Pheromones and their use in temperate fruit pest management.
1987
Bhardwaj S.P.
The objective of the present study was to provide information on the optimal trap density and determine critical catch levels for spray timing on which no information is available. Pheromone 1C traps were positioned in the upper half and on the periphery of tree canopy (5.3 m above ground). One capsule containing 1 mg of pheromone was placed in each trap for eight weeks. The trapped moths were counted once a week and removed. The catch of Archips promivora increased with the number of traps/unit area. Trap density of 4/ha and 0.25/ha captured the highest and lowest number of moths, respectively. The percent cumulative catch of A. pomivora over the previous catch in subsequent weeks of observation exhibited a sharp increase up to a trap density of 1/ha and reached almost a plateau. A. pomivora was present from April-November but most abundant during May, July and September. Lymantria concolor was present from July-September. The fruit infestation was found to be highly correlated to A. pomivora catch. A cumulative catch of 100-103 moths/trap from July-September corresponded to 1 % fruit infestation. An application of contact insecticide during last week of May when the cumulative moth catch beginning from April exceeds 100/trap, was suggested for A. pomivora. A single spray of contact insecticide during September if the L. concolor catch exceeded 4/trap/week for two consecutive weeks, was also suggested. The studies indicate that optimal trap density is one of the key factors which influence the magnitude of the catch and critical catch levels corresponding to economic injury levels should be determined for standardized monitoring systems employing pheromone traps.
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