CONTACT TOXICITIES OF FIVE PYRETHROID AND FOUR ORGANOPHOSPHOROUS INSECTICIDES TO TOUMEYELLA PARVICORNIS (COCKERELL) CRAWLERS

The use of pyrethroids in southern pine seed orchards to control seed and cone insects has sometimes resulted in outbreaks of scale insects (Nord et al. 1985). Onset of these infestations has been related in part to the relatively low contact toxicities of pyrethroids (Clarke et al. 1988). Pyrethroids have lower contact toxicities than organophosphorous insecticides against crawlers of the striped pine scale, Tourneyella pini (King). Our objective was to determine if a similar relationship existed for the pine tortoise scale, Tourneyella parvicornis (Cockerell), another scale insect pest that infests southern pine seed orchards.