Effect of weather factors on populations of Helicoverpa armigera moths at cotton‐based agro‐ecological sites

Abstract

Pheromone trapping was used to monitor populations of the moth Helicoverpa armigera at five cotton‐based agro‐ecological sites – river, vegetable, orchard, forest and clean cultivation (areas under only cotton cultivation) – in the Bahawalpur district, Pakistan. Three locations at each site were chosen and three pheromone traps at each location were installed in cotton fields. Moth catches were recorded at 15–20 day intervals from 24 October 2004 to 19 December 2006. In 2004, the river sites showed the maximum trapped population of H. armigera (0.22/trap) followed by 0.165 per trap at the vegetable sites. Orchard, clean cultivation and forest sites had zero moth catches. In 2005, the river sites again showed the highest trapped population (0.57/trap), followed by clean cultivation (0.45/trap), vegetable (0.44/trap), orchard (0.40/trap) and forest (0.29/trap). The moths appeared during July to December and March to May. In 2006, sites showed non‐significant difference, with a population range of 0.47 to 0.97 moths per trap. On average, river sites peaked at 0.49 per trap, followed by vegetable (0.38), clean cultivation (0.47), orchard (0.35) and forest (0.25) sites. The peak was observed on 3 April 2006, and moths appeared during February to July and October to December. The minimum temperature in river, forest and clean cultivation sites; the maximum temperature in orchard sites; and the average temperature in river, orchard, forest and clean cultivation sites showed significant positive correlations with trapped moth populations. Relative humidity showed significant negative correlation with population at the orchard sites in 2005. All weather factors during 2004 and 2006 showed non‐significant correlations with the moth populations. No model was found to be best fit by multiple linear regression analysis; however, relative humidity, minimum temperature, maximum temperature, minimum temperature and maximum temperature contributed 8.40, 10.23, 2.43, 4.53 and 2.53% to the population fluctuation of the moth at river, vegetable, orchard, forest and clean cultivation sites, respectively.

Distribution of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) in tomato fields and its relationship to weather factors

“…(1991) also found that the mean temperature had a positive correlation with the population density of H. armigera . In the case of cotton, the population fluctuation of bollworm was also influenced by the maximum temperature and relative humidity but minimum and average temperatures had no influence (Aheer et al . 2009; Khan et al .…”

“…Mehto et al (1985) and Yadava et al (1991) also found that the mean temperature had a positive correlation with the population density of H. armigera. In the case of cotton, the population fluctuation of bollworm was also influenced by the maximum temperature and relative humidity but minimum and average temperatures had no influence (Aheer et al 2009;Khan et al 2009). Similarly, Han (2000) found that the mild temperature was positively correlated; however, minimum temperature was negatively correlated with the infestation of H. armigera.…”

Responses of different aphid species on wheat crop with relation to abiotic factors

“…Incidence of these species was observed in order R. padi>S. graminum>S. avenae. period Aheer et al [30] found that aphid population decreased when maximum and minimum temperatures reached their optimum limits of 27.30°C and 24°C, respectively. Our findings are also support the above statement, as aphid populations are minimum at the beginning of February (temperature <16C 0 ) and the end of March (temperature > 27C 0 ).…”

Using multivariate cross correlations, Granger causality and graphical models to quantify spatiotemporal synchronization and causality between pest populations

“…However, this may have resulted from several factors, including the inherent properties of a species population in relation to environmental conditions [ 46 , 47 ]. Warmer temperatures and increased precipitation, for instance, can reduce the rates of population growth [ 48 ]. Additionally, because there is no similar analysis in the literature, some of the answers are difficult to translate from a strictly agro-ecological perspective.…”