Influence of spray volume and oil concentration on the efficacy of petroleum spray oil against <i>Myzus persicae</i> (Sulzer) (Hemiptera: Aphididae)

Abstract

A Potter spray tower was used to assess the efficacy of petroleum spray oils against the green peach aphid, Myzus persicae . Increasing spray volume (1.00–5.65 mL) of C23 D‐C‐Tron NR resulted in a significant ( P &lt; 0.001) increase in aphid mortality when oil deposits were held constant (40 g/cm 2 ). The practical implications of this result are discussed. LC95 (μg oil/cm 2 ) values of 107, 147 and 87 against C20 Total Citrole, C21 Caltex Lovis and C23 Ampol D‐C‐Tron NR, respectively, were calculated using a 35 mm Petri dish. These values are higher than those previously recorded for M. persicae using a large 70 mm Petri dish which restricted air flow and reduced deposit.