Tong, C.J., Tang, Z.Y., & Pan, W.Y. 1988 Preliminary study on the fluctuation of natural populations of Hemiberlesia pitysophila.. Forest Science and Technology (No. 2): 6-11.

Notes: A study in 1984-86 on H. pitysophila, which infested 6.5 million mu of Pinus massoniana stands in Guangdong, showed that the annual peak of population fluctuation occurred in March-April. There were various factors influencing the population changes. Air temp. was considered to be the main influence with 19.5øC averaged over 10 days being the optimum for growth and development of the insect, but monthly precipitation >100 mm was detrimental to reproduction. (1 mu = 0.067 ha).