TITLE:
Potential of Two Metarhizium anisopliae (Clavicipitaceae) Isolates for Biological Control of Diatraea saccharalis (Lepidoptera: Crambidae) Eggs
AUTHORS:
Camila Vieira da Silva, Bruno Vinicius Daquila, Larissa Carla Lauer Schneider, Ronaldo Roberto Tait Caleffe, Julio Cesar Polonio, Daniele Araujo Canazart, Satiko Nanya, Helio Conte
KEYWORDS:
Entomopathogen, Fungi, Management, Sugarcane, Sustainability
JOURNAL NAME:
Advances in Entomology,
Vol.10 No.1,
December
7,
2021
ABSTRACT: Chemical
pesticides tend to accumulate in soil, resulting in human and environmental
health risks. Hence, alternative methodologies involving chemical pesticides
are beneficial for the control of agricultural pests. Metarhizium
anisopliae is an
entomopathogenic fungus that acts on different developmental stages of pest
insects such as Diatraea
saccharalis, a holometabolic lepidopteran with high potential for
infestation in sugarcane crops. The present study evaluated the biocontrol
effect of M. anisopliae isolates MT and E9 on D.
saccharalis eggs at different ages by investigating the external
and internal morphological alterations in treated eggs. Conidial suspensions of
M. anisopliae isolated from MT and E9 at concentrations of 107
conidia/mL were applied to eggs of D.
saccharalis aged 0, 24, 48, 72, 96 and 120 h. The eggs were
observed every 24 h during development (0 h to 144 h). Samples were collected
for observational, histological, and ultrastructural analyses. We found that
the MT isolate caused 100% inviability of eggs aged 0 - 72 h, 144 h after the
bioassays, while the effect of the E9 isolate varied between 49.40% and 93.75%.
Melanization was observed on the periphery of the eggs 24 h after the
bioassays. Fungal hyphae developed 48 h after bioassays, crossed the egg
chorion, and dispersed through the yolk region, inhibiting embryonic
development. After 72 h, hyphae and conidiophores were observed on the eggs,
which persisted for 144 h. In sum, M.
anisopliae MT isolate can be used as a biological controller for D. saccharalis eggs.