Pseudococcidae (mealybugs) is a large taxonomic group, including a number of agronomic pests. Taxonomic identification of mealybug species is a recurrent problem and represents a major barrier to the establishment of adequate pest management strategies. We combined molecular analysis of three DNA markers (28S-D2, cytochrome oxidase I and internal transcribed spacer 2) with morphological examination, for the identification of 176 specimens collected from 40 mealybug populations infesting various crops and ornamental plants in Egypt and France. This combination of DNA and morphological analyses led to the identification of 17 species: seven in Egypt (Planococcus citri (Risso), Planococcus ficus (Signoret), Maconellicoccus hirsutus (Green), Ferrisia virgata (Cockerell), Phenacoccus solenopsis Tinsley, Phenacoccus parvus Morrison and Saccharicoccus sacchari (Cockerell)) and 11 in France (Planococcus citri, Pseudococcus viburni Signoret, Pseudococcus longispinus (Targioni-Tozzetti), Pseudococcus comstocki (Kuwana), Rhizoecus amorphophalli Betrem, Trionymus bambusae (Green), Balanococcus diminutus (Leonardi), Phenacoccus madeirensis Green, Planococcus vovae (Nasonov), Dysmicoccus brevipes (Cockerell) and Phenacoccus aceris Signoret), Pl. citri being found in both countries. We also found genetic variation between populations considered to belong to the same species, justifying further investigation of the possible occurrence of complexes of cryptic taxa.

Climate change is relevant to life around the globe. A rise in ambient temperature and carbon dioxide (CO2) may have various impacts on arthropods such as altered life cycles, modified reproductive patterns, and changes in distribution. The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a global pest responsible for significant losses of agricultural yields annually. This study was conducted to determine the impacts of changing temperature and CO2 levels on selected life history parameters of B. tabaci biotype B. Populations were established at three temperature regimes (25,28, and 33°C), and each population was evaluated in all three environments. Collard, Brassica oleracea ssp. acephala de Condolle (Brassicaceae), was used as the host. These results were based on data from 5 to ≈30 generations. Oviposition, nymphal survival, and reproduction were significantly affected by temperature, with net reproductive success declining to 36.4% at 33°C. Overall, 28°C was most favorable for whitefly fitness. However, the optimal temperature for B. tabaci reproduction may be between 28 and 33°C. There were no temperature effects on total nonstructural carbohydrate concentrations in collard, and impacts of the host plant on whitefly development in the different environments were determined to be minimal. An environment of enriched CO2 (750 ppm) was not observed to have an adverse effect on whitefly reproduction. Temperature was negatively correlated with adult body size. Length and width of males and females were affected by temperature. Data regarding population dynamics of B. tabaci in response to climate change are important for accurate predictions and improving management practices.

Understanding the relationship of parasitoids with their insect hosts and crop plants is needed to develop good management strategies for Bemisia tabaci (Gennadius), a whitefly pest. The abundance and establishment of parasitoids of B. tabaci B-biotype were tested with taxonomically diverse plants in the greenhouse (7 plant species) and in the field (16 plant species in Egypt). Greenhouse tests were conducted on plants free of whitefly nymphs to avoid this influence on parasitoid behavior, and field tests were conducted in crops with feral populations of B. tabaci. In the greenhouse, the parasitoid, Encarsia pergandiella Howard, was most abundant on Vigna unguiculata (L.) Walpers, followed by Gossypium hirsutum L. The propensity for this parasitoid to forage on the bottom leaf surface compared with the top surface varied among crops (45–90% were on the bottom leaf surface) and over time (≈50% were on the bottom leaf surface around sunrise, whereas ≈90% were on the bottom surface by mid-day). Inundative releases of laboratory-reared parasitoids, Eretmocerus mundus (Mercet), into field crops increased parasitization rates in all crops tested. Some crops (e.g., two Brassica species and V. unguiculata) were more conducive to parasitism of B. tabaci than other crops (e.g., Cucumis sativus L. and Lycopersicon esculentum Miller). Findings from this research may be useful in the enhancement and conservation of parasitoids of Bemisia.