Immersion time of cysts in metidathion solution to control ground-pearl Eurhizococcus brasiliensis

Abstract

The root immersion of grapevine seedlings in insecticide solution is a pre-planting technique
recommended to control some eventual infestation of ground-pearl, Eurhizococcus brasiliensis (Hempel) (Homoptera: Margarodidae). However the minimum time in order to get 100% of insect mortality as well as the eventual insect protection against insecticide in clods must be determined. Clean and incrusted cysts of ground-pearl were immersed for zero, 1, 10, 60, and 120 seconds in a 0.08% a.i. metidathion solution. Incrusted cysts in fungi coat were
used to simulate the clod protection against insecticide. Each experimental unit, replicated three times, had 20
clean cysts or almost 10 incrusted cysts. The number of death cysts was checked in 15 or 20 days intervals and was transformed in percent of insect mortality. The percentage of insect mortality was proportional to the immersion time in insecticide solution and the time of 120 seconds resulted in 100% mortality, for both clean and incrusted cysts. So 120 seconds is the minimum time for grapevine root immersion in metidathion solution in order
to control 100% of ground-pearl infestation.