Alternaria infectoria, a promising biological control agent for the fig wax scale, Ceroplastes rusci (Homoptera: Coccidae), in Egypt

Alternaria infectoria E.G. Simmons was isolated from naturally infected eggs of the fig wax scale insect, Ceroplastes rusci L. (Homoptera: Coccidae), that were showing different degrees of shriveling. This fungus proved to be pathogenic to eggs, nymphs and adults of this pest. The fungus had significant effects on both the mortality and hatchability of the eggs (P = 0.0001). Three days after exposure to the fungus, nearly one-third (31.5%) of the fungus-treated eggs became discolored and 17% showed moderate shrinking but no mortality. Fifteen days post-application, 91% of the fungus-treated eggs were diseased (74.8% of them were dead) due to A. infectoria, while no disease developed on the untreated eggs. Hatching den eased by 39.6% over a 15-day period in the fungus-treated eggs compared to the control. Additionally, crawlers hatching from fungus-treated eggs became infected. The fungus seemed to induce crawlers to enter. the settling stage. Seventy-two per cent of the fungus-treated crawlers vel sus 9% of the untreated controls entered the settling stage 6 days after exposure to the fungal inoculum. The highest level of nymphal mortality attributed to A. infectoria occurred wizen 30% (wet w:v blended mycelium in water containing 0.5% w:v Metamucil) inoculum was applied, and a high relative humidity was maintained for the following 48 h. This is the first record of A. infectoria on the fig wax scale and for the genus Alternaria as an entomopathogenic fungus.