• Korean journal of applied entomology
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• v.31 no.4
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• pp.492-495
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• 1992

Life cycle of the mirid predator, Cyrtorhinus lividipennis, was observed on the constant temper¬ature. Egg periods were 14.43, 9.33 and 6.94 days at $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$, respectively. Nymph periods were 24.3, 14.42, and 11.90 days at $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$, respectively and fe¬male longevity was 11.20, 11.93 and 11.87 days at above temperatures. Relationships between constant temperature and the developmental velocity of egg, nymph and egg-nymph were lin¬ear over temperatures tested. The calculated threshold temperatures of development were $10.7^{\circ}C$ in egg, $9.8^{\circ}C$ in nymph and $10.2^{\circ}C$ in egg-nymph. Total effective day-degrees were 133.9 in egg, 235.8 in nymph and 368.0 in egg-nymph. Number of eggs laid was 26.0 and 22.4 at $24^{\circ}C$ and $30^{\circ}C$, respectively.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.234-242
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• 1995

The functional responses of the female Cyrtorhinus lividipennis on brown planthopper (BPH), Nilaparvata lugens, eggs and their predation behavior were investigated at six temperature conditions; 20, 23, 26, 29, 32, and $35^{\circ}C$. C. lividipennis was found to prefer young BPH eggs, especially 3-day-old eggs the most. The functional responses for female C. lividipennis on BPH eggs fitted the Holling's Type-I true predator-prey Rogers' (1972) model at all temperatures tested except $35^{\circ}C$ at which the negative Th value was produced. With the temperature increased up to 32$^{\circ}C$, the instantaneous attacking rate(a) increased from 0.1923 at $20^{\circ}C$ to 0.5085 at $32^{\circ}C$, while the handling time (Th) was gradually decreased as low as 0.0151 at $32^{\circ}C$. C. lividipenis preferred the BPH eggs laid on the upper part of rice stem when the BPH egg density was high, but there was no significant difference in the preference when the egg density was low. The preference was more obvious in high temperature conditions such as above 29$^{\circ}C$.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.52-57
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• 1996

This experiment was carried out to evaluate the effect of sublethal doses of BPMC, etofenprox,and buprofezin on N. lugens. and its predator C. lividipennis. Buprofezin was found to be the most toxic to N. lugens and the most safe to C. lividipennis among the three insecticides, based on LD50 values. Selective toxicity index calculated by dividing LDSo value of C. lividipennis by that of N. lugens indicated that buprofezin was very safe to C. lividipennis, showing selective toxicity of 2703.3. Longevity and fecundity of N. lugens treated with LDIU and LDm of buprofezin and BPMC were not significantly different with those of untreated brown planthoppers. However, egg hatchability' of N. lugens was greatly reduced when treated with LDm of buprofezin, having the highest inhibition rate of 17.7%. Hatchability of eggs from insects treated with BPMC was similar to that of control. The oviposited peak of treated hoppers appeared late as compared to the untreated which showed the peak at early part of the ovipositional period. The longevity and fecundity of C. lividipennis treated with BPMC were significantly reduced as compared with the untreated. Etofenprox also induced fecundity reduction when treated with LDlo, and LDm. However, C. lividipennis treated with sublethal doses of buprofezin showed no redution in logevity and fecundity. From these results, it may be said that buprofezin can be used to control brown planthopper without disrupting of C. lividipennis population in the rice field.