Indirect control of the ground-pearl Eurhizococcus brasiliensis (Wille, 1992) (Hemiptera: Coccomorpha: Margarodidae) using ants toxic baits.

Linepithema micans (Forel, 1908) (Hymenoptera: Formicidae) is the main ant species responsible for spreading the ground pearl, Eurhizococcus brasiliensis (Wille, 1992) (Hemiptera: Margarodidae). The effect of different formulations of hydramethylnon toxic baits (TB) was evaluated on the control of L. micans and E. brasiliensis. Four formulations of TB were evaluated in a greenhouse to control L. micans. Based on the greenhouse experiment results, the small pellet formulation of the TB was selected to be evaluated, through weekly applications, in two vineyards naturally infested by L. micans and E. brasiliensis. Later, in order to establish the number of applications, 1, 3, 6 and 10 applications in the season were evaluated. The bait treatments were compared with the number of ants and ground pearls counted on one area free of TB and one area with the drench application of thiamethoxam. Hydramethylnon (0.5%) TB in the small pellet (SP) and large pellet (LP) formulations were the most efficient in L. micans control. The SP TB, applied six times during the vine cycle, effectively control the number of L. micans, reducing 100% of the ant population, as well as the E. brasiliensis, reducing 99.9% of the scale population on plants. Keywords: Linepithema micans, ground pearl, dispersal, hydramethylnon, pest management.