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Subject: Agricultural Entomology × End date: 2002 × Start date: 2002 × Type: Thesis ×
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    ThesisItemOpen Access
    Management of stingless bee Trigona iridipennis Smith (Meliponinae: Apidae) in the homesteads of Kerala
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2002) Nisha, M M; KAU; Devanesan, S
    With the objective of studying the management of stingless bees, Trigona iridipennis Smith in the homesteads of Kerala, studies were conducted at the College of Agriculture, Vellayani during 2000-2001. Different management practices were tried. Division of the• bee colony could be successfully carried out by transferring equal amount of brood cells, pollen and honey pots along with queen to the different hives VIZ., wooden, bamboo and earthen pot with different capacities. Bamboo hive with capacity 1500cc was found to be more suitable for hiving T. iridipennis since the brood development, pollen storage, population buildup and honey storage were superior in this type of hive. Observations on handling of bees indicated that wooden hives were easy to handle compared to bamboo and earthen pot. Brood development and pollen storage were shown maximum during the month of February, while maximum honey storage was noticed during the month of April. Bee strength increased as the colony got established well. Presence of queen cells and drones were noticed from November to March during which population build up existed. The bee strength was also found to be . maximum in bamboo hive which had maximum brood, pollen and honey storage. Investigation on the reuse of emptied honey pots by the bees indicated that the bees reused it for reconstruction of worn off honey pot parts beneath and nearby. Investigations on the foraging activity of T. iridipennis showed two peak periods of activity one at 1200h and the other at 1500h and with maximum activity during July. It was observed in the present study that 76 plants were visited by the stingless bees for nectar or pollen or both. Of this twenty plants provided both nectar and pollen. Thirty five plants provided nectar only and 20 plants provided pollen only. The Trigona honeys collected from different tracts around Kerala varied widely in colour from light yellow to dark amber colour with all intermediate shades. The percentage of moisture varied from 18.96 to 20.48 in different districts of the state and pH ranged from 3.76-4.4. In all the honey samples the acidity ranged from 0.17-0.29 while the ash content varied from 0.17-0.19 per cent. The specific gravity also ranged from 1.3507-1.3775. The observations of reducing sugar indicated that it ranged from 77.12-69.85 per cent. The refractive index value also indicated variation from 1.4855 to 1.4891. The values on glucose and fructose per cent varied from 35.92-33.53 and 38.16-39.74 respectively. The glucose fructose ratio observed indicated variation from l.17 -1. 05. The sucrose per cent also seen varied from 1.23-l.81 and the values on specific heat varied slightly from 60.50-60.9. A dipteran fly Hermetia illucens L., a mite, Amblyscius sp. and Megachile disjuncta was newly identified as pest of T. iridipennis. Solenopsis geminata was also observed to attack weak colonies. No disease incidence was noticed.
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    ThesisItemOpen Access
    Effect of entomopathogenic fungi on sucking pests and leaf feeders of vegetables under in vitro conditions
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2002) Jincy, Simon; KAU; Susamma, Mathai
    Investigation on "Effect of entomopathogenic fungi on sucking pests and leaf feeders of vegetables under in vitro conditions" was carried out II1 the Insect Pathology Laboratory, Department of Agricultural Entomology. College of Agriculture, Vellayani. Among the seven entomopathogenic fungi tested, Be auver ia r a l it ura and Peri call ia ricini, an aphid isolate of Fusarium pallidoroseum infected aphids Aphis craccivora and Myzus pers icae while Rhizop us oryzae caused mortality of Dysdercus cingula/us. The LCso values for B. bassiana were calculated as S.75 x 108. 6.99 X J08 and 2.72 x 105 spores m]"1 against S. derogat a. S. l it ura and P. rici ni respectively. F. pallidoroseum caused SO per cent mortality of A. cracci vora and M. persicae at 3.86 x 106 and 0.72 x 106 spores 111]"1 respectively. R. oryz ae caused 50 per cent mortality of D. cingula/us at 4.15 x 106 spores mrl. Evaluation of different naturally available substrates for mass multiplication of B. bassiana. F. p all i dor o se um and R. oryz ae revealed that both rice bran and gingelly oil cake were suitable for the mass multiplication of these fungi.'Among the liquid substrates. coconut water produced maximum mycelial growth of all the fungi. At room temperature. B. bassiana retained the vi.ulerice up to five months after inoculation in rice bran and gingelly oil cake. hut the vi rulence of the fungus was drastically reduced after two months or storage. F. p al lidorosetnn retained the virulence upto six months in rice bran and gingelly oil cake but R. oryzae lost the virulence after two months of storage. Coconut water and starch solution could not retain the \ i a h i lit y all d vir u I e n c e 0 f the fu n g i a ft e r t w 0 III 0 nth s 0 f s tor age. l-, p allidoroseum and R. OITZ(/(! with different pesticides revealed that two per cent neem oil emulsion could be incorporated with B. bassiana and R. oryzae without any inhibitory effect while sporultio n of F. pallidoroseum was inhibited by nee m oil. Mancozeb, dimethoate malathion, quinalphos and chlorpyriphos greatly inhibited the growth and sporulation of the three fungi tested.
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    ThesisItemOpen Access
    Management of the american serpentine leaf miner Liriomyza trifolii (Burgess) Dietars on cowpea, Vigna unguiculata (L.) Walp
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2002) Reji, G V; KAU; Hebsy Bai
    Survey conducted in Kailiyoor panchayat of Thiruvananthapuram district revealed that Liriomyza trifol ii caused maximum damage to cowpea at the reproductive phase of the crop III summer. Raising susceptible varieties, applying high doses of nitrogen and frequent use of insecticides were noted to intensify the pest incidence. The weeds, Achyranthus aspera, Amaranthus viridis, Cleome viscosa, Cleome monophylfa, Heliotropium indicum, Physalis minima and Desmodium gyrans were identified as host plants of the pest. Seven larval parasitoids were recorded of which Chrysonotomyia rexia and Asecodes sp. were predominant. Twenty accessions of ccwpea including trailing and bush types were screened in the laboratory for resistance to L. trifolii. Accessions of trailing type were more susceptible to the pest. VU-12 was least susceptible among the trailing type while Sharika and Vyjayanthi were highly susceptible. Among the bush type, VU-4, VU-6, VU-3 and Arka Garima were less susceptible. Four plant oils and four synthetic insecticides when evaluated in the laboratory at two doses along with neem oil (2.5 per cent) and dimethoate (0.05 per cent) showed no significant diffe. ence in efficacy between the doses. Neem oil, marotti oil and ilIupai oil at 2.5 per cent and abamectin, 0.003 per cent, thiamethoxam, 0.02 per cent and profenophos, 0.025 per cent were found to be effective in controlling the pest. All the treatments reduced the pest infestation significantly in the field. Abamectin, 0.003 per cent was significantly superior. Neem oil, marotti oil and illupai oil 2.5 per cent also reduced pest infestation. Considering the cost and safety to the natural enemies, the oils were found more advantageous to the farmers. Based on the results, cultivation of the tolerant accession VU -12 111 endemic areas, destruction of weed host plants, judicious application of nitrogen and need based application of neem oil / marotti oil / illupai oil at 2.5 per cent can be recommended for inclusion in rPM strategies of L. trifolii.