Factors affecting captures of male citrus leafminer, Phyllocnistis citrella Stainton, in pheromone-baited traps L. L. Stelinski & M. E. Rogers Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, FL, USA Introduction The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a world-wide pest of citrus (Heppner 1993) described originally in India (Stainton 1856). In the USA, it was initially found in Homestead, Florida and parts of Dade, Broward and Collier counties in 1993 (Heppner 1993). Its distribution is now widespread across Florida in citrus-growing regions, and is spreading throughout the Gulf Coast and into Alabama, Lou- isiana, Texas and west to California (Gil 1999); in 2000 it was also recorded in Hawaii (Nagamine and Heu 2003). P. citrella attacks all varieties of citrus as well as other Rutaceae and certain orna- mentals; however, grapefruit, tangerine and pum- ello are the most susceptible hosts (Legaspi and French 2003). Keywords leafminer, mating disruption, monitoring, pheromone traps Correspondence Dr Lukasz Stelinski (corresponding author), Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA. E-mail: stelinski@ufl.edu Received: August 19, 2007; accepted: November 7, 2007. doi: 10.1111/j.1439-0418.2007.01258.x Abstract The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillar- iidae), is an important world-wide pest of citrus. Larval mining within leaf flush impacts yield and predisposes trees to infection by citrus can- ker, Xanthomonas axonopodis pv. citri. The present series of studies sought to identify factors affecting male P. citrella catch in pheromone-baited traps with the intent of developing effective monitoring. A commercially available pheromone lure (Citralure, ISCA Technologies, Riverside, CA, USA) was highly effective in attracting male P. citrella to traps. Pherocon VI Delta (Tre ´ce ´ Inc., Adair, OK, USA) traps baited with a Citralure cap- tured more male P. citrella than identically baited Pherocon IC Wing traps (Tre ´ce ´ Inc.). The superiority of the Delta-style trap was found to be due to a 3 cm long closing latch that likely prevents males from fly- ing directly through the trap without capture. Within canopies of mature citrus trees (approximately 3.5 m high), traps at mid-canopy height (2.0 m) captured more males than traps placed higher (3.5 m) or lower (0.6 m). On the canopy perimeter and in between canopies, traps near ground level (0.6 m height) captured more males than traps at 2.0 and 3.5 m heights. Male catch was greater within the tree canopy or on the canopy perimeter than 2.0 away from the canopy. Traps deployed in trees on the edge of groves captured more males than traps placed 120 and 240 m away from the grove edge and within the grove interior. In non-pheromone-treated grove plots, the optimal dosage for catching males was between 0.1 and 1.0 mg of the 3 : 1 blend of (Z,Z,E)-7,11,13- hexadecatrienal and (Z,Z)-7,11-hexadecadienal; however, in phero- mone-treated plots a higher 10.0 mg dosage lure was most effective. Male catch in pheromone-baited traps exhibited a diel rhythm with most males captured during scotophase (22:00–23:00 h) and no males captured during photophase. J. Appl. Entomol. J. Appl. Entomol. 132 (2008) 143–150 ª 2008 The Authors Journal compilation ª 2008 Blackwell Verlag, Berlin 143