Effect of weather parameters on the seasonal dynamics of tobacco caterpillar, Spodoptera litura (Lepidoptera: Noctuidae) in castor in Telangana State

Abstract

Field experiments were carried out for four years (2012-13 to 2015-16) to study the seasonal dynamics of tobacco caterpillar, Spodoptera litura in castor and its relationship with different weather parameters during kharif season in Telangana State. Moth catches of S. litura were observed throughout the crop season, wherein maximum catches (44.8 to 124 moths/trap/week) were observed during mid- August to late-October [33rd to 43rd Standard Meteorological Week (SMW)]. Peak oviposition (2.0 to 14.8egg-masses/5 plants) and larval incidence (14.4 to 48 larvae/5 plants) of S. liturawas recorded during mid-August to mid-November (33rd to 46th SMW) coinciding with the vegetative to primary spike development stage of the crop. The correlation analysis indicated that the moth catches and larval population of S. litura showed significant positive correlation with weather parameters viz., maximum temperature, minimum temperature, rainfall and rainy days, while egg-masses of S. litura showed significant negative correlation with morning relative humidity and minimum temperature.The stepwise regression analysis revealed that minimum temperature, rainy days, wind speed and evening relative humidity could explain 64 per cent variation in S. litura moth catches. Among all the variables morning relative humidity was found to contribute significantly and showed 59 per cent effect on the population fluctuation of eggmasses, while rainy days and maximum temperature could explain 51 per cent variation in larval population of S. litura in castor.The models were validated with independent data 2015-16. The overall results suggested that the models can be used for predicting the population of S. litura in castor for optimizing management strategies.

Population Dynamics of Leafhopper (Empoasca flavescens) and Thrips (Scirtothrips dorsalis) of Castor (Ricinus communis L.)

“…According to Bhede et al [14] "thrips population exhibited significant negative correlation with morning and evening relative humidity and rainfall and positive correlation with bright sunshine". Duraimurugan and Jagadish [15] reported "significant negative correlation with mean relative humidity which confirms the present finding".…”

Elementos del clima y su relación con la polilla guatemalteca Tecia solanivora (Povolný, 1973) (Lepidoptera: Gelechiidae) en cultivo de papa (Solanum tuberosum L.)

“…Aunque la relación directa entre la temperatura y T. solanivora ha sido poco estudiada, existen investigaciones en otras especies de polillas como Spodoptera litura (Fabricius, 1775) (Lepidoptera: Noctuidae), en donde también se encontró correlación positiva entre la especie y la temperatura máxima, lo que indica que las poblaciones se ven favorecidas por temperaturas extremas (Duraimurugan, 2018). Los correlogramas de temperatura máxima (20 -°C 23 ±0,7 °C) y velocidad del viento (132 -214 km/día ±24 km/día), indicaron un comportamiento posterior en la población de adultos de T. solanivora, representado en una alta tasa de aumento de sus poblaciones al detectar temperaturas máximas y velocidades del viento estables, lo que coincide con comportamientos de otros insectos que al exponerse a altas temperaturas (19 -25 °C, 28 -32 ° C) generan una respuesta al aumentar sus tasas metabólicas y generar un crecimiento más rápido (González-Tokman et al, 2020;Gillooly et al, 2002;Li & Gong, 2017).…”

Comparative seasonal analysis of Eri silkworm (Samia ricini Donovan) gut composition: implications for lignocellulose degradation

“…Recent evidences have reported that gut bacteria of Lepidoptera contain bacteria capable of producing digestive enzymes which helps in leaf constitute degradation (Dillon and Dillon 2004). Silkworms being poikilothermic in nature, their body temperature are directly controlled by the temperature in environment (Duraimurugan 2018). While microbes are ectotherms, and they are uctuated as similar temperature as their host.…”

“…At the phylum level, no signi cant changes were observed in gut microbiota composition of S. ricini across the seasons. Considering the complete life cycle of the Eri silkworm that lasts about 44 days in the summer and 85 days in the winter, gut bacterial diversity might be due to difference in temperature and other environmental factors as they are reported to play crucial role in larval development(Das et al 2021;Duraimurugan 2018). We noted no depletion of bacterial diversity during summer with presence of total 11 bacterial families.…”