Browsing by Author "Vijayasree, V"

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Behavioural response of cucumber moth Diaphania indica (Saunders) (Lepidoptera:Pyralidae) towards select host plant extracts
(Department of Entomology, College of Agriculture,Vellayani, 2024-02-09) Geethu Gopakumar.; Vijayasree, V
An investigation entitled “Behavioural response of cucumber moth Diaphania indica (Saunders) (Lepidoptera: Pyralidae) towards select host plant extracts” was conducted at the Department of Entomology, College of Agriculture, Vellayani during 2021-2023 with an objective to evaluate plant extracts and synthetic volatiles for the behavioural and electrophysiological responses of D. indica and identify the components of the plant extract. The plants evaluated in the study were Momordica charantia L, Trichosanthus anguina L., Cucumis sativus L., Coccinia grandis (L.) Voigt (wild and cultivated type), Cucumis melo var. acidulus Naudin., Solanum melongena L. and Amaranthus tricolor L. The behavioural bioassay of adult D. indica in Y-tube and modified olfactometer using plant extracts did not give any reliable response. The olfactory response of D. indica larvae was highest to C. grandis (wild) with a mean attraction of 23.33% followed by M. charantia, C. grandis and C. sativus with 10.83%, 9.17% and 8.33% attraction, respectively. In the GC-MS analysis of fresh leaf extracts, fatty acid, (Z,Z,Z)- 9,12,15-Octadecatrienoic acid (α-linolenic acid) and n-hexadecanoic acid (palmitic acid) was detected in all plant extracts except C. grandis (wild) and M. charantia, respectively. The alkane, dotriacontane was found in M. charantia, T. anguina, C. grandis (wild), A. tricolor and C. melo var. acidulus. The volatile compound benzaldehyde was identified in all samples except C. grandis (wild) and C. melo var. acidulus in headspace GCMS analysis of dried leaves. Electroantennographic studies showed gravid females are more responsive to plant extracts followed by unmated females. Gravid females showed highest response to extracts of M. charantia (0.25mV) and unmated females to C. sativus extract (0.14 mV). The synthetic volatile compounds, benzaldehyde and benzyl, alcohol when tested alone elicited the highest responses in the crude state. Among different combinations of these compounds, a mixture of 10µL of crude benzaldehyde and 30 µL of crude benzyl alcohol had the highest response (0.210 mV). This was on par with the response values of M. charantia and C. sativus extracts. While evaluating synthetic compounds for behavioural responses, a mixture of plateiiiiiii that D. indica shows a considerable electrophysiological, oviposition and feeding preference for M. charantia and C. sativus compared to other host plants. Linolenic acid, palmitic acid, dotriacontane and benzaldehyde were identified as common components in these plants which have reported kairomonal properties. The kairomonal property of benzaldehyde in combination with benzyl alcohol was proved in this study.
Efficacy and biosafety of new generation insecticides for the management of fruit borers of cowpea, brinjal and okra
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2013) Vijayasree, V; Hebsy Bai
Enzyme profiling of floral nectar, honey bee gut secretion and honey
(Department of Entomology, College of Agriculture , Vellayani, 2025-02-17) Harithasree, V S; Vijayasree, V
The study on ‘Enzyme profiling of floral nectar, honey bee gut secretion and honey’ was carried out at Quality control lab for honey, AICRP on Honey bees and Pollinators, Department of Entomology, College of Agriculture, Vellayani during the period 2022-2024. The main objective of the study was enzyme profile comparison of floral nectar and pollen, gut secretions of Indian honey bee (Apis cerana Fabricius), raw honey from different bee species, processed honey and market samples of honey. Activity of enzymes like diastase, invertase, glucose oxidase and catalase profiling during nectar to honey transformation of Indian bee (Apis cerana) (Hymenoptera; Apidae) in two predominant nectar sources, pumpkin and rubber was done. Results of the study revealed higher activity of all the enzymes analyzed in honey stomach content in both pumpkin (43.82 DN, 56.72 IN, 21.88 GLOx and 9.52 CAT) and rubber (42.91 DN, 56.16 IN, 20.98 GLOx and 12.26 CAT) derived samples. Lowest activity of diastase, invertase and glucose oxidase was found in pumpkin pollen and extra floral nectar of rubber, while catalase showed lowest activity in head gland secretions in both cases. Highest catalase activity was noticed in plant derived samples like nectar (4.53 Ug-1) and pollen (6.44 Ug-1). Higher enzyme activity was noticed in pumpkin honey on comparison with rubber honey, making it superior among two. Determination of enzyme activity in raw honey samples of Indian bee honey, western bee honey, rock bee honey and stingless bee honey showed higher activity of diastase, invertase, glucose oxidase and catalase in stingless bee honey (58.53 DN, 49.35 IN, 23.06 GLOx and 21.87 CAT), while the lowest activity was found in Indian bee honey (32.96 DN, 36.24 IN, 16.45 GLOx and 15.86 CAT). Enzymes in processed honey samples showed higher activity of all the enzymes in machine processed rubber honey (26.15 DN, 25.56 IN, 14.33 GLOx and 13.75 CAT) and lowest activity was observed in manually processed rubber honey (24.64 DN, 22.45 IN, 11.86 GLOx and 12.53 CAT). All the processed samples showed a significant reduction in ii the enzyme activity compared to their raw samples. Saffola honey showed higher enzyme activity among the nine market samples analyzed. All the nine samples satisfied FSSAI honey standards (DN ≥3) whereas, four among the nine samples satisfied the codex alimentarius honey standards (DN ≥8). Enzyme analysis in adulterated raw honey of Indian bee, western bee, rock bee and stingless bee, adulterated with 50 % sugar syrup showed a reduction in enzyme activity with a sudden decrease in the first 24 h. Decline in enzyme activity was less in adulterated stingless bee honey compared to other three samples. Indian bee honey treated at different temperatures (30 °C, 60 °C, 90 °C and 120 °C) revealed a reduction in enzyme activity with increase in temperature and at 120 °C activity of all the enzymes was negligible. To conclude, enzyme activity during nectar to honey transformation confirms the source of diastase, invertase and glucose oxidase as head glands and catalase as plant origin. Enzyme studies on raw honey samples showed stingless bee honey as superior with highest enzyme activity followed by western bee honey. Moreover, all the market samples analyzed satisfied FSSAI standards.
Field tolerance of chilli varieties against sucking pest complex
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2022) Haritha, N K; Vijayasree, V
Origin and composition of stingless bee propolis
(Department of Agricultural Entomology, college of Agriculture, Vellayani, 2023-05-03) Abhijith, R L.; Vijayasree, V
Pests of coccinia (cocinia grandis (L) voigt) and their management
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2006) Vijayasree, V; Nalinakumari, T
The occurrence, distribution and magnitude of pests of coccinia in ten locations of Kalliyoor Panchayath in Thiruvananthapuram district were studied in a survey conducted at monthly intervals for one year. A field trial was carried out to evaluate the efficacy of various botanicals and chemical insecticides in managing the pests of the crop in the Instructional Farm, College of Agriculture, Vellayani. The results of the survey revealed that the dominant pests in coccinia were scale insect Saissetia hemispherica (Targ.), aphid Aphis spiraecola Patch, fruit fly Bactrocera cucurbitae Coq. and gall fly Lasioptera cephalandrae Mani. The minor pests recorded were leaf footed bug Leptoglossus australis F., pentatomid bug Aspongopus obscurus F., epilachna beetle Henosepilachna vigintioctopunctata F., pumpkin beetles viz., Aulacophora foveicolllis (Lucas), Aulacophora impressa Fabricius, Aulacophora bicolor Weber, vine borer Apomecyna saltator Fabricius leaf folder Diaphania indica Saunders and red spider mite Tetranychus sp. Very low infestation of green stink bug Nezara viridula Linn., mealy bug Ferrisia virgata (Ckll.) and woolly bear Pericallia ricini Fb. The infestation of coccinia by A. spiraecola, L. australis, N. viridula, H. vigintioctopunctata, A. bicolor, A. impressa and Tetranychus sp. was reported for the first time. Location wise variations in the incidence and distribution of the pest were noticed. All the major and minor pests except A. dispersus and Tetranychus sp. were observed through out the year. These pests were found only in summer season. Seasonal occurrence of the pests showed higher population and more damage in summer than rainy season. Five fold increase in the damage was caused by L. cephalandrae in summer. Among the various natural enemies observed, only the spiders were seen in all the locations and throughout the year. Correlation studies revealed strong positive correlation between maximum temperature and population of the pests and extent of damage. Rainfall had significant negative relationship with both population and extent of damage. An important finding of the present investigation was that the galls of L. cephalandrae served as the site for multiplication of B. cucurbitae. Eighty per cent of the fruits and thirty per cent of the galls showed infestation by B. cucurbitae. The number of fruit flies emerged from fruit and gall did not show any variation. Evaluation of botanicals and chemical insecticides against pests and spiders revealed that botanicals were effective in controlling all the pests except S. hemispherica and L. cephalandrae and the chemical insecticides were comparatively more effective in the management of the pests other than L. cephalandrae. Imidacloprid offered long lasting protection of the crop from S. hemispherica and A. spiraecola. All the treatments tried were safe to spiders. The findings of the study clearly indicated that coccinia is severely infested with two hemipteran and two dipteran pests resulting in heavy yield loss. Imidacloprid which was found to be the best treatment could be recommended for the management of the pests especially the hemipteran pests. The treatments failed to manage L. cephalandrae.
Stingless bee foraging pattern in ornamental plants
(Department of Agricultural Entomology, College of Agriculture , Vellayani, 2023-05-03) Anchu, C L; Vijayasree, V
The present investigation on “Stingless bee foraging pattern in ornamental plants” was conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani, during 2020-2022. The objective of the study was documentation of the foraging pattern of stingless bees in nectariferous and polleniferous ornamental plants and preparation of floral calendar. Flowers were observed from identified ornamental plants at full bloom stage and their flowering period and floral characteristics were studied. Foraging activity of stingless bee was studied and observations were recorded from 0700 h to 1800 h from September 2021 to August 2022. A total of 20 ornamental plant species were identified on the basis of stingless bee foraging for nectar and pollen of which, 9 plant species were found producing flowers year round and remaining as seasonal. Major nectar producing plants were identified as coral vine (Antigonon leptopus Hook. and Arn) and scarlet bush (Hamelia patens Jacq). Pollen producing plants were identified as moss rose/sun plant (Portulaca grandiflora L), water lily (Nymphaea sp), rose (Rosa spp), scented rose (Rosa bourboniana L), ornamental palm (Syagrus romanzoffiana cham), lemon vine (Pereskia aculeate L), marigold (Tagetes erecta L) and sunflower (Helianthus annuus I). The ornamental plants providing both nectar and pollen were found to be hibiscus (Malvaviscus arboreus B, Hibiscus rosa-sinensis L), peacock plant (Caesalpinia pulcherrima L), chinese powder puff (Combretum constrictum L), chinese ixora (Ixora chinensis L), cape honey suckle (Tecoma capensis L), peregrina/ spicy jatropha (Jatropha Pandurifolia L) and euphorbia (Euphorbia mili L). Among the ornamental plants foraged by bees, the predominant family was Asteraceae followed by Rubiaceae, Malvaceae and Euphorbiaceae. The majority of bee flora were of strong orange, yellowish white followed by strong red and vivid reddish orange and tubular and cup-like shapes. Studies on foraging activity of stingless bee revealed that the peak activity was recorded during January and March with peak foraging activity from 1000 h to 0100 h. Among the year round flowering plants, maximum foraging rate was observed in Antigonon leptopus and among seasonal flowering plants, it was Syagrus romanzoffiana. Longest time spent by foragers was recorded as 30.44 sec during 1000-1200h of the day. Maximum time spent was observed in Nympheae sp. followed by Malvaviscus arboreus. Relationship between foraging rate and weather parameters viz temperature, relative humidity, wind velocity, rainfall and sunshine hours were done. Significant positive correlation was observed with temperature and number of foragers in case of Antigonon leptopus (0.221), Caesalpinia pulcherrima (0.271), Portulaca grandiflora (0.402), Jatropha pandurifolia (0.454) and Syagrus romansoffiana (0.213). Significant negative correlation was observed between relative humidity and number of foragers in case of Antigonon leptopus (-0.157), Hamelia patens (-0.216), Nymphaea sp. (-0.356), Caesalpinia pulcherrima (-0.256), Portulaca grandiflora (-0.295), Jatropha pandurifolia (-0.311), Malvaviscus arboreus (-0.142), Combretum constrictum (-0.293) and Syagru sromansoffiana (-0.401). Significant negative correlation was found between rainfall whereas significant positive correlation was recorded with sunshine hours and foraging rate. Thus in this study two nectar producing plants, eight pollen providing plants and 10 nectar and pollen producing ornamental plant species were identified. The foraging activity of bees varied in a day with the peak foraging activity during 1000 h to 0100 h. Bee floral calendar was prepared by using data of year round observation which can aid the farmers in providing the identified bee flora in particular month so that the bees can exploit these resources available in their surroundings.