Spatial Survey of Cotton (Gossypium hirsutum L.) Insect Pests and Leaf Curl Virus (CLCuV) in Relation to Weather Parameters in Muzaffargarh, Punjab, Pakistan
Spatial Survey of Cotton (Gossypium hirsutum L.) Insect Pests and Leaf Curl Virus (CLCuV) in Relation to Weather Parameters in Muzaffargarh, Punjab, Pakistan
Muhammad Nasir1, Muhammad Usman Asif2*, Abdul Hayee Abid1, Qurat ul Ain Haneef1 and Muhammad Awais2
ABSTRACT
A three year spatial field survey of different insect pests of cotton and leaf curl virus (CLCuV) in relation to weather parameters was conducted in four tehsils viz. Alipur, Jatoi, Kot Addu and Muzaffargarh of district Muzaffargarh (Punjab, Pakistan). In each tehsil pest scouting was conducted in 40-50 spots (five acres each) per week selected randomly starting from 1st June to 30th October each year. Hot spots (pest incidence at and above Economic Threshold level, ETL) for each tehsil were determined weekly, and then the combined infestation was calculated at the district level. The results showed that the weather conditions, during all the three years, had a significant impact on the insect pest abundance. The maximum percentage of whitefly hot spots ranged in line from 8.36-24.14% during three years study period followed by mealybug (6.71-11.79%), jassid (4.56-7.22%), thrips (1.36-6.22%), pink bollworm (0.99-5.42%) and armyworm (2.77-4.23%). The population of dusky cotton bug, spotted bollworm and American bollworm were negligible with 1.22% hot spots of dusky cotton bug and 0.02% of spotted bollworm during 2020. CLCuV hot spots ranged from 15.66-22.74% during 2018-2020. Correlation matrix revealed that population fluctuations of whitefly, mealybug, pink bollworm and armyworm were negatively correlated with maximum and minimum temperature and positively correlated with jassid and thrips. Relative humidity exhibited a positive association with all the insect pests and CLCuV incidence. Multiple regression analysis was used to estimate the combined as well as individual impact of maximum and minimum temperature and relative humidity on population fluctuation of insect pests. The R2 values indicated that maximum and minimum temperature were the most influential factors and played a significant role in the population fluctuation of the studied insect pests as well as CLCuV. The results of the study may be helpful to the pest managers as a pest forecasting tool for initiating management strategies at appropriate time during the cotton season.
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