ประสิทธิภาพของเหยื่อล่อที่ใช้ในการดึงดูดมอดยาสูบ (Lasioderma serricorne Fabricius)

Abstract

The objectives of this experiment are 1.) to study the suitable survival rate of cigarette beetle (Lasioderma serricorne F.); 2.) to study the responses of food sources of cigarette beetle and 3.) to study insect response to the potential food sources combined with female pheromone and 2-sex pheromone of cigarette beetles. In experiment 1, for the survival rate of insects was conducted in tobacco go down in San Sai district, Chiang Mai province during July 2021 to June 2022. The measurement of go down temperature (indoor) was classified into 3 seasons; summer season (28.24±6ºC) rainy season (27.61±5ºC) and winter season (23.85±7ºC). Then cigarette beetle was examined when fed with food sources as followed; 1.) Virginia tobacco, 2.) Burley tobacco, 3.) Turkish tobacco, 4.) roll you own tobacco (RYO tobacco), 5.) Virginia strip and 6.) Burley strip. The life table of cigarette beetles was analyzed. The net reproductive rate (R0) among the food sources are not significantly different. The potential of high R0 was found in Virginia tobacco which is higher than in Turkish and Burley. In summer time, it showed higher R0 than in rainy and winter time. The mean of generation time or T value which shows time for increasing insect population took longer in winter season than in rainy and summer season. The intrinsic increase rate (r) and finite rate of increase (λ) which presented the increasing of population in each time were higher than in rainy and winter seasons. Cigarette beetle spent time for population doubling in summer season shorter than in rainy and winter season. In another word, the cigarette beetle spends shorter time in each food source to increase double population in summer.

The age specific survival rate, rate of insect hatching from egg and developing to further stage or lx of cigarette beetle was highest in Turkish tobacco in winter season, Virginia and Burley in summer season (80 days) while in the rainy season the survival rate of RYO tobacco and Burley tobacco was low (40 days). For the age of specific fecundity or mx which is the average number of eggs in entire of population, the cigarette in rainy season fed on Virginia tobacco strip starts to lay egg earlier in day 20 followed by the Burley tobacco strip = Roll Your Own tobacco (day 30) <Turkish tobacco =Burley tobacco and Virginia tobacco (day 40). In summer, cigarette beetles develop themselves faster in Virginia tobacco (20 days) and slower in rainy season (40 days) while in the winter season insect slowly developed for 60 days.

In the experiment 2, the response of cigarette beetle to food baits were done in laboratory using olfactometer and the Excess-proportion indexes (EPI) were calculated. Thirteen food baits composed of 1.) Virginia tobacco, 2.) Burley tobacco, 3.) Turkish tobacco, 4.) Virginia tobacco strip, 5.) Burley tobacco strip, 6.) Roll your own (RYO) tobacco, 7.) wheat flour, 8.) parchment coffee, 9.) soybean, 10.) feed corn, 11.) job’s tears, 12.) dried mulberry leaves and 13.) Garlic. The eight-armed airflow olfactometer was conducted in 3 times; 8.00-12.00 (morning), 13.00-16.00 (afternoon) and 18.00-20.00 (evening). Experiment was done for 3 replicates. The results showed that food sources non- significantly attracted cigarette beetles in afternoon with the EPI at 0.88 higher than in morning time at 0.73 and evening at 0.67. The Burley tobacco strip, job’s tear and wheat flour showed potential to be food attractant of cigarette beetles.

In the experiment 3, the three food attractants were tested alone and combined with female sex pheromone of cigarette beetles in Y shape olfactometer individually. The result showed that female pheromone combined with food attractants were higher number of insects caught significant difference from pheromone alone. On the other hand, the female pheromone combined with food attractants did not show significant different from 2-sex pheromone alone.

In conclusion, cigarette beetles develop their growth well in Virginia tobacco and Turkish tobacco in summer and rainy season but different better from in winter season. The factors of food attractants involved in potential of insect caught in female pheromone traps are not significant from 2-sex pheromone application.