Document Type : Original research articles
Authors
1
Cotton and Filed Crops Mites Department Plant Protection Research Institute, Agricultural Research Centre, Dokii, Giza, Egypt
2
Cotton and Filed Crops Mites Department Plant Protection Research Institute, Agricultural Research Centre, Dokii, Giza
3
Fruit Trees Mites Department, Plant Protection Research Institute (Manssoura), ARC, 12611, Dokki, Giza,
Abstract
ABSTRACT
The effect of three fig cultivars Ficus carica L. (i.e., Adsi, Black michan, and Sultani) at three constant temperatures of 22, 27, and 32 °C, 70% RH, and 12 h photoperiod on the developmental duration and reproductive rate of the two-spotted spider mite Tetranychus urticae Koch was studied. Results indicated that temperature degree plays a key role in the time needed for T. urticae developmental stages to reach adulthood. Increasing the temperature accelerated the developmental rate and female fecundity and daily rate of egg production were positively affected. The shortest average life cycle was 10.0 & 10.03, 6.40 & 6.90, and 8.8 & 8.90 days for male and female at 32°C on Adsi, Black michan, and Sultani cultivars, respectively. Mean fecundity was highest at a temperature of 27°C (97.33 eggs/ female), and lowest was at 22°C (73.20 eggs/ female). The fig cultivar affected significantly on duration of immature stages, oviposition period, longevity, and average fecundity of T. urticae. The development thresholds (t0) of the eggs and immature stages varied from 8.26 to 17.11°C, and the total effective temperatures (K) ranged from 40.42 to 152.17 degree-days for females. The highest intrinsic rate of increase (rm) and net reproductive rate (R0) was on 'Black michen' at 27 and 32ºC, while the lowest value was on 'Adsi' at 22 ºC. As the temperature increased, the values of the mean generation time (T) and generation doubling time (DT) decreased. Gross reproductive rate (GRR) was also affected by fig cultivar and temperature where the highest value was 94.8 offspring/ individual achieved when mites were kept at 27°C on 'Black michen' while the lowest value was 42.4 offspring/individual on 'Adsi' at 22°C. The results suggested that temperatures between 27 and 32°C are the most suitable conditions for the development, survival, and reproduction of T. urticae. While, the Black michen cultivar is the most favorable host for the development and reproduction of spider mite T. urticae.
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