The flight activity of two lepidopteron insect pests, Spodoptera litura and Helicoverpa armigera,
(Lepidoptera: Noctuidae) was monitored using sex pheromone traps during two consecutive vegetation
periods in 3 different potato field locations situated at altitudes of around 2500, 1500 and 650 mas/ in
Sindupalchowk, Kavrepa1anchowk and Dang district, respectively. Pheromone traps were installed at
three locations in each site and data were recorded at 2 days interval. Populations of the two pests
were observed the highest in Kavrepalanchowk during both vegetation period 2010111 and 2011112.
Data were pooled weekly and pheromone traps detected distinct peaks for S. litura in Sindupalchowk
on 10'h April (1034±219), Kavrepalanchowk on 6'h April (2932±224) and Dang on 20'1' November
(527±32) in 20101011. Likewise, in Kavrepalanchowk and Dang, the highest peak was observed on
22nd March (950±733) and IO'h November (747±468) during 20111012. respectively. Population of H.
armigera at Kavrepalanchowk peaked on 23nl March with an economically significant number
(373±38 per week in Tukucha VDC and 1207±359 per week in Panauti VDC) where as visible damage
was observed on potato foliage in 2011. In Dang, H. armigera moth captured reached its peak on 30'h
November (32±32 adult/week). This trend clearly indicated that these pests can outbreak at tuber
bulking and maturation stage of potato in all three ecological regions of Nepal. Therefore, these pests
cause severe economic damage during the vegetation period of the potato crop. These dates on which
the highest number of moths were trapped could be used as a benchmark to determine the occurrence
and population buikfup duration for these two species of moths. Understanding the pest population
dynamics are useful technical knowledge needed for researchers, technicians and· growers to decide
more precise timing for applying appropriate management options.

The flight activity of two lepidopteron insect pests, Spodoptera litura and Helicoverpa armigera,
(Lepidoptera: Noctuidae) was monitored using sex pheromone traps during two consecutive vegetation
periods in 3 different potato field locations situated at altitudes of around 2500, 1500 and 650 mas/ in
Sindupalchowk, Kavrepa1anchowk and Dang district, respectively. Pheromone traps were installed at
three locations in each site and data were recorded at 2 days interval. Populations of the two pests
were observed the highest in Kavrepalanchowk during both vegetation period 2010111 and 2011112.
Data were pooled weekly and pheromone traps detected distinct peaks for S. litura in Sindupalchowk
on 10'h April (1034±219), Kavrepalanchowk on 6'h April (2932±224) and Dang on 20'1' November
(527±32) in 20101011. Likewise, in Kavrepalanchowk and Dang, the highest peak was observed on
22nd March (950±733) and IO'h November (747±468) during 20111012. respectively. Population of H.
armigera at Kavrepalanchowk peaked on 23nl March with an economically significant number
(373±38 per week in Tukucha VDC and 1207±359 per week in Panauti VDC) where as visible damage
was observed on potato foliage in 2011. In Dang, H. armigera moth captured reached its peak on 30'h
November (32±32 adult/week). This trend clearly indicated that these pests can outbreak at tuber
bulking and maturation stage of potato in all three ecological regions of Nepal. Therefore, these pests
cause severe economic damage during the vegetation period of the potato crop. These dates on which
the highest number of moths were trapped could be used as a benchmark to determine the occurrence
and population buikfup duration for these two species of moths. Understanding the pest population
dynamics are useful technical knowledge needed for researchers, technicians and· growers to decide
more precise timing for applying appropriate management options.