Evaluation of local clay particles as coating agent and carrier of entomopathogen and mycoparasite against cacao mirid bug, helopeltis bakeri poppius (hemiptera:miridae) and black pod rot caused by phytophthora (peronosporales:peronosporaceae)

• Main Author: Albacete, Sharin C.
• Format: text
• Language: English
• Published: Animo Repository 2018
• Subjects: Insect pests > Biological control; Biological insecticides
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/5537
• Institution: De La Salle University

Evaluation of the efficacy of clay particles as a coating agent and carrier of entomopathogen, Metarhizium anisopliae Sorokin and mycoparasite Trichoderma (manufactured by Biospark Corporation) for the control of cacao mirid bug (CMB), Helopeltis bakeri Poppius and black pod rot (BPR), Phytophthora, respectively was conducted. Choice and no choice tests were performed to evaluate local clay particles as a coating agent of pods to deter CMB from feeding on cacao pods, in comparison with the commercially available particle film (US kaolin Sorround®). Cacao pods were coated separately with the different local clay particles such as the local kaolin, zeolite, bentonite, and compared to the US kaolin; coating of water and commercial synthetic insecticide (Actara®) were included as negative control and positive control, respectively, in order to determine which among the local clay particles is the most efficient in protecting the pods from CMB feeding. Among the clay particles tested in both choice and no choice tests, local zeolite showed significant coating and deterred CMB from feeding and in comparable with US kaolin and the positive control insecticide treatment. Pods sprayed with water had the highest number of feeding punctures. All insects died when exposed on cacao sprayed with insecticides after 24 hours. Since US kaolin and zeolite showed significant feeding deterrent effect on CMB, both were included in the test as carrier of entompathogen, Metarhizium anisopliae. Three control checks were included in the tests: positive control (insecticide), negative control (water only), water with M. anisopliae. Results showed that US kaolin and zeolite were effective carrier of the spores of M. anisopliae. It was observed that the CMB died 24 hours after exposure of cacao pods from M. anisopliae infection as confirmed by positive M. anisopliae extraction from dead CMB through potato dextrose agar (PDA) plating. CMB exposed in water with M. anisopliae remained alive after 48 hours exposure and not all PDA plates showed positive growth of the fungi. In the positive control (use of insecticide) all CMB died after exposure for 24 hours, whereas negative control (use of water only) all CMB remained alive throughout the duration of the experiment. As for Phytophtora growth inhibition experiment, the result showed that in both preventative and curative tests, zeolite with Trichoderma was successful in inhibiting the growth of Phytophthora as compared to control check water-treated pods. Furthermore, it was also noted that the effect of M. anisopliae was not affected by the presence of Trichoderma which means that the two fungal species can be formulated together with zeolite for the control of both CMB and Phytophthora.