Browsing by Author "Anitha, N"

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Arthropod diversity in drumstick Moringa oleifera Lam.
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2023-04-12) Niveditha K P; Anitha, N
Bioecology and integrated management of banana pseudostem weevil odoiporus longicollis oliv
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2000) Anitha, N; Madhavan Nair, G
Bioecology and management of spiralling whitefly Aleurodicus disperus Russell (Homoptera : Aleyrodidae)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2004) Rani, J; Anitha, N
A study on bioecology and management of spiralling whitefly, Aleurodicus dispersus Russell was carried out in laboratory and pot culture experiments at the Department of Entomology, College of Agriculture, Vellayani, Thiruvananthapuaram during the period 2003-2004. The survey conducted in the instructional Farm, College of Agriculture, Vellayani for a period of one year revealed that Aleurodicus dispersus attacked 50 host plants belonging to 30 families. Averrhoea bilimbi L, Capsicum chinense Jacq., Vigna unguiculata (L.) Walp. Vitis vinifera Linn, Passiflora edulis L., Jacquemontia violaceae Choisy, Spathoglottis aurea Lindle, Ixora chinensis Lam, Alysicarpus vaginalis (L.) DC Chromolaena odorata (L) King and Robinson, and Phaseolus sp, were reported for the first time in India as host plants of spiralling whitefly in the present study. Biology of A. dispersus on cassava, tomato and chilli revealed that cassava was the most susceptible host plant with shorter developmental period and longer adult period and higher fecundity. The eggs were laid on the under surface of leaves in characteristic spiral manner. Eggs were stalked, elliptical and light yellow to tan coloured. There were three nymphal instars and a pupal stage. Adult resembled tiny moths. The wings were clear first, later covered with a waxy powder. The nymphs and adults caused damage to the plants by sucking cell sap from the tender parts of the plants. They excrete honey dew which served as the substrate for the development of sooty mould. Heavy infestation of A dispersus combined with sooty mould infection resulted in loss of plant vigour, unsightly appearance and reduction in yield. The predators reported during the survey were Allograpta javana Wiedemann (Syrphidae; Diptera ), Axinoscymnus puttarudriahi Kapur and Munshi (Coccinellidae; Coleoptera), Cybocephalus indicus Tian and Ramani (Nitidulidae; Coleoptera) and spiders. Two doses each of the formulation viz., Neemazal, Econeem, and plant extract of Andrographis paniculata and Hyptis suaveolens were evaluated with Dimethoate 0.05 per cent as check against A. dispersus on tomato. Three sprayings were given at 45, 60 and 75 days after transplanting. Among the formulated neem products, Neemazal 4 ml 1-1 recorded highest population reduction of eggs, nymphs and adults of A. dispersus on tomato. The neem products were of only moderate efficiency in reducing various life stages of the pest compared to Dimethoate. However, the products can be included in the integrated management of this whitefly, considering the lower toxicity to the natural enemies and environmental safety. Based on the results of the present study, destruction of weed host plants and use of neem products can be suggested for the management of A. dispersus, as an adhoc recommendation.
Bioecology of major coccinellid predators of Kerala
(Department of agricultural entomology, college of agriculture , Vellayani, 2023-07-07) Anusree, S S; Anitha, N
An investigation on “Bioecology of major coccinellid predators of Kerala” was carried out at Department of Entomology, College of Agriculture, Vellayani during 2017-2022 with the objective to identify major coccinellid predators of pests infesting agricultural crops from agro ecological zones of Kerala and to study biology and predatory potential of select coccinellids. In the present investigation, 40 species of predatory coccinellids belonging to 23 genera under 6 tribes in the Subfamily Coccinellinae were illustrated. Taxonomic study on tribes Aspidimerini and Chilocorini resulted in the identification of three species in each tribe. Examination on specimens of tribe Coccidulini resulted in identifying 16 species within five genera. 11 species belonging to nine genera were illustrated under tribe Coccinellini. A single species was illustrated and studied under tribe Hyperaspidini. The specimens studied under tribe Sticholotidini belonged to six species within four genera. Among the 40 illustrated species, 28 species were identified, while identity of 12 species are to be confirmed, of which three are putative new species. Phrynocaria perfida Poorani collected and illustrated during this investigation were confirmed and described as a new species (Poorani et al., 2021). Chilocorus sp.1 and Scymnus (Pullus) sp.4 are the other two putative new species. Phrynocaria perrotetti (Mulsant), Cryptogonus orbiculus (Gyllenhal) and Sticholotis ferruginea (Gorham) are new records from Kerala.
Effect of root-knot nematode meloidogyne incognita (Kofoid and White) chitwood and reniform nematode rotylenchulus reniformis linford and oliveria on cowpea
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Anitha, N; Arthur Jacob, J
Three pot culture experiments were laid out with the objectives (i) to study the effect of M. incognita on cowpea, (ii) to study the effect of R. reniformis on cowpea and (iii) to study their combind effect. The individual effects were assessed with nine population levels ranging from 0 – 1000 larvae/100 ml soil each replicated thrice. In the combined experiment three population levels, 100, 200 and 400 and their three combinations were tried each replicated four times. The results indicated that at initial inoculam levels of 100, 200, 400 and 600 larvae/ 100 ml of soil of the two nematodes, M. incognita and R. reniformis extered severe damaging influence on cowpea. The higher inoculum levels of 800 and 1000 larvae/100 ml soil did not show a progressive increase in crop loss. It is evident that the threshold levels of the nematodes will fall within the range of 100 to 600 larvae/100 ml soil. In the combined inoculation of the nematodes, an inoculum level of 400 M. incognita followed by 400 R. reniformis/100 ml soil 15 days later exerted a highly deleterious effect on cowpea. Simultaneous inoculation did not lag for behind in its debilitating effect. Considering the nematode population in soil, multiplication rate of both nematodes were found higher in lower inoculum levels than in the higher inoculum levels. In the combined inoculation, reniform nematode dominated root - knot nematode. Reniform nematode had an adverse effect on the multiplication of root-knot nematode. Both nematodes thrived well when M. incognita was inoculated prior to R. reniformis.
Entomopathogenic fungi for the management of banana rhizome weevil (cosmopolites sordidus germer)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Varsha Vijayan; Anitha, N
The study entitled “entomopathogenic fungi for the management of banana rhizome weevil, Cosmopolites sordidus Germer” was conducted at College of Agriculture, Vellayani during 2015-17. Objective of the study was to evaluate the biocontrol potential of entomopathogenic fungi for the management of banana rhizome weevil. Adults and grubs of the rhizome weevil were collected from Thiruvananthapuram district and were observed for infestation by entomopathogenic fungi. From the infected adult weevil, Fusarium solani (Mart.) Sacc. was isolated and its pathogenicity was proved on adults and grubs of C. sordidus. Pathogenicity studies with entomopathogenic fungi Metarhizium anisopliae (Metchnikoff) Sorokin (Ma4), Beauveria bassiana (Balsamo) Vuillemin (Bb5), Beauveria bassiana (ITCC6063), Purpureocillium lilacinum (Thorn) Samson (ITCC6064) and F. solani were carried out on adults and grubs of C. sordidus. Grubs of C. sordidus treated with M. anisoliae (Ma4) caused mortality at 24 Hours after treatment (HAT) and white mycelial growth initiated two days after death which later changed to green color. In case of adults, mortality occurred 72 HAT. B. bassiana treated on grubs of C. sordidus caused mortality at 24 HAT and developed pink color after three days and later white cottony mycelial growth was observed on body. On adults, death occurred 72 HAT and extensive mycelial growth covered the body except the dorsal elytra after four days of treatment. P. lilacinum when treated on grubs caused mortality at 48 HAT and produced pink color one day after death and white mycelia covered the body. In adults, mortality initiated four days after treatment and extensive mycelial growth was observed on dorsal and ventral side. At 48 HAT, F. solani caused mortality of grubs of C. sordidus and produced brown color on shrunken grubs which later changed to creamy white stiff grubs. All the tested fungi were found to be pathogenic to both adults and grubs of C. sordidus. Under laboratory conditions the effective spore concentrations of the fungi were found out by testing different concentrations on adults and grubs. M. anisopliae (Ma4) @ 1.29×108 spores mL-1recorded 100 per cent mortality of grubs at 168 HAT. On adults M. anisopliae @ 2.1×108 spores mL-1 recorded 35 per cent mortality. B. bassiana (Bb5) @ 1.2×108 spores mL-1 when treated on grubs caused 95 per cent mortality at 216 HAT. Whereas in adults, B. bassiana caused 40 per cent mortality @ 2.5× 108 spores mL-1. P. lilacinum @ 1.9×108 spores mL-1 recorded 85 per cent mortality at 192 HAT when treated on grubs. At a spore concentration of 2.1×108 spores mL-1 P. lilacinum caused 30 per cent mortality. B. bassiana (ITCC6063) and F. solani caused less than 50 per cent mortality of both grubs and adults of C. sordidus. Evaluation of entomopathogenic fungi for the management of C. sordidus under field conditions was done by conducting three pot culture experiments; viz. rhizome dip method, prophylactic soil drenching and curative soil drenching. The study revealed that spore suspension of M. anisopliae @ 108 spores mL-1 when applied as rhizome dip method was more effective with least damage in rhizomes (10.83 per cent), lowest number of tunnels (0.49) and the least number of live immature stages (0). In the prophylactic soil drenching, spore suspension of M. anisopliae @ 108 spores mL-1 was found to be effective with least rhizome damage (14.16 per cent), number of tunnels (1.08) and number of live immature stages (1.25) followed by its talc formulation with a rhizome damage, number of tunnels, and immature stages of 14.16 per cent, 1.16 and 0.66 respectively. In curative soil drenching, spore suspension of M. anisopliae recorded least rhizome damage (10 per cent) and was statistically on par with talc formulation of M. anisopliae and B. bassiana @30 g L-1 (12.49 per cent). Soil drenching given as curative treatment was more effective than the prophylactic method. Talc formulation of Ma4 and Bb5 was equally effective when applied as curative soil drenching. To conclude, isolate F. solani was isolated from the cadaver of C. sordidus. F. solani, NBAIR isolates viz. M. anisopliae (Ma4) and Beauveria bassiana (Bb5) and local isolates available in department of Agricultural Entomology B. bassiana (ITCC6064), P. lilacinum (ITCC6064), were identified to be pathogenic to grubs and adults of C. sordidus. In laboratory conditions, M. anisopliae @ 108 spores mL-1 was found to cause 100 per cent mortality of grubs. Curative application by soil drenching of talc formulation of M. anisopliae and B. bassiana 108 spores mL-1 @ 30g L-1 was found to be effective for the manangement of C. sordidus.
Insecticide mixtures for the management of pest complex in brinjal
(Department of Agricultural Entomology College of Agriculture, Vellayani, 2019) Bista Jeba Bakthiyar; Anitha, N
Management of American serpentine leaf miner Liriomyza trifolil (burgess) dietars in tomato
(Department of Agriculture Entomology, College of Agriculture, Vellayani, 2017) Mithra Mohan; Anitha, N
Management of banana pseudostem weevil odoiporus longicollis oliv.using entomopathogenic fungi
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2005) Sahi Beegum, M K; Anitha, N
Investigation on “Management of banana pseudostem weevil, Odoiporus longicollis Oliv. using entomopathogenic fungi” was carried out in the Department of Agricultural Entomology, College of Agriculture, Vellayani. The study was conducted to screen four entomopathogenic fungi, to evaluate their biocontrol potential and to standardize the effective dose and method of application for the management of the banana pseudostem weevil. Four entomopathogenic fungi viz., Metarhizium anisopliae, Beauveria bassiana, Paecilomyces lilacinus and Nomuraea rileyi were tested against O. longicollis. Among them M. anisopliae and B. bassiana were found to infect O. longicollis grubs. Susceptibility of different stages of grubs to fungal infection was tested by using first, second, third, fourth and fifth instar grubs of O. longicollis and the results revealed that first and second instar grubs were more susceptible to fungal infection. Determination of effective dose of fungi against second instar grubs of O. longicollis was carried out by spraying the grubs with different concentrations of M. anisopliae and B. bassiana. The LC50 values of M. anisopliae and B. bassiana were 3.9 x 106 spores ml-1 and 1.6 x 105 spores ml-1 respectively. Evaluation of six naturally available solid media viz., rice bran, wheat bran, guinea grass, gingelly oil cake, coir pith, and neem cake were carried out for mass multiplication of M. anisopliae and B. bassiana. The results revealed that both rice bran and wheat bran were suitable for the mass multiplication of these fungi. The spore production was 9.26 x 106 spores ml-1 and 8.71 x 106 spores ml-1 respectively for M. anisopliae on first week after inoculation. For B. bassiana, the spore count was 503.42 x 106 spores ml-1 and 320.32 x 106 spores ml-1 respectively on first week after inoculation. Among the liquid media tried, coconut water and rice bran extract produced maximum mycelial growth and sporulation of fungi. For M. anisopliae the spore count was 7.77 x 107 spores ml-1 and 0.49 x 107 spores ml-1 respectively. B. bassiana recorded 440.03 x 106 spores ml-1 and 232.26 x 106 spores ml-1 respectively. M. anisopliae and B. bassiana grown in rice bran and wheat bran recorded maximum virulence on two weeks after storage and decreased thereafter. However, coconut water and rice bran extract showed maximum virulence on first week after storage and then found decreasing. Studies conducted to evaluate the compatibility of fungi with NeemAzal 0.4 per cent, chlorpyriphos 0.03 per cent, copper oxychloride 0.4 per cent and mancozeb 0.3 per cent revealed that all the pesticides tested inhibited the growth of M. anisopliae and B. bassiana. But the per cent inhibition was least in the case of NeemAzal 0.4 per cent. Field experiments were conducted with M. anisopliae and B. bassiana with chlorpyriphos (0.03 per cent) and NeemAzal (0.4 per cent) as checks. The plants were artificially infested with known number of grubs. Two experiments were conducted, one with prophylactic treatments and the other with curative treatments. Three application methods viz., leaf axil filling of spore suspension of M. anisopliae and B. bassiana, leaf axil filling of fungi in rice bran and stem injection of spore suspension were tested. Among these treatments leaf axil filling of B. bassiana spore suspension at 1.8 x 107 ml-1 as prophylactic treatment was most effective which gave 52.42 per cent mortality of grubs.
Management of beetle pests in stored rice using botanicals
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Binseena, S R; Anitha, N
Management of sucking pests of brinjal (Solanum melongena L.)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2015) Arya, V C; Anitha, N
An investigation on “Management of sucking pests of brinjal (Solanum melongena L.)” was carried out at College of Agriculture, Vellayani during 2013-2014. The objectives were to assess the intensity of damage caused by sucking pests in brinjal and evolve a suitable management strategy using newer insecticides. Survey conducted in 60 homesteads of vegetable growing tracts of Thiruvananthapuram district revealed the incidence of seven sucking pests namely leaf hopper, Amrasca biguttula biguttula (Ishida), aphid, Aphis gossypii Glover, whitefly, Bemisia tabaci Gennadius, spiralling whitefly, Aleurodicus dispersus, brinjal mealy bug, Coccidohystrix insolita Green, lace wing bug, Urentius hystricellus (Richt) and mite, Tetranychus sp. on brinjal grown in garden land and terrace. The leaf hopper, aphid, whiteflies and mealy bug were the major sucking pests infesting brinjal in the garden land and terrace during the vegetative and flowering stages. The infestation of the leaf hopper was recorded from all the locations surveyed and aphid, whitefly (B. tabacii) and mealy bug in 89.17, 86.67 and 85 per cent homesteads respectively. The damage caused by the pests ranged from 35.35 to 58.88, 30.11 to 40.24, 34.46 to 50.50 and 34.16 to 49.28 per cent by leaf hopper, B. tabacii, aphid and mealy bug respectively. A predator viz., Spalgis epius (Westwood) and a pathogen Fusarium sp. were isolated from the mealy bug, C. insolita. Two field trials conducted to evaluate the efficacy of the new generation insecticides viz., spiromesifen 96 g ai ha-1, thiamethoxam 50 g ai ha-1, acetamiprid 10 g ai ha-1, dinotefuran 30 g ai ha-1, dimethoate 600 g ai ha-1 and biopesticides viz., oxuron 5ml l-1 and Beauveria bassiana 20 g l-1 revealed that the new generation insecticides reduced the population of sucking pests significantly. Thiamethoxam 50 g ai ha-1 resulted in significant reduction in the population of leaf hopper (1.10 plant-1) and was on par with spiromesifen 96 g ai ha-1 (1.12 plant-1) in the first crop. Spiromesifen treated plot recorded highest yield of 10.36 kg plot-1 and it was on par with thiamethoxam (9.56 kg plot-1). Spiromesifen 96 g ai ha-1 reduced the population of whitefly (1.13 plant-1) and it was on par with thiamethoxam 50 g ai ha-1 (1.34 plant-1) in the second crop. Highest yield was also recorded from spiromesifen 96 g ai ha-1 treated plot (10.95 kg plot-1) followed by thiamethoxam 50 g ai ha-1 (9.42 kg plot-1). The results of the study thus indicated that the leaf hopper A. biguttula biguttula and whitefly B.tabaci were the predominant sucking pests infesting brinjal in the homesteads of Thiruvananthapuram district. The new generation insecticides viz., spiromesifen 96 g ai ha-1 and thiamethoxam 50 g ai ha-1 can be used as alternatives to the highly toxic conventional insecticides against the sucking pests, leaf hopper and whitefly.
Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs
(Department of Agricultural Entomology, College of Agriculture ,Vellayani, 2022) Mithra Mohan; Anitha, N
The study on “Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs” was conducted at College of Agriculture, Vellayani during 2017 to 2020 with the objectives to identify mealybugs and their natural enemy fauna in solanaceous and cucurbitaceous vegetables, to carry out the molecular characterization of mealy bugs in solanaceous and cucurbitaceous vegetables and to find out the tritrophic interactions of mealybugs infesting brinjal. An investigation on mealybug diversity in solanaceous and cucurbitaceous crops of Kerala revealed a total of six mealybug species viz., Coccidohystrix insolita, Ferrisia virgata, Paracoccus marginatus, Phenacoccus solenopsis, Planococcus citri and Pseudococcus jackbeardsleyi. Besides, four mealybugs viz., Crisicoccus hirsutus, Maconellicoccus hirsutus, Planococcus lilacinus and Rastrococcus iceryoides infesting other vegetable crops were also recorded from Kerala. The study also revealed that the population of mealybug, C. insolita collected from different regions of Kerala exhibited significant morphological variation. The molecular characterization studies proved that the population belongs to C. insolita and the variations may be environmental induced. An exploration of the host range of mealybugs infesting solanaceous and cucurbitaceous vegetables in Kerala revealed a total of 113 plants under 73 genera belonging to 31 families, out of which 14 plants were recorded as new host reports. A rich natural enemy fauna on mealybugs belongs to five orders viz., Coleoptera, Lepidoptera, Diptera, Neuroptera and Hymenoptera were documented from Kerala. Twenty species of mealybug predators from five different families were recorded, among which the predominant family was Coccinellidae with 16 species under six genera. Among the various predators collected, Cacoxenus sp. was recorded for the first time as a predator of P. jackbeardsleyi. Eleven hymenopteran parasitoids belonging to five families were documented from mealybugs, of which the majority belongs to the family Encyrtidae. Four new host-parasitoid associations were also recorded for the first 288 time. The study also identified six hyperparasitoids under the family Encyrtidae, of which two species were recorded as new report which includes Cheiloneurus sp. and Prochilonerus sp. associated with the mealybug P. solenopsis. The ants associated with mealybugs in different agroecosystems were also investigated and a total of 14 species of ants belonging to nine genera under three subfamilies were recorded, of which the most dominant subfamily was Formicinae followed by Myrmicinae and Dolichoderinae. The present study also revealed 15 new ant-mealybug associations for the first time. The molecular characterization of eight mealybug species was carried out that complemented the morphological identification of species. A total of eight nucleotide sequences were submitted to NCBI GenBank and accession numbers were generated. The sequences were also submitted to BOLD and illustrative barcodes were generated. The barcodes of C. insolita, C. hirsutus and P. jackbeardsleyi were generated for the first time. The diversity of endosymbionts of the mealybug C. insolita was carried out for the first time. The study revealed a total of 15 phyla of endosymbionts on C. insolita, of which Proteobacteria was the predominant one. An experiment was conducted at Instructional Farm, Vellayani to identify the tritrophic interaction in brinjal, C. insolita and its natural enemies. The study revealed that out of the ten brinjal cultivars evaluated, the lowest mean population of mealybugs was observed in Pusa Uttam whereas the hybrid cultivar, Udit recorded the highest number of mealybugs. The lowest mean per cent leaf infestation was recorded in Pusa Purple Long which was statistically on par with Pusa Uttam whereas the hybrid cultivar, Udit was severely damaged by the mealybugs. Among the tested cultivars, Pusa Purple Long was recorded under the group resistant whereas Udit and Haritha were included under the highly susceptible group based on the mean per cent leaf infestation caused by C. insolita. The cultivar Haritha attracted the highest number of predators whereas the maximum mean population of spiders were observed in Pusa Purple Long. 289 The correlation analysis on the mean population of mealy bugs with biophysical parameters revealed that trichome density, length width ratio of leaf and number of branches exhibited a significant positive correlation with mean population of mealybugs. Correlation studies on the mean population of natural enemies with biophysical parameters revealed that plant height exhibited a significant negative correlation whereas leaf thickness and number of branches revealed a non-significant negative correlation with the mean population of natural enemies. Among the biochemical parameters of brinjal cultivars, total phenol content exhibited a significant negative correlation with the mean population of mealybugs whereas total chlorophyll content showed a significant positive correlation. The correlation between biochemical parameters of brinjal cultivars with the mean population of natural enemies revealed that total phenol and carotenoid content exhibited a non-significant negative correlation whereas total protein content, reducing sugar and total chlorophyll content showed a nonsignificant positive correlation. The info-chemical mediated interactions in brinjal cultivars, mealybug and its natural enemies were studied using a multi-armed olfactometer and Y-shaped olfactometer assay. The results revealed that the cultivar Udit attracted the highest number of natural enemy Chrysoperla zastrowii sillemi while the cultivar Pusa Uttam attracted the lowest number. The variation in preference shown by the natural enemies may be related to the difference in volatile compounds emanating from the host cultivar. The GC-MS analysis of the synomonal compounds of the cultivar, Udit revealed a total of eleven compounds whereas the cultivar Pusa Uttam was recorded with a total of five compounds. The Y shaped olfactometer studies revealed that C. zastrowi sillemi adults showed more preference towards the synomonal compounds of mealybug infested plants than that of healthy plant synomonal extracts. On comparing the volatile profile of synomones of mealybug infested and healthy plants revealed that the synomonal extracts of the mealybug infested cultivar Udit comprised of 11 compounds whereas healthy plant synomonal extracts contained nine compounds. 290 The relative response of C. zastrowi sillemi towards the kairomonal compounds of C. insolita was evaluated in a Y tube olfactometer and the results revealed that the highest mean number of adult lacewings were attracted to the kairomonal compounds of mealybug compared to control. The kairomonal extracts of the mealybug comprised of seven compounds and the composition of these hydrocarbons may determine the selectivity of natural enemies towards the preferred host. The present study recorded a total of six mealybug species infesting solanaceous and cucurbitaceous vegetables and its host range, natural enemies and associated ants in different agro ecological regions of Kerala. The molecular characterization studies supported the morphological taxonomy and the sequences were submitted to NCBI Genbank and BOLD. The study also elucidated the interactions mediated by plant traits and info-chemicals in brinjal-mealybugnatural enemy tritrophic systems. The study recorded Pusa Purple Long as resistant cultivar and Udit and Haritha as highly susceptible cultivar to C. insolita. The plant traits viz., trichome density, length width ratio of leaf, number of branches, total phenol content and total chlorophyll content exhibited significant correlation with mean population of mealybugs whereas plant height exhibited significant correlation with mean population of natural enemies. The study on info-chemical mediated tritrophic interactions revealed that the concentration and composition of volatile compounds determine the differential selectivity of natural enemies. The volatile compounds identified in this study can also be used as a cue in moderating the behavior of natural enemies in the ecosystems. So a thorough knowledge on the tritrophic relations in the ecosystem will aid in manipulating these interactions to devise a better pest management strategy.
Microbial consortium for the management of insect pests of bitter gourd (Momordica charantia L.)
(Department of Agricultural Entomology College of Agriculture, Vellayani, 2018) Naveeda, S; Anitha, N
Shoot Feeders of mango and their management
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2013) Preetha, L; Anitha, N
Species diversity of ants and their association with plants and other arthropods in vegetable ecosystem
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2023) Shabana, P M; Anitha, N
The study titled “Species diversity of ants and their association with plants and other arthropods in vegetable ecosystem” was carried out at Department of Agricultural Entomology, College of Agriculture, Vellayani during 2019 to 2021. The study was conducted with an objective to document ant species in vegetable ecosystem and their association with plants and other arthropods The documentation was conducted from nine vegetable ecosystems such as coccinia, cowpea, sword bean, okra, chilli, brinjal, amaranthus, bitter gourd and snake gourd in Thiruvananthapuram district. Eighteen ant species belonging to sixteen genera were documented from these vegetable fields. The ants documented were trap-jaw ant (Odontomachus simillimus Smith), African ant, Bothroponera sulcata (Mayr), Bornean queenless ant (Diacamma rugosum (Le Guillou)), Ponerinae ant (Leptogenys sp.), belonging to Ponerinae subfamily. Ants of the subfamily Dolichodorinae include white footed ant (Technomyrmex albipes (Smith)). Ants of the subfamily Myrmecinae include acrobat ant (Crematogaster rothneyi Mayr), shield ant (Meranoplus bicolor (Guerin-Meneville)), hunch back ant (Myrmicaria brunnea Saunders), Asian marauder ant (Carebara diversa (Jerdon)), tropical fire ant (Solenopsis geminata (Fabricius)), destructive trailing ant (Trichomyrmex sp.). Ants of the subfamily Formicinae include yellow crazy ant (Anoplolepis gracilipes (Smith)), carpenter ants (Camponotus compressus (Fabricius)), Camponotus sericeus (Fabricius), Camponotus parius Emery, weaver ant (Oecophylla smaragdina (Fabricius)), black crazy ant (Paratrechina longicornis Latreille) and spiny ant (Polyrhachis exercita (Walker)). Morphological characters of eighteen species were documented in this study. The ant species D. rugosum, M. brunnea, P. exercita and A. gracilipes were observed to be highly diverse and Leptogenys sp., C. diversa and T. albipes were found to be the least diverse ant species. Coccinia and cowpea were observed to have the highest diversity of ants foraging on it. Amaranthus was found to have the least number of ant species foraging on it. Association of ants with vegetable seeds in the nursery was observed. Larger black ants like C.compressus, C. sericius and D. rugosum were seen foraging the area. It was found that ant species involved in various functions in the vegetable ecosystem. They are found to be phytophagous, in mutualistic associations with sucking pests, as predators, plant foragers feeding on extra floral nectaries on the crop and pollinators. Five species of ants were found to be phytophagous. D. rugosum, M. brunnea , C. diversa,149 Trichomyrmex sp., C. Compressus and C. diversa was observed making holes on the shoots and fruits of okra. C. compressus was observed cutting the shoots of nursery plants. C. compressus was also observed chewing on the brinjal shoot and feeding on them by making holes, M. brunnea is found making holes on young cowpea pods. Eight species of ants were observed associated with other arthropods in these vegetable ecosystems. They are C. compressus, T. albipes, A. gracilipes, M. brunnea, O. smaragdina, P. longicornis, S. geminata and C. parius. Ant arthropod associations were observed more in brinjal. C. compressus was found to be associated with homopterans. Five genera of ants were seen tending to homopteran sucking pests, they were Oecophylla, Anoplolepis, Paratrechina, Solenopsis and Camponotus. In okra four genera of ants were observed tending to homopteran sucking pests. They were Camponotus, Technomyrmex, Anoplolepis and Solenopsis. In chilli four genera of ants were seen tending to homopteran sucking pests. They were Camponotus, Solenopsis, Anoplolepis and Paratrechina. In cowpea four genera of ants viz. Myrmicaria, Camponotus, Solenopsis and Anoplolepis were seen associated with various sucking insect pests. Thus, these ant species are indirect pests by promoting ant- homopteran mutualisms and thereby destroying the crop. Seven species of ants viz. O. simillimus, D. rugosum , M. brunnea , S. geminata, C. compressus, O. smaragdina and A. gracilipes were observed to have predatory nature. Extra floral nectaries were observed to be fed upon by T. albipes, C. rothneyi, C. compressus, C. parius, O. smaragdina, A. gracilipes and P. longicornis. M. bicolor, M. brunnea, C. compressus, C. parius, A. gracilipes and P. longicornis were seen foraging inside the flowers, giving a possible indication of aiding in pollination of flowers. The study concluded that eighteen species of ants were found associated with vegetable ecosystems. D. rugosum, M. brunnea, P. exercita and A. gracilipes were observed to be highly diverse and coccinia and cowpea were observed to have the highest diversity of ants foraging on it. They were found to be phytophagous, in mutualistic association with sucking pests, as predators, plant foragers feeding on extra floral nectaries on the crop and foraging inside the flowers and acting as pollinators.