Browsing by Author "Ushakumari, R"

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Biocontrol of cowpea aphid aphis craccivora(koch) using entomopathogenic fungi
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2009) Saranya, S; Ushakumari, R
Biorational management of major pests in brinjal (Solanum Melongena L.)
(2015) Gowrish, K.R; Ramesha, B; Ushakumari, R
Epilachna beetle complex in vegetables
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1997) Sreekala, S; Ushakumari, R
Studies on the epilachna beetle complex occuring on selected vegetable crops were carried out at the College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1995-1997 to establish their taxonomic identities. The morphology, biology and the natural enemy association of these beetles were also studied. Based on the male and female genitalial characters, the epilachna beetles feeding on brinjal, bittergourd and cowpea were identified as Henosepilachna vigintioctopunctata (Fabricius), Henosepilachna septima (Dieke) and Afidenta misera (W eise) respectively. The salient features to distinguish between these three species are the curvature of the apex of sipho which is a part of the male genitalia and the shape of the female genital plates. The apex of sipho is curved outwards with a bluntly rounded tip in both H. vigintioctopunctata and A. misera, while it is curved inwards with a sharply pointed tip in H. septima. A semicircular notch is present on the female genital plates of H. vigintioctopunctata, while there is a slit like notch in H. septima. The notch on female genital plate is absent in A. misera. It was confirmed that the beetles are highly host specific. Henosepilachna vigintioctopunctata showed a strict host restriction to solanaceous plants, while H. septima and A. misera are restricted to a few cucurbitaceous and leguminous plants respectively. There was not much gross morphological variations between the species except for their body size, H. septima being the largest and A. misera the smallest. The different spot variants met within the species by the variations in elytral maculation was found to be a morphological character only. Though the grubs of the three species are similar in external appearance, they can be easily distinguished by the structure and sclerotisation of the scoli on body surface and the details have been discussed. The three species showed similar biological attributes with a life cycle period of 25.25, 2l. 59 and 24.76 days for H. vigintioctopunctata, H. septima and A. misera respectively at 27.6°C and 89.5 per cent relative humidity. Under . field conditions, the grubs and pupae of the three species were parasited by Pediobius foveolatus (Crawford) (Eulophidae:Hymenoptera) and the egg masses were parasitised by Tetrastichus ovu/orum Ferriere (Eulophidae:Hymenoptera).
Management of root knot nematode in rice
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2005) Renitha Govind; Ushakumari, R
The objectives of the study entitled ‘Management of root knot nematode in rice’ was to identify the species of rice root knot nematode and to study the management of this nematode by different bio agents, chemical pesticides and a neem formulation. A survey was conducted for the collection of soil and root samples from the rice growing tracts, already infected with root knot nematodes. The species of root knot nematode attacking rice plant was identified as Meloidogyne graminicola Golden and Birchfield. Pot culture experiments were conducted to study the management of rice root knot nematode under flooded and non flooded condition by different bio agents, chemicals and a neem formulation The effect of the treatments on the shoot characters, yield, root characters and nematode population were tested. Seed treatment with B. subtilis, P. fluorescens, T. viride and P. fluorescens + T. viride produced more vigorous seedlings with more number of leaves and height compared to other treatments. At the time of harvest also B. subtilis was superior. All other treatments except carbosulfan showed significant effect on the number of leaves, tillers and height of the plant. In non flooded condition, B. subtilis followed by AMF and carbofuran showed superior effect in terms of root characters (length and weight of roots). In flooded condition also B. subtilis showed its superior effect. This was closely followed by AMF, carbofuran and P. fluorescens. Carbosulfan was the least effective treatment in both the conditions. Control plants showed poor root growth with only very short roots. The yield attributes (days to flowering, days to harvest, number of panicles, number of grains per panicle, wet weight of grains, dry weight of grains and straw weight) in both flooded and non flooded conditions were superior in plants treated with B. subtilis. This was followed by carbofuran, AMF and P. fluorescens in non flooded condition and AMF, carbofuran, P. fluorescens and neem granules in flooded condition. There was no effect for enhancing the yield characters by carbosulfan. Plants in control pots were dwarf with only less number of leaves and tillers. The nematode population characters with reference to reduction in number of nematodes in soil and root and gall count in root was superior in carbofuran treated plants in non flooded condition with 99.08, 99.26 and 97.50 percent reduction over the control respectively. B. subtilis treated plants showed superiority in flooded condition with 98.36, 98.79 and 95.56 per cent reduction over the control. There was statistically significant reduction in nematode population in all the other treatments (AMF, P. fluorescens, neem granules, T. viride and P. fluorescens + T. viride) except carbosulfan.
Platygasterid parasitoids in rice and vegetables
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2003) Arjitha, P V; Ushakumari, R
The survey was conducted in the rice fields of Ollukkara and Madakkathara panchayats of the Thrissur district, Kerala during J line 2002 to January 2003. Six species of Platygaster namely, P. coorgensis (Mukerjee), P. inderdaadi (Mukerjee), P. malabaricus (Mukerjee), P. minimus (Mukerjee), P. orzyae Cameron and P. sasii Ushakumari have been recorded as pupal parasitoids of the rice gall midge Orseolia oryzae (Wood-Mason). All the species except P. oryzae are new reports from rice gall midge 0. oryzae (Wood-Mason). Parasitism by platygasterid parasitoids in cecidomyiid galls, mealy bugs and white flies of vegetables was recorded during the survey. The species composition as well as seasonal and varietal variation in the incidence of the parasotoids and the other relevant aspects of the study have bee discussed. P. coorgensis is 1.13 mm in length; antenna 10 segmented with five club forming segments; notauli absent; submarginal vein present. P. inderdaadi is 1.21 mm in length; antenna 10 segmented with five club forming segments, fourth segment large sized; notauli absent; submarginal vein present. . P. malabaricus and P. minimus differ in case of notauli character. In P. minimus notauli is present where as in P. malabaricus it is absent. P. oryzae is the smallest among the six species studied i.e., 1.1 mm in length; antennal segments 10 with four club forming segments; notauli present and is faint, submarginal vein absent. P. sash is the largest among the six species, 2 mm in length. It is the solitary species while all others are gregarious, antenna 10 segmented with five club forming segments, notauli distinct and submarginal vein present. The peak Platygaster population was recorded in the 'virippu' season and during the first week of September. In the 'mundakan' season, the maximum population was observed during the second week of November. There is significant difference in Platygaster populations between the two seasons, the 'mundakan' season, showing significantly higher population of Platygaster parasitoids than in the 'virippu' season. The maximum' per cent parasitism was observed during the third week of September in 'virippu' season (25.69) and last week of October in 'rnundakan' season (44.17) in both panchayats. The mean per cent parasitism in 'virippu' season was 20.67 and in 'mundakan' season it was 33.94. The per cent parasitism was found to be significantly higher in 'mundakan' season. Two types of Platygasfer were observed based on the number of parasitoids emerging from the galls, namely, the solitary and gregarious types. The solitary type is identified as P. sasii and the gregarious types are identified as P. coorgensis, P. minimus and P. oryzae. Seven species of other hymenopteran parasitoids also recorded from the galls. They are Eurytoma sp. (Eurytomidae), Litus sp. (Pteromalidae), Neanastatus cinctiventris Girault (Eupelmidae), Telenomus sp. (Scelionidae), one species of Eucoilidae and two species ofMymaridae. There was no gall fly infestation and platygasterid parasitoids in the rice varieties studied during 'mundakan' 2002 season at RARS, Pattambi. During 'virippu' 2003, out of the 50 varieties' observed, gall infestation was seen in the varieties Red Ponmani, CO-42, IET-13358, MTU-7 and Kuruva, but no Platygaster parasitoids were recorded from these varieties.