EFFECT OF THE FORMAMIDINE ACARICIDE CHLORDIMEFORM ON MOBILITY AND CHEMORECEPTION OF HETERODERA-SCHACHTII MALES (NEMATODA, HETERODERIDAE)

Incubation of Heterodera schachtii with 500 mumol/l chlordimeform for 120 min caused a significantly reduced sex pheromone reception from 30 min until the conclusion of a 120 min bioassay. When 5 mmol/l chlordimeform was applied for 30, 60 or 120 min, significant differences between treated and untreated males were observed at all times. A 30 min incubation of males with 5 mmol/l chlordimeform and 10 mmol/l octopamine significantly increased reception of sex pheromone compared with chlordimeform controls from 60 to 120 min after beginning the test. Males pretreated with chlordimeform were almost totally paralyzed. Although most regained normal mobility during the test, a significant reduction in the reception of sex pheromone persisted. It is hypothesized that chlordimeform binds to octopamine receptors at synapses of chemosensory head neurons and motor neurons.