Phosphine resistance in the cigarette beetle<i>Lasioderma serricorne</i>(Coleoptera: Anobiidae) and overcoming control failures during fumigation of stored tobacco

A new assay method was developed for easily and precisely determining whether beetles were knocked down (define knockdown) by phosphine fumigation for the purpose of evaluating the phosphine resistance of the cigarette beetle. The knockdown time (KT) was investigated for six strains of beetles exposed to phosphine. The susceptibilities of the six strains were investigated by checking adult mortalities from phosphine exposure. One strain showed high resistance and almost all beetles survived even at 1,000 ppm. The KT 50 values of the high resistant strain exposed to 100, 200 and 300 ppm phosphine were 32,800, 5,000 and 3,650 min, respectively. The KT 50 values of susceptible and low resistant strains, with LC 50 values lower than 50 ppm, were smaller than 250 min even at 100 ppm. The KT 50 values of the middle resistant strain, with an LC 50 value of 140 ppm, were 920, 340 and 290 min at 100, 200 and 300 ppm, respectively. The time difference between the low resistant beetles knocked down last and the highly resistant beetles knocked down first was 86, 18 and 8 h at 100, 200 and 300 ppm, respectively. The probit regression line for the middle resistant strain lay between that of the susceptible strain and that of the highly resistant strain, although it was nearer to that of the susceptible strain.

Section: Introductionmentioning

confidence: 99%

Development of a new assay method for quickly evaluating phosphine resistance of the cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), based on knockdown of the adult beetles

Hori

Kasaishi

2005

“…Phosphine fumigation is the only applicable method for disinfestation in warehouses. Nevertheless, resistant beetles have continued to spread, and present fumigation techniques are becoming less efficient (Rajendran and Narasimhan, 1994;Zettler and Keever, 1994). In addition to the emerging difficulty of resistance, public concern has been growing regarding the potential health and environmental hazards of pesticides.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature as an alternative to fumigation to disinfest stored tobacco of the cigarette beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae)

Imai

Harada

2006

Time-temperature-mortality relationships for egg, larval, pupal, and adult stages of the cigarette beetle, Lasioderma serricorne were investigated to determine disinfesting conditions for stored tobacco. Susceptibility to low temperatures changed according to the developmental stage. Eggs were most susceptible to low temperatures that were higher than Ϫ5°C. Larvae acquired cold tolerance during exposure to 15°C for 1 mo. These acclimated larvae were the most tolerant of all. LT 99 values of acclimated larvae were calculated as 7.2 h at Ϫ15°C, 23.7 h at Ϫ10°C, 376 h at Ϫ5°C, 1,140 h at 0°C, and 1,880 h at 5°C. As the most susceptible stage, egg susceptibility to moderately low temperatures (16-20°C) was specifically examined. At 20°C, most eggs (Ͼ80%) normally hatched within 4 wk, but all eggs died within 6 wk at temperatures less than 18°C. This fact indicates that the reproductive cycle can be blocked at temperatures less than 18°C, and that tobacco stored in such conditions will never become infested, even if eggs are deposited by invading adults. Consequently, if the tobacco temperature is reduced to 5°C for 3 mo in winter and is subsequently maintained below 18°C throughout the rest of the year, tobacco can become and remain pest-free without any chemical control.

“…Recently, the emergence of phosphine-resistant cigarette beetles has been confirmed in all parts of the world; for example, in India (Rajendran and Narasimhan, 1994), USA (Zettler and Keever, 1994) and also in Japan (Hori and Kasaishi, 2005). For successful fumigation of the beetles with phosphine, it is important to evaluate the resistance of the beetles' population beforehand.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the phosphine resistance level of the cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), by the knockdown time of adult

Hori

Kasaishi

2005

In a previous study, the assay method was developed for determining easily and precisely whether cigarette beetles are knocked down by phosphine fumigation. In the study, it was shown that knockdown times and mortalities of adults exposed to phosphine fumigation were closely correlated to each other. However, it is important, for successful fumigation, to evaluate the susceptible level of eggs in the beetles' population beforehand because eggs are the least susceptible stage to phosphine of all the life stages of the beetle. Therefore, we investigated the correlation between the lethal concentration (LC) of eggs and the knockdown time (KT) of adults. The susceptible level to phosphine was investigated by a mortality test and a knockdown test for 15 strains. The correlation between the log LC of eggs and the log KT of adults was shown by the following logistic function showing a correlation coefficient of 0.933: log LCϭ0.370ϩ(2.743Ϫ0.370) / [1ϩexp{Ϫ2.155ϫ(log KTϪ2.521)}]. It was suggested that the substitution of the value of log KT 99.9 into the above logistic function yielded sufficient information for determination of the most appropriate phosphine concentration for successful fumigation.