Invasive Species Compendium

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Abstract

Pear rust mite (Acari: Eriophyidae) fecundity and development at constant temperatures.

Abstract

Longevity, preoviposition period and fecundity of deutogynes of the pear pest Epitrimerus pyri were measured at 3 constant temperatures (10, 15 and 20°C), and compared between deutogyne and protogyne females at 20°C. Relationships between temperature (10, 15, 20 and 25°C) and the rate of development (days-1) of eggs, nymphs and generations (egg to adult) were described using least-squares linear regression. Mean longevity and preoviposition period of deutogynes decreased with increasing temperature. The average rate of oviposition increased with temperature, but lifetime fecundity did not differ among temperatures. At 20°C, protogynes began ovipositing sooner than deutogynes and laid more eggs at a faster rate, but average longevity of the 2 morphs was the same. Significant linear relationships were found between temperature and the development rates of eggs, nymphs and generations. Threshold temperatures for development of eggs, nymphs and generations were 2.2, 3.3 and 3.8°C, resp. Degree-day (± SEM) requirements for median development of eggs, nymphs and generations were 93.5 ± 2.5, 78.7 ± 3.4 and 144.9 ± 3.6 above their respective threshold temperatures. These results are compared with estimated development requirements calculated from Easterbrook (1978).