Resistance of Rhizopertha dominica (F.) (Coleoptera: Bostrychidae) to phosphine in the Philippines.
Sayaboc, P. D.; Gibe, A. J. G.; Caliboso, F. M.;
Philippine Entomologist Year: 1998 Vol: 12 Issue: 1 Pages: 91-95 Ref: 10 ref.
1998
บทคัดย่อ
Five field and 1 laboratory strain of Rhizopertha dominica [Rhyzopertha dominica] were tested for phosphine resistance using the FAO discriminating dose test for adult insects. Three of the field strains were collected from National Food Authority (NFA) warehouses, in selected sites where phosphine fumigation is commonly practiced. The sites represented the 3 major islands in the Philippines, namely, Metro Manila in Luzon, Cebu City in the Visayas and General Santos City in Mindanao. The other field strains were collected from private warehouses in South Cotabato and Rizal. High resistance levels of >400x were observed in the field strains collected from the NFA warehouses in Cebu City, Metro Manila and General Santos City. In contrast, low levels of resistance were detected in a strain from a private warehouse in South Cotabato (1.13x) and in the laboratory strains (1.65x), while the Rizal strain was still susceptible to phosphine. The Cebu City strain, which was most resistant, was tested to d
etermine the phosphine concentrations and minimum exposure period required for effective control. A concentration of 0.89 mg/litre phosphine for 7 days at 25 plus or minus 2 deg C controlled the insect. Based on this result, a dosage rate of 2 mg/m3 for a minimum of 7 days at 25 deg C and above is recommended.