Studies on seasonal incidence of sucking pests and pink bollworm, Pectinophora gossypiella (Saunders) in cotton (Gossypium spp.) (original) (raw)
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Population dynamics of insect pests of cotton in Southern dry zone of Karnataka
Journal of entomology and zoology studies, 2021
A field experiment was conducted during kharif season of 2019-20 at AICRP on Cotton scheme, Chamarajanagara, to study the seasonal variation of sucking pests incidence in non Bt cotton hybrid (DCH-32). From the data it is observed that the population of leafhopper was above ETL in almost all standard meteorological week (SMW) with peak population of 7.20 and 6.80/3 leaves during 35 th and 36 th SMW, respectively. While, the occurrence of aphids was noticed throughout the cropping season. The peak incidence was observed at 36 th SMW (55.15/3leaves). Mirid bug incidence was started from 35 th SMW and attained its peak during 42 nd SMW and declined thereafter. The population of whiteflies and thrips didn't cross ETL during the entire cropping season. Correlation study revealed that the morning and evening relative humidity had a positive influence on the population of sucking insect pests including the activity of natural enemy (coccinellid beetles). Whereas, maximum and minimum temperature had a detrimental effect on the population of sucking insect pests.
Experiments on the seasonal incidence of some sucking pests in cotton and their correlation with abiotic factors was conducted at the Central Research Farm, Orissa University of Agriculture and Technology, Bhubaneswar during kharif 2016. Various sucking insects recorded on cotton during the period of study were leaf hopper, Amrasca biguttula biguttula Ishida., aphid, Aphis gossypii Glover., whitefly, Bemisia tabaci Gennadius. and mealybug, Phenacoccus solenopsis Tinsley. Among the sucking pests leaf hopper was found to be the dominant pest and its peak population (4.70 nos/leaf) was observed during 39th SW (Sep.24-30). Maximum activity of whitefly (4.50 nos/leaf) and aphid (11.58/leaf) was observed during 39th SW (Sep.24-30) and 34th SW (Aug. 20-26), respectively. Mealybug was active from the 30th SW (July 23-29) to 52nd SW (Dec. 24-31) with highest incidence during 47th SW (Nov.19-25) with 26.35 per cent branch infestation. Among the natural enemies, various predators viz., ladybird beetle, Menochilus sexmaculata Fabricius., green lacewing, Chrysoperla carnea Stephens and one species of spider were recorded during the period of study. Peak activity of ladybird beetle (2.75/plant) and spider (2.68/plant) was recorded during 39th SW (Sept. 24-30). The other predator green lacewing was active throughout the crop growth period with its peak occurrence 1.30/plant during 41st SW (Oct. 8-14). The abiotic factors such as maximum temperature, minimum temperature, evening relative humidity and rainfall had a positive effect on the leafhopper, whitefly and aphid population. Mealybug incidence showed negative correlation with minimum temperature, evening relative humidity and rainfall.
Indian Journal of Agricultural Sciences, 2009
A study was conducted during 2005-06 to develop a weather―based forecasting model for sucking pest in Bt-cotton (Gossypium hirsutum Linn.). The population dynamics of jassid, whitefly and thrips with respect to meteorological parameters on Bt-cotton ('Ankur 651' during rainy (kharif) season 2005 and 'RCH 34' during rainy season 2006) under 3 dates of sowing was conducted during crop seasons at research farm of the University, Ludhiana. The results revealed that a decrease in maximum temperature (6-7°C from normal of>38°C) and minimum temperature (4-5°C from normal of >27°C) and sunshine hours (5-7 hr from normal of >8 hr) favour the population build-up of cotton jassid (Amrasca bigutulla Shir). Whereas an increase in temperature (maximum temperature >32°C; minimum temperature >25°C) and sunshine hours (>9 hr) coupled with decreased relative humidity favoured the build-up of cotton whitefly (Bemisia tabaci Genn.). Of these parameters, the contribution of increase in the number of sunshine hours has been significant with respect to its build-up. Cotton thrips (Thrips tabaci Lindi.) appeared on cotton during its early vegetative stage and ceased its activity with the onset of south-west monsoon. Peak population of thrips was recorded as soon as the maximum and minimum temperature crossed 39 and 25°C and morning and evening relative humidity was below 55 and 35%, respectively along with more than 9 hr of sunshine. On the contrary a decrease in temperature and sunshine hours and increase in relative humidity coupled with a heavy rainfall led to cessation of thrips activity in cotton.
A field experiment was carried out to study the effect of weather factors on seasonal incidence of major sucking insect pests on Bt and non-Bt hybrid (Bunny) cotton during Kharif, 2013 and 2014 at Regional Research and Technology Transfer Station farm at Bhawanipatna, Kalahandi, Odisha. The incidence of sucking pests was observed from 1 st week of August (32 nd SMW) and continued up to last week of December (52 nd SMW). The population of aphids (42.16 and 59.32/ 3 leaves) at 37 th and 36 th SMW; jassids (15.62 and 16.40/ 3 leaves) at 40 th and 41 st SMW; thrips (2.32 and 2.82/ 3 leaves) at 41 st SMW and 35 th SMW; whiteflies (5.72 and 5.40/ 3 leaves) at 41 st and 41 st SMW; and red cotton bug (7.78 and 7.96/ plant) at 48 th and 48 th SMW attended the peak in the year 2013 and 2014 respectively. No significant difference was observed with respect to the population of any of the sucking pests on Bt and non-Bt cotton. The population buildup of aphids, jassids and thrips were positively correlated with the mean minimum, mean maximum and mean average temperature, morning, evening and mean relative humidity and rainfall while whiteflies positively correlated with mean minimum, mean maximum and mean average temperature and rainfall. Red cotton bug showed negatively non-significant correlation with all the weather parameters.
Indian Journal of Agricultural Sciences
A study was conducted during 2005 and 2006 to develop a weather-based forecasting model for sucking pest in Bt-cotton (Gossypium hirsutum). The population dynamics of Jassid, Whitefly and Thrip with respect to meteorological parameters on Btcotton (cv. Ankur 651 during rainy season 2005 and cv RCH 34 during rainy season 2006) under 3 dates of sowing was conducted during crop seasons at research farm of the Punjab Agricultural University, Ludhiana. The results revealed that a decrease in maximum temperature (6-7 o C from normal of >38 o C) and minimum temperature (4-5 o C from normal of >27 o C) and sunshine hours (5-7 hr from normal of >8 hr) favour the population build up of cotton jassid (Amrasca bigutulla Shir). Whereas an increase in temperature (maximum temperature >32 o C; minimum temperature >25 o C) and sunshine hours (>9 hr) coupled with decreased relative humidity favoured the build up of cotton whitefly (Bemisia tabaci Genn.). Of these parameters, the contribution of increase in the number of sunshine hours has been significant with respect to its build up. Cotton thrip (Thrips tabaci Lindi.) appeared on cotton during its early vegetative stage and ceased its activity with the onset of southwest monsoon. Peak population of thrips was recorded as soon as the maximum and minimum temperature crossed 39 and 25 o C and morning and evening relative humidity was below 55 and 35%, respectively along with more than 9 hr of sunshine. On the contrary a decrease in temperature and sunshine hours and increase in RH coupled with a heavy rainfall led to cessation of thrips activity in cotton.
Influence of weather factors on population dynamics of major sucking pests of Bt cotton
International Journal of Advanced Biochemistry Research, 2024
A field experiment conducted over Kharif seasons of 2020 and 2021 at All India Coordinated Cotton Improvement Project, MPKV, Rahuri, examined the impact of weather factors on sucking pest populations in Bt cotton. The data reveal that aphids were predominant, ranging from 4.60 to 120.86/3 leaves in 2020 and 0.64 to 63.60/3 leaves in 2021. Jassids ranged from 2.04 to 11.46/3 leaves in 2020 and 0.52 to 5.76/3 leaves in 2021. Thrips ranged from 0.26 to 13.78/3 leaves in 2020 and 0.18 to 57.46/3 leaves in 2021. Whiteflies varied from 0.24 to 8.32/3 leaves in 2020 and 0.04 to 5.82/3 leaves in 2021 with peak activity recorded in the 42 nd SMW of 2020 and the 46 th SMW of 2021. Natural predators like lady bird beetles, green lace wings and predatory spiders were observed throughout the cropping season, showing peak activity in specific weeks.
Cotton is a major foreign currency earner in Zimbabwe. It is attacked by many insect pests which limit its productivity. A trial carried out at the Cotton Research Institute investigated the effects of planting date and cotton variety on the incidence of bollworms and insect sucking pests of cotton. Three varieties SZ 9314, CRI MS1 and CRI MS2 were planted on three different dates (20 October, 17 November and 15 December), representing early, mid-season and late planting times. Scouting for pests commenced from the fifth week after emergence to 10% boll split. Both planting date (p = 0.027) and cotton variety (p = 0.012) had significant effects on pest incidence. Early planted cotton had lower aphids, jassids and red bollworm population than later-planted cotton. This was due to the higher natural enemies' population and the effects of the "closed season" in the early crop. CRI MS2 hosted significantly lower populations of aphids, jassids and red bollworms compared to the other varieties. There was interaction between planting date and variety, with early-planted CRI MS2 hosting the lowest populations of aphids and red bollworms. The study concluded that early planting resulted in lower incidence of insect sucking pests and recommended the early planting of CRI MS2.
International Journal of Environment and Climate Change
Population dynamics of sucking pests in cotton ecosystem were studied at Tamil Nadu Agricultural University, Coimbatore during winter (2021) and summer (2022) seasons. Weekly observations were recorded on 20 randomly selected plants representing top, middle and bottom canopy of the crop which was raised in regular planting dates of winter and summer and were maintained as per the recommended regular agronomic practices except insect management interventions. During winter season, sucking pests viz., leafhopper, aphids, thrips, and whitefly were first observed in field from 39th SMW i.e. one month after sowing. Mealybugs were first observed during 41st SMW i.e. 43 days after sowing (DAS) of crop. The highest population of leafhopper, aphids, thrips, whitefly and mealybug recorded was 4.7, 18.7, 4.6, 2.45 no. per 3 leaves and 13.7 no. per 3 twigs, respectively. The mean population of sucking pests was high in October, 2021 and coincided with square formation to flowering stage except ...