MANAGEMENT OF A POPULATION OF AUSTRALIAN COCKROACH (PERIPLANETA AUSTRALASZAE) IN A TROPICAL PLANT HOUSE IN THE UK

Abstract:
The control of a population of Australian cockroaches, Periplaneta australasiae, causing serious damage to valuable plant species in a UK tropical plant house, was attempted using a combination of trapping and spraying with an insect growth regulator. After determining the degree and extent of infestation using sticky monitoring traps, the population was significantly reduced over a six week period of intensive trapping. The plant house was then treated every three months with hydroprene, an insect growth regulator applied as a ULV cold mist. Over the next 12 months the cockroach population, assessed by trapping, was reduced by 38.5% while the percentage of adults exhibiting wing-twisting, indicative of juvenile hormone effect: increased from 0.7% to 66.3%. The number of small nymphs recorded in traps during the trial fell by 35.3%. A difference between the wing-twisting effect in males and females was recorded, with females apparently more susceptible to the insect growth regulator, with indications that female longevity was reduced as a result, leading to an imbalance in sex ratio. Wing-twisting was not a reliable indicator of reproductive inability. The hydroprene treatment had no negative impact on the effectiveness of the biological control programme employed at the site to manage other plant pest species. The findings, in terms of cost, practicability and success, are discussed in relation to wider applications in public health pest control.