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ThesisItem Open Access Biodiversity of the termite (isoptera) fauna in crop environments(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2011) Jyothy, Narayanan; KAU; Jim, Thomas (Guide)Termites (Insecta: Isoptera) are eusocial insects living in a highly organised and small to large extent of communities in different ecosystems. A termite colony has morphologically and functionally distinct caste system which includes functional reproductives / ‘royal pair’ of king and queen, sterile soldier and worker castes and the immature stages or nymphs along with other inquiline species of organisms. The present investigation on the ‘Biodiversity of the termite (Isoptera) fauna in crop environments’ was undertaken in a few selected crop environments in the instructional farm area of the College of Horticulture at Vellanikkara during 2010-11. The main objectives of the study were to identify the composition of the termite fauna up to the family/ genus level in mango, cashew, cocoa and coconut crop environments, elucidation of their feeding nature, behaviour, association and their mound forming characteristics and to prepare a primary termite colonisation map in the selected plantation and orchard systems in this tract. A preliminary survey was conducted by transect walk throughout the instructional farm area of the campus to select the termite prone plantation and orchard systems for the study. The soldier castes of termites were sampled from a unit area of 200 sq. m each from different crop environments and kept under preservation. The soldier castes from earthen mounds were collected by a special “Glue trap technique” designed and standardised for the purpose by the author through 20 numbers of encounter samplings per unit area of observation. The soldier castes were identified based on the standard keys (Bose, 1984; Roonwal and Chhotani, 1961 and Sornnuwat et al., 2004) with reference to their characteristics of head capsule, mandibles and pronotum. The diversity pattern of termite genera in different agro ecosystems in Vellanikkara were assessed by using various diversity indices. Based on these information, a preliminary termite colonisation map was prepared by depicting the distribution, spread and colonisation density of the identified termite genera in the selected crop environments. The morphometry of the aerial mounds along with some of the physical properties of the termitarial soils were also determined. The influence of temperature and humidity on the termite colonisation process was also observed. A total of nine termite genera under two families were identified in Vellanikkara. Out of this, seven termite genera viz., Odontotermes, Procapritermes, Dicuspiditermes, Homallotermes, Microtermes, Microcerotermes and Nasutitermes were under the family Termitidae, while, Heterotermes and Coptotermes were coming under the family Rhinotermitidae. Odontotermes was found to be the most dominant genus in all the selected crop environments accounting for about 62.03 per cent of the total genera identified from the Vellanikkara tract. The least present genus was Coptotermes which constituted only 1.27 per cent among all the identified genera. Based on the distribution, spread and colonisation density, a primary termite faunal distribution map was prepared in selected systems. The genera viz., Odontotermes, Microcerotermes, Nasutitermes, Heterotermes and Coptotermes were identified as wood feeders while, Procapritermes, Dicuspiditermes, Homallotermes and Microtermes were observed as soil/ humus feeders. Various diversity indices were worked out for the faunal distribution of the termites in this tract to find out their relative dominance, spread and evenness in its distribution. The genus richness of the termite genera at Vellanikkara tract was found to be 9 and the value of Simpson- Yule diversity Index (D) was found to be 2.44 and that of the Shannon- Weiner Diversity Index (H) was found to be 1.38. The Evenness Index (E) when worked out was found to be 0.63 and the Berger Parker Dominance Index (d) for the genus Odontotermes was found to be 0.62. When different systems were compared, the genus richness was found to be the highest in cashew plantation with a value of 6 while, the mango, cocoa and coconut systems were having a value of 3 only. The D value of 4.65, H value of 1.64 and the E value of 0.92 was found to be highest in cashew plantation, which indicated that the cashew system was supporting maximum generic diversity of the termites with a more evenness in its distribution. The values of these indices were found to be the lowest in cocoa which indicated that the cocoa based systems was having the lowest diversity and very low evenness in the distribution of various genera. The mango and coconut based systems were having intermediate values with these indices. The “d” value indicating the dominance of the particular termite genus viz., Odontotermes was found to be the highest in the cocoa based system with a value of 0.75 and the least in cashew with a value of 0.33. The mean density of the mounds in mango, cashew and cocoa based systems varied only slightly indicating their relative uniform distribution. The mean number of buttresses or young mounds ranged from 5- 7 per mound formation. The mean height of the mounds present in all the three systems showed only very slight variation, but there was difference in the mean basal circumference of the mounds in the three systems. Accordingly, the mean external volume (above ground) of the mounds in cubic centimetres was found to be the highest in cocoa and least in mango based systems. Statistical analysis of the data revealed that there was no significant difference in the relative per cent increase in the external volume of the mounds in cocoa plantation, while, there was significant difference in the change of volume as observed in July’10- Aug’10 and Jan’11- Feb’11 in mango and cashew based systems implicating the degree and period of termite activity within the termitaria. Regarding the physical properties, the soil colour of the mounds and of the adjacent soil during the wet season was found to be dark reddish brown as per the visual comparison through the standard Munsell colour chart. However, the colour of the mound soil and of the adjacent soil during the dry season was found to be brown and dark reddish brown, respectively. Particle size distribution in the soil samples of the termitarial mounds from the three crop environments viz., mango, cashew and cocoa based systems showed no significant difference among them. But within the same crop systems, the clay content of the mound soil was observed to be increasing by 10-12 per cent while, the sand content was decreasing by about 10-15 per cent. There was not much variation in silt content between the mound soil and adjacent soil. However, gravel was found to be totally absent in the mound soil as compared to the adjacent soils. When the temperature and relative humidity were recorded and compared between inside and outside of the mounds, it was found out that both temperature and relative humidity inside the mounds were significantly higher than that of the external environment which prove that the termites have to essentially maintain their homoeostasis with respect to the internal ambience for their survival and other activities irrespective of the external ambience. To conclude, the study reveals that the Vellanikkara tract is diverse in the faunal distribution of termites with nine genera under two families and five subfamilies with a dominant mound dwelling genus viz., Odontotermes in all the crop environments of mango, cashew, cocoa and coconut systems. The identification of the termite genera can very well be undertaken based on head capsule and mandibular characteristics of the soldier caste by collecting them easily by the newly designed method of “glue trap technique” by the author. The termites colonize these systems without any major environmental or resource degradation and thereby their role may be further investigated for the eco restoration and conservation activities.ThesisItem Open Access Insect pollinators of oil palm in Kerala(Department of Agriculture, College of Horticulture, Vellanikkara, 2010) Sambath, Kumar; KAU; Ranjith, A MOil palm, Elaeis guineensis (Jacq.) (Arecaceae) is one of the most commonly available and extensively cultivated perennial trees in many parts of the world. Previously pollination was considered as a serious constraint, so manual pollination was often carried out, to sustain the yield. Wind and honey bees play an important role in pollination of many crops. But they alone can not give adequate level of pollination in all circumstances. In nature, pollination by specific insect species is vital for many crops. In this context, the present investigation on the “Insect pollinators of oil palm in Kerala” was carried out in the Plantation Corporation of Kerala, Athirappilly and Laboratory trails were conducted in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara during 2009 to 2010. Fifteen different insect species were observed to visit on the inflorescence. Insect species such as, African oil palm weevil, Elaeidobius kamerunicus (Coleoptera: Curculionidae); an earwig, Forficula sp.? (Dermaptera); a moth, Pyroderces sp.? (Lepidoptera: Cosmopterigidae) and Indian honey bees, Apis cerana indica (Hymenoptera: Apidae) were main species from the collection on male and female inflorescences. Population of different insect visitors on anthesising female inflorescence was highly varied and E. kamerunicus was found to be more, among all insect species. Weevils were found to be visiting the female flowers between 10.00 a.m. to 2.00 p.m. and the peak weevil population was observed on the 1st and 2nd day of anthesis, around 12.00 noon. But, on male inflorescence weevil population was less during 10.00 to 2.00 p.m. Thereafter, it was gradually increased and attained the maximum at 4.00 p.m. Highly significant positive (r = 0.712**) correlation was observed between population of E. kamerunicus on 1st day of anthesis of female flowers and per cent pollination whereas, it was not significant (r = 0.199) on the 2nd day of anthesis which indicates that maximum amount of pollination occurred in the 1st day of anthesis. Weevils of E. kamerunicus were congregating on the male inflorescence during the entire period of anthesis and their statistical median weevil population was 48, 76, 80 and 35, 56 and 72 on top, middle and bottom portions of male inflorescence during rainy and summer seasons respectively. Adult weevils of E. kamerunicus feed on anthers of male inflorescence and multiply. Everyday, during occasional visits to female inflorescence, they would shed the pollen grains and get back to its original place of host which would cause adequate level of pollination of female flowers. The anise seed like odour (estragole 5, 4 allylanisole) attract the weevils towards both male and female inflorescences. The biology of E. kamerunicus was carried out in both rainy and summer seasons under wire cage. The female weevil laid eggs singly on the spent male inflorescence of oil palm. The fecundity ranged from 32 to 33 eggs (median = 32) in rainy and 34 to 35 eggs (median = 35) in summer seasons with an ovipositional period of 1 to 2 days during both seasons. The eggs hatched into grubs within 1 to 2 days. The grub period lasted for 8 to 10 days in rainy and 7 to 9 days in summer seasons respectively with three larval instars. The grubs pupated for 3 to 4 days in rainy and summer seasons and the adult weevils emerged out. The total life cycle from egg to adult was completed within 14 to 16 and 11 to 14 days in rainy and summer seasons respectively. The longevity of adult weevils varied with the sex and males lived longer than females. The life span of male weevils was 5 to 7 and 4 to 6 days during both rainy and summer seasons respectively. Female weevils lived for 4 to 6 days in rainy and 4 to 5 days in summer seasons. Among the duration of different life stages viz., egg, larva, pupa and adult of E. kamerunicus, the grub period was found to be longest (7 to 9 days) followed by adult longevity (male = 5 to 6 days; female = 5 days), pupa (3 to 4 days) and egg (1 to 2 days). The number of female weevils in the field was more, when compared to the male with the sex ratio (♂ : ♀) of 1 : 1.87 in rainy and 1 : 1.96 in summer seasons respectively. Morphometric study of different life stages of E. kamerunicus showed that the diameter of egg measured 0.258 mm. The freshly laid eggs were creamy white in colour. The first instar grub was pinkish yellow in colour with brown head capsule and other instars are yellow coloured. The average length of I, II and III instar grubs were 1.59, 2.73 and 3.84 mm. Similarly mean body width of corresponding instars was 0.52, 0.86 and 1.62 mm. The pupa also showed yellow colour with the length of 3.53 mm and width of 1.63 mm. The newly emerged adult weevil was light brown in colour and later on changed to dark brown. The male and female weevils could be differentiated based on their size and additional structures on their body. Males (length = 4.13 mm; width = 1.54 mm)) were bigger than female (length = 3.81 mm; width = 1.28 mm). Males also had setae on the peripheral side of elytra with some dorsal spines. Female has smaller body and absence of above mentioned structures over its body. Both male and female inflorescences were produced separately in successive whorls. Production of male inflorescence ranged from 0 to 2 from 10 different marked palm trees and at least one male inflorescence (mode = 1) could be seen in each tree from July ‘09 to Jan ‘10 except during Sep ‘09 (mode = 2). Female inflorescence production ranged from 0 to 1 during July ‘09 to Feb ‘10 except during Aug ‘09 (1 to 6) and Oct ‘09 (0 to 3). The mode value of female inflorescence production was 1 during July ‘09 and Aug ‘09 and it was zero from Sep ‘09 to Feb ‘10. Anthesis period of male inflorescence accounted for 10 to 14 days with more weevil population between 4th to 7th days which coincided with the maximum odour emission. Stigma receptivity lasted for 2 to 3 days but, insect visit was observed for only 2 days. So, assisted pollination can be done only up to 2 days of anthesis of female flowers. The bunch set was not found to be uniform in each month. The mode value of bunch set was varied in different months like 0, 1, 5, 5, 4, 6 and 2 from July ‘09 to Feb ‘10. Production pattern of male and female inflorescence with regard to different climatic factors was recorded from July ‘09 to Feb ‘10. An increasing trend of male inflorescence production was observed from July ‘09 to Sep ‘09 (mode = 2) with the maximum and minimum temperature of 29.91 and 24.28 oC, relative humidity of 94.37%, rain fall of 12.67 mm and sun shine hours of 0.52 hrs. Later on uniform production was recorded until Jan ‘10 and no inflorescence was seen during Feb ‘10. Similarly female inflorescence production was found to be uniform during July ‘09 and Aug ‘09 (mode = 1) which coincided with monthly maximum (28.4 and 29.94 oC), minimum temperature (23.45 and 24.08 oC), relative humidity (98.38 and 93.52%), rain fall (19.72 and 12.31 mm) and sun shine hours of 2.48 and 3.05 hrs. There after, it was very much reduced (mode = 0). Bunch set was low in July ‘09 which, gradually increased and reached the maximum during Jan ‘10 (mode = 6) with the weather parameters such as, maximum (32.24 oC), minimum temperature (21.7 oC), relative humidity (85.23 %), rain fall (0.18 mm) and sun shine hours (8.96 hrs). Correlation study of inflorescence production and various weather parameters showed that there was a significant positive correlation with relative humidity and rain fall and significant negative correlation with maximum temperature and sunshine hours. On the contrary, monthly bunch set showed a significant negative correlation with relative humidity. Wind could be offer only less contribution towards pollination and fruit set and, it was also not influenced by birds. Totally 336 to 800 flowers were counted from female inflorescences (mean = 596.4) and the range of fruit count was from 186 to 583 (mean = 393) with 27 to 132 partially developed fruits (mean = 73.8) per bunch. Per cent pollination was from 60.36 to 88.37 (mean = 77.13 %). It took around 145 to 161 days for the complete development of fruits (mean = 153.3) and the bunch weight was 5 to 29 kg (mean = 17.13) with a mean fruit weight of 32.52 g per bunch. Observations on period of stigma receptivity of female inflorescence and time of weevil visit to female flowers may be helpful to the farmers when they would need assisted pollination either manually or through artificial means by using E. kamerunicus. The present study showed that, they can restrict the pollination just for 2 days after anthesis which will ultimately save labour, money and time spent on this. Artificial culturing of weevils can be done with kairomones to maintain their population during summer season since, very poor inflorescence production was noticed during summer. It is also necessary to retain the male inflorescence at least for one month after anthesis. This will help for multiplication of weevils. During rainy months, the spent inflorescence must be removed within 40 to 45 days to avoid disease occurrenceThesisItem Open Access Potency of bioinsecticides against the cowpea bruchid, Callosobruchus maculatus (F.) (Coleoptera:Cysomelidae) in storage(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2011) Amritha Kumari, S; KAU; Sosamma, JacobThe present study entitled ‘Potency of bioinsecticides against cowpea bruchid, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) in storage’ was undertaken to understand the feasibility of utilizing few biologically based grain protectants in post harvest storage of cowpea by investigating their biological efficacy and persistent/ residual toxicity. The bioinsecticides under study were two entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae; spinosad, an actinomycete based broad spectrum insecticide with low mammalian toxicity and lemongrass oil- an essential oil from the aromatic plant, Cymbopogon flexuosus. Laboratory bioassays were carried out to investigate the dosage-mortality response of the bioinsecticides against C. maculatus. Toxicity of entomopathogens was studied by two bioassay techniques-direct dipping and residue film. B. bassiana and M. anisopliae were tested at five different concentrations 1 x 104, 1 x 105, 1 x 106, 1 x 107 and 1 x 108 spores/ml. Observations on mortality were taken at 24 hours interval upto five days. Results on the mortality of C. maculatus indicated an increase in mortality with increase in dosage and period of exposure. Cumulative mortality data of C. maculatus by B. bassiana and M. anisopliae at five days after treatment with five concentrations revealed no significant difference in mortality between the two entomopathogens and the two bioassay methods. Probit analysis of dosage-mortality response of B. bassiana and M. anisopliae indicated lower LC50 value for M. anisopliae than B. bassiana (5.12 x 106 and 6.7 x 106 spores/ml) than B. bassiana (5.38 x 106 and 7.49 x 106 spores/ml). However the difference was not remarkable. Time-mortality effect of B. bassiana and M. anisopliae indicated an increase in LT50 values as the spore concentration decreased. Toxicity of spinosad to C. maculatus was also investigated by direct dipping and residue film bioassay methods. LC50 of spinosad was 4.02 ppm by direct dipping where as a higher LC50 value (36.39 ppm) was observed by residue film bioassay. Spinosad brought about 50 per cent mortality in 20.51 to 33.09 hours and 90 per cent mortality in 2.6 to 3.3 days. Lemongrass oil, at eight concentrations (1 to 8 μl/l of air), was tested to study the fumigant toxicity action against C. maculatus and the mortality ranged from 16.67 to 96.67 per cent. Lemongrass oil caused 50 per cent mortality at 3.93 ppm in one day and 90 per cent mortality at 7.51 ppm in 2.6 days. Bio-efficacy of the four bioinsecticides along with coconut oil as a recommended check was assessed for a period of 30 days in the storage by studying their effects on adult mortality, fecundity, egg hatchability, progeny emergence, developmental period, extent of infestation, grain weight loss and seed viability. Regarding adult toxicity, lemongrass oil caused highest adult mortality (87.1 to 100%) followed by spinosad (75.87 to 100%) at three days after treatment. Spinosad was most effective as an inhibitor of oviposition and egg hatchability. On comparing the progeny emergence in different treatments, no progenies were produced in the cowpea grains treated with coconut oil. Spinosad and lemongrass oil also showed higher inhibition of progeny emergence. Data on the effect of bioagents on the extent of infestation by C. maculatus revealed that coconut oil was the most effective treatment as it caused zero infestation. Spinosad and lemongrass oil were the next effective ones as they resulted in 49 and 52 per cent reduction of seed damage. Entomopathogens were found to be ineffective in reducing bruchus damage to seeds. Effects on weight loss also recorded the same trend. Results on the impact of bioagents on seed viability indicated that spinosad treated grains showed the highest germination followed by lemongrass oil and coconut oil. Results of the persistent toxicity action of the tested bioinsecticides revealed that spinosad had highest persistence with a PT value of 5699.7. All other bioagents showed less persistence. Lemongrass oil showed the least persistent toxicity against in storage. It can be concluded from the present investigation that among the four bioagents, spinosad is the most effective one in terms of bioefficacy as well as persistent action in cowpea seeds. It can be recommended as an alternative option for bruchid management in storage. The existing recommendation of coconut oil is also proved to be effective against C. maculatus in storage of cowpea seeds. Lemongrass oil is also a very effective bioagent as a fumigant for protecting cowpea grains from C. maculatus with a limitation of short persistence that warrants frequent applications in storage. B. bassiana and M. anisopliae are not effective against C. maculatus in cowpea storage.ThesisItem Open Access Biological control of root-knot nematode, Meloidogyne incognita (Kofoid and White, 1919) in banana Musa (AAA) var. Robusta(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2011) Lini, G; KAU; Susannamma KurienA study entitled ‘Biological control of root-knot nematode, Meloidogyne incognita (Kofoid and White, 1919) in banana, Musa (AAA) var. Robusta’ was carried out in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara and Banana Research Station, Kannara during April 2010 to June 2011. The objective of the study was to identify an effective biocontrol agent for the management of root-knot nematode in banana. The species of root-knot nematode was identified and confirmed as M. incognita by the perineal pattern of the white females collected from the infested roots of banana plants from BRS, Kannara. Pot culture experiments were conducted to study the effect of different biocontrol agents viz., Arbuscular Mycorrhizal Fungi (AMF), Pseudomonas fluorescens, Paecilomyces lilacinus, Bacillus subtilis and Heterorhabditis indica (EPN) alone and in different combinations in comparison with the commonly used chemical nematicide, carbofuran on the management of root-knot nematode in banana. The effect of the treatments on the biometric characters of banana viz., height of the plant, girth of pseudostem and number of leaves were observed at monthly intervals. When the plants were about to form bunches (seven months after planting) these plants were uprooted and the effects of different treatments on various parameters viz., fresh weight of the whole plant, corm, roots, gall formation on roots and the nematode population in soil and roots were recorded. Among the various treatments tried, the combined application of P. fluorescens and P. lilacinus was found to be very effective in enhancing the biometric characters of banana which was on par with that of carbofuran, followed by P. lilacinus and AMF when treated alone, whereas EPN was found to be the least effective one With regard to nematode population in soil and roots, though carbofuran was found to be the best treatment, this was closely followed by P. fluorescens and P. lilacinus treatment. Same trend was noticed in the case of root knot index, gall formation, fresh weight of whole plant, corm and roots. Application of AMF and EPN were observed as the least effective treatments and recorded maximum nematode population both in soil and roots. . Considering the above results, the present study indicated that the combined application of P. fluorescens and P. lilacinus was found to be the most effective substitute for the chemical nematicide carbofuran for the management of root-knot nematode in banana.ThesisItem Open Access Infestation of the pumpkin caterpillar, diaphania indica saunders in cucurbits and its management(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2011) Neena, Lenin; KAU; Hebsy, BaiSurvey conducted in the Kalliyoor panchayath of Thiruvananthapuram district during 2009-2010 revealed the incidence of the pumpkin caterpillar, Diaphania indica Saunders in bitter gourd, snake gourd, cucumber and coccinia. The extent of infestation was high in bitter gourd, snake gourd and cucumber and low in coccinia. The infestation was significantly higher during the fruiting followed by the flowering and vegetative stages. Leaves and fruits of bitter gourd, snake gourd and coccinia were damaged by the pest. Only the leaves of cucumber were damaged. No significant differences were noted in the extent of infestation when more organic manures or more fertilizers were applied by the farmers. Similarly, the high and low doses of fertilizers applied also did not influence the extent of damage. The plant protection measures adopted by the farmers too had no significant effect on the extent of damage. The red amaranth (Amaranthus tricolor Linn.) and green amaranth (Amaranthus dubius L.) and the weed plants, the slender amaranthus (Amaranthus viridis L.) and bristly starbur (Acanthospermum hispidum DC.) were recorded as host plants of D. indica. The parasitoid Apanteles sp. was the only natural enemy recorded during the survey. Among the botanicals screened, annona seed extract 5%, neem oil garlic emulsion 2%, neem seed kernel extract 5%, Anosom 2ml l-1, Derisom 2ml l-1 and NeemAzal T/S 2ml l-1 resulted in high mortality of the caterpillars upto three days after treatment both when applied topically and released on treated leaves. The efficacy of Anosom 2ml l-1 extended to the seventh day when released on treated leaves. Topical application of spinosad 0.015%, flubendiamide 0.004%, profenophos 0.05%, diafenthiuron 0.02%, triazophos 0.05% and chlorpyriphos 50%+ cypermethrin 5% 0.05% resulted in 100 per cent mortality of the caterpillars one day after treatment. When released on treated leaves, flubendiamide 0.004% and spinosad 0.015% proved to be the better treatments, registering mortality of the pest upto 15 days after treatment. 80 Field evaluation with annona seed extract 5%, Anosom 2ml l-1, B. bassiana 2g l-1, B. thuringiensis 2g l-1, flubendiamide 0.004% spinosad 0.015% and carbaryl 0.15% indicated that flubendiamide 0.004% was the most effective, the reduction in the pest population being 60 per cent. Spinosad 0.015% and Anosom 2ml l-1 also resulted in significant reduction in the pest population, the extent of reduction being 46 and 43 per cent, respectively. Annona seed extract 5% too was equally effective as Anosom 2ml l-1 in its efficacy, the population of the pest being reduced by 40 per cent. The extent of reduction in the pest population in carbaryl 0.15%, B. bassiana 2g l-1 and B. thuringiensis 2g l-1 treatments was 35, 35 and 33 per cent, respectively. More than 50 per cent reduction in the number of fruits damaged was recorded B. bassiana 2g l-1, flubendiamide 0.004%, B. thuringiensis 2g l-1 and spinosad 0.015% treatments. Anosom 2ml l-1 and annona seed extract 5% resulted in more than 40 per cent reduction in the fruit damage. Carbaryl 0.15% registered 39 per cent reduction in the fruit damage. All the treatments increased the yield of the crop significantly, the extent of yield increase ranging from 36 to 44 per cent in the insecticide, 39 to 41 per cent in the botanical and 26 to 39 per cent in the microbial treatments. Based on the results of the study, destruction of the weed and other volunteer host plants and early detection of the pest and its management with either the botanicals or microbials would be a viable option for controlling the pest. The safer insecticides flubendiamide 0.004% or spinosad 0.015% could be used when there is a substantial increase in the pest population.ThesisItem Open Access Characterization of bud necrosis virus infecting tomato(College of Agriculture, Vellayani, 2011) Simi, S; KAU; Umamaheswaran, KStudies were conducted to characterize the tospovirus causing the bud necrosis disease of tomato in Kerala. The characteristic symptoms observed were, necrotic ring spots on leaves and severe necrosis, death of the emerging buds, stem necrosis and concentric yellow colored rings on fruits. Host range studies were conducted and the virus was found to infect members of family Chenopodiaceae, Solanaceae, Fabaceae, and Cucurbitaceae. The virus was efficiently transmitted by mechanical means using 0.01 M phosphate buffer (pH 7.2) containing 0.1 per cent 2-mercaptoethanol. No seed transmission was recorded. However successful graft transmission was observed. The virus recorded a DEP in the range of 10-3 to 10- 4 , TIP of 50 oC to 55 oC, and LIV of 8 h at room temperature (28±2oC) and 24 h at 80C. The carbohydrate levels in inoculated plants were lower compared to the uninoculated tomato plants. Similarly the content of chlorophyll a, b and total chlorophyll were also lower in inoculated tomato plants. The phenol content was found to be more in inoculated plants. There was an increase in protein content in inoculated plants compared to the healthy plants. In case of inoculated plants the activity of the defense related enzymes were higher than the control plants. Protein profile of tospovirus infected tomato plants using SDS - PAGE showed three extra novel proteins with molecular weights of 28, 15 and 12 kDa respectively. Isozyme analysis of PPO produced three isoforms in both healthy and inoculated plants with relative mobility (Rm) values of 0.60 and 0.77. The activity of the two isoforms were more in the inoculated plants. The virus causing bud necrosis disease in tomato was confirmed as tospo virus by serological analysis such as ELISA and DIBA. The virus isolate showed close relationship with WSMV. The virus was also detected using PCR and an amplicon of size 800 bp was obtained using primer specific to tospovirus. The meristem from the infected tomato plants were regenerated into plantlets and were tested for the presence of the virus by subjecting it to DAC- ELISA. The absorbance of the plantlet regenerated from healthy and infected meristem were found to be 0.13 and 0.12 respectively which was on par with the healthy field sample but much lower than that of the infected field sample which was used as the positive control which recorded an absorbance of 0.81.ThesisItem Open Access Management of melon fly(Bactrocera cucurbitae coquillett) using local isolates Beauveria bassiana(Bals.)Vuill,Paecitomyces lilacinus(Thom.)Samson and Aspergillus candidus Link:Fries(College of Agriculture, Vellayani, 2010) Amala, U; KAU; Jiji, TA study on “Management of melon fly, Bactrocera cucurbitae Coquillett using local isolates entomopathogenic fungi viz., B.bassiana (ITCC 6063), P.lilacinus (ITCC 6064), A.candidus (ITCC 5428)” was conducted in the Department of Agricultural Entomology, College of Agriculture, Vellayani.These fungi were screened against the pupae and adults of melon fly. The most promising fungus was selected based on its efficacy, mass multiplied for field application, standardized for field dosage and method of application. Dietary constituents comprising of honey, sucrose, jaggery, sugar and water in combination with yeast were evaluated for the laboratory rearing of melon fly. Bait preparation in 100 ml water containing 20g jaggery and 10g yeast was the best suitable diet for in vitro rearing of melon fly.The bioassay of the fungi on the pupae and adults was conducted and the most promising fungus was selected. The studies were conducted by soil drenching (pupae) and spraying (adults) using different spore concentrations of the fungi. Based on the percentage mortality and LC50 value, Paecilomyces lilacinus was identified as the most promising fungus for the management of melon fly. The fungus was mass multiplied on locally available cheaper solid (rice bran, wheat bran, gingelly oil cake, coir pith, neem cake) and liquid substrates(rice bran extract, wheat bran extract, boiled rice water, coconut water and water). Rice bran recorded the maximum spore count of P.lilacinus on 28th day after inoculation. The fungus cultured in rice bran, showed the maximum efficacy in causing pathogenicity on the pupae and adults of melon flies.In vitro studies were conducted to evaluate the efficacy of the P. lilacinus on adults and pupae of melon flies under cage and trough conditions. Soil drenching with P. lilacinus @ 1.3x109 spores /ml (30 ml per trough) resulted in 92.45% mortality in pupae, five days after inoculation in soil, under trough conditions. Spraying with P. lilacinus @ 2.4x109 spores/ml recorded cent per cent mortality in adults, three days after treatment, under cage conditions.Food baits containing banana, jaggery and malathion in different combinations were used to document the peak time of activity of melon fly. Bait preparations in water (100 ml) containing 30g banana, 10g jaggery, 0.2 ml malathion and 10g yeast, showed superior performance in the trap catch of melon flies, with the peak during 8-10 a.m.Field experiment was conducted with the treatments viz., soil drenching (P. lilacinus), spraying (P. lilacinus), soil drenching + spraying (P. lilacinus), 0.2% malathion spray and control. Soil drenching with P. lilacinus at a spore concentration of 1.3x109 spores/ml (170 g P. lilacinus multiplied in rice bran in 17 litres of water per 40 m2) + spraying with P. lilacinus at 2.4x109 spores/ml (20 g P. lilacinus multiplied in rice bran in 2 litres of water per 40 m2) recorded the minimum percentage infestation of melon fly. The same treatment recorded significantly higher yield (16.6 t/ha) and a B: C ratio of 2.92 in bittergourd. Soil drenching with P. lilacinus recorded the maximum number of infected pupae in soil under field conditions. Lower incidence of pumpkin caterpillar was observed in soil drenching + spraying with P. lilacinus.. This treatment supported the maximum incidence of natural enemies under field condition.ThesisItem Open Access Management of major sucking pests in cowpea vigna unguiculata (L.) Walp.with entom opathogens and plant defense inducing rhizobacteria(College of Agriculture, Vellayani, 2010) Kavitha, S J; KAU; Faizal, M HA study was conducted at the Department of Entomology, College of Agriculture, Vellayani during 2007-2009 to major sucking pests in cowpea Vigna unguiculata (L.) Walp. with entomopathogens and plant defense inducing rhizobacteria.All PGPR screened viz., Pseudomonas putida, Pseudomonas sp., Bacillus subtilis, Bacillus pumilus and Serratia marcescens significantly enhanced seedling vigor in cowpea. Seed treatment with PGPR gave superior results over soil drenching and foliar application. Population build up of A. craccivora was slow in PGPR treated plants compared to control. B. subtilis, B. pumilus and S. marcescens were identified as potential PGPR suited for growth promotion and aphid suppression in screening experiment in glass house.Fusarium pallidoroseum and S. marcescens proved very effective entomopathogen against A. craccivora and R. pedestris respectively showing consistently higher mortality with increase in exposure time. B. bassiana and M. anisopliae were found moderately effective.In dual culture plate assay, all PGPR were compatible with each other, Among the entomopathogens, M. anisopliae inhibited growth of F. pallidoroseum strongly. In combination of PGPR and entomopathogens, B. subtilis, Pseudomonas sp. and P. putida strongly inhibited the growth of M. anisopliae. In pot culture studies, B. subtilis was the best PGPR treatment in enhancing the biometric characters and yield of cowpea.F.pallidoroseum gave maximum per cent mortality of A. craccivora. B. subtilis applied in combination with F. pallidoroseum was effective in suppressing aphids and increasing the yield. Dual application of B. subtilis and S. marcescens against R. pedestris resulted insignificantly higher yield. Combined infestation of A. craccivora and R. pedestris could be managed by seed treatment with B. subtilis followed by application of F. pallidoroseum and S. marcescens.