Prager, Sean2022-09-2920222022-092022-09-29Septemberhttps://hdl.handle.net/10388/14243Pea aphids (Acyrthosiphom pisum) (Hemiptera: Aphididae) cause significant yield loss in pulse crops. However, Saskatchewan lacks the management information required to determine when control of pea aphid is necessary in faba beans (Vicia faba) and lentils (Lens culinaris Medik). To address this knowledge gap, the efficacy of three different insecticides and yield loss due to aphid infestation was assessed over two field seasons at 6 sites in the Saskatoon area. Results showed that lambda-cyhalothrin at 100g/L and lambda-cyhalothrin at 50g/L in combination with chlorantraniliprole at 100g/L significantly suppressed pea aphid populations in both crops, while cyantraniliprole at 120 g/L was less effective for population knock-down. With respect to economic thresholds, earlier control of pea aphids resulted in a better yield return. The average economic threshold (ET) for faba beans was 33 to 49 aphids per main branch of a plant and 36 ± 7 aphids per one standard sweep net on lentils. Estimated ETs provide a 7-day lead time before aphid populations exceed the economic injury level (EIL) of 610 to 936 cumulative aphid days in faba bean and 743 ±137 aphids in lentils. This project also examined the pea aphid growth rate on tannin and low tannin faba bean as well as on four varieties of small red lentils. For faba bean, pea aphid growth rate did not differ between varieties. On lentil, pea aphids had a faster development on CDC Impact and CDC Impulse when compared to CDC Maxim. In conclusion, we found that application of foliar contact insecticides can significantly reduce the base number of pea aphids in both faba bean and lentil, providing effective population control and yield loss prevention. These more accurate economic thresholds will provide growers with more information on the timing of pea aphid control relative to specific population numbers, potentially reduce unnecessary insecticide use, increase profits, and result in overall better-integrated pest management for this potentially devastating pest of pulse crops.application/pdfenPea aphid, Acyrthosiphon pisum, economic threshold, economic injury level, lentil, faba beanThesis2022-09-29