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Theses

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1980 - 198723
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Subject: Agricultural Entomology × End date: 1987 × Start date: 1980 × Type: Thesis ×
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    ThesisItemOpen Access
    Relative susceptibility of cashew types to infestation by the tea mosquito helopoltis antonii signoret (hemiptera:miridae)
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1981) Thomas, K M; KAU; Abraham, C C
    The relative susceptibility of fourteen cashew accessions (Anacardium occidentale L.) to infestation by the tea mosquito bug Helopeltis antonii signoret (miridae: HEmiptera ) was evaluated in the field experiments conducted at the Cashew Research Station , Madakathara during September 1979-March1980. The field damage Intensites and the extent of damage Inflicted by the insect consequent on confinement on shoots and panicles were recored on a 0-5 scale and it was found that the accessions 22,1112, 1430 and 1097 were least susceptible with regard to the intensity of natural field infestation of the vegetative shoots. Regarding the intensity of field infestation on floral branches, the accessions, 22, 1112,1352,1469 and 1097 were significantly less susceptible than the other types . With reference to the intensity of damage to vegetative shoots under confinement none of the accessions was found to be promising . The accession numbers 1219 , 1469 and 1431 were found to be least susceptible to H. antonii infestation under confinement on floral branches . Since the damage to the floral branches, particularly under confinement , Is relatively more important factor responsible for yield reduction these trees can be identified to be relatively more promising . The influence of certain biochemical factors (total nitrogen , soluable sugar and tannins ) on pest infestation in shoots and floral branches was ascertained by working out simple correlation coefficients. The only significant association detected was between the tannin content in the vegetative shoots on the one hand and the pest infestation intensities under confinement , on the other. The shade intensities within the canopies had no the extent of susceptibility to the pest. The tree architecture patterns were found to be of two basic types, namely, extensively branching (spreading ) and intensively branching (bushy ). Variations in the canopy configuration did not influence the susceptibility trends. The inconsistencies in the relative susceptibility of different accession with reference to shoot and panicle damage intensities have been discussed.
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    ThesisItemOpen Access
    Plant parasitic nematodes associated with pineapple in Kerala
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1981) Hamza Koya, C P; KAU; Venkitesan, T S
    As a part of the studies on the occurrence of plant parasitic nematodes associated with pineapple in Kerala, a survey was carried out in different agro climatic regions of the Kerala State and it was found that R. reniformis occurred in more than 76 per cent of the locations sampled. Helicotylenchus spp. were recorded in about 50 per cent of the locations. The other plant parasitic nematodes detected in association with the crop included Meloidogyne spp., Creconemoides spp., Pratylenchus spp., Hoplolaimus and Hemicyclophora occurred in very low population densities. A new species of Helicotylenchus closely resembling H. digitatus ( Hussain and Siddique, 1964) but differing with respect to spear knob characters and location of excretory pore has been reported to be associated with the crop. The pot culture trial with M. incognita indicated that this nematode could not induce pathogenic effect on the cv kew even at the highest inoculum levels of 10,000 larvae per 7.5 kg soil during the period of 180 days.
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    ThesisItemOpen Access
    Pest complex associated with mango inflorescence and their control
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1984) Satheesan, N V; KAU; Abraham, C C
    In a survey conducted during 1982-83 in the State of Kerala to study the incidence of various insect pests associated with mango inflorescence with reference to their seasonal history, a total of ten insect pests were recorded. The hoppers idioscopus niveosparaus Leth. and I. clypealis Leth. were found to be widely distributed in the State. Significant variability was not detected among the population loads of I. niveosparsus in different districts, while in the case of I. clypealis such variations were significant. The heaviest populations of the latter was recorded from the Calicut District. The seasonal changes in I. clypealis populations were recorded only in the two Districts of Calicut and Trivandrum. I. niveosparsus showed a well defined peaks in the Palghat and Wynad districts. The fluctuations I. niveosparsus and I. clypealis populations have been discussed with reference environmental conditions. Procystiphora mangiferae Felt. is reported for the first time from the State from the Wynad and Cannanore Districts. Infestations by the pest led to transformation of the floral buds to conical galls. In the Wynad District, there was a well defind population peak in March, while in the Cannanore District a district crest waslacking. The mango blister midge, Erosomyia indica grover and Prasad was recorded to occur in association with P. mangiferae in these two districts. The larvae of E. indica tunnel into inflorescence axis and cause ovate galls thereby causing losses. Bombotelia jocosatrix Gn. was recorded from the Cannanore, Palghat, Trichur and Alleppey Districts throughout the flowering season. Eublemma anguilifera Moore as well as another unidentified spp. of Eublemma were recorded to occur throughout the State, except in the wynad District. The seasonal fluctuations of this pest were significant only in the Palghat District. An unidentified species of Cacoecia was recorded for the first time as a minor pest of mango inflorescence. The larvae fed on flowers and floral buds. The other pests observed during the course of the survey were Rapala manea Hewitson, Haplothrips ganglbaueri Schmutz, Dichocrosis punctiferalis Guenee and an unidentified Geometrid. The bio-efficiency of monocrotophos applied by two methods, namely, stem injection and stem banding, against the Idiocerine hoppers infesting mango inflorescence was evaluated in a separate experiment. The relative toxicity of the insecticide was determined from the time- mortality relationship between the insecticide reaching the inflorescence of treated trees and the mortality of the fourth instar nymphs of I. niveosparsus. The LT -50 values of the nymphs following application of the insecticides by the stem injection method was found to be substantially lower than the corresponding values for the stem banding method of application. It was thus evident that the toxicant moved at a faster pace when administered by the stem injection method. The variations in the pattern of translocation of the toxicant under the two methods of administration have been discussed. The residues of monocrotophos on freshly formed mango fruit at five weeks after application by the stem injection method at 4 ml and 2 ml ai/tree were 0.3600 ppm and o.3750 ppm respectively. The corresponding residues in the mango fruit consequent on stem banding method of administration were 0.0550 ppm. The implications of the above results in formulating control methods against Idiocerine hoppers infesting mango inflorescence have been discussed.
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    ThesisItemOpen Access
    Taxonomic studies of leaf and plant hoppers associated with paddy in Kerala
    (Department of Entomology, College of Horticulture, Vellanikkara, 1984) Abdulla, K; KAU; Mammen, K V
    Taxonomic study on the leaf and plant hoppers of paddy was conducted to find out the various specious of leaf and plant hoppers associated with paddy in Kerala. Paddy fields from two important paddy growing tracts of Kerala viz., Trichur and Palghat were selected and weekly collections of hoppers were made. Collections were made with a fine mesh hand net for the entire cropping season from transplanting upto harvest. Fixed numbers of sweeps were taken from the same field in order to get an idea about the population fluctuations. Collections from each field for each week were separately preserved in homeopathic vials with collection data. Later insects in all vials were sorted out, number of specimens collected in each week were noted, sexes separated, and each species were preserved in separate vials. Vials were serially numbered and collection data were noted under each serially numbered species. Genitalia of males as well as general form and colouration of all species were stidied. However genitalic studies of Exitianus indicus (Dist.) and Nisia nervosa (Motsch.) could not be conducted for want of male specimens. Altogether nine species were collected viz., Nephotettix Virescens (Dist.), N. nigropictus (Stal), Recilia dorsalis (Motsch.) and Exitianus indicus (Dist.) coming under Cicadellidae, Nilaparvata lugens (Stal), Sogatella furcifera (Horv.),Matutinus pusanus (Dist.) belonging to Delphacidas and Nisia nervosa (Leth) under Meenoplidas. Among these species all but M. pusanus were reported to be occurring on paddy in India and other East Asian countries, while E. indicus and N. nervosa were not observed by earlier workers from Kerala. Apart from these, two male and two female specimens of Nephotettix showing variations in characters from N. nigropictus and N. virescens were also obtained. These may be natural hybrids between N. virescens and N. nigropictus. Certain morphometric studies were conducted using head measurements viz., eye diameter to interocular distance and /or vertical distance next to eye to median length of Vertex. It was found that there is difference between male specimens of N. virescens and N. nigropictus with regards to the ratio of vertical distance next to eye to median length of vertex; and in females of these species there is difference between the ratios of eye diameter to interocular distance. Similarly there is difference between male specimens of N. lugens and S. furcifera with regards to the ratio of eye diametor to interocular distance. Studies on the seasonal abundance of leaf and plant hoppers revealed that there is variation in the predominant species present in each area.
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    ThesisItemOpen Access
    Studies on the pests of chromolaena in Kerala
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1983) Lyla, K R; KAU; Joy, P J
    A detailed survey was conducted in Trichur District and an objective survey in five other selected districts of the Kerala State during November 1980 to October 1981 to study the pests of choromolaena odorata Linn. Observations on the nature of damage and population density have been made during the survey. Details of the insects recorded on the weed are given below. 1. Hemipteran pests 1.1 Aphis spiraecola patch These aphids were recorded in all the areas surveyed and alate and apterous forms were available. There are four instars each occupying one to two days and the adult six to ten days. The alate forms occurred at relatively lower levels compared to apterous form. In both cases, maximum population was in July irrespective of the topographic conditions. Both the nymphs and adults such sap from the tender shoots thereby reducing the vigour of the plant. 1.2 Aphis fabae scopoli Both apterous and alate forms were observed. Here also the aphid population attained peak level in July both in medium hilly areas and plains. The aphid infested leaves presented a crinkled appearance. 1.3 Braschycaudus helichrysi kitb These were noted in higher elevations like Idukki and Wynad areas and were absent in Trichur District. The aphid attacked leaves become folded and rolled longitudinally. 1.4 Coptosoma sp. These bugs were observed throughout the growth phase of the weed. Adults suck sap from tender parts of the plant without causing any serious damage. 1.5 Sepontia nigrofusea Dist. These bugs suck sap from the weed causing negligible damage and were present in very few number at Pananchery Village. 1.6 Tettigella ceylonica melich. These appeared only as casual feeders of C.odorata and their populations were extremely low for affecting any appreciable damage. 1.7 Bemisia tabaci. Gen. The adult suck sap from tender parts of the weed and the population level was very low. 1.8 Leptocorisa acuta thumb. These were found in the Puzhakkal Village and the bugs suck sap from the weed. 1.9 Riptortus pedestris Fb. The adults suck sap from tender shoots and were found in few number. 1.10 Dysdercus koenigii Fb. The adults suck sap from the weed without causing any appreciable damage. 1.11 Leptocentrus sp. These bugs suck sap from the plant throughout the growth phase of the weed, but the population count was very low. 1.12. Cocosterphus minutes Fabricius These insects were present in few numbers and suck sap from the weed. 2. Coleopteran pests 2.1 Apion sp. As a result of feeding of the weevil irregular holes are formed on leaf surface. These feed on the flowers during the flowering season. 2.2 Unidentified curculionid They eat away portions of the leaf creating holes on the surface. 2.3 Astycus aurovittatus Heller The weevil was found feeding the foliage of the weed during December. 2.4 Amblyrrhinus sp. They feed on the leaves and flowers by cutting small holes on them. 2.5 Mylabris sp. These feed on the weed flowers occasionally. 2.6 Corynodes sp. These beetles feed on the leaves making irregular holes here and there. 2.7 Carvedon sp. These insects were found feeding on the flowers occasionally. 3. Lepidopteran pests 3.1Pericallis ricini Fb. The young larvae feed on the surface tissue of young leaves and in the later instars they feed both by scrapping and by eating the whole leaf lamina. 3.2 Discrisia oblicua wlk. Larvae found defoliating the weed 4. Dipteran pest 4.1 Unidentified agromyzid The larvae mine into the leaves and eat through the mesophyll leaving the two epidermal layers intact. 5. Thysanopteran pest 5.1 Haplothrips gowdeyi franklin Both nymphs and adults feed by lacerating the tissues of the inflorescence and found in numbers. Out of 23 species of insects recorded to occur on c. odorate coptosoma sp.(plataspididae:Hemiptera),Sepontia nigrofusca (Plataspididae: Hemiptera),Tettigella ceylonica (Cicadelliade: Hemiptera)Leptocorisaacuta (Coreidae: Hemiptera)Riptortus pedestris(Coreidae: Hemiptera)Coccosterphus minuts(Membracidae: Hemiptera)Astycus aurovittatus (Curculionidae:Coleoptera) Amblyrinus sp.(Curculionides sp. Coleoptera)Mylabris sp.(Meloidae:Coleoptera)Corynodes sp.(chrysomelidae: Coleoptera) Caryedon sp.(Bruchidae: Coleoptera),pericallia ricini (Arctide:Lepidoptera) and Haplothrips gowdeyi(phloethripidae:Thysanoptera) are reported for the first time. Among the insects, the most widespread and numerous were A.spiraecola and A.fabae in that order.
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    ThesisItemOpen Access
    Integrated control of nematode pests of bhindi with special reference to root-knot nematode
    (Department of Entomology, College of Agriculture, Vellayani, 1981) Hebsy Bai; KAU; Nair, M R G K
    A field experiment was undertaken to ascertain the effect of the treatment with carbofuran and aldicarb treatment of soil, when applied individually and in combinations on the control of the root-knot nematode N. incognita infesting bhindi. A randomised block design was adopted for the experiment with eight treatments including control and four replications each . To ensure uniform population of the nematode in the different plots a crop was raised and the root system of the plants ploughed back into the soil on the forty-fifth day of sowing. Further , galled roots of bhindi collected from different parts of the farm were chopped and added to the soil to ensure a high and uniform initial population of the nematode. Deep ploughing was done to a depth of 20 cm. Seed treatment was done using the flowable concentrate of carbofuran, to give a 3 per cent deposit. Aldicarb was applied to the soil as granules, raked into it and sealed with a layer of water, a day prior to sowing.
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    ThesisItemOpen Access
    Studies on movement and placement of systematic granular insecticides in soil in relation to control of pests of pulses
    (Division of Agricultural Entomology, College of Agriculture, Vellayani, 1981) Nanda Kumar, C; KAU; Visalakshi, A
    The horizontal movement of three systemic granular insecticides phorate, carbofuran and disulfoton in four different types of soils of Kerala viz. sandy, alluvial, red and laterite, was studied by observing the mortality of aphids released on cowpea plants at different distances from point of application of the granules . The effect of age of cowpea plants on the uptake of phorate was assessed by growing plants of different ages. Vertical movement of phorate and disulfoton in red soil was assessed in terms of residue levels after broadcast and point application by colorimetric and bioassay methods. The effect of placements of the systemic granules on pest infestation of cowpea was observed in a field experiment laid out in RBD and the incidence of leaf miner , aphids, flea beetle, leaf webber and pod borer was assessed . The effect of different placements of insecticides in soil on their persistance in cowpea was assessed by observing the mortality of aphids confined on the treated plants at ten-day intervals after application of the insecticides . The effect of placement of insecticide granules on plant growth characters viz. plant height, number of branches, weight of shoot, weight of root , length of tap root, number of nodules, dry weight of nodules and yield was assessed. Residues were estimated in the green pods forty-five days after application of the systematic granules.
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    ThesisItemOpen Access
    Control of root-knot nematodes in brinjal
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1980) Susannamma Kurien; KAU; John Kuriyan
    The egg plant (Brinjal) which is one of the most common vegetable crops is highly susceptible to the root-knot nematode Meloidogyne spp. An effective control can often be achieved by the complete elimination of nematodes from transplants. Hence the present study was undertaken with a view to find out the efficacy of nursery treatment with four nematicides viz. DECP, aldicarb, carbofuran and metham sodium in control of the root-knot nematode Meloidogyne incognita in brinjal seedlings and their subsequent performance in the mainfield. Seeds of brinjal local was seen in nematicide treated nursery beds. On 30th day after sowing seedlings were uprooted from each treatment and plant characters like number of leaves, height of the plants , galls per plant and weight of 25 seedlings were compared to study the effect of the treatment in the nursery . All the characters were found to be superior over the check.
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    ThesisItemOpen Access
    Studies on the cyst nematode of rice in Kerala
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1980) Usha Kumari, R; KAU; John Kuriyan, K
    The cyst nematode Heterodera cryzioola was observed to be an important pest of rice , affecting the growth and yield of paddy plant . However detailed investigations on this nematode was done earlier. The present study was hence undertaken to study the extent of loss, host range and control of this cyst nematode. The extent of loss caused by Hetrodera cryzicola on rice variety Triveni was studied at four inoculum levels of 6,000, 9,000, 12,000 and 18,000 larvae per sq.m. in the field experiment and 5, 10, 20 and 30 cysts per pot in pot culture study. There was considerable reduction in growth and yield of the paddy plant in both field and controlled conditions at all the different levels tried. This nematode caused considerable damage to the crop by supressing the height of the plant, number of tillers, number of leaves, earhead length, shoot weight, root weight, total yield and grain weight.