Population fluctuation and damage from Grapholita molesta (Lepidoptera: Tortricidae) in two peach production systems

With the objective to know the population fluctuation of Grapholita molesta and to verify the phenological stage that the peach tree is more sensitive to the attack of the insect ill two production systems, four peach Orchards were selected, two Under the conventional production system (CP) and two Under the good agricultural practice system (GAP), in 2005/06 and 2006/07 growing seasons, in Araucaria, PR, Brazil. To verify the fluctuation, two Delta model traps were installed per orchard, halted with synthetic sexual pheromone, where the capture of G. molesta adults was recorded weekly. To determine the most sensitive phase of the peach tree to G molesta attack, the bud and fruits were evaluated on the primary branch turned to the West on twenty plants per orchard, in the thinning, stone hardening and maturing phases. The G. molesta population in the 2005/2006 growing season was greater than in 2006/07, and the GAP orchards presented greater occurrences than the CP. The biggest populations of the insect occurred postharvest. The maturation phase was the most susceptible in both production systems, but there was a lower percentage of damage to the GAP orchards.