- Author: Shimat Villanassery Joseph
Citrus leafminer, Phyllocnistis citrella, is yet another invasive insect recently found attacking lemon trees in Salinas. It was first detected in Imperial County in 2000. As per 2012 Monterey County crop report, lemon acreage is 1,239 with the total value of $15.2 million. This miner larva makes serpentine mines (as it leaves frass) on the citrus leaves (photo 1) and prefers young foliage. As the name suggests, it mostly attacks citrus such as oranges, mandarins, lemons, limes, grapefruit, kumquat and calamondin. Mature larva (Photo 2) moves close to the edge of the leaves, folds the leaf margin (Photo 3) and pupates (Photo 4). Adults are short lived (2 weeks maximum). Upon emergence from pupae, female attracts male by emitting sex pheromone, mates and lays eggs on the underside, midvein of the young leaves.
Damage from citrus leafminer is not considered serious. Mature trees have plenty of foliage to cope with substantial levels of infestation but severe infestation on young trees may retard growth. Chemical management for citrus leafminer is not often necessary because naturally occurring biological control agents such as parasitic wasps suppress leafminer infestation. Pheromone traps are commercially available to monitor their populations.
Further reading:
For garden and landscape folks: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74137.html
For commercial citrus growers: http://www.ipm.ucdavis.edu/PMG/r107303211.html