Natural incidence ofCladosporiumspp. as a bio‐control agent against whiteflies and aphids in Egypt

Five species of entomopathogenic fungi were tested against whiteflies and aphids.Cladosporiumspp. showed a high incidence on the two insect species tested (81% of the total isolated species). However,C. uridenicolawas the predominant species isolated from both insect species during the two successive seasons of 1998 and 1999. Natural infection byCladosporiumranged from 18.19 to 44.38% and 16.4 to 45.27% in 1998 and 1999, respectively, according to insect species and the host plant. Statistical analysis revealed a high correlation (R = 0.8759 ± 0.093) between the total investigated and total infected of each insect species during the two successive years of the study. The natural infection ofCladosporiumto whitefly life stages was higher on whitefly nymphs (87.8%) than adults (8.08%) and eggs (4.15%) in 1998 and 1999. The results showed that the seasonal distribution ofCladosporiumoccurred all year around, but rates were higher during the period from June until November which coincided with the high populations of whiteflies and aphids. The weather had a significant effect on infection of insects and had no effect on other fungi species. The laboratory tests showed a higher pathogenicity of the candidate onAphis gossypii,Aphis craccivoraandBemisia agrentifolliithan other reported fungi.