Browsing by Author "Kumara, A.D.N.T."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Advances in research on biological control of the coconut mite, Aceria Guerreronis Keifer in Sri Lanka
    (2009) Aratchige, N.S.; Fernando, L.C.P.; Kumara, A.D.N.T.; Suwandharathne, N.I.; Perera, K.F.G.; Hapuarachchi, D.C.L.; de Silva, P.H.P.R.
    Biological control is considered as the most economical, sustainable and environment-friendly approach for the control of coconut mite, Aceria Guerreronis Keifer. In Sri. Lanka, several research have been done on the local predatory mite, Neoseiulus baraki Athias-Henriot and the entomopathogenic fungus, Hirsutella thompsonii Fisher to evaluate their effectiveness against the coconut mite in an augmentative biological control approach. This paper reports the development in research on N. baraki and H, thompsonii in Sri Lanka as potential biological control agents of the coconut mite. Two technologies, "dry culture" arena method and the "sachet" method were developed for mass rearing of N. baraki. The effect of a single augmentative release of N. baraki in the field to reduce the coconut mite populations was not consistently significant. Release of N. baraki at the rate of 5000 mites/ palm in two-months intervals increases the number of nuts with discontinued damage scars and reduces the number of nuts that are sold at half-price in the harvest. H. thompsonii isolate IMI 391722 showed the highest efficacy in reducing the coconut mite populations. Single application of//. thompsonii in the field is effective only for a short duration. Application of the fungus both at 2- and 3-month intervals caused similar mortality levels of the coconut mites. Perspectives of these findings in the biological control of coconut mite are discussed.
  • Thumbnail Image
    Item
    On farm production of green muscardine fungus to combat rhinocerose beetle
    (2007) Suwandhrathne, N.I.; Kumara, A.D.N.T.
  • Thumbnail Image
    Item
    Portable acoustic device for detection of coconut palms infested by Rynchophorus ferrugineus (Coleoptera: Curculionidae)
    (2010) Siriwardena, K.A.P.; Fernando, L.C.P.; Nanayakkara, N.; Perera, K.F.G.; Kumara, A.D.N.T.; Nanayakkara, T.
    Acoustic methods have been developed and used to detect insects in concealed habitats. The larvae of red palm weevil, Rynchophorus ferrugineus (Olivier), a serious pest of the coconut palm, Cocos nucifera L. feed on the soft tissues inside the stem and bud region. Detection of infested coconut palms in the early stages by the conventional method of checking for external symptoms is time consuming, labour intensive and costly. This paper describes the development of a portable and efficient acoustic device and its potential in detection of infested palms in the field. The device comprises a sensor to mount on the palm and to acquire the sounds of red palm weevil larvae, an electronic unit that processes the acquired sounds and a set of headphones to receive the output sound by the listener. It is light weight, user-friendly andpowered by batteries. The highest accuracy of identifying infested palms was obtained when the palm was checked at four positions; either side of palm base and bases of the two lowermost leaves. The infested palms were detected with over 97% accuracy, while the probability of not detecting uninfested palms was over 92%. A second check increased the rate of accuracy. Many difficulties encountered with conventional methods could be overcome by the use of this device.
  • Thumbnail Image
    Item
    Use of polypropylene bags for mass rearing Neoseiulus baraki (Acari: Phytoseiidae), a predatory mite of Aceria guerreronis Keifer (Acari: Eriophyidae)
    (2014) Kumara, A.D.N.T.; Fernando, L.C.P.; Suwandhrathne, N.I.; Aratchige, N.S.
    An efficient, low cost and practicable mass rearing method for the predatory mite, Neoseiulus baraki Athias-Henriot (Acari: Phytoseiidae) was developed using a bag made of two-ply polypropylene (gauge 150, 24 cm × 36 cm) sheets. Introducing 20 N. baraki females into the bag produced a mean number 5218 ± 212.10 offspring in 6 weeks with a 260-fold increase of the initial population.