Citation: Kabaale, F.P.; Tumuhaise, V.; Tinzaara, W.; Turyasingura, G.; Subramanian, S.; Khamis, F.M.; Akutse, K.S. First Report of Field Efficacy and Economic Viability of Metarhizium anisopliae-ICIPE 20 for Tuta absoluta (Lepidoptera: Gelechiidae) Management on Tomato. Sustainability 2022, 14, 14846. https://doi.org/10.3390/ su142214846 Academic Editor: Sean Clark Received: 23 September 2022 Accepted: 7 November 2022 Published: 10 November 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article First Report of Field Efficacy and Economic Viability of Metarhizium anisopliae-ICIPE 20 for Tuta absoluta (Lepidoptera: Gelechiidae) Management on Tomato Fred Peter Kabaale 1,2,3 , Venansio Tumuhaise 2, *, William Tinzaara 2 , Geoffrey Turyasingura 4 , Sevgan Subramanian 1 , Fathiya Mbarak Khamis 1 and Komivi Senyo Akutse 1, * 1 International Centre of Insect Physiology and Ecology (icipe), Nairobi P.O. Box 30772-00100, Kenya 2 Department of AgricultureProduction, Faculty of Agriculture, Kyambogo University, Kyambogo P.O. Box 1, Uganda 3 National Teachers’ College, Kaliro P.O. Box 65, Uganda 4 Department of Crop Production and Management, Faculty of Agriculture and Animal Sciences, Busitema University, Arapai Campus, Soroti P.O. Box 203, Uganda * Correspondence: venanceus@gmail.com (V.T.); kakutse@icipe.org (K.S.A.); Tel.: +256-782-844-673 (V.T.); +254-799-716-741 (K.S.A.) Abstract: Eco-friendly pest control options are highly needed in food crop production systems to mitigate the hazards of synthetic chemical pesticides. Entomopathogenic fungal biopesticides— Metarhizium anisopliae strains ICIPE 20 (oil-formulation containing 1.0 × 10 9 conidia/mL) and ICIPE 69 (commercialized biopesticide known as Mazao Campaign ® )—were evaluated against Tuta absoluta on tomato through inundative foliar spray and compared with the commonly used pesticide Dudu Acelamectin 5% EC (Abamectin 20 g/L + Acetamiprid 3%) and untreated plot. All the treatments were arranged in a randomized complete block design with three replicates. The field experiments were conducted for two consecutive cropping seasons in Mukono district, Uganda. Tuta absoluta infestation, injury severity on leaves and fruits, fruit yield loss, marketable fruit yield gain and cost– benefit ratio of the treatments were assessed. The results during both seasons showed a significant lower fruit yield loss in M. anisopliae ICIPE 20-treated plots compared to untreated plots, with a marketable fruit yield gain exceeding 22% and a cost–benefit ratio greater than 2.8 (BCR~3). Dudu Acelamectin 5% EC outperformed all the other treatments, but needs to be considered with caution due to its non-target effect and resistance development, whereas M. anisopliae ICIPE 69 performed the least well. In addition, the findings showed the high degree of efficacy and economic viability of these biopesticides as a potential T. absoluta control option in the field. However, it is important to further explore different formulations of these eco-friendly biopesticides, inoculum delivery approach, application frequency, their effectiveness in different agro-ecological zones and compatibility with commonly used pesticides in tomato production systems for sustainable management of T. absoluta. Keywords: Metarhizium anisopliae; biopesticide; entomopathogen; Tuta absoluta; fruit yield loss; marketable fruit yield gain; cost–benefit ratio 1. Introduction Tomato (Solanum lycopersicum L.) is grown and consumed worldwide for its nutritional and health benefits to humans [1,2]. Socioeconomically, the crop is a source of livelihood to many rural, peri-urban and urban farmers. In Africa, tomato yield loss due to biotic stress has been worsened by the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) [3]. Tomato is the primary host of this pest [4,5] onto which the larvae instars penetrate all aerial parts (stems, leaves, flowers and fruits) during cryptic feeding. This invasive pest from South America [6], if not aptly managed, could cause yield loss as high as 100% in certain situations [7,8]. In addition, it is classified as a quarantine pest which Sustainability 2022, 14, 14846. https://doi.org/10.3390/su142214846 https://www.mdpi.com/journal/sustainability