Bemisia tabaci: The current situation in the UK and the prospect of developing strategies for eradication using entomopathogens

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) remains a serious threat to crops worldwide. The damaging B-biotype is of specific economic concern because it is an effective vector of over 111 viruses from several families, particularly geminiviruses. Bemisia tabaci is regularly intercepted on plants coming into the UK where it is subjected to a policy of eradication. The UK maintains Protective Zone status against this pest. A main pathway of entry of B. tabaci into the Protected Zone involves propagating material, especially Poinsettia (Euphorbia pulcherrima). With increased insecticide resistance continuously being recorded, B. tabaci is becoming more difficult to control/eradicate. Recent research involving both entomopathogenic nematodes and fungi is showing much potential for the development of control programs for this pest. Both the nematode Steinernema feltiae and the fungus Lecanicillium muscarium have been shown to be most effective against second instar B. tabaci. Fine-tuning of the environmental conditions required has also increased their efficacy. The entomopathogens have also shown a high level of compatibility with chemical insecticides, all increasing their potential to be incorporated into control strategies against B. tabaci.