Debugging pest control

Is any real progress being made in the development of safer and better controls for pests in the built environment? Is anyone trying to understand the ecology of pests in the artificial environments of our homes and cities? Do the control measures applied against pests in our homes really work? The Second International Conference on Insect Pests in the Urban Environment  held in Edinburgh in July 1996 addressed these issues and many others.

The proceedings of this conference have now been published, and the resulting volume is a revelation to anyone who still believes that urban pest control only exists in a world of rat catchers, yellowing fly papers and moth balls.
    The opening lecture set the tone for the conference. Entitled 'Prospects for genetic manipulation of insect vectors as a strategy for the control of vector-borne disease', the paper addressed some of the key issues facing urban pest management and suggested appropriate solutions. Although some environmental and biological controls are applied, the control of disease vectors as well as most other urban insect pests relies heavily on chemical insecticides. However difficulties which include pest resistance, environmental contamination by chemical pesticides and the high cost and time taken to develop new pesticides emphasise the need for different approaches to be developed.
    In the case of the opening lecture, as the title suggests, the new approach proposed uses genetic manipulation to influence the way in which insect vectors transmit disease organisms. For example, by focusing on the relationship between vector and disease organism genetically modifying mosquitoes in order to reduce their ability to carry or transmit malaria may be one route. Another may be to reduce the viability of the insect vector populations in the environment by introducing sexually active but sterile male mosquitoes. Female mosquitoes mate only once, and if this is with a sterile male then no fertile eggs are laid. The technique has been used for some time using chemicals or electromagnetic radiation to sterilise the males. Genetic modification may prove to be a more efficient method. Clearly however, issues related to the release of genetically modified organisms into the environment need to be addressed, and may not be overcome.
    The use of novel chemical products, biological control agents and environmental control strategies featured in several papers and in relation to many pest organisms. Thus the success of the chitin synthesis inhibitor triflumuron in the control of German cockroaches reported in one paper could be balanced against the new bait containing a nutritional metabolism disrupter (NMD) made of oxypurinol and xanthine which was tested on German cockroaches and the results reported in another paper. Could botanical extracts be used to control both mosquito vectors of the parasitic disease Filariasis and water snail vectors of the parasitic disease Schistosomiasis which inhabit the same environments? And could we see a future where the pests of stored products, furniture and textiles are suffocated by having oxygen displaced from their environments by nitrogen, rather than poisoned with chemicals?
    Clearly new ideas for the control of pests in the built environment abound. The motivation for their development, as mentioned earlier, is a combination of the development of resistance in pests, concern about the hazards of chemical pesticides and the lack of new chemical pesticides being introduced into this market. A number of papers addressed these issues in their own right. An entire session was devoted to resistance management discussing resistance in houseflies, malaria vectors, termites and cockroaches. In relating to the health and environmental hazards resulting from pesticide use in urban pest control, researchers looked at protective clothing for pest control professionals in one paper and conservation and biodiversity concerns in another. Issues relating to commercial aspects of pest control products and their registration are discussed in two papers on the new EU Biocides Directive and another discussing the importance of support for urban insecticides through generation and communication of health related information.
    Pest management as opposed to pest control also features among the papers. A session on pest management includes papers on building design as a pest reduction feature and IPM in non-agricultural pest control among others. Interestingly perhaps, according to a paper from Germany, IPM seems to have been introduced via  US Military establishments. However, the US holds no monopoly over IPM which, whether referred to explicitly or by implication features in papers from researchers based in other regions, including Europe.
    Public health pest control is of direct significance to much of the world's population, yet the economics of mosquito or fly control are far less clear than that of cotton or wheat pest control. New pesticides tend to be developed almost exclusively for the major agricultural crops and other sectors learn to adapt what is made available in the market place. Perhaps it is this somewhat 'poor relation' attitude given to the public health sector which has forced it to become more innovative. Perhaps the practitioners in this sector are less conservative in their approach to the problems they are dealing with. Whatever the reason it is gratifying to note the high proportion of low and no pesticide controls reported in these proceedings.
    The control of public health pests is clearly not a new discipline. The range and sophistication of control methods is impressive. Perhaps the only surprise from this volume is that it is reporting on only the second international conference on Insect Pests in the Urban Environment; why have there not been many more? This is a biannual event and the next will be held in the Czech Republic in 1999. It is undoubtedly a valuable forum for presentation and discussion of new thinking and new developments in public health pest control. The proceedings are a commendable representation of the conference and make fascinating reading to anyone with an interest in this very broad subject area. (MD)

Proceedings of the 2nd International Conference on Insect Pests in the Urban environment, Ed. K.B. Wildey, ICIPUE Secretariat, The Old School House, Castle Camps, Cambs CB1 6SX, UK, December 1996 £35, 640pp.

[This article first appeared in Pesticides News No. 35, March 1997, page 15]