Field Evaluation of Botanical and Biorational insecticides for sustainable Management of Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) in Potato cultivation

Mohamed.elaalaoui@inra.ma EL AALAOUI¹Fatima Zahra Kamal²SAID RAMMALI³Ciobica Alin⁴Cristina Albert^5*Bodgan Novac^6*Vasile Burlui⁷Mohamed Sbaghi⁸

• ¹National Institute of Agricultural Research, Avenue Ennasr, BP 415 Rabat principal, 10090 Rabat, Mo-rocco, Rabat, Morocco
• ²Higher Institute of Nursing Professions and Health Technical (ISPITS), Casablanca, Morocco, Casablanca, Morocco
• ³Human Nutrition, Bioacives and Oncogenetics Team, Faculty of Sciences, Moulay Ismail University, Meknes 11201, Morocco, Meknes, Morocco
• ⁴Alexandru Ioan Cuza University, Iași, Romania
• ⁵Clinical Department, Apollonia University, Păcurari Street 11, 700511 Iasi, Romania, Iasi, Romania
• ⁶Faculty of Medicine, University of Medicine and Pharmacy “Grigore T. Popa”, 700115 Iasi, Romania, Iasi, Romania
• ⁷Universitatea Apollonia, Iași, Romania
• ⁸National Institute of Agricultural Research, Avenue Ennasr, BP 415 Rabat principal, 10090 Rabat, Morocco, Rabat, Morocco

The potato tuber moth Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) is a major pest threatening potato crops worldwide. This study evaluated the effectiveness of twelve treatments— including biorational insecticides, plant extracts, and their combinations—over two years (2024 and 2025) under field conditions. Treatments included Spinosad (200 cc/hL) (SD), mineral oil (1000 cc/hL) (MO), potassium salts of fatty acids (300 cc/hL) (PFA), Nicotiana glauca (NG) and Ricinus communis (RC) extracts (10% w/v), and their combinations. Applications were made five times per year, starting three weeks after planting and repeated every three weeks, using a randomized complete block design with two replicates. Parameters measured included leaf damage, larval density, canopy area, tuber number, tuber weight, and total yield. The combination of mineral oil with R. communis consistently resulted in the lowest leaf damage, reducing it to 18.2% and 15.8% at three months after the first treatment (MAFT) in 2024 and 2025, respectively. Larval density was also suppressed, with MO + RC This is a provisional file, not the final typeset article reducing larvae to 1.5 (2024) and 1.2 (2025) per plant at 3 MAFT. Canopy area remained stable across treatments in 2024 but decreased significantly in Spinosad combinations in 2025. The highest tuber number (9.4 and 9.16 per plant) and tuber weight (160.85 g and 158.73 g) in 2025 were recorded with MO + NG and MO + RC treatments. Total tuber yield peaked at 43.5 t/ha with MO + NG. These results demonstrate the superior efficacy of mineral oil combined with botanical extracts in reducing pest damage and improving potato productivity.