Efficacy of Metarhizium anisopliae and (E)–2–hexenal combination using autodissemination technology for the management of the adult greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae)

Abstract

The efficiency of an autodissemination technique in controlling adult whiteflies, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) on tomato, Solunum lycopersicum was investigated with previously identified potent fungal isolates of Metarhizium anisopliae ICIPE 18, ICIPE 62 and ICIPE 69 under screenhouse or semi-field conditions. The autodissemination device was inoculated with dry conidia of the M. anisopliae isolates, while control insects were exposed to a fungus–free device. Sampling for conidia uptake, conidial viability and persistence, and insect mortality was done at 1, 2, 3, 5 and 8 days post–exposure, and collected insects were monitored for mortality over ten days. Overall, mortality was higher in insects exposed to ICIPE 18 (62.8%) and ICIPE 69 (61.8%) than in those exposed to ICIPE 62 (42.6%), with median lethal times, (LT50) ranging between 6.73–8.54 days. The control group recorded the lowest mortality rates (18.9%). A general linear reduction in conidial viability with exposure time was observed, although this was more pronounced with M. anisopliae ICIPE 62. Insects exposed to M. anisopliae ICIPE 69 also recorded the highest conidia uptake, hence selected for further evaluation with a T. vaporariorum attractant volatile organic compound, (E)–2–hexenal. The volatile inhibited fungal germination in laboratory compatibility tests, therefore, spatial separation of M. anisopliae ICIPE 69 and (E)–2–hexenal in the autodissemination device was conducted. The inhibitory effects of the volatile were significantly reduced by spatial separation at a distance of 5 cm between the fungus and the volatile, which was found to be more suitable and chosen for the subsequent experiments. Results showed that (E)–2–hexenal did not influence conidia uptake by the insects, while fungal viability and the subsequent mortality variations were more related to duration of exposure. The fungus–volatile compatibility demonstrated with spatial separation provides a basis for the optimisation of the volatile formulation to achieve better T. vaporariorum suppression with an excellent autodissemination efficiency when used in the management of whiteflies under screenhouse conditions.

First Report of <i>Cladosporium dominicanum Zalar</i>, de Hoog & Gunde-Cim. Infecting Whitefly on Ornamental Plants in Bali, Indonesia

“…An in vitro study was carried out to assess the pathogenicity of an A. aleyrodis isolate against blackfly and whitefly (Bhosale et al 2020). On the other hand, Metarhizium has reportedly been highly effective in controlling whiteflies (Paradza et al 2021(Paradza et al , 2022. The pathogenicity of dry conidia and fungal suspensions of ten strains Metarhizium anisopliae and six strains Beauveria bassiana strains were evaluated against adults and second instar nymphs of the greenhouse whitefly (Paradza et al 2021).…”

Integrating Metarhizium anisopliae entomopathogenic fungi with border cropping reduces black bean aphids (Aphis fabae) damage and enhances yield and quality of French bean

“…Natural pest regulation using biological agents such as predators, parasitoids, or entomopathogenic fungi and companion planting as an intercrop or border crop present safe alternatives to synthetic pesticides [ 16 ]. Several species of entomopathogenic fungi (EPF) have been studied for use as an eco-friendly strategy for management of a wide range of agricultural pests [ [17] , [18] , [19] , [20] ] presenting an opportunity to be used to manage insect pests such as aphids. Entomopathogenic fungi are a beneficial group living in the soil that infects insects by penetrating insect cuticles and their bodies to eventually kill the pest [ 21 ].…”