{'fraction_non_alphanumeric': 0.02204261572373255, 'fraction_numerical': 0.01322556943423953, 'mean_word_length': 5.548076923076923, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Resistance potential of Culex quinquefasciatus against the insect growth regulators methoprene and diflubenzuron

Bioassay procedures for the insect growth regulators diflubenzuron (a chitin synthetase inhibitor) and methoprene (a juvenile hormone mimic) were evaluated on the mosquito Culex quinquefasciatus Say to determine the most sensitive larval stages and the effects of varying exposure periods. Sensitivity to diflubenzuron decreased gradually during instars I and II; instars III and IV were relatively insusceptible. Sensitivity to methoprene increased with larval age. Standard test procedures were devised for diflubenzuron involving continuous exposure from the early third instar and for methoprene as 6 h exposure during instar IV. Selection for ten generations of strains from Dar‐es‐Salaam which were multiresistant to insecticides increased the LC50 to diflubenzuron by 2.8‐fold and increased the LC50 to methoprene by 3.9‐fold. When compared to a standard susceptible strain from Colombo the resistance ratios of Dar‐es‐Salaam strains rose from 2.4 × to 6.6 × for diflubenzuron and from 6.1 × to 21.3 × for methoprene, with no significant effects detected on the pattern of cross‐resistance. These results are discussed in relation to standardization of IGR testing and the need for integrated control programmes against Cx quinquefasciatus.