| dc.description.abstract | The study was conducted to explore the abundance and diversity of insect pests
dwelling in boro and aman rice fields, Shahparan, Sylhet during the period from
November 2013 to April 2014 in boro rice season and May to November 2014 in
aman rice season. The results revealed that 16 and 14 different insect pest species
were found in boro and aman rice fields, respectively. The relative abundance of rice
green leafhopper (GLH) was highest in both the seasons. The highest incidence of
insect pest was observed in boro season. The average occurrence of insect pests was
higher at tillering stage (55 days after transplanting, DAT) and lower at seedling stage
(15 days after sowing, DAS) in two seasons. The Diversity Indices of insect pests
varied among the Order groups and feeding habits in two seasons. Shannon's
Diversity Index (H) and Margalef's Index of insect pest richness were found highest in
boro rice whereas, Pielou's Evenness (J) of insect pests was found highest in aman
rice. The Order Lepidoptera exhibited highest diversity and the order Coleoptera
exhibited lowest diversity in respect of Shannon's Index (H), Evenness (J) and
Richness (M.I.) for both the seasons. On the other hand, Shannon's Diversity Index
(H) and Pielou's Evenness (J) were found highest in case of defoliators and stem
sucker pests in both the seasons whereas, Margalef's Index of richness was found
highest in boro season in case of defoliators. The abundance of insect pest species
between two seasons ranked as Boro > Aman. The abundance of insect pest species
among the Orders ranked as Hemiptera > Lepidoptera > Orthoptera > Coleoptera in
boro season and Hemiptera > Orthoptera > Lepidoptera > Coleoptera in aman season. | en_US |
