# Molecular identification and eco-friendly management of rice brown planthoppers in Bangladesh

## TL;DR

This study identifies rice brown planthoppers in Bangladesh and tests plant-based insecticides as eco-friendly alternatives to control them.

## Contribution

The study provides molecular confirmation of rice brown planthopper species and evaluates the efficacy of plant-based insecticides for eco-friendly pest management.

## Key findings

- Abamectin 10% caused 100% mortality in brown planthoppers.
- Neem oil at 10% concentration showed higher efficacy than lower concentrations.
- Castor oil had limited effectiveness compared to Abamectin and Neem oil.

## Abstract

Infestation by various insect pests is the main constraint for growing rice where rice brown planthopper (Nilaparvata lugens Stål) can severely damage rice plants directly through feeding. Therefore, the study aims to detect rice brown planthoppers (BPH) and provide environment-friendly management tactics to mitigate the problem which caused by brown planthoppers. The BPH samples were collected from rice fields of different locations in the Patuakhali of Bangladesh for molecular identification. A molecularly single species of rice brown planthopper, Nilaparavata lugens was identified using mitochondrial cytochrome oxidase subunit I (mtCOI) universal marker. The nucleotide sequences of collected samples were compared with other nucleotide sequences from the GenBank database of NCBI, which make single clades in the phylogenetic tree at an insignificant distance. Moreover, brown planthopper management observations were recorded in laboratory conditions after providing an artificial diet with different treatments of plant-based insecticides Neem oil (1 %, 5 %, and 10 %), Castor oil (1 %, 5 %, and 10 %) where only 20 % sucrose solution was used as negative control and Abamectin (1 %, 5 % and 10 %) were also used as a positive control for comparing the efficacy of plant-based insecticides on rice brown planthoppers. The results showed the highest mortality (100 %) of rice brown planthoppers was recorded by Abamectin 10 %, followed by Abamectin 5 %. Neem 10 % performed better than Abamectin 1 % during 1st hour. Initial after exposure of 2nd hour for Abamectin 1 % revealed greater mortality (59 %) than Neem 10 %. Neem 5 % showed less effect on mortality in brown planthopper than Neem 10 % but was higher than Neem 1 % during 6 h of observation. The Castor oil of 10 % caused higher mortality than the Castor of 5 % but not up to the marks of Abamectin and different concentrations of Neem oil. Castor oil of 1 % and control have shown no mortality of brown planthopper for 6 h of observation.