments namely: Ten percent aqueous extracts of Piper guinneense (schum and Thonn), Azadirachta indica A Juss, Xylopia aethiopica (Dunal) A. Rich, Garcinia kola (Heckel), Aframomum Melegueta (Rosch) K.schum and control (Distilled water) were assessed using a completely Randomized Design (CRD) replicated three times. The results showed that 10% aqueous extract of Piper guineense and Azadirachta indica had the highest percentage repellence values (100%) while control (Distilled water) had the least value (0%). Hence, 10% aqueous extracts of Piper guineense and Azadirachta indica could be used as repellents in the control of okra flea beetles.

Corcyra cephalonica, the rice moth was treated with andrographolide at a concentration of 5 µg per day in fluid volume of 5 µl of acetone. The effects of such a treatment were studied till the adult emergence. There was nearly 60 % pupal mortality and the adults that emerged, demonstrated morphological aberrations. The application of andrographolide mimics the juvenile hormone, appears to cause desruption in the metamorphic events leading to mortality of pupae, delayed pupal – adult transformation and structural abnormalities. From this study it is evidence that andrographolide possesses properties similar to juvenile hormone and its analogue.

In the present study, ethanol extract of Clerodendrum inerme L. (Verbenaceae), Withania somnifera L. (Solanaceae), Gliricidia sepia L. (Fabaceae), Cassia tora L. (Caesalpiniaceae) and Eupatorium odoratum L. (Asteraceae) were evaluated for their efficacy on mortality and progeny production of rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae). Adult insects were exposed to the 2.5 and 5% extracts treated wheat and mortality was assessed after 1, 2, 7, 14 and 21 days. Subsequently, all adults were removed and the treated grains remained at the same conditions for an additional 45 days. After this interval, the commodity was checked for progeny production. All extracts, the beetles mortality was increased in dose dependent manner. Results indicated that C. inerme and W. somnifera extracts were more effective than G. sepia, C. tora and E. odoratum against adult insects. Interestingly, the progeny production (Fl) was complete by suppressed even in lowest dose. It was concluded that both C. inerme and W. somnifera can be used for the protection of stored wheat from infestations of S. oryzae.

The potential of crude extracts of Artemisia judaica L. were evaluated for toxic and repellent effect against adult females and immature stage of Tetranychus urticae Koch and its predator Phytoseiulus persimilis Athias-Henriot in the laboratory. Ethanolic leaf extraction was more effective as toxic and repellent effect against adult females and immature stage of T. urticae , followed by acetone, petroleum ether and aqueous extraction (P < 0.05). The results indicated that adults are more susceptible to the leaf extracts than immature. LC50 values of P. persimilis against ethanolic extract was very low (167.3 gm / ml) as compared to the LC50 values of both adult and immature of T. urticae which where 0.29 and 2.97 gm / ml, respectively.

Petroleum ether extract (1000, 500, 250, 125 ppm) of Toddalia asiatica L., Aegle mermelos Corr., Murraya koengili Spreng., leaves and seed extracts of Alocasia indica Schott., were tested for their larvicidal activity on fourth instar larvae of Culex quinquefasciatus Say results showed that tested plant extracts possessed insecticidal activity. The synergetic effect of mixture of methanol extracts of T. asiatica seeds and the leaves of A. indica (1:1) at 10.265 ppm concentration showed larval mortality, pupal mortality, half ecdysed organisms, larval-pupal intermediates and colour changes during fourth instar stage. It is suggested that all the plants possess larvicidal properties that could be developed and used as natural insecticides for mosquito control.