Wei J.-R.,Chinese Academy of Forestry |
Wei J.-R.,Key Laboratory of Forest Protection |
Wei J.-R.,Hebei University |
Ding B.-F.,Chinese Academy of Forestry |
And 4 more authors.
Rhizophagus grandis (Coleoptera: Rhizophagidae) is an important predator of Dendroctonus valens which is an invasive alien pest attacking pine trees in China. It was first introduced into China in 2000 and mass rearing techniques had been developed by the authors since then. This paper dealed with the study on the developmental threshold temperature and the effective accumulated temperature of R. grandis. The result showed that the developmental threshold temperatures of egg, larva and pupae were 3. 59 ± 2. 92 °C, 1.96 ±0.73°C and 9. 27 ± 1.19 °C respectively, and the effective accumulated temperatures were 98.32 ± 16.26 degree-day, 296.94 ± 12.45 degree-day and 449. 67 ±53. 19 degree-day respectively. Therefore, the total effective accumulated temperature from egg to pupa was 844.93 degree-day. Source
Wang M.-Y.,Chinese Academy of Forestry |
Wang M.-Y.,Key Laboratory of Forest Protection |
Shu L.-F.,Chinese Academy of Forestry |
Shu L.-F.,Key Laboratory of Forest Protection |
And 4 more authors.
The data of forest fires from 1980 to 1999 in Heilongjiang Province, NIN03.4 index and Southern Oscillation Index were analyzed by spectral analysis and correlation method, and the spectral periodicities were got individually. The periodicities of fire number and fire area were 10.00 years and 6.67 years respectively. The periodicities of both El Niño and La Niña were 5.00 years in these 20 years. The correlations between fire number or area and La Niña or El Niño were very significant. The fire area and fire number were negatively correlated with El Niño, and the correlation coefficients were -0.523 1 and -0.659 4 respectively. The fire number and fire area were positively correlated with La Niña, and the correlation coefficients were 0.525 4 and 0.536 3 respectively. The influence of La Niña was less than that of El Niño. The fire area and fire number increased abnormally after warm ENSO events year. Source