First Report of Field Efficacy and Economic Viability of Metarhizium anisopliae-ICIPE 20 for Tuta absoluta (Lepidoptera: Gelechiidae) Management on Tomato

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 × 109 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.