Pathogenicity and persistence of entomopathogenic fungi against Asian citrus psyllid, <i>Diaphorina citri</i> Kuwayama

The increased development of insecticide resistance has necessitated the development of alternative control strategies against citrus psyllids. Entomopathogenic fungi are viewed as complementary and effective alternatives to synthetic insecticides. These investigations aim to determine the pathogenic potential of two different fungal strains, viz.,
Beauveria bassiana
and
Metarhizium anisopliae,
against citrus psyllid under laboratory and natural field conditions. Both fungal strains were used at five different concentrations consisting of 1 × 10
4
, 1 × 10
5
, 1 × 10
6
, 1 × 10
7
and 1 × 10
8
conidia mL
-1
. The mortality of
D. citri
was recorded 3, 7 and 14 days after fungal treatment, which was dose and time-dependent. Under laboratory environment at 14 days after treatment, the
M. anisopliae
used at higher concentrations of 1 × 10
7
and 1 × 10
8
conidia mL
-1
caused &gt; 80% mortality of
D. citri
having significant variation from 61.8 and 66.4% corrected mortality on plants treated with
B. bassiana
at similar concentrations, respectively. Additionally, under natural field conditions,
M. anisopliae
was more pathogenic and caused maximum (80%) mortality of
D. citri
at the maximum concentration of 1 × 10
8
, having a significant difference from 64% cumulative mortality on plants treated with
B. bassiana
at the same concentration. Among the two tested fungal strains,
M. anisopliae
 caused higher mortality of
D. citri
adults compared with
B. bassiana
and persisted up to 14 days after being applied. The present study highlights the potential of both tested entomopathogenic fungi strains as effective biological control agents against citrus psyllids.