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 (LD
50) and lethal time 50 (LT
50), for each of the four life stages of the female. The doses tested were 105, 106,
10
7 and 10
8 conidia mL
-1. Also fecundity, egg size, fertility, and longevity of adult females were evaluated at doses of 10
5
and 10
6 conidia mL
-1, the evaluations were made every 2 d throughout the insect life time. The LD
50 and LT
50 obtained were
variable for each life stage, although without statistical differences among life stages (P > 0.05), ranging from LD
50 = 7.3 ×
10
5 to 4.9 × 10
9 conidia mL
-1 and LT
50 = 7.74 to 9.97 d at 10
8 conidia mL
-1. Significant differences (P ≤ 0.05) were observed
on longevity at 10
6 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).
