Informatics Publishing Limited

K. Karthikeyan ¹, Sosamma Jacob ²

Affiliations
1 Regional Agricultural Research Station, Pattambi 679 306, Kerala, IN
2 College of Horticulture, Vellanikara 680 656, Kerala, IN

Abstract

Laboratory studies were conducted during the year 2005-2006 to find out the efficacy of the white muscardine fungus, Beauveria bassiana (Balsamo) Vuillemin and the entomopathogenic nematode, Heterorhabditis indica (Poinar) against adult and grubs of rice blue beetle, Leptispa pygmaea Baly. B. bassiana caused a cumulative adult mortality of 56.67-80.00 per cent at 105-109 spores ml^-1 and the LC₅₀ value was 2.26x10⁴ spores ml^-1. The entomopathogenic nematode, H. indica caused a cumulative mortality of 66.67-91.67 per cent at concentrations of 5IJs to 9IJs in the grubs of L. pygmaea. The cumulative LC₅₀ value was 3.83IJs. The mortality of L. pygmaea was found to increase with reducing dose and increasing exposure period of both B. bassiana and H. indica. The effective pathogenicity of B. bassiana and H. indica against L. pygmaea is reported for the first time.

Keywords

Beauveria bassiana, Heterorhabditis indica and Rice Blue Beetle.

Full Text

   

K. Karthikeyan ¹, Sosamma Jacob ², S. M. Purushothman ¹, Smitha Revi ¹

Affiliations
1 Regional Agricultural Research Station, Kerala Agricultural University, Pattambi, 679 306, Kerala, IN
2 College of Horticulture, Kerala Agriculturtal University, Vellanikara, Trichur-680 656, Kerala, IN

Abstract

Field experiments were carried out to evaluate the efficacy of spinosad 45 SC, a biological product from actinomycetes, Saccharopolyspora spinosa @ 45 and 54 g a.i/ha in comparison to three other insecticides, viz., lambdacyhalothrin (12.5 g a.i./ha), chlorpyriphos 50% + cypermethrin 5% @ 344 g a.i./ha and monocrotophos @ 500 g a.i./ha as check against major insect pests of rice at Regional Agricultural Research Station, Pattambi, Kerala Agricultural University for three seasons viz., Kharif 2005, Rabi 2005 and 2006. Pooled analysis of three crop seasons indicated that spinosad @ 54 g a.i./ha was the most effective against rice stem borer, gall midge, leaffolder and whorl maggot. It caused 63 and 49 per cent reduction in dead hearts and white ears, respectively. The lower dosage of spinosad @ 45 g a.i./ha reduced whorl maggot infestation by 34 per cent. Spinosad @ 54 g a.i./ha resulted in 94 per cent reduction in leaffolder and 50 per cent reduction in gall midge infestation. Spinosad treatment also resulted in 14 per cent increase in rice yield. Spinosad caused no significant effect on spider population and was safe to spiders that predominate the predatory fauna in rice. Monocrotophos and lambdacyhaiothrin significantly reduced the spider and larval parasitoid populations in the rice ecosystem.

Keywords

Leaffolder, Rice Gall Midge, Spinosad, Stem Borer, Whorl Maggot.

Full Text

   

K. Karthikeyan ¹, Sosamma Jacob ², S. M. Purushothaman ¹

Affiliations
1 Regional Agricultural Research Station, Kerala Agricultural University, Pattambi-679306, Kerala, IN
2 College of Horticulture, Kerala Agricultural University, Vellanikkara-6, Thrissur, Kerala

Abstract

Field evaluation of two egg parasitoids, Trichogramma japonicum Ashmead against rice stem borer, Scirpophaga incertulas (Walker), and Trichogramma chilonis Ishii against leaf folder, Cnaphalocrocis medinalis (Guenee), was carried out in farmers' fields in three locations at Karakkad village, Palakkad district, Kerala, during three seasons in 2003 and 2004 in comparison with insecticide application. Release of T. japonicum @ 100000/ha followed by application of azadirachtin 1 per cent against yellow stem borer reduced dead hearts from 12.21 to 91.02 per cent and from 27.4 to 58.2 per cent over insecticide application during kharif and rabi seasons, respectively. Incidence of white ears was reduced by 72.41 to 92.86 per cent. T. chilonis reduced leaf folder damage by 41.68-98.60 per cent over conventional insecticide application. Release of egg parasitoids in rice resulted in an increase of yield by 25.79-45.13 per cent over insecticide treated plots, with a mean cost-benefit ratio of 1:2.6 and 1:1.9 in parasitoid released and insecticide applied plots, respectively.

Keywords

Cnaphulacrocis medinalis, Rice, Scirpophaga incertulas, Trichogramma chilonis, Trichogramma japonicum.

Full Text