Effect of Temperature On the Life Cycle of Pratylenchus Penetrans On Cryptomeria Seedlings and Observations On Its Reproduction

Abstract

The life cycle of P. penetrans on Cryptomeria seedlings was studied at each of five temperatures, 15°, 20°, 24°, 30°, and 33°C by following the reproduction of a solitary female inoculated per seedling root and the development of its offspring. The life cycle was completed in 86 days at 15°, in 42-44 days at 20°, in 35 days at 24°, and in 30-31 days at 30°. At 33°, the development was inhibited. The incubation period of eggs was 25 days at 15°, 14-16 days at 20°, 8-10 days at 24°, and 9-10 days at 30°. The nematode produced nearly the same number of offspring within a generation period at each temperature of 15°, 20°, and 24°. At 30°, however, reproduction was slightly suppressed. At 24°, females of P. penetrans laid an average of 1.1 eggs each day for about 35 days. The maximum number of eggs laid by a female was 68. Males were necessary for reproduction in this species.