Interactions of plant resistance and insecticides on the development and survival of Bactericerca cockerelli [Sulc] (Homoptera: Psyllidae)

Relatively few studies have investigated potential interactions of host plant resistance and insecticides for insect control. To examine possible interactions, host plant resistance was measured independently for four tomato cultivars and one wild tomato accession against tomato psyllids, Bactericerca [Paratrioza] cockerelli [Sulc] (Homoptera: Psyllidae). Plant lines tested included the commercial cultivars 'Shady Lady', 'Yellow Pear', '7718 VFN', 'QualiT 21' and the plant accession PI 134417. Cultivars showed variable resistance; PI 134417 was the most resistant line tested with significantly reduced developmental rates and survivorship. Insecticides tested against the commercial cultivars included a kaolin-based particle film, pymetrozine, pyriproxyfen, spinosad and imidacloprid. Although all chemicals significantly reduced egg-adult survivorship, the effectiveness of some insecticides varied between-plant lines as measured by survivorship, development time and growth index (GI) data, which indicated significant interactions between-plant lines and insecticides. For example, survivorship from egg to adult varied significantly between cultivars under pymetrozine treatment. For kaolin-based particle film applications, numbers of days required to reach the adult stage were significantly different between cultivars. GI values were also variable between cultivars for pymetrozine and spinosad. Although all chemicals tested had potential for psyllid control within an integrated pest management program, imidacloprid and pyriproxyfen worked consistently well on all cultivars tested. For the other chemicals, cultivar selection could influence pesticide efficacy.