Entomopathogenic Fungus and Enhanced Diatomaceous Earth: The Sustainable Lethal Combination against Tribolium castaneum

Abstract

This study determined the efficacy of the Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) alone or combined with the diatomaceous earth DEA (a mixture of DE + abamectin) against adults and larvae of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). DEA was evaluated at 50 ppm while the fungi at 1.6 × 105, 1.6 × 106, and 1.6 × 107 conidia/kg wheat). Mortalities were assessed after 7 or 14 days of exposure, while progeny reduction in adults after 30, 60, 90, or 120 days. The radial fungus growth was significantly affected by the dose of DEA. Mortalities were higher in the combined treatments compared to the application of DEA or B. bassiana alone for both larvae and adults. Larvae were more susceptible than adults in all treatments and exposure intervals. Insect survival and progeny production were recorded for four months. Significantly fewer progeny was noted on wheat treated with DEA + B. bassiana treatments compared with control. The maximum number of mycosed cadavers and the rate of sporulation were observed at the lowest dose of B. bassiana alone, followed by the higher doses gradually. These findings indicate that the DEA + B. bassiana combinations can efficiently control T. castaneum, providing long-term protection of wheat.

The Potential of Two Entomopathogenic Fungi and Enhanced Diatomaceous Earth Mixed with Abamectin: A Comprehensive Study on Mortality, Progeny Production, Application Method, and Surface Application against Tribolium castaneum

“…In the realm of EPF, virulence is predicated upon the attachment of conidia to the body of the host, their subsequent germination, and, ultimately, their penetration into the insect [ 42 , 43 ]. The variable virulence of EPF may be partially explained by the fact that insect stages possess different cuticular layers, which vary in the morphology, softness, and thickness of the epicuticle [ 102 , 103 ], as suggested in previous research on the susceptibility of T. castaneum to EPF [ 77 , 104 ].…”

“…The DE formulation (DEA) consisting of freshwater DE (90%) + 0.25% abamectin as an active ingredient (a.i.) was utilized at 35 ppm or 25 ppm for bioassays related to grains, and 2 gr/m 2 for surface treatment, against larval and adult individuals of T. castaneum [ 77 ]. The origin of the DE is fresh water, and it is constituted by 89% amorphous silicon dioxide, along with 1.7% Fe 2 O 3 , 4.0% Al 2 O 3 , <1% K 2 O and MgO, 1.4% CaO, and 3% moisture.…”

“…One control group was used for larvae, and the other one was used for adults of T. castaneum . The treatment for the control was water that contained Tween 80 (0.05%) [ 77 ]. For each treatment, 1 kg lots were laid in slim layers on individual trays.…”

“…There are several reports on the additive effects of DEs combined with either B. bassiana [ 77 , 78 ] or M. anisopliae [ 55 , 79 ] against T . castaneum.…”

Natural Warriors against Stored-Grain Pests: The Joint Action of Beauveria bassiana and Steinernema carpocapsae

“…Later, dead insects were placed on SDA dishes at 25 °C and 75% RH for 7 days. The emergence of conidial spores from the insect cadavers was examined using a stereomicroscope [ 66 ]. For the single treatment of S. carpocapsae, dead individuals of each pest species were removed from the Petri dishes and dissected under a stereomicroscope to validate the existence of S. carpocapsae within their bodies [ 67 ].…”