ChileanJAR

Obscure mealybug, Pseudococcus viburni (Signoret), is a cosmopolitan pest that causes damage by suction of vascular juices and the production of honeydew, as well as for being a quarantine insect. Within control options, entomopathogenic fungi are a good alternative, nevertheless, more research is needed. In this research, the Metarhizium anisopliae var. anisopliae (Metschnikoff) isolate Qu-M984 was evaluated on P. viburni under laboratory conditions. Virulence was evaluated by lethal dose 50 (LD₅₀) and lethal time 50 (LT₅₀), for each of the four life stages of the female. The doses tested were 10⁵, 10⁶, 10⁷ and 10⁸ conidia mL^-1. Also fecundity, egg size, fertility, and longevity of adult females were evaluated at doses of 10⁵ and 10⁶ conidia mL^-1, the evaluations were made every 2 d throughout the insect life time. The LD₅₀ and LT₅₀ obtained were variable for each life stage, although without statistical differences among life stages (P > 0.05), ranging from LD₅₀ = 7.3 × 10⁵ to 4.9 × 10⁹ conidia mL^-1 and LT₅₀ = 7.74 to 9.97 d at 10⁸ conidia mL^-1. Significant differences (P ≤ 0.05) were observed on longevity at 10⁶ conidia mL^-1. Longevity was 29% less compared to the control. This result on longevity at relatively low dose is relevant due to the fact that decrease possibilities to find live quarantine insects at the moment of harvest. Fertility, fecundity and egg size showed no differences (P > 0.05).