Comparison of two different spray volumes for the control of the whitefly Paraleyrodes minei (Hemiptera: Aleyrodidae)in citrus crops

Abstract: The presence of the whitefly Paraleyrodes minei (Hemiptera: Aleyrodidae) has increased significantly in citrus orchards of the Valencian Community. This situation forced us to look for a control strategy for this whitefly. In this paper we assess the efficacy of two different volume sprays, 1,000 l/ha and 2,000 l/ha, for the control of Paraleyrodes minei. Movento 150 O-teq (spirotetramat) at 0.05% was applied on 23th October 2015. The population was sampled by observing 50 branch segments containing 4-5 leaves each, and determining the percent of leaves infested and the percent of surface area occupied in the most infested leaf of each branch segment. Overall, the impact of the sprays on P. minei populations was low, reaching its maximum between 19 and 35 days after treatment. The efficacy values obtained were insufficient for controlling the population or reducing the damage. This can be due to the chemical used or to the natural resistance of the insect, which makes its control with chemicals difficult. The high volume performs slightly better than the low volume, so we recommend spraying P. minei with high volume (2,000 l/ha) to maximize the efficacy.