Browsing by Author "Asogwa, E.U."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evaluation of the toxicity of Actara 25 WG for the control of the cocoa mirid Sahlbergella singularis Hagl. (Hemiptera: Miridae) in Nigeria
    (2009) Anikwe, J.C.; Okelana, F.A.; Asogwa, E.U.; Ndubuaku, T.C.N.
    In Nigeria, the brown cocoa mirid Sahlbergella singularis is responsible for over 30% yield loss in cocoa. Insecticides still remain a very important component among the strategies for effective control of major insect pests of cocoa in Nigeria. The Cocoa Research Institute of Nigeria (CRIN) has the “National Mandate” to evaluate and recommend new insecticides for use on cocoa in Nigeria. The mortality rates of mirids on exposure to the various concentrations (0.01, 0.013, 0.015 and 0.02%) of Actara 25 WG increased with period of exposure of the mirids in the laboratory. Both Actara and the Standard Miricide were similar at 0.020% concentration as both gave a 100% kill of mirids at the 90th min. No mortalities were recorded in control cages throughout the exposure period. The insecticide did not produce any adverse side effects on cocoa seedlings and mature plants sprayed with the various concentrations over the years. The relative toxicity of the insecticide at the four different concentrations to adult mirids, 24 h after the first field treatment application, was 93.3, 82.4, 81.8 and 100% adult mortality, respectively. In the case of the nymphal mirids, percentage mortality was 89.6, 81.5, 86.8 and 94.3% for the various concentrations, respectively. The population of both the adult and nymphal mirids crashed to almost zero (0) in most cases suggesting about 100% mortality 24 h after the second spraying on the residual mirid populations. Mirid numbers remained so low until the third spray application after which it was unnecessary to spray the sub-plots, thereafter. Spraying of mature and fruiting cocoa farms at application rate of 0.015% was found adequate and recommended taking into consideration the impact of the product on the environment and for economic reasons.
  • Thumbnail Image
    Item
    Problems associated with pesticide usage and application in Nigerian cocoa production: A review
    (2009) Asogwa, E.U.; Dongo, L.N.
    The use of pesticides for effective pests control has generated a lot of concerns relating to public health and environmental pollution. With the new European Union (EU) Legislation on Maximum Residue Levels (MRLs) allowed on cocoa beans and its products, efforts are now intensified to seek measures towards its reduction. The Cocoa Research Institute of Nigeria (CRIN) has the mandate to screen and recommend potential cocoa pesticides and spraying equipment in Nigeria. The Institute has screened and recommended many of these pesticides and equipment in the past. However, with the new EU Legislation on MRLs allowed on cocoa beans and products, some of the pesticides still undergoing screening and the previously recommended pesticides were banned. This new regulation, which came into effect September 1, 2008, has left very few pesticides for use on cocoa both on farm and post farm activities in Nigeria.