Isolation and molecular characterization of Cordyceps sp. from Bemisia tabaci (Hemiptera: Aleyrodidae) and pathogenic to Glycaspis brimblecombei (Hemiptera: Aphalaridae)

Abstract

The Brazilian forestry sector stands out for its technology, forestry management practices, social and environmental responsibility and, mainly, for its high productivity and exotic pests can reduce it. The red gum lerp psyllid Glycaspis brimblecombei (Moore, 1964) (Hemiptera: Aphalaridae) is an important pest in Eucalyptus plantations. The parasitoid Psyllaephagus bliteus (Riek, 1962) (Hymenoptera: Encyrtidae), predatory bugs and entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae are the natural enemies and used in the biological control of the red gum lerp psyllid. The use of entomopathogenic fungi against exotic pests is increasing in the forestry sector and the prospecting and identification of fungus isolates is important for integrated pest management. The objective of this work was the isolation and molecular identification of Cordyceps spp. And to evaluate the pathogenicity of isolates, obtained from Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae) adults, against to the red gum lerp psyllid G. brimblecombei. The fungi were isolated from B. tabaci adults found in soybean and tomato crops and molecularly identified. The conidia obtained were suspended in solution with Tween 80 (0.1%) at a concentration of 1.0 × 108 conidia/mL and sprayed on ten G. brimblecombei nymphs per Eucalyptus leaf cut and placed on a hydroretentive gel inside per Petri dishes as a replication. The number of dead insects was quantified, daily, for seven days, and transferred to humid chambers. Cordyceps javanica (LCBPF 11) and C. fumosorosea (LCBPF 12 and LCBPF 63) were identified with a molecular analysis and all isolates were pathogenic to the insects and indicates that they could be used to manage G. brimblecombei and adds to reports that, normally, fungi cause greater mortality on insects of the same order as that from which they were isolated.

Diversity of entomopathogenic fungi from soils of eucalyptus and soybean crops and natural forest areas

“…The PCR was amplified with a reaction in the ITS1-5.8S-ITS2 region of the rDNA using a total volume of 50 μL with 1X Taq DNA polymerase buffer, 1.5 mM MgCl2; 0.4 μM of each primer ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'), 0.2 mM of dNTPs and 0.2 U of Taq DNA polymerase and 25ng of DNA. This amplification was carried out in a thermocycler, programmed for an initial denaturation of 95 °C for 5 min, followed by 30 cycles of denaturation at 95 °C for 30s; annealing at 62 °C for 1min; extension at 72 °C for 2 min and final extension at 72 °C for 5 min (Domingues et al, 2022). The products from DNA extractions and PCR reactions (50 μL) were submitted to electrophoresis in 1% agarose gel and analyzed under UV light, with the amplified samples being purified using magnetic beads and sent to IBTEC at UNESP/Botucatu for Sanger sequencing.…”