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<p>The present experiment was carried out in District Seed Farm of BCKV located at Kalyani, Nadia, West Bengal. Results showed that the Bihar hairy caterpillar first occurred on blackgram during the 13th SMW and 14th SMW of 2022 and 2023, respectively. Highest population of the pest (44.67 &amp; 40.58 larvae/meter row length) and plant damage (81.42% &amp; 78.62%) was noticed during the 17th and 16th SMW of summer 2022 and 2023, respectively. In this peak period of infestation, the pest caused havoc leaf loss (9.80%—82.06%) which turned the leaves in white papery structure. The pest population got reduced after 20th and 21st SMW during 2022 and 2023, respectively. Correlation studies revealed that maximum temperature and evening relative humidity had significant positive (r = 0.769 and r = 0.786) and negative effect (r =—0.752 and r =—0.784) on the pest incidence during both the seasons. Multiple step wise linear regression suggested that, among all the weather parameters, being the principle influencing factor maximum temperature described the pest population up to 59% and 62% during those years, respectively. Efficacy of five relatively newer insecticides e.g. alpha cypermethrin, afidopyropen + abamectin, teflubenzuron, chlorantraniliprole and Bt was evaluated against third instar larvae of Bihar hairy caterpillar using leaf dip and residue contact bioassay methods with three doses viz. one standard dose and another two was 25% below and above the standard dose. Larval mortality demonstrated that alpha cypermethrin caused the highest mortality at 12&#xa0;h after treatment (HAT), 24 HAT, 48 HAT and 72 HAT followed by chlorantraniliprole, teflubenzuron and afidopyropen + abamectin in all the three aforementioned doses. Bt caused the lowest larval mortality compared to the others in both bioassay methods. Larval mortality was less in residue contact bioassay compared to leaf dip bioassay. In leaf dip bioassay lowest LC<sub>50</sub> value and highest toxicity index (100.00) was recorded from alpha cypermethrin treatment followed by chlorantraniliprole and teflubenzuron in both the bioassays. From these results it can be concluded that alpha cypermethrin and chlorantraniliprole had higher toxicity and better efficacy against the pest.&#xa0;</p>

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Incidence pattern of bihar hairy caterpillar (Spilosoma obliqua Walk.) on summer blackgram [Vigna Mungo (L.) Hepper] and laboratory efficacy of some newer insecticides against the pest

  • 期刊论文

  • 发表日期：

    2025年5月22日

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  • Sabyasachi Ray,
  • Pritam Maity,
  • Soumita Bera,
  • Amitava Banerjee

摘要

The present experiment was carried out in District Seed Farm of BCKV located at Kalyani, Nadia, West Bengal. Results showed that the Bihar hairy caterpillar first occurred on blackgram during the 13th SMW and 14th SMW of 2022 and 2023, respectively. Highest population of the pest (44.67 & 40.58 larvae/meter row length) and plant damage (81.42% & 78.62%) was noticed during the 17th and 16th SMW of summer 2022 and 2023, respectively. In this peak period of infestation, the pest caused havoc leaf loss (9.80%—82.06%) which turned the leaves in white papery structure. The pest population got reduced after 20th and 21st SMW during 2022 and 2023, respectively. Correlation studies revealed that maximum temperature and evening relative humidity had significant positive (r = 0.769 and r = 0.786) and negative effect (r =—0.752 and r =—0.784) on the pest incidence during both the seasons. Multiple step wise linear regression suggested that, among all the weather parameters, being the principle influencing factor maximum temperature described the pest population up to 59% and 62% during those years, respectively. Efficacy of five relatively newer insecticides e.g. alpha cypermethrin, afidopyropen + abamectin, teflubenzuron, chlorantraniliprole and Bt was evaluated against third instar larvae of Bihar hairy caterpillar using leaf dip and residue contact bioassay methods with three doses viz. one standard dose and another two was 25% below and above the standard dose. Larval mortality demonstrated that alpha cypermethrin caused the highest mortality at 12 h after treatment (HAT), 24 HAT, 48 HAT and 72 HAT followed by chlorantraniliprole, teflubenzuron and afidopyropen + abamectin in all the three aforementioned doses. Bt caused the lowest larval mortality compared to the others in both bioassay methods. Larval mortality was less in residue contact bioassay compared to leaf dip bioassay. In leaf dip bioassay lowest LC50 value and highest toxicity index (100.00) was recorded from alpha cypermethrin treatment followed by chlorantraniliprole and teflubenzuron in both the bioassays. From these results it can be concluded that alpha cypermethrin and chlorantraniliprole had higher toxicity and better efficacy against the pest.