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Woolly apple aphid - Fecundity |
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Most of the woolly apple aphid population in New Zealand is composed of wingless females. These give birth to large numbers of female nymphs mainly over a period of about 40-50 days at temperatures up to about 20°C but reducing to about 20 days as temperatures rise to 25°C. Several estimates of fecundity have been found in the literature:
| Location | Conditions | Nymphs per female | Range | |||
| New Zealand (1938) | about 100 | |||||
| Netherlands (1958) | over 100 | |||||
| U.S.A. (1988) | laboratory 16°C | average = 131 | ||||
| laboratory 20°C | average = 102 | |||||
| laboratory 24°C | average = 124 | |||||
| Australia (1991) | laboratory 15°C | average = 112 | 58-174 | |||
| laboratory 20°C | average = 107 | 31-176 | ||||
| laboratory 25°C | average = 77 | 16-174 |
The recent Australian research showed that peak net reproduction rate occurred at 15°C and that an optimum temperature for growth and development is about 20°C. Much lower fecundity was achieved at the extremes of 10°C (average 36 nymphs, range 8-84) and 30°C (average 19 nymphs, range 2-39). These results are similar to the U.S.A. study with optimum fecundity in the temperature range of 16-24°C.