Population Ecology Of Brown Planthopper (Nilaparvata Lugens Stal) And White Backed Planthopper (Sogatella Furcifera Horvath) In Myanmar
The ecological studies on the brown planthopper (BPH) Nilaparvata lugens (Stal) (Hemiptera: Homoptera) and the white backed plant hopper (WBPH) Sogatella furcifera (Horvath) (Hemiptera: Homoptera) were carried out in Myanmar. BPH is one of the major pests of rice and damage by this pest could cau...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2010
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/12414/1/FP_2010_9A.pdf |
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| Summary: | The ecological studies on the brown planthopper (BPH) Nilaparvata lugens (Stal)
(Hemiptera: Homoptera) and the white backed plant hopper (WBPH) Sogatella
furcifera (Horvath) (Hemiptera: Homoptera) were carried out in Myanmar. BPH is
one of the major pests of rice and damage by this pest could cause hopper burns due
to intensive sucking of the plant. This suggested an urgent need for alternative
control measures besides using chemical insecticides. This study was conducted with
the objectives to establish the biological life tables of BPH and WBPH, investigate
their feeding and movement behaviours and examine the relationships between
population fluctuations, host plant, rainfall and humidity in the field. The studies
were conducted in an unsprayed rice field at Hmawbe Research Area, Myanmar from
July 2007 to May 2008. Age specific survival and fecundity rates of BPH and WBPH
were measured under field conditions. A life table was constructed using single sex
methods. The population parameters of BPH fed on rice showed that the intrinsic rate
of natural increase (rm) of BPH was 0.0677 per female per day. The daily finite rate of increase (λ) was 1.07 females per female per day with mean generation time (T) of
34.64 days. The net reproduction rates (Ro) of the population was 10.02. The
population doubling in time (DT) was within 10.42 days. The population parameter
of WBPH fed on rice showed that the intrinsic rate of natural increase (r m) of WBPH
were 0.0699 per female per day. The daily finite rate of increase (λ) was 1.0255
females per female per day with mean generation time (T) of 34.97. The net
reproduction rates (Ro) of the population was 9.2732. The population doubling time
(DT) was within 10.88 days. Feeding behaviour studies suggested that in both choice
and no choice experiments, the patterns of feeding lesions between BPH and WBPH
were quite similar. Higher numbers of feeding lesions were observed on 30 day old
plants than 45 day and 60 days old plants. More feeding on leaf sheath than on leaf
blade was observed for both planthoppers. In the movement behaviour study, it was
revealed that BPH adults were found to be more active than the nymphal instars. In
older rice plants, the highest movement (4.7 cm per two hours) was observed on 60-
day-old plants and lowest (2.7 cm per two hours) on 30-day-old plants. Increased
movements of planthoppers were observed at 13:00hrs. Population fluctuation study
revealed that BPH population was high at 64 and 74 DAT (in mid September 2007)
associated with heavy rainfall, high temperature and high humidity. The population
was lowest at 138 DAT (in the mid week of October 2007) suggesting that low
rainfall and low humidity were, at least partially responsible for the decrease
population of the BPH. During the dry season, the population was low at 8 DAT
(early week of January 2008) and then increased at 31 DAT (first week of February
2008). However, the population declined at 56 DAT and increased to moderate
numbers at 86 DAT. The population development trend of WBPH was almost similar
to those observed for BPH. During the dry season, the highest WBPH population was recorded at 90 DAT and the lowest at 33 DAT. During the first cropping coinciding
with the rainy season, the fluctuation of planthoppers was correlated with
temperature and rainfall. During the second cropping coinciding with the dry season,
there was no rainfall and planthoppers population was observed to be correlated to
temperature and relative humidity. Therefore, temperature, rainfall and relative
humidity influenced planthopper populations during two different rice growing
seasons. |
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