Leafminers (Liriomyza spp.) are important insect pests of lettuce. Major leafminer species in the Coastal lettuce is Liriomiza langei. Adult leafminers are small flies with yellow triangular spots between wings (Fig. 1). These flies lay eggs inside lettuce leaves. Leafminer adult flies puncture leaves to suck up plant sap, causing holes or bumps on the leaves, while the hatched larvae (maggots) feed inside leaves causing tunnels (mines). Feeding damage caused adults and larvae provide entrances of disease organisms and can render the lettuce unmarketable.
Chemical control is an important component in the integrated management of leafminers. Due to the emergence of insecticide resistance, introduction of novel insecticides with distinct modes of action into the current system for control of leafminers is urgently needed. We recently started a project to evaluate novel insecticides and their mixtures with other insecticides against leafminers in lettuce (Fig. 2). These include cyazypyr (a novel chemistry that has not been registered in lettuce), Coragen, Durivo (a pre-mixture of active ingredients from Platinum and Coragen), Voliam Xpress (a pre-mixture of active ingredients from Warrior and Coragen). Trigard and Agri-mek were applied as comparisons. Broader spectrum of insect pest control is expected from these mixtures. We expect to finish this trial in late August.
Fig. 1. Adult leafminers are small flies with yellow triangular spots between wings.
Fig 2. We recently started a project to evaluate novel insecticides and their mixtures with other insecticides against leafminers in lettuce.