Life table parameters and mortality factors of potato psyllid (Bactericera cockerelli) on potato and tomato under laboratory and field conditions in the LRGV of Texas

Management of potato ‘Zebra Chip’ disease caused by Cadidatus Liberibacter Solanacearum depends largely on the management of its vector insect, potato psyllid (Bactericera cockerelli). In order to test the biotic or abiotic factors affecting the mortality of B. cockerelli, the life table parameters were determined on potato and tomato under both the laboratory and field conditions from March to May 2008 and 2009 in the Lower Rio Grande Valley (LRGV) of Texas. Under field conditions, the mortality factors were mainly categorized as missing, dislodgement, predation, parasitism (for nymphs only), natural death, and egg inviability. Compare to the laboratory life table results, the number of eggs were largely declined due to the meteorological factor of wind. Furthermore, the predators, including spiders, ladybeetles, and lacewings, were most often observed during the investigation. Parasitism by Tamarixia triozae (Eulophidae) was also found mainly on 4th or 5th instar of B. cockerelli nymphs. Based on the major life table parameters, the B. cockerelli suffered higher mortality under the field conditions, which may indicate the biotic factors are essentially affecting the B. cockerelli population dynamic in the LRGV of Texas.