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Duration times of the immature stages of Cacopsylla pyri L. (Hom., Psyllidae), estimated under field conditions, and their relationship to ambient temperature
Author(s) -
Kapatos E. T.,
Stratopoulou E. T.
Publication year - 1999
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1046/j.1439-0418.1999.00417.x
Subject(s) - biology , zoology , larva , ecology
The duration of the immature stages of Cacopsylla pyri L. was studied under field conditions by artificially infesting pear branches on several dates during the year. The duration of the egg stage decreased from winter to summer, as the season progresses and temperature rises, and slightly increased in September. It ranged from 27.4 to 6.7 days. The same trend was observed in the duration of the first three larval stages (L 1−3 ) which ranged from 18.8 to 10.3 days. For eggs deposited during the period February–August the duration of the last two larval stages (L 4−5 ) ranged from 17.5 to 12.1 days. However, the duration of L 4−5 developed from eggs deposited in September and which give rise to winter‐form adults were the longest observed. The rate of egg development was related to average ambient temperature with a highly significant linear relationship. This relationship indicates that the egg stage requires a constant number of 158.9 (SD = 5.0) of day‐degrees above an average temperature of 2.31°C to complete development. The rate of development both of L 1−3 and L 4−5 were related to average ambient temperature with curvilinear relationships. These relationships indicate a proportional increase in the developmental rate as temperature rises between 10–22°C. At the higher average temperatures that occurred in the summer experiments (24–27°C) the acceleration of development of L 1−3 is reduced and the developmental rate of L 4−5 decreases. The developmental rates of L 4−5 developed from eggs deposited in September did not follow the established relationship with temperature and they were lower than those in the other periods of the year with the same average temperature.