Nepid Consultants, P.O. Box 4349, White River, 1240, South Africa; Institute for Water Research, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa
Palmer, R.W., Nepid Consultants, P.O. Box 4349, White River, 1240, South Africa; Rivers-Moore, N.A., Institute for Water Research, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa
PALMER, R.W. & RIVERS-MOORE, N.A. 2008. Evaluation of larvicides in developing management guidelines for long-term control of pest blackflies (Diptera: Simuliidae) along the Orange River. Onderstepoort Journal of Veterinary Research, 75:299-314 In 2000 and 2001 Orange River levels were higher than normal: associated serious outbreaks of blackfly had a substantial detrimental impact on the local economy. The poor control was attributed to the suspected development of larval resistance to temephos. A long-term solution to blackfly control, through the identification of a suitable replacement to temephos for use during high flow conditions, was proposed. This study, however, failed to identify or register a suitable larvicide for use during high flow conditions. Although permethrin was highly effective against blackfly larvae, it was rejected because of its detrimental impacts on non-target fauna. Various formulations of locally produced dry Bacillus thuringiensis var. israelensis (B.t.i.) were tested, but these were ineffective against blackflies. The study also confirmed that resistance to temephos has developed among Simulium chutteri in the middle and lower Orange River. The feasibility of "reversing" the resistance to temephos through the use of the synergist piperonyl butoxide (PBO) was investigated, but the results were not favourable. Furthermore, PBO was highly toxic to blackflies and non-target organisms, and was not recommended for further testing. This means that B.t.i. currently remains the only symptomatic measure of treatment currently applied. Although resistance to B.t.i. has not been reported for blackflies elsewhere in South Africa, there is a need to remain vigilant and to implement an operational strategy that minimizes the risks of resistance developing.
insecticide; temefos; animal; animal disease; article; Bacillus thuringiensis; biological pest control; epidemic; fly; growth, development and aging; insecticide resistance; larva; methodology; microbiology; pest control; physiology; prevalence; South Africa; treatment outcome; Animals; Bacillus thuringiensis; Disease Outbreaks; Insecticide Resistance; Insecticides; Larva; Pest Control; Pest Control, Biological; Prevalence; Simuliidae; South Africa; Temefos; Treatment Outcome; Bacillus thuringiensis; Bacillus thuringiensis serovar israelensis; Diptera; Simuliidae; Simulium chutteri