Seasonal Abundance of the Whitefly Bemisia tabaci (Gennadius) on Some Cotton Cultivars in Diyala Governorate, Iraq

• Hussein Ali Mutney Al-Anbaki

  Author

  whitefly Bemisia tabaci (Gennadius) is an important pest of cotton Gossypium hirsutum , and cultivar-associated differences in infestation can provide a practical component of integrated pest management. A field experiment was conducted during 2025 in Al-Mujaddad village, Al-Khalis District, Diyala Governorate, Iraq, to compare the susceptibility of three Cultivars cotton cultivars, Ashur-1, Lachata, and Coker 310, to naturally occurring B. tabaci. The experiment was arranged in a RCBD with four replicates. Twenty leaves were collected from each replicate at weekly intervals from 15 June to 15 November 2025, providing 23 sampling dates and 5,520 examined leaves. Whitefly density was expressed as individuals (nymphs and adult) / leaf, and an area under the pest population curve (AUPPC) was calculated to integrate seasonal pest pressure. Seasonal mean density differed significantly among cultivars (F(2, 6) = 341.37, P < 0.001). Coker 310 recorded the highest density (0.486 ± 0.011 whiteflies leaf−1), followed by Ashur-1 (0.388 ± 0.014), whereas Lachata recorded the lowest density (0.304 ± 0.009). The corresponding AUPPC values were 76.24, 60.78, and 47.64 whitefly-days leaf−1 for Coker 310, Ashur-1, and Lachata, respectively (F(2, 6) = 365.77, P < 0.001). Whitefly abundance increased from early summer, peaked on 7 September, and declined thereafter. The mirid predator Campylomma unicolor Poppius, 1914 (Hemiptera: Miridae) was also documented qualitatively in the field, with adults and eggs observed on cotton leaves associated with B. tabaci. Relative to Coker 310, seasonal mean density was 20.2% lower on Ashur-1 and 37.4% lower on Lachata. These results identify Lachata as the least susceptible cultivar under the tested conditions and Coker 310 as the most susceptible. Multi-season and multi-location validation is recommended before broad agronomic recommendations are made.

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