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ThesisItem Open Access Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii(Burgess) (Diptera:Agromyzidae)(Department of agricultural entomology, College of horticulture, Vellanikkara, 2014) Jyothi Sara, Jacob; KAU; Maicykutty P, MathewA study on “Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)” was carried out at the Department of Agricultural Entomology, College of Horticulture, K.A.U., Vellanikkara during 2011-2013 with the objectives of collection and identification of indigenous natural enemies and to assess the pathogenicity of the entomopathogens to explore the feasibility of utilizing them for its management. Surveys were conducted in the vegetable fields for the collection and identification of natural enemies associated with L. trifolii in three districts, namely, Thrissur, Ernakulam and Kottayam from January to March, 2011. The surveys revealed the occurrence of nine species of hymenopteran parasitoids. The per cent parasitism varied from 10.96 to 58.99 per cent among the crops surveyed. Three species of eulophids, namely, Cirrospilus acadius Narendran, C. brevicorpus Shafee & Rizvi and Aprostocetus sp. as well as the braconid, Toxares sp. are new reports for India. Among the parasitoids, Closterocerus spp. were the dominant group followed by Chrysonotomyia sp. All parasitoids were solitary, larval endoparasitoids except Toxares sp. which was larval-pupal in nature. One species each of small ants (Formicidae) and a dipteran fly (Dolichopodidae) were observed as predators on L. trifolii. In the study, no entomopathogens were observed from L. trifolii. Considering the level of pesticide consumption in vegetable crops that undermine the potential of insect parasitoids and also that no entomopathogens could be observed during the survey, it was decided to evaluate entomopathogenic nematodes (EPNs) as biocontrol agents against L. trifolii. Isolation of EPNs from 72 soil samples from Thrissur, Ernakulam and Kottayam districts yielded four isolates of Steinernema carpocapsae. Bioefficacy studies carried out on these four isolates along with Steinernema bicornutum and Heterorhabditis indica showed that S. carpocapsae Isolate - 1 had the lowest LC 50 , LC 90 and LT values indicating their higher effectiveness against the maggots of the pest. 50 Pot culture study conducted to compare the potential of S. carpocapsae Isolate - 1 with other treatments showed that azadirachtin 1 EC at 0.005% was the most effective causing 84.51 per cent mortality to the maggots of L. trifolii. This was followed by the foliar application of H. indica at 32 infective juveniles (IJs)/ maggot which caused 18.98 per cent mortality. Application of Beauveria bassiana at 1×10 7 spores/ ml was not effective. In the field evaluation, fipronil 5 SC at 0.002% was found to be the most effective treatment for controlling L. trifolii followed by azadirachtin 1 EC at 0.005%. Compatibility of the IJs of the S. carpocapsae Isolate - 1, S. bicornutum and H. indica was studied with ten commonly used insecticides in the laboratory by direct exposure method. Chlorantraniliprole 18.5 SC at 0.005% was found to be the most compatible insecticide with S. carpocapsae isolate - 1 causing only 0.17 per cent mortality to IJs at 72 hours after treatment (HAT). Quinalphos 25 EC at 0.05% and chlorpyriphos20 EC at 0.05% were highly incompatible, causing 96.17 and 92.87 per cent mortality of the nematodes. Dimethoate 30 EC at 0.04% was the most compatible insecticide with S. bicornutum and caused only 0.60 per cent mortality at 72 HAT and was followed by azadirachtin 1 EC at 0.005% with 0.78 per cent mortality to the IJs. Quinalphos 25 EC at 0.05% caused 99.93 per cent mortality at 72 HAT. Heterorhabditis indica was compatible with all insecticides except quinalphos 25 EC at 0.05% which was moderately toxic resulting in 39.6 per cent mortality. The virulence, pathogenicity and multiplication of the survived IJs were not affected by the insecticide treatments. Parasitoids and EPNs were observed as potential candidates for the management of L. trifolii. Hence future studies on the bio-ecology and mass production of dominant parasitoids and standardization of methods to improve the efficacy of EPNs are suggested for the successful control of L. trifolii in polyhouses as well as in the field.ThesisItem Open Access Biorational management of major pests in brinjal (Solanum Melongena L.)(Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2014) Gowrish, K R; KAU; Ramesha, BBrinjal (Solanum melongena L.) is a plant of considerable conomic importance in many tropical and sub tropical parts of the world. It is a popular vegetable grown as poor man’s crop in India. It is a native of India and is grown throughout the country. The brinjal crop is usually infested by a number of pests right from nursery stage till harvest. Among the insect pests, the most important and destructive ones are shoot and fruit borer, Leucinodes orbonalis; epilachna beetle, Epilachna vigintioctopunctata; leaf roller, Antoba olivacea and hairy caterpillar, Selepa docilis. For the management of these pests, the conventional pest management practices often provide unsatisfactory results. Further, the use of chemical pesticide results in insecticide resistance, pest resurgence, destruction of natural enemies and pesticide residue in the harvested produce and related environment and health hazards. Hence, there is an impetus for research and development of eco-friendly and biorational alternative for the sustainable management of major pests of brinjal. A survey was conducted in the three agro climatic regions of Kasargod district viz., low, mid and high land area. The survey revealed that per cent incidence of pests like L. orbonalis, E. vigintioctopunctata and A. olivacea were severe on brinjal in low, mid and high land area of Kasargod district. However, severe infestation of S. docilis was noticed in low land, compared to mid and high land area of Kasargod district. Spinosad 45 SC was found to be effective in controlling the shoot and fruit borer of brinjal during both summer and kharif season. Azadirachtin 1% was found to be most effective in controlling E. vigintioctopunctata adults as well as grubs. It was also found to be effective in reducing mean per cent of leaf infestation during both summer and kharif season. The Bt formulation was found to be highly effective for early instar larvae of A. olivacea. However, for older instar caterpillars, malathion 50 EC was found to be effective during both summer and kharif season. The azadirachtin 1% was found to be highly effective against S. docilis as compared to other treatments during both summer and kharif season. The spinosad 45 SC was safer to natural enemies like predatory coccinellids and spiders in brinjal ecosystem. The yield of brinjal plant was higher in spinosad 45 SC treated plots and a higher return was obtained worth Rs. 2.52 and Rs. 2.67 during both summer and kharif season respectively for every one rupee invested. Effect and compatibility of spinosad 45 SC on entomopathogenic fungi using poisoned food technique under in vitro condition revealed that spinosad 45 SC is not compatible with M. anisopliae and B. bassiana in terms of colony development, sporulation and spore germination. Residue of major and minor component of spinosad 45 SC were below the maximum residue limit.ThesisItem Open Access Bio-ecology and management of papaya mealybug on mulberry(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Rajan, V P; KAU; Krishnakumar, RThe experiment entitled “Bio-ecology and management of papaya mealybug on mulberry” was carried out at College of Agriculture, Vellayani, Kerala Agricultural University and in farmers’ fields at Agali, Sholayur and Puthur panchayats during October 2009 to July 2012. The main objectives of the study were to identify and assess the extent of infestation of papaya mealybug on mulberry, its role in disease transmission and population dynamics and to evolve an Integrated Pest Management (IPM) strategy to contain the pest. Preliminary survey conducted in sericulture practising districts of Kerala revealed heavy infestation of the pest in three panchayats of Palakkad district in Kerala. The mealybugs identified in the survey were papaya mealybug, Paracoccus marginatus Williams and Granara de Willink, pink hibiscus mealybug, Maconellicoccus hirsutus (Green) and breadfruit mealybug, Icerya aegyptiaca (Douglas). The occurrence of papaya mealybug and its egg masses were found to be high during the period of May to August. The competition between these three mealybugs and also the influence of weather parameters on the population of the papaya mealybug was studied. The mealybug population showed positive correlation with maximum temperature, sunshine and wind speed and negative correlation with minimum temperature, rainfall and humidity. The different plants belonging to families Asteraceae, Euphorbiaceae, Malvaceae and Solanaceae were observed to be the most preferred hosts for papaya mealybug. The highest number of all life stages of papaya mealybug was observed on Parthenium, Parthenium hysterophorus L., which augmented the perpetuation of papaya mealybug in the absence of other crop hosts. Sprouted potatoes were the host material used for studying the biology of the papaya mealybug, pink hibiscus mealybug and breadfruit mealybug. The average number of eggs laid by an adult papaya, pink hibiscus and breadfruit mealybug were 361.50, 281.30 and 141.30 respectively. The mean larval period of papaya, pink hibiscus and bread fruit mealybugs were found to be 16.7, 21.2 and 47.1 days respectively. DAC-ELISA was performed with infected mulberry plants using antibodies of SCBMV and BSV showed the absence of virus in the infected samples collected from the mealybug infested mulberry gardens. The phenol content was also assessed in the infested samples to get an indication of the level of resistance showed by the host plant against mealybug. The level of resistance of the plant found to be increasing with the increase in the per cent damage. The fifth instar larvae of the predator, Spalgis epius was found as the most active feeder with a feeding potential of 21.69, 118.88, 40.88 and 20.49 of ovisacs and first, second and third instars of papaya mealybug respectively. Third instar larvae of green lacewing, Chrysoperla carnea (Stephens) and fourth instar grubs of ladybird predator, Cryptolaemus montrouzieri (Mulsant) were the most voracious feeders and they consumed significantly higher number of ovisacs, first, second and third instar nymphs of papaya mealybug as compared with first and second instar larvae of the predators. Among the different insecticides evaluated in the laboratory against the first instar and adult papaya mealybugs, dimethoate 0.1% was superior followed by imidacloprid 0.01%. Among the combinations, dimethoate 0.05% + econeem plus 2 ml L-1 was found to be superior with the highest per cent mortality of 93.33% and 96.67% for adult and first instar papaya mealybugs respectively. The silkworm larvae fed with the leaves after 15 days of treatment with the combination of dimethoate 0.05% + econeem plus 2 ml L-1 gave the highest yield of (91 /100 larva reared) cocoons with a total larval duration of 576 hours. Single cocoon weight was found to be high (1.56 g) with the highest shell ratio (22.09). The mean larval weight of different instars were 0.54, 0.87, 1.16, 8.80 and 36.61 gram respectively in first, second, third, fourth and fifth. In the above treatment, effective rearing rate (ERR) by number and weight were 9050.00 and 13744.69 g respectively. Field evaluation with the combination of pruning and weeding along with application of dimethoate (0.05%) 1.7 ml + econeem plus 2 ml L-1 and also providing a second spraying with dichlorvos (0.05%) 2 ml + econeem plus 2 ml L-1 was observed to be superior among all the treatments with minimum leaf damage, shoot damage and highest leaf yield per plant. B: C ratio worked out also confirmed the superiority of this treatment. Hence this treatment can be recommended as an IPM strategy for the management of papaya mealybug on mulberry.ThesisItem Open Access Bioefficacy of neonicotinoid insecticides against insect pests of okra (Abelmoschus esculentus(L.) Moench)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2014) Jijisha, P K; KAU; Sosamma, Jacob (Guide)An investigation on “Bioefficacy of neonicotinoid insecticides against insect pests of okra (Abelmoschus esculentus (L.) Moench)” was undertaken in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara, Kerala Agricultural University during 2013- 2014. The study was carried out by conducting two field experiments at the Instructional Farm, College of Horticulture in two seasons viz., April 2013 to July 2013 and October 2013 to January 2014. Two neonicotinoid insecticides - thiamethoxam and imidacloprid - were fieldevaluated for their biological efficiency against major insect pests of okra, safety to naturaenemies, influence on plant growth parameters and terminal residues in okra fruits. The twoinsecticides were applied in three methods viz., seed treatment (ST), two foliar treatments (2FT) and a combination of seed treatment followed by a single foliar treatment (ST+FT). Thetreatments comprised of ST thiamethoxam 30FS @ 3 g a.i. kg -1 (T1) and ST imidacloprid48FS @ 6 g a.i. kg -1 (T2) before sowing, two foliar sprayings ( 2FT) with thiamethoxam25WG @ 25g ai ha -1 (T3) and imidacloprid 70WG @ 25 g a.i. ha-1 (T4) at 15 and 30 daysafter sowing (DAS) and a combination of seed treatment followed by a foliar spraying(ST+FT) with thiamethoxam (T5) and imidacloprid (T6) at 30 DAS. A standard checkinsecticide quinalphos 25EC @ 250 g a.i. ha -1 as two foliar sprayings (FT) at 15 and 30DAS (T7) along with an untreated control (T8) were also included in the field experiment. Both thiamethoxam and imidacloprid were found to be significantly effective than quinalphos against Amrasca biguttula biguttula Ishida in okra. All the three methods of application with thiamethoxam and imidacloprid showed equal effectiveness upto 30 DAS. However, both the foliar treatment and the combination of seed treatment followed by a single foliar treatment with thiamethoxam proved to be equally effective throughout the season to A. biguttula biguttula. Thiamethoxam and imidacloprid by all the three application methods (seed treatment, foliar treatment and combination of seed treatment followed by foliar treatment) were equally effective against Aphis gossypii Glover upto 25 DAS. From 30 to 50 DAS, two foliar sprayings at 25 g a.i. ha -1 revealed a highest reduction of 88.49 per cent in the population of A. gossypii. Two foliar sprayings with imidacloprid 70 WDG @ 25 g a.i. ha-1 at 15 and 30 DAS recorded the lowest population of Bemisia tabaci Gennadius and least leaf damage by Sylepta derogata Fabricius in okra. Thiamethoxam 25WDG with two foliar sprayings (2 FT) @ 25 g a.i. ha -1 at 15 and 30 DAS significantly reduced the shoot and fruit damage by Earias vitella Fabricius. With regard to the impact of thiamethoxam and imidacloprid on natural enemies, two foliar sprayings with thiamethoxam at 25 g a.i. ha -1 showed highest coccinellid population in the first season. In the second season, seed treatment with thiamethoxam @ 3 g a.i. kg indicated the highest population of coccinellids. However, imidacloprid was found to be safer than the standard check quinalphos to coccinellids in both seasons. But the spider population was observed to be relatively less in all the treatments of thiamethoxam and imidacloprid as compared to the untreated control. Thiamethoxam and imidacloprid showed no adverse effect on other predators such as syrphids, chrysoperla and rove beetles in okra field. Thiamethoxam and imidacloprid indicated phytotonic effects on okra plant for they exhibited significant effects on plant growth parameters. Two foliar sprayings of thiamethoxam significantly increased the plant height, number of leaves, flowers per plant, fruit weight and fruit length. Seed treatment with both thiamethoxam and imidacloprid reduced the days for flower initiation. Terminal residue in fruits was below detectable limit at 15 days after spraying in all the treatments with thiamethoxam and imidacloprid.ThesisItem Open Access Morphological and biochemical bases of resistance to melon fruit fly, [Bactrocera cucurbitae(Coquillett)(Diptera:Tephritidae) in Bitter gourd(Momordica charantia L.)](Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2014) Manju, Roshni K; KAU; Madhu, SubramanianA study titled “Morphological and biochemical bases of resistance to melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) in bitter gourd (Momordica charantia L.)” was undertaken at College of Horticulture, Vellanikkara during 2013-2014 with the objectives of evaluation of the degree of resistance to melon fruit fly in selected accessions of bitter gourd, identification of morphological and biochemical bases of resistance and assessment of the olfactory response of melon fruit flies to fruit extracts of bitter gourd accessions. A field experiment was carried out in Randomised Block Design with ten treatments and three replications at Instructional Farm, Vellanikkara. The treatments consisted of accessions Priya, Preethi, Priyanka, CO-1, VKB-136, VKB-130, VKB-196, IC-0596980, IC-0596981 and IC-0596983. The resistance of bitter gourd accessions to melon fly was evaluated in terms of per cent fruit damage and larval density. The results showed significant variation in fruit infestation among the accessions evaluated. The lowest damage of 9.13 per cent was recorded in VKB-196 followed by CO-1 at 10.17 per cent, both being on par. Four accessions, including Priya (49.08 %), Priyanka (50.99 %), VKB-130 (53.14 %) and Preethi (64.56 %) recorded higher levels of infestation and were on par. Melon fly damage was found to be influenced by the fruit characters of different accessions. Correlation of infestation with fruit characters such as colour, weight, length, width, flesh thickness, spine length, spine form and spine density revealed that spine density and flesh thickness were negatively and significantly correlated with per cent fruit damage (-0.81 and-0.69 respectively) and larval density (-0.74 and -0.69 respectively). VKB-196, which recorded the highest values for flesh thickness and spine density (0.52 cm and 9.83/cm , respectively) recorded the lowest incidence of 9.13 per cent while VKB- 130 with flesh thickness of 0.32cm2 and spine density of 4.81 cm2 recorded higher damage of 53.14 per cent. Analysis of parameters like protein content, moisture content, peroxidase activity and polyphenol oxidase activity showed a negative and significant correlation of peroxidase activity with fruit fly infestation. Studies on olfactory responses of gravid female melon fly to fruit extracts recorded higher response to hexane fruit extract as against aqueous extract. Similarly melon flies showed greater attraction to those accessions which had recorded higher per cent damage, suggesting presence of volatile chemicals which might have mediated response of melon fly towards the accessions. Based on present investigations, VKB-196 and CO-1 may be rated as highly resistant to melon fly, IC-0596983 as resistant, IC-0596981, VKB-136, IC-0596980 and Priya as moderately resistant and VKB-130, Preethi and Priyanka as susceptible. The studies also show that resistance could be mediated by fruit characters like flesh thickness, spine density and peroxidase activity. Sustained efforts could lead to development of melon fly resistant bitter gourd varieties, providing the much needed edge to melon fly management in bitter gourd.ThesisItem Open Access Evaluation of entomopathogenic fungi against pest complex of chilli (Capsicum annuum L.)(Department of agricultural entomology, College of agriculture, Vellayani, 2014) Lokesh, S; KAU; Sudharma, KAn investigation entitled “Evaluation of entomopathogenic fungi against pest complex of chilli (Capsicum annuum L.)” was carried out during 2012-14 at College of Agriculture, Vellayani. The objectives were to evaluate the efficacy of Beauveria bassiana (Balsamo) Vuillemin, Lecanicillium lecanii Zare & Gams and Metarhizium anisopliae (Metschnikoff) Sorokin against pests of chilli, assess the compatibility of the fungi with pesticides and develop products of the fungi. Three fungi viz. Fusarium solani (Mart.) Sacc and Penicillium oxalicum Currie and Thom infecting Aphis gossypii Glover and Isaria javanica (Friederichs & Bally) Brown & Smith infecting Bemisia tabaci Gennadius were isolated and the reports on these insects are new in India. An yeast, Meyerozyma caribbica (Vaughan-Martini, Kurtzman, S.A. Meyer & E.B. O'Neill) Kurtzman & M. Suzuki infecting B. tabaci has been isolated and the report of the yeast is new. The pathogenicity of fungal isolates was evaluated against A. gossypii, B. tabaci, P. latus and S. dorsalis. All the treated insects showed symptoms of infection by all the isolates except Llm. The virulence of the fungi was evaluated @ 108 spores ml-1. At 48 hours after treatment, the highest mortality of 99.97 per cent to A. gossypii was caused by L. lecanii (Ll8). I. javanica caused the maximum mortality of 83.61 per cent to B. tabaci. With respect to P. latus, the highest mortality of 80.65 per cent was recorded in B. bassiana (Bb5a) and it was on par with the mortality in L. lecanii (Ll8) and B. bassiana (Bb21). The effect of all the fungi except L. lecanii (Llm) to S. dorsalis was on par. The LC50, LC90 and LT50 values of the fungal pathogens to A. gossypii, B. tabaci, P. latus and S. dorsalis were worked out. To achieve control of these sucking pests in the shortest period, the field doses fixed for B. bassiana (Bb5a), B. bassiana (Bb21), L. lecanii (Ll8) and M. anisopliae (Ma4) ranged from 1.68 × 108 to 5.10× 109, 1.68× 108 to 5.75× 109, 2.76× 108 to 4.12× 109 and 3.11× 108 to 3.12× 109 spore ml-1 respectively. Talc based products of the fungi were prepared and their shelf life was determined. The cfu observed at 60 days after storage was 1.03× 108 ml-1, 0.44× 108 ml-1, 0.68× 108 ml-1 and 1.18× 108 ml-1 for B. bassiana (Bb5a), M. anisopliae (Ma4), L. lecanii (Ll8) and Bb21 respectively. The compatibility of the fungal pathogens with pesticides was assessed. Dimethoate (0.06%) was the most inhibitory to all the fungal isolates. M. anisopliae (Ma4) was least inhibited by the pesticides. Field experiment was conducted to evaluate the fungal pathogens and newer molecules of insecticides against pests of chilli. The treatments B. bassiana (Bb5a) and L. lecanii (Ll8) @ 20 g l-1 and acetamiprid (0.004%) were found to be on par in reducing the P. latus population. B. bassiana (Bb5a) 20 g l-1 was found on par with acetamiprid (0.004%), spiromesifen (0.02%) and emamectin benzoate (0.002%) in their effectiveness to S. dorsalis at 7 DAT. The fungal isolates did not affect the spider population. The benefit cost ratio was highest for the treatment with B. bassiana (Bb5a) 20 g l-1 (2.62). To conclude, the fungal pathogens viz. B. bassiana (Bb5a and Bb21), L. lecanii (Ll8) and M. anisopliae (Ma4) @ 20 g l-1 are safe, economical and ideal for integration with newer pesticide molecules viz. emamectin benzoate (0.002%), spiromesifen (0.02%) and acetamiprid (0.004%) for management of pest complex of chilli.ThesisItem Open Access Evaluation of entomopathogenic fungi for the management of coleopteran pests and characterisation of pesticide tolerant strains(Department of agricultural entomology, College of agriculture, Vellayani, 2014) Anis Joseph, R; KAU; Sudharma, KDevelopment of safe and sustainable technologies for pest management is the need of the hour to counter the adversities created by the synthetic pesticides. Considering this, the research on “Evaluation of entomopathogenic fungi for the management of major coleopteran pests and characterisation of pesticide tolerant strains” was carried out in the Department of Agricultural Entomology, College of Agriculture during 2007-2014. The main objectives of the study were to assess the pathogenicity of entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillimen and Metarhizium anisopliae (Metschnikoff) Sorokin against coleopteran pests, determination of LC 50 , LC 90 and LT 50, development of formulations, of field efficacy, compatibility with pesticides and development of pesticide tolerant strains and molecular characterization of the fungi. assessment The isolates PDBC Bb 5 and PDBC Ma 4 were evaluated against nine coleopteran pests viz. Aulacophora foveicollis Lucas, Basilepta fulvicorne Jacoby, Cylas formicarius F., Cosmopolites sordidus Germ., Henosepilachna vigintioctopunctata F., Lanka ramakrishnai Prathapan & Viraktamath, Metriona circumdata H., Oryctes rhinoceros Linn. and Rhynchophorus ferrugineus F. Both the fungi were pathogenic to the grubs as well as adults of all the nine insects tested. Though the symptoms produced in the test insects by both the fungi were more or less the same, differences in the behavior of the infected insects were seen. The period taken for the expression of symptoms also varied. The virulence of these two fungi was determined against these nine coleopterans. Ma 4 was found inferior to Bb 5 in its ability to infect the adults of all the test insects except to that of O. rhinoceros at the comparable dose of 10 8 spores ml -1 . Further, bioassay was conducted against the adults and grubs of all the nine test insects and the LC 50 , LC 90 and LT were worked out. From the probit analysis, it was seen that to achieve fifty per cent mortality of the adult coleopterans 50 with B. bassiana within the shortest periods, spore concentrations of 5. 27 × 10 , 6.53 × 10 8 , 4.24 ×10 9 , 5.62 × 10 7 , 3.99 × 10 8 , 6.76 × 10 8 , 7.26 × 10 9 , 1.56 × 10 and 3.76 × 10 13 spores ml -1 was essential for A. foveicollis, B. fulvicorne, C. sordidus, C. formicarius, H. vigintioctopunctata, L. ramakrishnai, M. circumdata, O. rhinoceros and R. ferrugineus respectively. The LC values were much less for the grubs when compared to the adult coleopterans and the values were 2. 15 × 10 50 , 1.87 × 10 6 , 3.83 × 10 8 , 2.94 × 10 7 , 2.79 × 10 7 , 5.72 × 10 6 , 4.96 × 10 and 4.64 × 10 11 spores ml -1 respectively for the grubs of the above mentioned insects. Corresponding LC values were also worked out. The lethal time to obtain fifty percent mortality also varied with insects. With respect to M. anisopliae 11.42 × 10 10 , 3.99 × 10 8 90 , 8.86 × 10 10 , 6.27 × 10 9 , 6.96 × 10 8 , 3.66 × 10 11 8 8 15 , 6.22 × 10 , 6.13 × 10 , 2.58 × 10 13 and 2.73 × 10 15 spores ml -1 respectively was required for the adult coleopterans and 4.91 × 10 7 , 6.09 × 10 8 , 4.81 × 10 8 , 5.83 × 10 8 , 4.95 × 10 7 , 2.42 × 10 , 4.64 × 10 9 , 3.79 × 10 8 and 10.29 ×10 13 spores ml -1 respectively for the grubs. From the LC 50 and LC values, information on the effective field doses of these two fungi against the nine coleopterans could be garnered. 90 Inorder to identify cost effective materials for the multiplication of the fungus, nine substrates were evaluated. The ideal substrates that maintained the viability of B. bassiana were cow dung, wheat bran, rice bran and neem cake. Cow dung and wheat bran supported maximum cfu of M. anisopliae. The peak sporulation of the fungi was observed in the samples drawn two months after storage. Talc based formulations of both fungi maintained the required standards of colony forming units in the formulation upto three months after storage. The cfu at third month after storage for B. bassiana and M. anisopliae were 0.2 × 10 9 cfu g -1 10 8 and 0. 24 × 10 respectively. The bioefficacy of fungi cultured in different substrates and stored for different months was also evaluated against the grubs and adults of C. formicarius. With respect to bioefficacy also, the fungi cultured in cow dung, wheat bran and neem cake proved better. 7 11 9 The results of the field experiment in banana, variety Nendran to assess the effect of spore suspensions of B. bassiana and M. anisopliae, fungi in cow dung and neem cake substrates and talc based formulations of the fungi in comparison with insecticide revealed that the best treatment was talc based B. bassiana @ 30 g l excepting the insecticide check, chlorpyrifos 0.03 per cent for the management of C. sordidus. In the succeeding crop of banana talc based B. bassiana @ 30 g l was even superior to the insecticide check, chlorpyriphos 0.03 per cent. The least number of galleries (0.63) and the least number of grubs in the rhizomes (0.29) besides the lowest number of adult C. sordidus in soil samples were seen in talc based B. bassiana @ 30 g l -1 . The B : C ratios calculated for the treatments with talc based B. bassiana @ 30 g l -1 in the main crop was 1.57 compared to 1.24 for chlorpyriphos 0.03 per cent. The B : C ratios for the treatments with talc based B. bassiana @ 30 g l -1 and spore suspension of B. bassiana 5 × 10 11 spores ml -1 in the succeeding crop of banana were 1.78 and 1.49 which were higher than that for chlorpyriphos 0.03 per cent. The results from the succeeding crop indicate the ability of these fungi to self perpetuate and bring about long lasting effect in the treated area. Field experiments were also conducted in sweet potato, variety Sree Bhadra to assess the effect of two fungi. Talc based B. bassiana @ 30 g1 was superior treatment excepting imidacloprid 0.006 per cent in reducing the galleries produced by the weevils. A similar trend was evident in the second trial also. The effect of application of B. bassiana and M. anisopliae in cow dung and neem based substrates showed moderate effect with respect to the number of galleries and number of grubs. Drenching of talc based formulation of B. bassiana @ 30 g l -1 was better than its foliar treatment. The compatibility of B. bassiana and M. anisopliae with two fungicides and six insecticides was also evaluated inorder to evaluate the suitability of integrating the fungi with pesticides in pest management programmes. Good compatibility of the insecticide, imidacloprid 0.006 per cent with B. bassiana and M. anisopliae was seen. Bioefficacy of the fungi cultured in this insecticide was also higher. Attempts were -1 -1 -1 also made to develop pesticide tolerant strains of B. bassiana and M. anisopliae. For this they were grown continuously in media with varying doses of pesticides. A total of ten passages through poison food media was made. It was seen that both the fungi tolerated high doses of pesticides though there was inhibition in growth, sporulation and bioefficacy. B. bassiana and M. anisopliae tolerated even 32 times higher the recommended field dose of imidacloprid. Subculturing reduced the spore production of both the fungi and the rate of reduction was higher for B. bassiana. Variations induced in B. bassiana and M. anisopliae after ten passages through poisoned media were analysed. Pesticides varied in their ability to induce such changes in the fungi. Polymorphism was higher for B. bassiana cultured in carbendazim. The polymorphism exhibited in B. bassiana was higher (83.19 per cent) compared to M. anisopliae (38.46 per cent). Among the ten universal fungal primers evaluated, RFu – 10 was found to give maximum polymorphism. To conclude, B.bassiana and M.anisopliae are pathogenic to the grubs and adults of all the nine test insects. Of the two fungi tested Bb 5 was more virulent than Ma 4 except to O. rhinoceros. Talc based formulation of both the fungi maintained the required standards of cfu in the formulations upto three months after storage. Cow dung, wheat bran and neem cake are ideal substrates for the multiplication of the fungi. Soil drenching of talc based formulation of B. bassiana @ 30 g l three months after planting was the best treatment for the management of C. sordidus. For the management of C. formicarius in sweet potato also soil drenching of talc based formulation of B. bassiana @ 30 g l -1 was superior. Compatibility of B. bassiana and M. anisopliae with insecticides and fungicides varied, the most compatible one was imidacloprid. Maximum tolerance to this insecticide, upto 32 times higher than the field dose was shown by B. bassiana and M. anisopliae. Pesticides induced changes in DNA, the polymorphism exhibited was higher for B. bassiana compared to M. anisopliae. Nine isolates of the fungi were also identified through ITS sequencing. The new isolates were Beauveria sp. from C. formicarius, B. bassiana -1 from B. fulvicorne, B. brongniartii from M. circumdata, Metarhizium sp. from B. fulvicorne; Metarhizium sp., Metarhizium album and Metarhizium anisopliae var majus from O. rhinoceros, Fusarium moniliformae from H. vigintioctopunctata and Paecilomyces sp. from C. sordidus and these isolates can be exploited in insect specific biocontrol programmes.ThesisItem Open Access Insecticide resistance in spotted pod borer, Maruca vitrata 9Fabricius) on vegetable cowpea and its management(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Pattapu, Sreelakshmi; KAU; Ambily, PaulA study on “Insecticide resistance in spotted pod borer Maruca vitrata (Fabricius) on vegetable cowpea and its management” was undertaken at College of Agriculture, Vellayani and in the farmer’s field at Kalliyoor and Venganoor panchayaths during January, 2013 to May, 2014. The main objectives were to assess the insecticide resistance in field population of spotted pod borer, M. vitrata, evaluate the efficacy of new generation insecticides against the resistant population and determine the harvest time residues in cowpea pods. A preliminary survey conducted among cowpea growers in Kalliyoor and Venganoor panchayaths of Thiruvananthapuram district revealed control failures in the field population of spotted pod borer due to the continuous application of a single insecticide like chlorpyriphos or lambda cyhalothrin. The survey data served as the benchmark for further studies on the insecticide resistance in M. vitrata. Bioassay was carried out in CRD to assess insecticide resistance in populations of M.vitrata collected from three different locations (location I- field with no previous history of pesticide application, location II- field where less control failures and location III- field where more control failures) using two chemicals viz. chlorpyriphos and lambda-cyhalothrin at different doses. Results revealed that population collected from location-I was found to be susceptible for both the chemicals with resistance ratio-1, population collected from location-II to be moderately resistant with a resistant ratio of 2.28 and 2.38 and population from location-III to be resistant with resistance ratios of 2.93 and 7.94 for chlorpyriphos and lambda-cyhalothrin respectively. Laboratory experiments conducted to evaluate the efficacy of new generation insecticides viz. novaluron - 0.015 per cent, flubendiamide - 0.01 per cent, spinosad - 0.015 per cent, emamectin benzoate - 0.002 per cent, indoxacarb 14.5 per cent + acetamiprid 7.7 per cent SC- 0.09 per cent, acephate 50 per cent + imidacloprid 1.8 per cent SP - 0.20 per cent, chlorantraniliprole - 0.03 per cent, indoxacarb - 0.10 per cent and chlorpyriphos - 0.05 per cent (as check) against the resistant population of M.vitrata revealed that the per cent mortality of the second instar larvae treated with insecticides viz. emamectin benzoate, indoxacarb+acetamiprid and spinosad were 97.28, 97.28 and 90.90 per cent respectively after 6 hours of treatment. Hence, these insecticides were selected for further field trials against the resistant population of M .vitrata. The field experiment was conducted in RBD with four treatments viz. emamectin benzoate 0.002 per cent, indoxacarb+acetamiprid 0.09 per cent and spinosad 0.015 per cent including control against the resistant population of M.vitrata. Application of emamectin benzoate, indoxacarb + acetamiprid and spinosad resulted in a reduction of 81-100, 64-100 and 69.96 - 99.6 per cent respectively in the case of flower infestation and 83 -100, 23.38 - 98.40 and 55.26 – 100 per cent respectively in case of pod infestation. Harvest time residue estimation done on 7th day after the application of insecticides showed the residues below the quantitative limit of 0.05 mg kg-1 revealing its safety for consumption. The study could indicate the development of insecticide resistance in the field population of M.vitrata. On the basis of the present study it could be concluded that spraying of emamectin benzoate @ 10 g ai ha-1 or indoxacarb + acetamiprid @100 g ai ha-1 or spinosad @ 75 g ai ha-1 could effectively manage the resistant population of M. vitrata in cowpea. This study forms a maiden attempt in assessing the extent of insecticide resistance development in the populations of M. vitrata in Kerala. Further studies have to be taken up to develop and popularize an Insecticide Resistance Management (IRM) strategy against this devastating pest of cowpea.ThesisItem Open Access Management of root-knot nematode, Meloidogyne sp. (Kofoid and White) in Coleus, Solenostemon rotundifolius(Poir) morton(College of Horticulture, Vellanikkara, 2014) Lakshmy, K Mohan; KAU; Susannamma, KurienThe study entitled ‘Management of root-knot nematode, Meloidogyne sp. in coleus, Solenostemon rotundifolius (Poir) Morton’ was conducted at College of Horticulture, Vellanikkara during 2012-2013 with the objectives of assessment of the population of plant parasitic nematodes infesting coleus at different coleus growing regions of Thrissur District, identification of the species of Meloidogyne infesting coleus and evaluation of biocontrol agents, organic amendments and a chemical insecticide against this root- knot nematode in coleus. Survey was conducted in the major coleus growing areas of Thrissur District, namely Mundathikode, Wadakkanchery, Varavoor, Thirur, Kolazhi, Vellanikkara, Madakkathara and Vadanapilly. Soil and tuber samples were collected from these localities and the nematodes were extracted to assess the population of plant parasitic nematodes associated with coleus. It was found that root-knot nematode was the major problem in all the eight locations and the species of root-knot nematode was identified as Meloidogyne incognita (Kofoid and White) Chitwood, 1949 on the basis of perineal pattern of white females. Other plant parasitic nematodes recorded from soil samples were reniform nematode (Rotylenchulus reniformis Linford and Oliveiria), burrowing nematode (Radopholus similis (Cobb, 1893) Thorne, 1949), lance nematode (Hoplolaimus sp.), spiral nematode (Helicotylenchus sp.) and rice-root nematode (Hirschmanniella oryzae Luc and Goodey, 1963) which were not harmful to the tubers of coleus. The highest average root-knot nematode population was recorded from Kolazhi with 450.4 nematodes/ 200g soil with a gall index of 3.9. Pot culture experiment was carried out to evaluate the efficacy of biocontrol agents, organic amendments and a chemical insecticide against root-knot nematode infesting coleus. The results showed that application of organic amendments namely whole plant of Tagetes erecta, leaves of Chromolaena odorata and neem cake resulted in the enhancement of plant growth characters and resulted in a reduction of root-knot nematode population. Incorporation of T. erecta whole plant ranked first among the organic amendments. Neem cake, cartap hydrochloride 4G and combination treatments of Bacillus subtilis + Pseudomonas fluorescens and P. fluorescens + Paecilomyces lilacinus improved the yield of coleus plants. Soil application of P. lilacinus, cartap hydrochloride 4G and incorporation of T. erecta suppressed the nematode population in soil, root and tuber respectively. Combination treatment of P. fluorescens + P. lilacinus and application of neem cake also reduced population buildup of nematode and kept the infestation at a lower level. Highest reduction in number of females, number of root knots and root knot index was also observed in T. erecta and was followed by P. lilacinus, P. fluorescens + P. lilacinus, neem cake and C. odorata. The study clearly indicated that application of organic amendments and biocontrol agents were found to be as effective as cartap hydrochloride 4G in managing the root-knot nematode population in coleus and can be considered as alternative to nematicide application.
