Browsing by Author "Nalinakumari, T"

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Biology of the brown plant hopper, nilaparvata lugens (stal) (delphacidae, hemiptera)
(Kerala Agricultural University, 1975) Nalinakumari, T; Mammen, K V
Effect of neem leaf extract and two JH analogues on the development of Callosobruchus Chinensis Linn. (Coleoptera:Bruchidae)
(Kerala Agricultural University, 1981) Ambika, B; Abraham, C C; Nalinakumari, T
In studies on the comparative effectiveness of neem extract and the juvenile hormone analogues Hydroprene (ZR-512) and MV-678 against Callosobrucbus chinensis, it was found that in greengram seeds treated with 0.25 wg of Hydroprene, there was significant reduction in fecundity and progeny production of the insect. The neem leaf extracts at 2.5 and 5.0% and MV-678 at 0.5 ug were as effective as Hydroprene in suppressing progeny production. The feasibility of utilising JH analogues and neem leaf extracts for the management of C, chinensis has been discussed.
Impact of different insecticides on pest natural enemy and neutral complex in rice ecosystem
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2004) Smitha Gopan; Nalinakumari, T
Investigations were carried out during the second crop season of 2003-2004 at CSRC, Karamana, to assess the status of pests, natural enemies and neutrals in the rice ecosystem and to evaluate the efficacy of different insecticides on these organisms. The results revealed that pests dominated in the rice ecosystem followed by predators, neutrals and parasitoids. The sizeable population of pests recorded were Cnaphalocrocis medinalis (Guenee), Leptocorisa acuta (Thunberg), Hydrellia philippina Ferino, Oxya chinensis (Thunberg) and Nephotettix spp. Predators were present in fairly good number. Parasitoids and neutrals were comparatively less. The neutrals observed in the study came under the family Chironomidae, Culicidae, Tanyderidae, Otitidae and Sciomyzidae. Arthropod population showed a fluctuating trend and the highest population of pests, predators, parasitoids and neutrals were at 45, 30, 60 and 15 DAT respectively. Chlorpyrifos 50 EC + cypermethrin 5 EC was the most effective and persistent insecticide in suppressing C. medinalis. It effectively suppressed the other pests also and the persistent toxicity against them was comparatively less. It was toxic to the beneficial organisms; with shorter persistence on predators and parasitoids and the effect on neutrals was same as in carbaryl and monocrotophos. Acephate was found to be equally effective as carbaryl against C. medinalis and H. philippina. The other pests were also suppressed with the insecticide but the persistent toxicity was less. The insecticide was observed to be toxic to predators and neutrals and safe to parasitoids. Highest toxicity of imidacloprid was observed on Nephotettix spp., and was same as that of monocrotophos. The insecticide was found to be equally toxic to C. medinalis, H. philippina and L. acuta and the toxicity was less persistent on O. chinensis. It was toxic to all the three groups of beneficial organisms and toxicity was for a shorter period. Carbofuran granule showed immediate toxic effect only to neutrals and the delayed toxicity was exhibited on Nephotettix spp. and L. acuta. The granule was observed to be safe to predators and parasitoids. Azadirachtin suppressed the population of pests effectively and the effect was for a shorter period. This botanical insecticide was comparatively lower in toxicity to predators, parasitoids and neutrals. Among the insecticides tested, Bacillus thuringiensis var. kurstaki showed lower percentage mortality of C. medinalis, H. philippina, O. chinensis and L. acuta and no toxic effect on Nephotettix spp. This insecticide was safe to parasitoids and less toxic to predators and neutrals. The overall effect of these insecticides on the total population of four groups of arthropods showed that all the insecticides significantly suppressed the population of pests and predators. Acephate and Bacillus thuringiensis var. kurstaki were safe to parasitoids while azadirachtin and Bacillus thuringiensis var. kurstaki were less toxic to neutrals. The grain and straw yield recorded and the percentage abundance of the total population of four groups of arthropods were same in all treatments including control. The study emphasizes the need for cultivation of tolerant varieties and periodical field assessment of arthropod community. If the pest population is high and beneficial organisms are very low, pocket application of appropriate insecticides can be resorted to. The study once again asserts that insecticidal interventions are rarely needed and the four groups of arthropods regulate themselves and manage the pests and maintain the yield.
Major predators in rice ecosystems and their potential in rice pest management
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2003) Premila, K S; Nalinakumari, T
Survey conducted in three heterogeneous rice ecosystems of Kerala viz., Kuttanadu rice fields of Alappuzha district with high load of pesticide, double cropped rice fields of Thiruvananthapuram district with moderate level of pesticide and Pokkali rice fields of Ernakulam district with no pesticide during two consecutive seasons at the vegetative, tillering and reproductive stages of the crop revealed a distinct change in the composition and status of natural enemies and pests in rice ecosystem. While pests dominated in Kuttanadu and double cropped rice fields of Thiruvananthapuram, natural enerm es dominated In Pokkali ecosystem. Among the natural enemies, population of predators was signi ficantly higher 111 all the three ecosystems. Population of pnr as lt o i d s was very low. Among the predators, insect predators dominated the predator fauna followed by the spiders in the three ecosystems. The important insect predators observed were the mirid bug Cyrtorhinus livi dipennis Reuter and the coccinellid beetle Micraspis di scol or (Fabricius) and the major spider predators recorded were Tetragnatho maxillosa Thorell and Lycosa pseudoannulata (Boesenberg et Strand). Among the pests seen in th~ three ecosystems, the sucking pests were dominant followed by the defoliators. Stage specific sucking pests like the ricebug Lept ocorisa acut a (Thunb) and earhead thrips Hapl ot hrips ganglb aueri Schmutz too were seen infesting the crop during the respective crop stages. Hoppers were the predominant sucking pests in all the three rice ecosystems. Population of other sucking pests was very low. Among the hoppers Nephot ettix sp. and Sogatella furcifera (Horvath) were predominant. Comparatively, population of the brown planthopper, Nilaparvata lugens (Stal) was low. Population of other pests considered as major ones in the State like yellow stem borer Scirpophaga incertulas (Walker), gall fly Orseolia oryzae (Wood-Mason), case worm Parapoynx stagnalis Zeller etc. was negligible. The population of neutrals was low in all the three rice ecosystems. On the other hand, high population of these 'other insects' was seen in the adjoining vegetation. Greater diversity of arthropod spec ies was observed in the insecticide-free Pokkali rice ecosystem and insecticide-rationally-used double cropped rice ecosystem of Thiruvananthapuram. Less diversity of species was seen in Kuttanadu rice ecosystem where insecticides were applied indiscriminately. Studies on the suitability of different prey for mass culturing C. l ivi dip enni s, M. discolor, T. maxillosa and L. pseudoannulata under controlled conditions indicated that the best prey for C. lividipennis was the first instar nymphs of N. I ugens ,for M. discol or its eggs, for T. maxillosa, Nephotettix sp. and for L. pseudoannul at a, N. lugens. Efficiency of the predators 111 suppressing hopper pests when assessed in terms of searching capacity, feeding potential, prey preference and hyperpredation revealed that the insect predators C. lividipennis and M. discolor showed better ability to search for plant hoppers, especially N. lugens and S. furcifera. Comparatively, the searching capacity of the spiders for hoppers was low. The feeding potential and prey preference of C. livi dipenni s was significantly high for first instar nymphs of N. l ugens . Similarly, M. discolor preferred more of its own eggs than the other prey tested. The spider, L. ps eu do annul at a was observed to be a significantly better predator of hoppers than T. maxill os a. None of the predators tested showed cannibalism. Hyperpredatory activity was observed in Crocothemis sp., Agri ocne mis sp., Polytoxus fuscovitt at us (Stal), T. maxillosa, Oxyopes sp. and L. pseudoannulata. The mirid bug C. lividipennis was a highly preferred prey for hyperpredation. The commonly used insecticides for nee pest control viz., carbaryl, phosphamidon, monocrotophos, quinalphos and methyl parathion caused 80 to 100 per cent mortality of predators at the dose normally recommended for pest control. The results of the study emphasized the need for periodical assessment of the arthropod community Jl1 nee ecosystems as agro- ecological conditions tend to shift the status of phytophages and entomophages from time to time. Based on the results, growing of varieties tolerant to major pests and regulation of incident pests by conserving naturally occurring predators through optimal habitat modification and use of predator-friendly insecticides when absolutely needed will go a long way in sustainable production of rice in Kerala.
Nature and extent of damage caused by insect pests on stored pepper, cardamom, ginger and turmeric
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1992) Jijy Joseph; Nalinakumari, T
The occurrence and distribution of insect pests in stored ginger, turmeric, pepper and cardamom in five districts of Kerala were assessed in a survey conducted at bimonthly intervals for a period of six months. In stored ginger, the major pests recorded were L. serricorne and A. fasciculatus and in turmeric, L. serricorne. Low infestation Of S. paniceum occurred in pepper. Cardamom was relatively free of insect infestation. Both adult and larval stages of these pests damaged these produces. Besides these, damages by T. castaneum, L. minutes, O. surinamensis and R. dominica in ginger and turmeric were observed in a few samples. Stray samples of turmeric also showed infestation by adults and grubs of S. paniceum. Caterpillars of P. manihotalis, E. zebrine and S. ruttella were seen infesting neglected stocks of ginger and P. manihotalis and E. zebrine in neglected stocks of turmeric and pepper respectively. Quantitative loss studies revealed a loss of 13.01 per cent and 17.97 per cent respectively in ginger and turmeric by L. serricorne in six months, where as A. fasciculatus caused 11.58 per cent loss in ginger. Pepper exposed to S. paniceum caused only 1.2 per cent loss over a period of six months. While the volatile oil content of ginger infested by L. serricorne and A. fasciculatus reduced significantly after five months, the non volatile acetone extract reduced significantly in the sixth month compared to the fixed quality standards. In turmeric L. serricorne infestation resulted in a significant decrease in volatile oil content after three months of storage and non volatile acetone extract after five months. Significant positive correlation existed between the population build up and weight loss in ginger infested by L. serricorne and A. fasciculatus and turmeric by L. serricorne. In pepper exposed to S. paniceum the correlation was not significant. Significant negative correlation existed between the population build up of L. serricorne and A. fascicultus and volatile oil content and non volatile acetone extract of ginger and L. serricorne and volatile oil content of turmeric. The correlation between the population build up of L. serricorne and non volatile acetone extract in turmeric was not significant. Significantly high incubation period of L. serricorne was recorded in ginger compared to turmeric and only insignificant differences were noticed in larval and pupal duration and adult longevity. S. paniceum showed significantly high incubation and pupal period in pepper compared to that in turmeric where as the adult longevity was significantly higher in turmeric. Compared to L. serricorne, A. fasciculatus took longer period to complete its development in ginger.
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.
Varietal preference, growth and development of pests necrobia Rufipes de geer and oryzaephilus surinamensis linn, in stored copra
(Kerala Agricultural University, 1998) Nalinakumari, T; Mammen, K V
Copra is subjected to the attack of various insect pests during storage. Necrobia rufipes De Geer and Oryzaephilus surinamensis Linn, were found to be the most important. The varieties / cultivars tested were Chavakkad Dwarf Orange x West Coast Tall, Laccadive Micro, Gangaboridam, West Coast Tall x Chavakkad Dwarf Orange, Chavakkad Dwarf Orange, West Coast Tall, Laccadive Ordinary, West Coast Tall x Chavakkad Dwarf Green and Chavakkad Dwarf Green. Data on larval period, larval mortality, Chavakkad Dwarf Green. Data on larval period, larval mortality, pupal period, pupal mortality, percentage of adult emergence, adult longevity and the fecundity of the beetles and incubation period of the eggs were recorded daily after releasing one day old larvae of the insects in these varieties. The growth index of the insects in each treatment was calculated by dividing the percentage of adult emerged with the mean number of days for adult formation. Studies conducted revealed that the severity of infestation varied with varieties and the growth index varied with respect to larval period, larval mortality, pupal period, pupal mortality, adult emergence, adult longevity and fecundity. In overall assessment of the study, CDO x WCT, LM and LO were identified as less desirable for keeping the population build up low, while CDG and WCT x CDG were better and the remaining varieties were found to be intermediate.